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16 pages, 4205 KiB

Open AccessArticle

Recycling of Periwinkle Shell Waste as Partial Substitute for Sand and Stone Dust in Lightweight Hollow Sandcrete Blocks towards Environmental Sustainability

by Oluwarotimi M. Olofinnade, Joshua U. Anwulidiunor, Kunle E. Ogundipe and David A. Ajimalofin

Materials 2023, 16(5), 1853; https://doi.org/10.3390/ma16051853 - 24 Feb 2023

Cited by 3 | Viewed by 1804

Abstract

Global consumption of nonrenewable natural aggregate for construction activities is now becoming a significant concern. Reusing agricultural or marine-based wastes could offer a promising alternative to achieve natural aggregate conservation and a pollution-free environment. This study investigated the suitability of using crushed periwinkle [...] Read more.

Global consumption of nonrenewable natural aggregate for construction activities is now becoming a significant concern. Reusing agricultural or marine-based wastes could offer a promising alternative to achieve natural aggregate conservation and a pollution-free environment. This study investigated the suitability of using crushed periwinkle shell (CPWS) as a reliable constituent material for sand and stone dust in producing hollow sandcrete blocks. The CPWS was used to partially substitute river sand and stone dust at 5, 10, 15 and 20% in sandcrete block mixes using a constant water–cement ratio (w/c) of 0.35. The weight, density and compressive strength of the hardened hollow sandcrete samples were determined after 28 days of curing along with the water absorption rate. Results showed an increase in the water absorbing rate of the sandcrete blocks as CPWS content increased. Mixes containing 5% and 10% CPWS substitute for sand with 100% stone dust surpassed the minimum targeted strength of 2.5 N/mm². The compressive strength results suggested that CPWS is most suitable to be deployed as a partial substitute for sand as a constant stone dust material, thus imply that the construction industry can achieve sustainable construction with agro or marine-based wastes in hollow sandcrete production. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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11 pages, 3479 KiB

Open AccessArticle

The Damage Performance of Uncarbonated Limestone Cement Pastes Partially Exposed to Na₂SO₄ Solution

by Yu Cui, Min Pei, Ju Huang, Wei Hou and Zanqun Liu

Materials 2022, 15(23), 8351; https://doi.org/10.3390/ma15238351 - 24 Nov 2022

Cited by 1 | Viewed by 969

Abstract

Pore structure and composition of cement paste are the main two factors in controlling the sulfate attack on concrete, but the influence of carbonization on pore structure and composition is often ignored in sulfate attack. Therefore, will the damage performance of concrete partially [...] Read more.

Pore structure and composition of cement paste are the main two factors in controlling the sulfate attack on concrete, but the influence of carbonization on pore structure and composition is often ignored in sulfate attack. Therefore, will the damage performance of concrete partially exposed to sulfate solution be different avoiding the alterations of pore structure and composition due to carbonation? In this paper, the cement pastes were partially immersed in 5 wt. % sodium sulfate solution, with N₂ as protective gas to avoid carbonation (20 ± 1°C, RH 65 ± 5%). Pore structures of cements were changed by introducing different contents of limestone powders (0 wt. %, 10 wt. %, 20 wt. %, and 30 wt. %) into cement pastes. The damage performance of the specimens was studied by ¹H NMR, XRD and SEM. The results showed that the immersion zone of pure cement paste under N₂ atmosphere remained intact while serious damage occurred in the evaporation zone. However, the damage of cement + limestone powders pastes appeared in the immersion zone rather than in the evaporation zone and cement pastes containing more limestone were more severely damaged. Compositional analysis suggested that the damage of the evaporation zone or the immersion zone was solely caused by chemical attack where substantial amount of gypsums and ettringites were filled in the pore volumes. Introduction of limestone powders led to the increase of the pore sizes and porosity of cement pastes, causing the damage occurred in the immersion zone not in the evaporation zone. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 5324 KiB

Open AccessArticle

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

by Ziqi Zhu, Xiaoqing Lian, Xiaowei Zhai, Xiaojun Li, Muhong Guan and Xiang Wang

Materials 2022, 15(21), 7552; https://doi.org/10.3390/ma15217552 - 27 Oct 2022

Cited by 7 | Viewed by 1641

Abstract

Coal gasification coarse slag (CGCS) is a by-product of coal gasification. Despite its abundance, CGCS is mostly used in boiler blending, stacking, and landfill. Large-scale industrial applications of CGCS can be environment-friendly and cost saving. In this study, the application of CGCS as [...] Read more.

Coal gasification coarse slag (CGCS) is a by-product of coal gasification. Despite its abundance, CGCS is mostly used in boiler blending, stacking, and landfill. Large-scale industrial applications of CGCS can be environment-friendly and cost saving. In this study, the application of CGCS as a substitute for river sand (RS) with different replacement ratios in ultra-high performance concrete (UHPC) was investigated. The effects of CGCS replacement ratios on the fluidity and mechanical properties of specimens were examined, and the effect mechanisms were explored on the basis of hydration products and the multi-scale (millimetre-scale and micrometre-scale) microstructure analysis obtained through X-ray diffraction (XRD), scanning electron microscopy, and X-ray energy-dispersive spectroscopy. With an increase in the CGCS replacement ratio, the water–binder ratio (w/b), flexural strength, and compressive strength decreased. Specimens containing CGCS of ≤25% can satisfy the strength requirement of non-structural UHPC, with flexure strength of 29 MPa and compressive strength of 111 MPa at day 28. According to the XRD results and multi-scale microstructure analysis, amorphous glass beads in CGCS positively influenced ettringite generation due to the pozzolanic activity. Porous carbon particles in CGCS showed strong interfacial bonding with cement slurry due to internal hydration; this bonding was conducive to improving the mechanical strength. However, CGCS hindered hydration in the later curing stage, leading to an increase in the unreacted cement and agglomeration of fly ash; in addition, at a CGCS replacement ratio of up to 50%, an apparent interfacial transition zone structure was observed, which was the main contributor to mechanical strength deterioration. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 25441 KiB

Open AccessArticle

Sustainable Use of Waste Oyster Shell Powders in a Ternary Supplementary Cementitious Material System for Green Concrete

by Shanglai Liu, Yannian Zhang, Bonan Liu, Zhen Zou, Qiang Liu, Yina Teng and Lei V. Zhang

Materials 2022, 15(14), 4886; https://doi.org/10.3390/ma15144886 - 13 Jul 2022

Cited by 8 | Viewed by 2242

Abstract

The increasing concern for decarbonization and sustainability in construction materials is calling for green binders to partially replace cement since its production is responsible for approximately 8% of global anthropogenic greenhouse gas emissions. Supplementary cementitious materials (SCMs), including fly ash, slag, silica fume, [...] Read more.

The increasing concern for decarbonization and sustainability in construction materials is calling for green binders to partially replace cement since its production is responsible for approximately 8% of global anthropogenic greenhouse gas emissions. Supplementary cementitious materials (SCMs), including fly ash, slag, silica fume, etc., can be used as a partial replacement for ordinary Portland cement (OPC) owing to reduced carbon dioxide emissions associated with OPC production. This study aims to investigate the sustainable use of waste oyster shell powder (OSP)-lithium slag (LS)-ground granulated blast furnace slag (GGBFS) ternary SCM system in green concrete. The effect of ternary SCMs to OPC ratio (0%, 10%, 20%, and 30%) on compressive strength and permeability of the green concrete were studied. The reaction products of the concrete containing OSP-LS-GGBFS SCM system were characterized by SEM and thermogravimetric analyses. The results obtained from this study revealed that the compressive strength of concrete mixed with ternary SCMs are improved compared with the reference specimens. The OSP-LS-GGBFS ternary SCMs-based mortars exhibited a lower porosity and permeability compared to the control specimens. However, when the substitution rate was 30%, the two parameters showed a decline. In addition, the samples incorporating ternary SCMs had a more refined pore structure and lower permeability than that of specimens adding OSP alone. This work expands the possibility of valorization of OSP for sustainable construction materials. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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19 pages, 7273 KiB

Open AccessArticle

Supercritical CO₂ Curing of Resource-Recycling Secondary Cement Products Containing Concrete Sludge Waste as Main Materials

by Min-Sung Kim, Sang-Rak Sim and Dong-Woo Ryu

Materials 2022, 15(13), 4581; https://doi.org/10.3390/ma15134581 - 29 Jun 2022

Cited by 2 | Viewed by 1511

Abstract

This study aims to develop highly durable, mineral carbonation-based, resource-recycling, secondary cement products based on supercritical carbon dioxide (CO₂) curing as part of carbon capture utilization technology that permanently fixes captured CO₂. To investigate the basic characteristics of secondary [...] Read more.

This study aims to develop highly durable, mineral carbonation-based, resource-recycling, secondary cement products based on supercritical carbon dioxide (CO₂) curing as part of carbon capture utilization technology that permanently fixes captured CO₂. To investigate the basic characteristics of secondary cement products containing concrete sludge waste (CSW) as the main materials after supercritical CO₂ curing, the compressive strengths of the paste and mortar (fabricated by using CSW as the main binder), ordinary Portland cement, blast furnace slag powder, and fly ash as admixtures were evaluated to derive the optimal mixture for secondary products. The carbonation curing method that can promote the surface densification (intensive CaCO₃ formation) of the hardened body within a short period of time using supercritical CO₂ curing was defined as “Lean Carbonation”. The optimal curing conditions were derived by evaluating the compressive strength and durability improvement effects of applying Lean Carbonation to secondary product specimens. As a result of the experiment, for specimens subjected to Lean Carbonation, compressive strength increased by up to 12%, and the carbonation penetration resistance also increased by more than 50%. The optimal conditions for Lean Carbonation used to improve compressive strength and durability were found to be 35 °C, 80 bar, and 1 min. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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19 pages, 6457 KiB

Open AccessArticle

Effects of Reserve Capacity on Seismic Response of Concentrically Braced Frames by Considering Brace Failure

by Zengyang Zhao, Wenyuan Zhang, Yukun Ding and Hongwei Li

Materials 2022, 15(13), 4377; https://doi.org/10.3390/ma15134377 - 21 Jun 2022

Cited by 2 | Viewed by 1595

Abstract

In order to study the influence of brace failure on the seismic response of concentrically braced frames and the improvement of the residual structure’s resistance to collapse due to reserve capacity, a series of concentrically braced frame prototypes with different story numbers is [...] Read more.

In order to study the influence of brace failure on the seismic response of concentrically braced frames and the improvement of the residual structure’s resistance to collapse due to reserve capacity, a series of concentrically braced frame prototypes with different story numbers is designed. A matrix of six finite-element concentrically braced-frame (CBF) models is established, which is varied by the number of stories and the level of reserve capacities. Accuracy of the numerical model is verified by comparing the responses of the shaking-table test of the concentrically braced frames, under 10 different working conditions. Then, a nonlinear time-history analysis, considering brace failure in one specified story, is carried out. The results show that the story-drift angle of the failure story as well as its adjacent stories increases greatly in the ideal pinned model. The above phenomenon is particularly serious, when the failure occurs at the top or bottom of the structure. With the reserve capacity brought by column continuity, and the semi-rigid rotation capacity of the beam-to-column and column-to-base connections are taken into consideration, the increase in story-drift angle caused by the brace failure is effectively reduced. However, the inherent reserve capacity has little influence on the dynamic characteristics of concentrically braced frames in the elastic stage. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 3380 KiB

Open AccessArticle

Study of a Modified Time Hardening Model for the Creep Consolidation Effect of Asphalt Mixtures

by Yunming Ma, Hongchang Wang, Kang Zhao, Lizhu Yan and Dagang Yang

Materials 2022, 15(8), 2710; https://doi.org/10.3390/ma15082710 - 07 Apr 2022

Cited by 4 | Viewed by 2082

Abstract

In the past, most researchers have explained the three-stage creep behavior of asphalt mixture in detail. Still, there is no reasonable model to describe the creep of the consolidation effect. To accurately describe the consolidation effect of an asphalt mixture during the viscoelastic [...] Read more.

In the past, most researchers have explained the three-stage creep behavior of asphalt mixture in detail. Still, there is no reasonable model to describe the creep of the consolidation effect. To accurately describe the consolidation effect of an asphalt mixture during the viscoelastic deformation process, a modified time hardening model was established by using the Malthus model and the Logistic function to change its creep strain and creep compliance. According to the characteristics of asphalt mixture creep, a single penetration creep test was conducted for high-elasticity modified asphalt mixtures at different temperatures (20 °C, 40 °C, 60 °C) and various loading levels (0.55 MPa, 0.70 MPa, 0.85 MPa, 1.00 MPa). The test results showed that the effect of stress on deformation within the normal range of variation was more significant than that of temperature. In addition, the test results were simulated by the modified time hardening model using surface fitting and compared with a time hardening model and a modified Burgers model. A fitting analysis showed that the modified time hardening model more accurately represents the asphalt mixture’s consolidation effect and creep behavior. Therefore, the modified time hardening model can better show the consolidation effect in the creep process. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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10 pages, 4102 KiB

Open AccessEditor’s ChoiceArticle

Face Mask Wastes as Cementitious Materials: A Possible Solution to a Big Concern

by Marta Castellote, Eva Jiménez-Relinque, María Grande, Francisco J. Rubiano and Ángel Castillo

Materials 2022, 15(4), 1371; https://doi.org/10.3390/ma15041371 - 12 Feb 2022

Cited by 14 | Viewed by 7303

Abstract

After more than two years wearing surgical masks due to the COVID-19 pandemic, used masks have become a significant risk for ecosystems, as they are producing wastes in huge amounts. They are a potential source of disturbance by themselves and as microplastic contamination [...] Read more.

After more than two years wearing surgical masks due to the COVID-19 pandemic, used masks have become a significant risk for ecosystems, as they are producing wastes in huge amounts. They are a potential source of disturbance by themselves and as microplastic contamination in the water system. As 5500 tons of face masks are estimated to be used each year, there is an urgent need to manage them according to the circular economy principles and avoid their inadequate disposal. In this paper, surgical wear masks (WM), without any further pretreatment, have been introduced as addition to mortars up to 5% in the weight of cement. Mechanical and microstructural characterization have been carried out. The results indicate that adding MW to the cement supposes a decrease in the properties of the material, concerning both strength and durability behavior. However, even adding a 5% of WM in weight of cement, the aspect of the mortars is quite good, the flexural strength is not significantly affected, and the strength and durability parameters are maintained at levels that—even lower than the reference—are quite reasonable for use. Provided that the worldwide production of cement is around 4.1 Bt/year, the introduction of a 5% of WM in less than 1% of the cement produced, would make it possible to get rid of the mask waste being produced. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 1716 KiB

Open AccessArticle

Studies on the Ageing of Cement Stabilized Rammed Earth Material in Different Exposure Conditions

by Łukasz Rosicki and Piotr Narloch

Materials 2022, 15(3), 1090; https://doi.org/10.3390/ma15031090 - 30 Jan 2022

Cited by 4 | Viewed by 2700

Abstract

This paper aims to test the deterioration of cement stabilized rammed earth and consider its characteristics during its lifespan in various exposure conditions. Both visual and mechanical properties were tested to determine the impact of long-term exposure to natural weather conditions. Cemented stabilized [...] Read more.

This paper aims to test the deterioration of cement stabilized rammed earth and consider its characteristics during its lifespan in various exposure conditions. Both visual and mechanical properties were tested to determine the impact of long-term exposure to natural weather conditions. Cemented stabilized rammed earth is a variation of the traditional rammed earth building material which has been used since ancient history and is strengthened by the addition of stabilizers in the form of Portland cement. This article analyzes the long-term properties of wall panels made of this material, which were subjected to varying exposure conditions for five years. After this period, compression tests of specimens cut from panels stored in various environmental conditions were carried out. Based on the results and visual properties of the specimens, long-term changes in unconfined compressive strength were observed and primary durability attributes were described. Despite minimal visible wear to the external layers of the wall panels, the natural weather conditions proved to deteriorate material strength characteristics, especially on specimens with high cement content. No correlation between visual characteristics and compressive strength measures were found. The present study is vital in adequately describing cement stabilized rammed earth behavior in natural weather conditions typical of a humid continental climate. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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10 pages, 5655 KiB

Open AccessArticle

Fundamental Studies on CO₂ Sequestration of Concrete Slurry Water Using Supercritical CO₂

by Sang-Rak Sim and Dong-Woo Ryu

Materials 2022, 15(1), 94; https://doi.org/10.3390/ma15010094 - 23 Dec 2021

Cited by 2 | Viewed by 2302

Abstract

To prevent drastic climate change due to global warming, it is necessary to transition to a carbon-neutral society by reducing greenhouse gas emissions in all industrial sectors. This study aims to prepare measures to reduce the greenhouse gas in the cement industry, which [...] Read more.

To prevent drastic climate change due to global warming, it is necessary to transition to a carbon-neutral society by reducing greenhouse gas emissions in all industrial sectors. This study aims to prepare measures to reduce the greenhouse gas in the cement industry, which is a large source of greenhouse gas emissions. The research uses supercritical CO₂ carbonation to develop a carbon utilization fixation technology that uses concrete slurry water generated via concrete production as a new CO₂ fixation source. Experiments were conducted using this concrete slurry water and supernatant water under different conditions of temperature (40 and 80 °C), pressure (100 and 150 bar), and reaction time (10 and 30 min). The results showed that reaction for 10 min was sufficient for complete carbonation at a sludge solids content of 5%. However, reaction products of supernatant water could not be identified due to the presence of Ca(HCO₃)₂ as an aqueous solution, warranting further research. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 6577 KiB

Open AccessArticle

Preparation of Cement Clinker from Geopolymer-Based Wastes

by Rabii Hattaf, Mohamed Benchikhi, Abdessamad Azzouzi, Rachida El Ouatib, Moussa Gomina, Azzeddine Samdi and Redouane Moussa

Materials 2021, 14(21), 6534; https://doi.org/10.3390/ma14216534 - 30 Oct 2021

Cited by 7 | Viewed by 2148

Abstract

In order to avoid potential environmental pollution from geopolymer-based material wastes, this work investigated the feasibility of using these materials as alternative raw materials in the preparation of cement clinker. The geopolymer binders and mortars were used as substitutes for natural mineral clays [...] Read more.

In order to avoid potential environmental pollution from geopolymer-based material wastes, this work investigated the feasibility of using these materials as alternative raw materials in the preparation of cement clinker. The geopolymer binders and mortars were used as substitutes for natural mineral clays since they are rich in silica and alumina. Simulated geopolymer wastes were prepared by the activation of metakaolin or fly ash by an alkaline silicate solution. The cement-clinkers fired at 1450 °C for 1h were characterized by XRD, XRF, SEM-EDS, and a free lime (CaO_f) content test. The anhydrous clinker mineral phases C₃S (Ca₃SiO₅), C₂S (Ca₂SiO₄), C₃A (Ca₃Al₂O₆), and C₄AF (Ca₄Al₂Fe₂O₁₀) were well-crystallized in all investigated formulations. The free lime was lower than 1.3 wt% in all elaborated clinkers, which indicates a high degree of clinkerization. The results demonstrate that geopolymer binder and mortar materials are suitable substitutes for natural mineral clay incement clinker preparation. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 7926 KiB

Open AccessArticle

Bio-Fibres as a Reinforcement of Gypsum Composites

by Alessandro P. Fantilli, Daria Jóźwiak-Niedźwiedzka and Piotr Denis

Materials 2021, 14(17), 4830; https://doi.org/10.3390/ma14174830 - 25 Aug 2021

Cited by 9 | Viewed by 2441

Abstract

Three series of tests performed on fibre-reinforced gypsum composites are described herein. Sheep wool fibres and hemp fibres were used as reinforcement. The aim was to evaluate the capability of these biomaterials to enhance the fracture toughness of the gypsum matrix. The mechanical [...] Read more.

Three series of tests performed on fibre-reinforced gypsum composites are described herein. Sheep wool fibres and hemp fibres were used as reinforcement. The aim was to evaluate the capability of these biomaterials to enhance the fracture toughness of the gypsum matrix. The mechanical properties were measured by means of flexural tests on small specimens, whereas scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction were used to analyse the microstructure and composition of the fibres and of the gypsum composites. As a result, wool fibres were shown to improve the mechanical performance of the gypsum matrix, better than hemp fibres. This is due to the high adhesion at the interface of the fibre and gypsum matrix, because the latter tends to roughen the surface of the wool and, consequently to increase the bond strength. This preliminary research carried out shows that this type of biofiber—a waste material—can be considered a promising building material in sustainable and environmentally friendly engineering. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 4829 KiB

Open AccessEditor’s ChoiceArticle

A Textile Waste Fiber-Reinforced Cement Composite: Comparison between Short Random Fiber and Textile Reinforcement

by Payam Sadrolodabaee, Josep Claramunt, Mònica Ardanuy and Albert de la Fuente

Materials 2021, 14(13), 3742; https://doi.org/10.3390/ma14133742 - 04 Jul 2021

Cited by 36 | Viewed by 6061

Abstract

Currently, millions of tons of textile waste from the garment and textile industries are generated worldwide each year. As a promising option in terms of sustainability, textile waste fibers could be used as internal reinforcement of cement-based composites by enhancing ductility and decreasing [...] Read more.

Currently, millions of tons of textile waste from the garment and textile industries are generated worldwide each year. As a promising option in terms of sustainability, textile waste fibers could be used as internal reinforcement of cement-based composites by enhancing ductility and decreasing crack propagation. To this end, two extensive experimental programs were carried out, involving the use of either fractions of short random fibers at 6–10% by weight or nonwoven fabrics in 3–7 laminate layers in the textile waste-reinforcement of cement, and the mechanical and durability properties of the resulting composites were characterized. Flexural resistance in pre- and post-crack, toughness, and stiffness of the resulting composites were assessed in addition to unrestrained drying shrinkage testing. The results obtained from those programs were analyzed and compared to identify the optimal composite and potential applications. Based on the results of experimental analysis, the feasibility of using this textile waste composite as a potential construction material in nonstructural concrete structures such as facade cladding, raised floors, and pavements was confirmed. The optimal composite was proven to be the one reinforced with six layers of nonwoven fabric, with a flexural strength of 15.5 MPa and a toughness of 9.7 kJ/m². Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 6945 KiB

Open AccessEditor’s ChoiceArticle

The Influence of Sewage Sludge Content and Sintering Temperature on Selected Properties of Lightweight Expanded Clay Aggregate

by Jolanta Latosińska, Maria Żygadło and Przemysław Czapik

Materials 2021, 14(12), 3363; https://doi.org/10.3390/ma14123363 - 17 Jun 2021

Cited by 7 | Viewed by 1902

Abstract

Wastewater treatment processes produce sewage sludge (SS), which, in line with environmental sustainability principles, can be a valuable source of matter in the production of lightweight expanded clay aggregate (LECA). The literature on the influence of SS content and sintering temperature on the [...] Read more.

Wastewater treatment processes produce sewage sludge (SS), which, in line with environmental sustainability principles, can be a valuable source of matter in the production of lightweight expanded clay aggregate (LECA). The literature on the influence of SS content and sintering temperature on the properties of LECA is scarce. This paper aims to statistically evaluate the effects of SS content and sintering temperature on LECA physical properties. Total porosity, pore volume, and apparent density were determined with the use of a density analyzer. A helium pycnometer was utilized to determine the specific density. Closed porosity was calculated. The test results demonstrated a statistically significant influence of the SS content on the specific density and water absorption of LECA. The sintering temperature had a significant effect on the specific density, apparent density, total porosity, closed porosity, total volume of pores, and water absorption. It was proved that a broad range of the SS content is admissible in the raw material mass for the production of LECA. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 2956 KiB

Open AccessArticle

Characterization of Glass Powder from Glass Recycling Process Waste and Preliminary Testing

by Ester Gimenez-Carbo, Lourdes Soriano, Marta Roig-Flores and Pedro Serna

Materials 2021, 14(11), 2971; https://doi.org/10.3390/ma14112971 - 31 May 2021

Cited by 7 | Viewed by 2793

Abstract

This work studies the possibility of incorporating different proportions of glass powder from the waste glass (rejected material called fine cullet) produced during the glass recycling process into the manufacturing of mortar and concrete. For this purpose, the material is characterized by its [...] Read more.

This work studies the possibility of incorporating different proportions of glass powder from the waste glass (rejected material called fine cullet) produced during the glass recycling process into the manufacturing of mortar and concrete. For this purpose, the material is characterized by its chemical composition and pozzolanic activity, and the shape and size of its particles are studied. It is then incorporated as a substitute for cement into the manufacturing of mortar and concrete at 25% and 40% of cement weight, and its effect on setting times, consistency, and mechanical strength is analyzed. Its behavior as a slow pozzolan is verified, and the possibility of incorporating it into concrete is ratified by reducing its cement content and making it a more sustainable material. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 2639 KiB

Open AccessEditor’s ChoiceArticle

Influence of Groundwater pH on Water Absorption and Waterproofness of Polymer Modified Bituminous Thick Coatings

by Barbara Francke and Maria Wichowska

Materials 2021, 14(9), 2272; https://doi.org/10.3390/ma14092272 - 27 Apr 2021

Viewed by 1835

Abstract

Polymer modified bituminous thick coatings are increasingly used in the construction industry to protect underground parts of buildings from groundwater. When assessing their durability, one vital issue related to their functional properties is the influence of water absorption on the waterproofness of the [...] Read more.

Polymer modified bituminous thick coatings are increasingly used in the construction industry to protect underground parts of buildings from groundwater. When assessing their durability, one vital issue related to their functional properties is the influence of water absorption on the waterproofness of the applied solution as a result of the action of groundwater with different pH values. As part of the research, the water absorption of the products in question was assessed using the method of total immersion in water with pH of 4.0, 7.0 and 7.5 as well as comparatively, as a result of one-way exposure to demineralized water under successively increasing pressure up to 0.5 MPa. The moisture susceptibility of the coatings was assessed both concerning the local surface damage and the continuous waterproofing coating. It was established that the coatings show the highest water absorption when the water pH is 4.0, which simulates the groundwater aggressiveness on construction products. It was proven that moisture absorbed by the coatings is retained within this layer and is not transferred to the substrate on which the coatings are laid. It was also found that water in contact with the tested coatings changes its reaction to alkaline, which can result in contamination of groundwater in the area of waterproofing coating. A modification of the method of assessing the water absorption of polymer modified bituminous thick coatings was proposed, taking into account their use in conditions of use. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 2473 KiB

Open AccessArticle

Improvement in the Carbonation Resistance of Construction Mortar with Cane Bagasse Fiber Added

by William A. Talavera-Pech, Diana Montiel-Rodríguez, Josefa de los A. Paat-Estrella, Ruth López-Alcántara, José T. Pérez-Quiroz and Tezozomoc Pérez-López

Materials 2021, 14(8), 2066; https://doi.org/10.3390/ma14082066 - 20 Apr 2021

Cited by 6 | Viewed by 2118

Abstract

In this work, sugarcane bagasse fiber, a waste product of agroindustry, was added to mortar mixes at different proportions looking to seal porosities so as to improve the resistance of concrete to carbonation and to improve its mechanical properties. To evaluate the behavior [...] Read more.

In this work, sugarcane bagasse fiber, a waste product of agroindustry, was added to mortar mixes at different proportions looking to seal porosities so as to improve the resistance of concrete to carbonation and to improve its mechanical properties. To evaluate the behavior of bagasse fibers in the alkaline media typical of mortars, bagasse fibers were subjected to solutions with alkaline pH values, and their chemical structure and morphological behavior was evaluated using FTIR (Fourier transform infrared spectroscopy) and SEM (Scanning Electron Microscopy). Using mortar cylinders in an accelerated carbonation chamber to obtain results in short lapses, the compressive strength and the carbonation were evaluated. The FTIR analysis results indicate that pH values of 11 and 12 causes a delignification, while at pH 9 and 10, a swelling of the molecule occurs because of the addition of hydroxyl ions, behavior that is confirmed with SEM images. A clear effect of the fiber addition on the performance of concrete was observed as the carbonation front of 35 mm for the sample without fibers was reduced to 2 mm for the sample with 2% fiber addition, resulting in an increase of 5 MPa in compressive strength. These results indicate that in the range of mortar pH, chemical changes occured over the sugarcane surface that could cause the growth of fibers and could partially seal the porosity in the mortars, thus enhancing its performance. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 3082 KiB

Open AccessArticle

Effect of Hydrogen Nanobubbles on the Mechanical Strength and Watertightness of Cement Mixtures

by Won-Kyung Kim, Young-Ho Kim, Gigwon Hong, Jong-Min Kim, Jung-Geun Han and Jong-Young Lee

Materials 2021, 14(8), 1823; https://doi.org/10.3390/ma14081823 - 07 Apr 2021

Cited by 6 | Viewed by 2356

Abstract

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the [...] Read more.

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the cement mortar for each curing day was improved by about 3.7–15.79%, compared to the specimen that used general water, when two concentrations of HNBW were used as the mixing water. The results of mercury intrusion porosimetry and a scanning electron microscope analysis of the cement paste showed that the pore volume of the specimen decreased by about 4.38–10.26%, thereby improving the watertightness when high-concentration HNBW was used. The improvement in strength and watertightness is a result of the reduction of the microbubbles’ particle size, and the increase in the zeta potential and surface tension, which activated the hydration reaction of the cement and accelerated the pozzolanic reaction. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 6544 KiB

Open AccessEditor’s ChoiceArticle

Regional Waste Streams as Potential Raw Materials for Immediate Implementation in Cement Production

by Matea Flegar, Marijana Serdar, Diana Londono-Zuluaga and Karen Scrivener

Materials 2020, 13(23), 5456; https://doi.org/10.3390/ma13235456 - 30 Nov 2020

Cited by 12 | Viewed by 2477

Abstract

There is an urgent need to apply available technologies to reduce the environmental impact of the construction industry. One of the possible solutions that can be implemented immediately is the industrial symbiosis between the waste-producing industries on the one hand and the cement [...] Read more.

There is an urgent need to apply available technologies to reduce the environmental impact of the construction industry. One of the possible solutions that can be implemented immediately is the industrial symbiosis between the waste-producing industries on the one hand and the cement industry, which consumes enormous amounts of raw materials for its production, on the other. In order for the industry to accelerate the use of these available materials and technologies, the potential of these materials must be disclosed. The present study shows a systematic approach to assess the potential of waste materials, by-products, and other raw materials available in the South East Europe that can be used in cement production. Their evaluation included the analysis of their availability, their chemical and physical properties, their chemical reactivity, and their contribution to the mortar’s strength. Based on the results and the analyses carried out, a recommendation for immediate use in the construction sector is given for each of the materials collected. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 3221 KiB

Open AccessArticle

Frost Damage in Tight Sandstone: Experimental Evaluation and Interpretation of Damage Mechanisms

by Shun Ding, Hailiang Jia, Fan Zi, Yuanhong Dong and Yuan Yao

Materials 2020, 13(20), 4617; https://doi.org/10.3390/ma13204617 - 16 Oct 2020

Cited by 14 | Viewed by 2209

Abstract

Low-porosity tight rocks are widely used as building and engineering materials. The freeze–thaw cycle is a common weathering effect that damages building materials in cold climates. Tight rocks are generally supposed to be highly frost-resistant; thus, studies on frost damage in tight sandstone [...] Read more.

Low-porosity tight rocks are widely used as building and engineering materials. The freeze–thaw cycle is a common weathering effect that damages building materials in cold climates. Tight rocks are generally supposed to be highly frost-resistant; thus, studies on frost damage in tight sandstone are rare. In this study, we investigated the deterioration in mechanical properties and changes in P-wave velocity with freeze–thaw cycles in a tight sandstone. We also studied changes to its pore structure using nuclear magnetic resonance (NMR) technology. The results demonstrate that, with increasing freeze–thaw cycles, (1) the mechanical strength (uniaxial compressive, tensile, shear strengths) exhibits a similar decreasing trend, while (2) the P-wave velocity and total pore volume do not obviously increase or decrease. (3) Nanopores account for >70% of the pores in tight sandstone but do not change greatly with freeze–thaw cycles; however, the micropore volume has a continuously increasing trend that corresponds to the decay in mechanical properties. We calculated the pressure-dependent freezing points in pores of different diameters, finding that water in nanopores (diameter <5.9 nm) remains unfrozen at –20 °C, and micropores >5.9 nm control the evolution of frost damage in tight sandstone. We suggest that pore ice grows from larger pores into smaller ones, generating excess pressure that causes frost damage in micropores and then nanopores, which is manifested in the decrease in mechanical properties. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 3706 KiB

Open AccessArticle

Performance of Rice Husk Ash as Supplementary Cementitious Material after Production in the Field and in the Lab

by Mareike Thiedeitz, Wolfram Schmidt, Michelle Härder and Thomas Kränkel

Materials 2020, 13(19), 4319; https://doi.org/10.3390/ma13194319 - 28 Sep 2020

Cited by 38 | Viewed by 5970

Abstract

Supplementary cementitious materials (SCM) can reduce the total amount of Portland cement clinker in concrete production. Rice husk ashes (RHA) can be converted from an agricultural by-product to a high-performance concrete constituent due to a high amount of reactive silica with pozzolanic properties [...] Read more.

Supplementary cementitious materials (SCM) can reduce the total amount of Portland cement clinker in concrete production. Rice husk ashes (RHA) can be converted from an agricultural by-product to a high-performance concrete constituent due to a high amount of reactive silica with pozzolanic properties if they are burnt under controlled conditions. The way and duration of combustion, the cooling process as well as the temperature have an effect on the silica form and thus, the chemical and physical performance of the RHA. Various studies on the best combustion technique have been published to investigate the ideal combustion techniques. Yet, the process mostly took place under laboratory conditions. Investigating the difference between the performance of RHA produced in a rural environment and laboratory conditions is useful for the assessment and future enhancement of RHA production, and its application both as building material, for example in rural areas where it is sourced in large quantities, and as additive for high performance concrete. Thus, the paper presents a comparison between RHA produced under rudimentary conditions in a self-made furnace in the rural Bagamoyo, Tanzania and under controlled laboratory conditions at the Technical University of Munich, Germany, with different combustion methods and temperatures. In a second step, RHA was ground to reach particle size distributions comparable to cement. In a third step, cement pastes were prepared with 10%, 20% and 40% of cement replacement, and compared to the performance of plain and fly ash blended cement pastes. The results show that controlled burning conditions around 650 °C lead to high reactivity of silica and, therefore, to good performance as SCM. However, also the RHA burnt under less controlled conditions in the field provided reasonably good properties, if the process took place with proper burning parameters and adequate grinding. The knowledge can be implemented in the field to improve the final RHA performance as SCM in concrete. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 5439 KiB

Open AccessArticle

The Impact of Interphase Precipitation on the Mechanical Behavior of Fire-Resistant Steels at an Elevated Temperature

by Jinghua Cong, Jiangwen Li, Jiajie Fan, Pengcheng Liu, Raja Devesh Kumar Misra, Chengjia Shang and Xuemin Wang

Materials 2020, 13(19), 4294; https://doi.org/10.3390/ma13194294 - 25 Sep 2020

Cited by 7 | Viewed by 2076

Abstract

In this study, we address the challenge of obtaining high strength at ambient and elevated temperatures in fire-resistant Ti–Mo–V steel with ferrite microstructures through thermo-mechanical controlled processing (TMCP). Thermally stable interphase precipitation of (Ti, Mo, V)C was an important criterion for retaining strength [...] Read more.

In this study, we address the challenge of obtaining high strength at ambient and elevated temperatures in fire-resistant Ti–Mo–V steel with ferrite microstructures through thermo-mechanical controlled processing (TMCP). Thermally stable interphase precipitation of (Ti, Mo, V)C was an important criterion for retaining strength at elevated temperatures. Electron microscopy indicated that interphase precipitation occurred during continuous cooling after controlled rolling, where the volume fraction of interphase precipitation was controlled by the laminar cooling temperature. The interphase precipitation of MC carbides with an NaCl-type crystal structure indicated a Baker–Nutting (B–N) orientation relationship with ferrite. When the steel was isothermally held at 600 °C for up to 3 h, interphase precipitation occurred during TMCP with high thermal stability. At the same time, some random precipitation took place during isothermal holding. The interphase precipitation increased the elastic modulus of the experimental steels at an elevated temperature. It is proposed that fire-resistant steel with thermally stable interphase precipitation is preferred, which enhances precipitation strengthening and dislocation strengthening at elevated temperatures. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 4606 KiB

Open AccessArticle

Study on Low-Temperature Cracking Performance of Asphalt under Heat and Light Together Conditions

by Limin Li, Zhaoyang Guo, Longfei Ran and Jiewen Zhang

Materials 2020, 13(7), 1541; https://doi.org/10.3390/ma13071541 - 27 Mar 2020

Cited by 20 | Viewed by 2460

Abstract

The low-temperature cracking performance of asphalt is considered one of the main deteriorations in asphalt pavements. However, there have been few studies on the low-temperature cracking performance of asphalt under heat and light together. Hence, the ductility test, bending beam rheometer (BBR) test, [...] Read more.

The low-temperature cracking performance of asphalt is considered one of the main deteriorations in asphalt pavements. However, there have been few studies on the low-temperature cracking performance of asphalt under heat and light together. Hence, the ductility test, bending beam rheometer (BBR) test, and asphalt composition analysis test are combined to investigate the low-temperature cracking performance under heat and light together based on the climatic conditions of China. The styrene–butadiene–styrene block copolymer (SBS)-modified asphalt binders were prepared with different modifier types and base asphalt in this research. The results show that the low-temperature cracking resistance of asphalt reduces under heat and light together. It is obviously reduced at the early stage, and it becomes worse with the increase of the aging time, temperature, and ultraviolet (UV) intensity. The asphalt composition has a significant impact on its low-temperature cracking performance, and the SBS modifier can improve the low-temperature cracking resistance of asphalt. The rational selection of base asphalt and modifier can improve the low-temperature cracking performance of asphalt. Under heat and light together, whether base asphalt or modified asphalt, the change trends of their ductility and component content are similar. Therefore, to improve the anti-cracking ability of the asphalt pavement, it is suggested to use the ductility of asphalt aged by heat and light together for 15 days as the evaluation index of the low-temperature cracking performance of asphalt, and asphalt should be selected according to the temperature and UV intensity of the asphalt pavement use area. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 14658 KiB

Open AccessArticle

Effect of Elevated Temperature on Compressive Strength and Physical Properties of Neem Seed Husk Ash Concrete

by Kizito Patrick Mwilongo, Revocatus Lazaro Machunda and Yusufu Abeid Chande Jande

Materials 2020, 13(5), 1198; https://doi.org/10.3390/ma13051198 - 06 Mar 2020

Cited by 6 | Viewed by 3034

Abstract

High temperature rise mostly caused by a fire outbreak is currently becoming a threat that endangers concrete’s structural performance for buildings and the safety of occupants. The behavior of concrete after fire subjection has been of much interest for the structural materials design [...] Read more.

High temperature rise mostly caused by a fire outbreak is currently becoming a threat that endangers concrete’s structural performance for buildings and the safety of occupants. The behavior of concrete after fire subjection has been of much interest for the structural materials design purposes. This study investigated the physical properties and the compressive strength of M25 concrete incorporating Neem Seed Husk Ash (NSHA), exposed to and through targeted different levels of temperature (200 °C to 800 °C) for a period of three hours in an electric furnace. The NSHA was produced by calcining neem seed husks at 800 °C for six hours and then sieved through the 125 μm sieve. Different amounts of NSHA were investigated while considering the plain concrete as the control sample. 150 concrete cubes of 150 mm sizes were cast and properly cured for 7 and 28 days. The experimental results show that the compressive strength of the 5% NSHA concrete exposed to temperatures up to 400 °C is 21.3% and 23.8% better than the normal concrete at 7 and 28 curing days, respectively. Surface cracks and spalling are noticeable at 600 °C and 800 °C for all samples considered in this study. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 4718 KiB

Open AccessArticle

Synthesis and Characterization of a Hybrid Cement Based on Fly Ash, Metakaolin and Portland Cement Clinker

by Adriagni C. Barboza-Chavez, Lauren Y. Gómez-Zamorano and Jorge L. Acevedo-Dávila

Materials 2020, 13(5), 1084; https://doi.org/10.3390/ma13051084 - 29 Feb 2020

Cited by 12 | Viewed by 3135

Abstract

Hybrid cement has become one of the most viable options in the reduction of CO₂ emissions to the environment that are generated by the cement industry. This could be explained by the reduction of the content of clinker in the final mixture [...] Read more.

Hybrid cement has become one of the most viable options in the reduction of CO₂ emissions to the environment that are generated by the cement industry. This could be explained by the reduction of the content of clinker in the final mixture and substitution of the remaining percentage with supplementary cementitious materials with the help of an alkaline activation. Following that, properties that are provided by an Ordinary Portland Cement and of a geopolymer are mixed in this type of hybrid material and could be achieved at room temperature. Thereafter, the main objective of this research was to synthesize hybrid cements reducing the clinker content of Portland Cement up to 20% and use metakaolin and fly ash as supplementary cementitious materials in different proportions. The mixtures were alkaline activated with a mixture of sodium silicate and sodium hydroxide, calculating the amounts according to the percentage of Na₂O that is present in each of the activators. The samples were then characterized using Compressive strength, X-ray diffraction, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy with energy-dispersive X-ray spectroscopy. The results indicated that the hybrid cements have similar mechanical properties than an Ordinary Portland Cement, and they resulted in a dense matrix of hydration products similar to those that are generated by cements and geopolymers. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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23 pages, 26104 KiB

Open AccessArticle

Second-Generation Implants for Load Introduction into Thin-Walled CFRP-Reinforced UHPC Beams: Implant Optimisation and Investigations of Production Technologies

by Benjamin Kromoser, Oliver Gericke, Mathias Hammerl and Werner Sobek

Materials 2019, 12(23), 3973; https://doi.org/10.3390/ma12233973 - 30 Nov 2019

Cited by 6 | Viewed by 3362

Abstract

Combining two high-performance materials—ultra-high-performance concrete (UHPC) as the matrix and carbon-fibre-reinforced composites (CFRP) as the reinforcement—opens up new possibilities for achieving very lightweight thin-walled concrete elements. This strategy, however, leads to a higher degree of material utilisation, resulting in the generation of higher [...] Read more.

Combining two high-performance materials—ultra-high-performance concrete (UHPC) as the matrix and carbon-fibre-reinforced composites (CFRP) as the reinforcement—opens up new possibilities for achieving very lightweight thin-walled concrete elements. This strategy, however, leads to a higher degree of material utilisation, resulting in the generation of higher forces around load introduction points and supports. The authors present a solution for increasing the performance of supports of very slender CFRP-reinforced UHPC beams by using metal implants. Implants are used in place of concrete in regions of stress concentrations and significant deviation forces. These are able to transfer high stresses and forces efficiently due to their ability to sustain both tension and compression in equal measure. A key issue in their development is the interface between the reinforced concrete and metal implant. Building on previous research, this paper deals with the conceptual design of three types of implants manufactured from different metals and with three different types of automated production technologies (water-jet cutting, metal casting with a 3D-printed plastic formwork and binder jetting of steel components). For this paper, tests were carried out to determine the load-bearing behaviour of beams with the three different types of support implants used for load introduction at the supports. A carbon rod served as bending reinforcement and a pre-formed textile reinforcement cage served as shear and constructive reinforcement. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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16 pages, 6715 KiB

Open AccessArticle

Application of Natural Plant Fibers in Cement-Based Composites and the Influence on Mechanical Properties and Mass Transport

by Kaiyue Zhao, Shanbin Xue, Peng Zhang, Yupeng Tian and Peibing Li

Materials 2019, 12(21), 3498; https://doi.org/10.3390/ma12213498 - 25 Oct 2019

Cited by 33 | Viewed by 4347

Abstract

Recently, there is ongoing interest in the use of natural plant fibers as alternatives for conventional reinforcements in cementitious composites. The use of natural plant fibers makes engineering work more sustainable, since they are renewable, biodegradable, energy-efficient, and non-toxic raw materials. In this [...] Read more.

Recently, there is ongoing interest in the use of natural plant fibers as alternatives for conventional reinforcements in cementitious composites. The use of natural plant fibers makes engineering work more sustainable, since they are renewable, biodegradable, energy-efficient, and non-toxic raw materials. In this contribution, a comprehensive experimental program was undertaken to determine the influence of pineapple leaf fiber and ramie fiber on the mechanical properties and mass transport of cement-based composites. The compressive strength, tensile strength, modulus of elasticity, modulus of rupture, fracture energy, flexural toughness, coefficient of capillary water absorption, and chloride diffusion were measured. Natural plant fiber-reinforced cement-based composites (NPFRCCs) containing pineapple leaf fiber and ramie fiber, as compared to the plain control, exhibited a slight reduction in compressive strength and a considerable improvement in tensile strength, modulus of elasticity, modulus of rupture, and flexural toughness; the enhancement was remarkable with a higher fiber content. The coefficient of capillary absorption and chloride diffusion of NPFRCCs were significantly larger than the plain control, and the difference was evident with the increase in fiber content. The present study suggests that the specimen with 2% pineapple leaf fiber content can be used in normal environments due to its superior mechanical properties. However, one should be careful when using the material in marine environments. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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21 pages, 3174 KiB

Open AccessArticle

Reactivity and Microstructure of Metakaolin Based Geopolymers: Effect of Fly Ash and Liquid/Solid Contents

by Oliver Vogt, Neven Ukrainczyk, Conrad Ballschmiede and Eddie Koenders

Materials 2019, 12(21), 3485; https://doi.org/10.3390/ma12213485 - 24 Oct 2019

Cited by 36 | Viewed by 3848

Abstract

Geopolymers are inorganic binders based on mixtures of an aluminosilicate powder with an alkali-silicate solution. Properties of geopolymers are strongly determined by the type of reactive solid, the liquid/solid ratio of paste and, amongst others, the Si/Al ratio of the formed geopolymer network. [...] Read more.

Geopolymers are inorganic binders based on mixtures of an aluminosilicate powder with an alkali-silicate solution. Properties of geopolymers are strongly determined by the type of reactive solid, the liquid/solid ratio of paste and, amongst others, the Si/Al ratio of the formed geopolymer network. In this study, fly ash blended metakaolin based geopolymers with varying liquid/solid ratios (l/s), activated by potassium silicate solution, are investigated. Reactivity of metakaolin and fly ash was investigated by powder X-ray diffraction (XRD) and dissolution tests. Reactivity, mechanical properties and microstructure of hardened pastes were analyzed by setting and compressive strength tests, mercury intrusion porosimetry (MIP), capillary water absorption tests, thermogravimetric analysis-differential scanning calorimeter (TGA-DSC), isothermal calorimetry and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results show that substitution of metakaolin by fly ash as well as variation of l/s brings advantages up to a certain degree, but also has a considerable influence on the pore size distribution, mechanical properties, Si/Al ratio of the geopolymer network and the content of bound water. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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11 pages, 7094 KiB

Open AccessArticle

Effects of Calcium Silicate Slag on Hydration of Cementitious Pastes

by Ju Zhang, Changwang Yan, Pucun Bai, Xiaoxiao Wang, Shuguang Liu and Zhigang Liu

Materials 2019, 12(19), 3094; https://doi.org/10.3390/ma12193094 - 23 Sep 2019

Cited by 5 | Viewed by 2360

Abstract

Calcium silicate slag (CSS) is waste slag and it contains a large amount of beta-dicalcium silicate. This study is mainly focused on the effect of CSS on the hydration of cementitious pastes. CSS was used to partly replace cement, and composite pastes containing [...] Read more.

Calcium silicate slag (CSS) is waste slag and it contains a large amount of beta-dicalcium silicate. This study is mainly focused on the effect of CSS on the hydration of cementitious pastes. CSS was used to partly replace cement, and composite pastes containing CSS and cement were prepared. The mineral composition and particle size distribution of CSS were characterized. The chemically combined water of the paste sample was measured at a given test age. Based on the value of chemically combined water, the hydration degree and the hydration rate of composite pastes were analyzed. The flexural strength of the samples was established. The pore structure and micromorphology of the sample were also observed. The results indicate the chemically combined water decreased, the hydration degree decreased, the hydration rate declined, and the spherical micromorphology of the calcium silicate hydrate gel was reduced after more cement was replaced by CSS in the composite pastes. Besides, the amount of pores increased, its size was bigger, and air content in the pore was higher. However, flexural strength was lower. CSS has a significant impact on the hydration of cementitious pastes, and it is thus suitable to regulate hydration. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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11 pages, 2696 KiB

Open AccessArticle

Waste Utilization: Insulation Panel from Recycled Polyurethane Particles and Wheat Husks

by Štěpán Hýsek, Pavel Neuberger, Adam Sikora, Ondřej Schönfelder and Gianluca Ditommaso

Materials 2019, 12(19), 3075; https://doi.org/10.3390/ma12193075 - 20 Sep 2019

Cited by 15 | Viewed by 2836

Abstract

This study provides a solution for the utilization of two waste materials, namely the residues of soft polyurethane foam from the production of mattresses and winter wheat husks. Thermal insulation panels with a nominal density of 50–150 kg/m³, bonded one-component moisture [...] Read more.

This study provides a solution for the utilization of two waste materials, namely the residues of soft polyurethane foam from the production of mattresses and winter wheat husks. Thermal insulation panels with a nominal density of 50–150 kg/m³, bonded one-component moisture curing polyurethane adhesive, were developed, and the effect of the ratio between recycled polyurethane foam and winter wheat husk on internal bond strength, compressive stress at 10% strain, water uptake, coefficient of thermal conductivity, and volumetric heat capacity was observed. The developed composite materials make use of the very good thermal insulation properties of the two input waste materials, and the coefficient of thermal conductivity of the resulting boards achieves excellent values, namely 0.0418–0.0574 W/(m.K). The developed boards can be used as thermal insulation in the structures of environmentally friendly buildings. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 3746 KiB

Open AccessArticle

Effect of Copper Tailing Content on Corrosion Resistance of Steel Reinforcement in a Salt Lake Environment

by Liming Zhang, Jia Li and Hongxia Qiao

Materials 2019, 12(19), 3069; https://doi.org/10.3390/ma12193069 - 20 Sep 2019

Cited by 4 | Viewed by 2254

Abstract

With the increasing proportions of copper tailings of concrete in the Qinghai Salt Lake area of China, there arises the problem of corrosion of steel reinforcement in concrete structures. In this study, we determine the corrosion rate (C_R), crack width, and [...] Read more.

With the increasing proportions of copper tailings of concrete in the Qinghai Salt Lake area of China, there arises the problem of corrosion of steel reinforcement in concrete structures. In this study, we determine the corrosion rate (C_R), crack width, and corrosion potential of the steel reinforcement with copper tailing. This was achieved by conducting the constant-current accelerated corrosion test with different proportions of copper tailing in the brine environment of the Qinghai province. The results demonstrate that the corrosion potential (E_corr) and the passivation area of the polarization curve decrease with the increase in the corrosion time, and the corrosion rate and crack width increase with the increase in the corrosion time. When the corrosion time is the same, the corrosion potential, crack width, and corrosion depth of the reinforcement decrease first and then increase with the increase in the copper tailing powder content. When the copper tailing powder content is 20%, the above parameters reach the minimum value. In the salt lake environment of Qinghai, China, the copper tailing powder content is recommended to be 20%. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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24 pages, 4481 KiB

Open AccessArticle

Mechanical Behavior of Brick Masonry in an Acidic Atmospheric Environment

by Shansuo Zheng, Lihua Niu, Pei Pei and Jinqi Dong

Materials 2019, 12(17), 2694; https://doi.org/10.3390/ma12172694 - 23 Aug 2019

Cited by 8 | Viewed by 2913

Abstract

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and [...] Read more.

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and the compressive strength of the masonry materials (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), the shear behavior of the masonry, and the compression behavior of the masonry were analyzed. The resistance of acid rain corrosion for the cement-lime mortar prisms was the worst, and the incorporation of fly ash into the cement mortar did not improve the acid rain corrosion resistance. The effect of the acid rain corrosion damage on the mechanical properties for the brick was significant. With an increasing number of acid rain corrosion cycles, the compressive strength of the mortar prisms, and the shear and compressive strengths of the brick masonry first increased and then decreased. The peak stress first increased and then decreased whereas the peak strain gradually increased. The slope of the stress-strain curve for the compression prisms gradually decreased. Furthermore, a mathematical degradation model for the compressive strength of the masonry material (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), as well as the shear strength attenuation model and the compressive strength attenuation model of brick masonry after acid rain corrosion were proposed. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 2266 KiB

Open AccessArticle

Composition Design and Performance Evaluation of Emulsified Asphalt Cold Recycled Mixtures

by Yuhui Pi, Zhe Huang, Yingxing Pi, Guangcan Li and Yan Li

Materials 2019, 12(17), 2682; https://doi.org/10.3390/ma12172682 - 22 Aug 2019

Cited by 27 | Viewed by 3025

Abstract

Based on an analysis of the cold regeneration mechanism of emulsified asphalt, the emulsified asphalt binders and cement were applied to prepare the cold recycled mixtures, and the main technical performances of the designed mixtures were evaluated, including high-temperature stability, water stability, and [...] Read more.

Based on an analysis of the cold regeneration mechanism of emulsified asphalt, the emulsified asphalt binders and cement were applied to prepare the cold recycled mixtures, and the main technical performances of the designed mixtures were evaluated, including high-temperature stability, water stability, and fatigue characteristics. A high content of 65% recycled asphalt pavement (RAP) material was used with some new aggregates and mineral powders, and the optimal emulsified asphalt binder and cement dosages were determined as 2.9% and 1.5% respectively. The technical performance test results show that: (1) The well-designed emulsified asphalt cold recycled mixtures have good high-temperature stability and water stability, and can meet the requirements of the road base layer and the lower layer. (2) When the stress level is lower, the fatigue performance of mixtures with lower emulsified asphalt binder dosage and lower cement content is better, but when the stress level is higher, the high dosage of emulsified asphalt binder is more favorable, while the cement content has little effect on the fatigue property. (3) The emulsified asphalt cold recycled mixtures have relatively poor fatigue resistance, and their fatigue life is significantly lower than that of the hot mixed asphalt mixtures. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 2381 KiB

Open AccessArticle

Applicability of Yielding–Resisting Sand Column and Three-Dimensional Coordination Support in Stopes

by Fanbao Meng, Zhijie Wen, Baotang Shen, Yujing Jiang, Shaoshuai Shi and Renle Zhao

Materials 2019, 12(16), 2635; https://doi.org/10.3390/ma12162635 - 19 Aug 2019

Cited by 2 | Viewed by 2516

Abstract

In view of the existing problems of stope roadways, which are difficult to maintain under the influence of high ground and mining-induced stresses, the structural characteristics and movement regularities of stopes surrounding rocks were analysed. Through the construction of a three-dimensional mechanical model [...] Read more.

In view of the existing problems of stope roadways, which are difficult to maintain under the influence of high ground and mining-induced stresses, the structural characteristics and movement regularities of stopes surrounding rocks were analysed. Through the construction of a three-dimensional mechanical model of the coordination support of a stope, the adaptability index of the support in stope is presented, and its mechanism of operation is expounded. Yielding–resisting sand column (YRSC) sidewall-support technology with satisfactory compressibility and supporting strength was developed. The structure and actual mechanical properties of the YRSC were investigated through laboratory experiments, and the optimum ratio of filling materials was obtained. The good applicability of the load and deformation adaptability index of the three-dimensional coordination support in the stope and YRSC sidewall-support technology were demonstrated in practice at the No. 12306 working face of the Dongda coal mine. It was shown that the designed carrying capacity and compression of the sand columns satisfied the site requirements. The actual stress and deformation of the YRSC exhibited three stages: Slow growth at the initial stage, a large increase in the medium term, and a stable trend at the end. The adaptability index of the three-dimensional coordination support in the stope considers all bearing structure units of the stope as an interconnected whole, and the stability conditions of the stope roadway can be quantitatively described. The supporting effect of the YRSC is remarkable and can be applied to the construction of tunnels, bridge systems and other engineering fields. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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11 pages, 37260 KiB

Open AccessArticle

Performance and Microstructure of Cold Recycled Mixes Using Asphalt Emulsion with Different Contents of Cement

by Yanhai Yang, Ye Yang and Baitong Qian

Materials 2019, 12(16), 2548; https://doi.org/10.3390/ma12162548 - 10 Aug 2019

Cited by 23 | Viewed by 2887

Abstract

Cold recycled mixes using asphalt emulsion (CRME) is an economical and environmentally-friendly technology for asphalt pavement maintenance and rehabilitation. In order to determine the optimum range of cement contents, the complex interaction between cement and asphalt emulsion and the effects of cement on [...] Read more.

Cold recycled mixes using asphalt emulsion (CRME) is an economical and environmentally-friendly technology for asphalt pavement maintenance and rehabilitation. In order to determine the optimum range of cement contents, the complex interaction between cement and asphalt emulsion and the effects of cement on performance of CRME were investigated with different contents of cement. The microstructure and chemical composition of the fracture surface of CRME with different contents of cement were analyzed in this paper as well. Results show that the high-temperature stability and moisture susceptibility of CRME increased with the contents of cement increasing. The low-temperature crack resistance ability gradually increased when the content of cement is increased from 0% to 1.5%. However, it gradually decreased when the content of cement is increased from 1.5% to 4%. Cold recycled mixes had better low-temperature cracking resistance when the contents of cement were in the range from 1% to 2%. The results of microstructure and energy spectrum analysis show that the composite structure is formed by hydration products and asphalt emulsion. The study will be significant to better know the effects of cement and promote the development of CRME. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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20 pages, 3693 KiB

Open AccessArticle

Investigation on the Cooling and Evaporation Behavior of Semi-Flexible Water Retaining Pavement based on Laboratory Test and Thermal-Mass Coupling Analysis

by Qiang Dong, Chonghui Wang, Chuhua Xiong, Xiulei Li, Hainian Wang and Tianqing Ling

Materials 2019, 12(16), 2546; https://doi.org/10.3390/ma12162546 - 09 Aug 2019

Cited by 9 | Viewed by 3004

Abstract

The Semi-Flexible Water Retaining Pavement (SFWRP) has the capability to cool down the temperature of the road surface through its evaporation behavior, including absorbing and evaporating water; this is an efficient approach to relieve the heat island effect in a big city. The [...] Read more.

The Semi-Flexible Water Retaining Pavement (SFWRP) has the capability to cool down the temperature of the road surface through its evaporation behavior, including absorbing and evaporating water; this is an efficient approach to relieve the heat island effect in a big city. The temperature feedback from different material surface were investigated in this paper in the same test condition, it has been proved that the SFWRP material can remarkably cool down the temperature of the road surface. The mechanism of the material evaporation behavior, including flux calculation formula of the water vapor inside the air void, were studied by inter-phase continuous function, in which the structural properties of the SFWRP material was taken into account. Furthermore, the function calculating the evaporation of the water vapor was then developed in this research through heat and mass transfer analogy. Besides, the calculating results can be captured by the self-coding program in Finite Element Modeling (FEM) for water evaporation simulation. Also, the results of laboratory tests were adopted to validate the calculating model. Finally, it has been proved that the mortar was recommended to be used in semi-flexible water retaining pavement to serve as material with permeable and water retaining property, and the semi-flexible water retaining pavement material is recommended to applied in the surface layer of the permeable pavement. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 1446 KiB

Open AccessArticle

Laboratory Performance of Hot Mix Asphalt with High Reclaimed Asphalt Pavement (RAP) and Fine Reclaimed Asphalt Pavement (FRAP) Content

by Sen Han, Xianpeng Cheng, Yamin Liu and Yacai Zhang

Materials 2019, 12(16), 2536; https://doi.org/10.3390/ma12162536 - 09 Aug 2019

Cited by 14 | Viewed by 3166

Abstract

Recently, there has been an increasing interest in the applications of recycled mixtures with a high reclaimed asphalt pavement (RAP) content. However, many government departments are hesitant about the applications of that due to being worried about the durability of its pavement, and [...] Read more.

Recently, there has been an increasing interest in the applications of recycled mixtures with a high reclaimed asphalt pavement (RAP) content. However, many government departments are hesitant about the applications of that due to being worried about the durability of its pavement, and few findings has been reported in terms of the percentage of fine reclaimed asphalt pavement (FRAP, 0~5 mm) in recycled mixtures. In this paper, 25% or more RAP by the weight of aggregates is defined as high RAP and high FRAP refers to 10% or more FRAP by the weight of aggregates. This paper examines the laboratory performances of mixtures with high RAP (30%, 40%, and 50%) and FRAP (10%, 15%, and 20%). Performance evaluations have been conducted by conventional tests, including the low-temperature bending test, fatigue test, and the moisture susceptibility test. The results show that with the increasing RAP and FARP contents, 41% (30-R-10) to 63% (50-R-15) of virgin asphalt can be saved, both the low-temperature and fatigue performance decrease, and the moisture performance firstly increases and then decreases. The results of analysis of variance (ANOVA) in terms of low-temperature and moisture performance show that RAP contents in recycled mixtures have a significant effect on the performance, while the effect of FRAP contents on the performance of recycled mixtures is insignificant. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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18 pages, 2438 KiB

Open AccessArticle

Optimal Design of the Cement, Fly Ash, and Slag Mixture in Ternary Blended Concrete Based on Gene Expression Programming and the Genetic Algorithm

by Xiao-Yong Wang

Materials 2019, 12(15), 2448; https://doi.org/10.3390/ma12152448 - 31 Jul 2019

Cited by 12 | Viewed by 2864

Abstract

Concrete producers and construction companies are interested in improving the sustainability of concrete, including reducing its CO₂ emissions and the costs of materials while maintaining its mechanical properties, workability, and durability. In this study, we propose a simple approach to the optimal [...] Read more.

Concrete producers and construction companies are interested in improving the sustainability of concrete, including reducing its CO₂ emissions and the costs of materials while maintaining its mechanical properties, workability, and durability. In this study, we propose a simple approach to the optimal design of the fly ash and slag mixture in blended concrete that considers the carbon pricing, material cost, strength, workability, and carbonation durability. Firstly, the carbon pricing and the material cost are calculated based on the concrete mixture and unit prices. The total cost equals the sum of the material cost and the carbon pricing, and is set as the optimization’s objective function. Secondly, 25 various mixtures are used as a database of optimization. The database covered a wide range of strengths between 25 MPa and 55 MPa and a wide range of workability between 5 and 25 cm in slump. Gene expression programming is used to predict the concrete’s strength and slump. The ternary blended concrete’s carbonation depth is calculated using the efficiency factors of fly ash and slag. Thirdly, the genetic algorithm is used to find the optimal mixture under various constraints. We provide examples to illustrate the design of ternary blended concrete with different strength levels and environmental CO₂ concentrations. The results show that, for a suburban region, carbonation durability is the controlling factor in terms of the design of the mixture when the design strength is less than 40.49 MPa, and the compressive strength is the controlling factor in the design of the mixture when the design strength is greater than 40.49 MPa. For an urban region, the critical strength for distinguishing carbonation durability control and strength control is 45.93 MPa. The total cost, material cost, and carbon pricing increase as the concrete’s strength increases. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 4560 KiB

Open AccessArticle

Influence of Different Modifiers on Bonding Strength and Rheological Performance of Bitumen Emulsion

by Changluan Pan, Deqiang Liang, Liantong Mo, Martin Riara and Juntao Lin

Materials 2019, 12(15), 2414; https://doi.org/10.3390/ma12152414 - 29 Jul 2019

Cited by 15 | Viewed by 3203

Abstract

Styrene butadiene rubber latex (SBR), waterborne epoxy adhesive (WE) and colloidal silica sol (SiO₂) were used to prepare modified bitumen emulsion for cold mix asphalt. The modification effects of the individual modifiers and the combination of these modifiers were investigated by [...] Read more.

Styrene butadiene rubber latex (SBR), waterborne epoxy adhesive (WE) and colloidal silica sol (SiO₂) were used to prepare modified bitumen emulsion for cold mix asphalt. The modification effects of the individual modifiers and the combination of these modifiers were investigated by using bonding strength and dynamic shear rheological property. Test results showed that the modifier dosage helped to balance the performance of modified bitumen emulsion by improving its bonding strength without compromising its rheological properties. The critical dosage at which the peak bonding strength occurred was 4%, 12% and 4% for SBR, WE and SiO₂ respectively. Improved rheological performance on the master curves was well distinguished, in particular, by increased complex modulus and reduced phase angle at the low frequency region. Abrupt changes, especially on phase angle occurred when the modifier dosage was beyond 12%. The measured ratio between bonding strength and complex shear modulus could vary ranging from 10⁻² to 10². Highly-modified bitumen emulsion with good adhesion, rheology and compatibility can be prepared by using the combination of SBR, WE and SiO₂. It is important to carefully select the type and dosage of modifier for a particular combination to optimize the performance of modified bitumen emulsion. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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12 pages, 3554 KiB

Open AccessArticle

Improvement of the Concrete Permeability by Using Hydrophilic Blended Additive

by José Luis García Calvo, Mercedes Sánchez Moreno, Pedro Carballosa, Filipe Pedrosa and Fabiano Tavares

Materials 2019, 12(15), 2384; https://doi.org/10.3390/ma12152384 - 26 Jul 2019

Cited by 17 | Viewed by 3855

Abstract

Crystalline hydrophilic additives are increasingly used as efficient methods for reducing water permeability in concrete. Their effectiveness in hindering water penetration has been proven in different cementitious materials, although scarce information has been reported concerning their action mechanism. In the present work, the [...] Read more.

Crystalline hydrophilic additives are increasingly used as efficient methods for reducing water permeability in concrete. Their effectiveness in hindering water penetration has been proven in different cementitious materials, although scarce information has been reported concerning their action mechanism. In the present work, the efficacy of a hydrophilic blended crystalline mix (Krystaline Add1) as a water-reducing additive has been confirmed. Furthermore, an extended study about how the presence of the additive influences both the fresh state and the hardened state properties is presented. Finally, characterization techniques such as Mercury Intrusion Porosimetry (MIP), X-ray Powder Diffraction (XRD) and Back-Scattered Scanning Electron Microscopy (BSEM) with Energy Dispersive X-ray analysis (EDAX) have been used for deducing the mechanism of the additive. No significant deleterious influence on the concrete properties due to the addition of the additive has been detected. In fact, the additive seems to have provided a positive influence on the concrete given that a slight reduction in the w/c ratio for similar consistency has been detected, with the subsequent improvement of the compressive strength values. Its effectiveness as a water permeability reducing additive has shown encouraging results having reduced the water permeability by approximately 50% during testing. The action mechanism of the studied additive seems to be related to hydration reactions in the presence of water, producing new solid amorphous phases in the concrete bulk. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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22 pages, 6798 KiB

Open AccessArticle

Research on the Method of Predicting Corrosion width of Cables Based on the Spontaneous Magnetic Flux Leakage

by Yinghao Qu, Hong Zhang, Ruiqiang Zhao, Leng Liao and Yi Zhou

Materials 2019, 12(13), 2154; https://doi.org/10.3390/ma12132154 - 04 Jul 2019

Cited by 26 | Viewed by 2734

Abstract

The detection of cable corrosion is of great significance to the evaluation of cable safety performance. Based on the principle of spontaneous magnetic flux leakage (SMFL), a new method for predicting the corrosion width of cables is proposed. In this paper, in order [...] Read more.

The detection of cable corrosion is of great significance to the evaluation of cable safety performance. Based on the principle of spontaneous magnetic flux leakage (SMFL), a new method for predicting the corrosion width of cables is proposed. In this paper, in order to quantify the width of corrosion, the parameter about intersecting point distance between curves of magnetic flux component of x direction at different lift off heights (D_x) is proposed by establishing the theoretical model of the magnetic dipole of the rectangular corrosion defect. The MATLAB software was used to analyze the influencing factors of D_x. The results indicate that there exists an obvious linear relationship between the D_x and the y (lift off height), and the D_x–y curves converge to near the true corrosion width when y = 0. The 1/4 and 3/4 quantiles of the D_x–y image were used for linear fitting, which the intercept of the fitting equation was used to represent the predicted corrosion width. After the experimental study on the corrosion width detection for the parallel steel wire and steel strand, it is found that this method can effectively improve the detection accuracy, which plays an important role in cable safety assessment. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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16 pages, 5444 KiB

Open AccessArticle

Microstructural and Mechanical Properties of Alkali Activated Materials from Two Types of Blast Furnace Slags

by Jun Xing, Yingliang Zhao, Jingping Qiu and Xiaogang Sun

Materials 2019, 12(13), 2089; https://doi.org/10.3390/ma12132089 - 28 Jun 2019

Cited by 37 | Viewed by 3215

Abstract

This paper investigated the effect of blast furnace slags (BFS) characteristics on the properties achievement after being alkali activated. The physical and chemical characteristics of BFS were determined by X-ray fluorescence (XRF), X-ray Diffraction (XRD) and laser granulometry. Multi-technical characterizations using calorimetry, XRD, [...] Read more.

This paper investigated the effect of blast furnace slags (BFS) characteristics on the properties achievement after being alkali activated. The physical and chemical characteristics of BFS were determined by X-ray fluorescence (XRF), X-ray Diffraction (XRD) and laser granulometry. Multi-technical characterizations using calorimetry, XRD, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG-DTG), scanning electron microscope (SEM), nitrogen sorption and uniaxial compressive strength (UCS) were applied to give an in-depth understanding of the relationship between the reaction products, microstructure and BFS characteristics. The test results show that the microstructure and mechanical properties of alkali activated blast furnace slags (BFS) highly depend on the characteristics of BFS. Although the higher content of basic oxide could accelerate the hydration process and result in higher mechanical properties, a poor thermal stabilization was observed. On the other hand, with a higher content of Fe, the hydration process in alkali activated BFS2 lasts for a longer time, contributing to a delayed compressive strength achievement. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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10 pages, 3309 KiB

Open AccessArticle

Effect of the Content of Micro-Active Copper Tailing on the Strength and Pore Structure of Cementitious Materials

by Liming Zhang, Songbai Liu and Dongsheng Song

Materials 2019, 12(11), 1861; https://doi.org/10.3390/ma12111861 - 09 Jun 2019

Cited by 5 | Viewed by 2623

Abstract

This study investigates the effect of micr-oaggregate filling with copper tailing on the pore structure of cement paste containing copper tailing (CPCT). The particle size of the CPCT and the pore structure of CPCT were analyzed by laser particle size analysis and mercury [...] Read more.

This study investigates the effect of micr-oaggregate filling with copper tailing on the pore structure of cement paste containing copper tailing (CPCT). The particle size of the CPCT and the pore structure of CPCT were analyzed by laser particle size analysis and mercury instruction porosimetry (MIP). Results showed that at the early stage of curing time, with increasing copper tailing content, the compressive strength of cement mortar with copper tailing (CMCT) was lower, and the porosity and pore diameter of CPCT were higher and greater; with the extension of curing age, when the content of copper tailing was less than 30%, the compressive strength of CMCT and the porosity of CPCT changed slightly with the increase of the content of copper tailing. However, the maximum hole diameter of CPCT decreased gradually (a curing age between 7 d and 365 d under standard conditions). Scanning electron microscopy analysis showed that at the early stage of cement hydration in the CPCT, the copper tailing did not fill the pores in CPCT well, while in the later stage of cement hydration, the microaggregates of copper tailing filled the pores well and closely combined with the surrounding hydration products. In the later stage of cement hydration, the microaggregate filling of copper tailing was primarily responsible for the strength increase of the CMCT. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 5465 KiB

Open AccessArticle

Real-Time Flow Behavior of Hot Mix Asphalt (HMA) Compaction Based on Rheological Constitutive Theory

by Guoping Qian, Kaikai Hu, Xiangbing Gong, Ningyuan Li and Huanan Yu

Materials 2019, 12(10), 1711; https://doi.org/10.3390/ma12101711 - 27 May 2019

Cited by 5 | Viewed by 3130

Abstract

Compaction is the most critical stage during pavement construction, but the real-time rheological behavior in the compaction process of hot mix asphalt has not received enough attention. Rheological properties directly reflect the of mixture performance, the intrinsic directly reflects the influencing factors of [...] Read more.

Compaction is the most critical stage during pavement construction, but the real-time rheological behavior in the compaction process of hot mix asphalt has not received enough attention. Rheological properties directly reflect the of mixture performance, the intrinsic directly reflects the influencing factors of compaction, and the pavement compactness and service life. Therefore, it is important to interpret the rheological properties of the asphalt mixture during the compaction process. In this paper, the improved Nishihara model was used to study the viscoelastic-plastic properties of the hot mix asphalt in the compaction process. Firstly, the improved Nishihara model was briefly introduced. Subsequently, the stress and strain correlation curves are obtained by the MTS (Material Testing System) compaction test, and the strain-time curve is fitted to determine the model parameter values. Finally, the parameters are substituted into the constitutive equation to obtain the strain-time curve and compared it with the test curve. The results show that the improved Nishihara model effectively depicts the real time behavior of the asphalt mixture in the compaction progress. The viscos and plastic parameters present certain differences, which reflects that the gradation and temperature have certain influence on the compaction characteristics of the mixture. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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9 pages, 2450 KiB

Open AccessArticle

Facile Approach to Develop Hierarchical Roughness fiber@SiO₂ Blocks for Superhydrophobic Paper

by Qing Wang, Jieyi Xiong, Guangxue Chen, Ouyang Xinping, Zhaohui Yu, Qifeng Chen and Mingguang Yu

Materials 2019, 12(9), 1393; https://doi.org/10.3390/ma12091393 - 29 Apr 2019

Cited by 16 | Viewed by 4188

Abstract

Papers with nanoscaled surface roughness and hydrophobically modification have been widely used in daily life. However, the relatively complex preparation process, high costs and harmful compounds have largely limited their applications. This research aims to fabricate superhydrophobic papers with low cost and nontoxic [...] Read more.

Papers with nanoscaled surface roughness and hydrophobically modification have been widely used in daily life. However, the relatively complex preparation process, high costs and harmful compounds have largely limited their applications. This research aims to fabricate superhydrophobic papers with low cost and nontoxic materials. The surface of cellulose fibers was initially coated with a film of SiO₂ nanoparticles via sol-gel process. After papermaking and subsequent modification with hexadecyltrimethoxysilane through a simple solution-immersion process, the paper showed excellent superhydrophobic properties, with water contact angles (WCA) larger than 150°. Moreover, the prepared paper also showed superior mechanical durability against 10 times of deformation. The whole preparation process was carried out in a mild environment, with no intricate instruments or toxic chemicals, which has the potential of large-scale industrial production and application. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 8874 KiB

Open AccessArticle

Effect of Microbiological Growth Components for Bacteria-Based Self-Healing on the Properties of Cement Mortar

by Xin Chen, Jie Yuan and Mohamed Alazhari

Materials 2019, 12(8), 1303; https://doi.org/10.3390/ma12081303 - 20 Apr 2019

Cited by 31 | Viewed by 3916

Abstract

Previous studies of bacteria-based self-healing concrete have shown that it is necessary to encapsulate and separate the self-healing ingredients (bacteria, nutrients, and precursors) in the concrete so that when a crack forms, capsules rupture, which allows the self-healing ingredients to come together and [...] Read more.

Previous studies of bacteria-based self-healing concrete have shown that it is necessary to encapsulate and separate the self-healing ingredients (bacteria, nutrients, and precursors) in the concrete so that when a crack forms, capsules rupture, which allows the self-healing ingredients to come together and precipitate calcite into the crack. Because of the shearing action in the concrete mixer, there is a chance that these capsules, or other carriers, may rupture and release the self-healing ingredients. This would affect the efficiency of self-healing, but may detrimentally affect the concrete’s properties. This work investigated the effects of multi-component growth media, containing germination and sporulation aids for the bacterial aerobic oxidation pathway, on the basic properties of fresh and hardened concrete instead of the potential self-healing efficiency in a structural service. Tests were carried out to measure the effects of growth media on air content, fluidity, capillary absorption, strength development of cement mortar following corresponding standards, hydration kinetics, setting properties, and the microstructure of cement paste, according to certain specifications or using specific machines. The research has demonstrated that a multi-constituent growth media will not have a significant effect on the properties of concrete in the proportions likely to be released during mixing. This important conclusion will allow further development of these novel materials by removing one of the key technical barriers to increased adoption. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 4374 KiB

Open AccessArticle

Value-Added Application of Waste Rubber and Waste Plastic in Asphalt Binder as a Multifunctional Additive

by Tianqing Ling, Ya Lu, Zeyu Zhang, Chuanqiang Li and Markus Oeser

Materials 2019, 12(8), 1280; https://doi.org/10.3390/ma12081280 - 18 Apr 2019

Cited by 22 | Viewed by 3887

Abstract

The feasibility and effectivity of recycling waste rubber and waste plastic (WRP) into asphalt binder as a waste treatment approach has been documented. However, directly blending WRP with asphalt binder brings secondary environmental pollution. Recent research has shown that the addition of WRP [...] Read more.

The feasibility and effectivity of recycling waste rubber and waste plastic (WRP) into asphalt binder as a waste treatment approach has been documented. However, directly blending WRP with asphalt binder brings secondary environmental pollution. Recent research has shown that the addition of WRP into asphalt binder may potentially improve the workability of asphalt binder without significantly compromising its mechanical properties. This study evaluates the feasibility of using the additives derived from WRP as a multifunctional additive which improves both the workability and mechanical properties of asphalt binder. For this purpose, WRP-derived additives were prepared in laboratory. Then, three empirical characteristics—viscosity, rutting factor, fatigue life were analyzed. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were employed to evaluate the effect of WRP-derived additive on the workability and chemical and mechanical properties of base binder. The dispersity of WRP-derived additive inside asphalt binder was also characterized using fluorescence microscope (FM). Results from this study showed that adding WRP-derived additive increases the workability of base binder. The WRP-derived additive appears positive on the high- and low- temperature performance as well as the fatigue life of base binder. The distribution of the WRP-derived additive inside base binder was uniform. In addition, the modification mechanism of WRP-derived additive was also proposed in this paper. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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18 pages, 5348 KiB

Open AccessArticle

Effect of Solid Waste-Petroleum Coke Residue on the Hydration Reaction and Property of Concrete

by Liang Wang, Hongzhu Quan and Qiuyi Li

Materials 2019, 12(8), 1216; https://doi.org/10.3390/ma12081216 - 13 Apr 2019

Cited by 7 | Viewed by 3376

Abstract

Taking advantage of the desulfurization petroleum coke residue obtained from circulating fluidized bed boiler technology to replace a part of cement clinker and prepare the concrete can not only reduce the production of cement clinker and related CO₂ emissions, but can also [...] Read more.

Taking advantage of the desulfurization petroleum coke residue obtained from circulating fluidized bed boiler technology to replace a part of cement clinker and prepare the concrete can not only reduce the production of cement clinker and related CO₂ emissions, but can also improve the utilization rate and utilization level of petroleum coke waste, which has good environmental and economic benefits. In this study, through the comprehensive analysis of a compressive strength test, X-ray diffraction test, and Cl⁻ penetration resistance test, the hydration mechanism of desulfurized petroleum coke residue in concrete is revealed, and the optimum replacement ratios of single-added petroleum coke residue, multi-added petroleum coke residue, and mineral admixtures in concrete are evaluated and proposed. The results showed that mixing the 10% petroleum coke residue and 40% blast furnace slag would be most appropriate to replace the cement in concrete, thus the effective utilization of mineral admixtures and coke residue in concrete without strength loss could be realized. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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12 pages, 1762 KiB

Open AccessArticle

Performance Evaluation of Asphalt Rubber Mixture with Additives

by Xianpeng Cheng, Yamin Liu, Wanyan Ren and Ke Huang

Materials 2019, 12(8), 1200; https://doi.org/10.3390/ma12081200 - 12 Apr 2019

Cited by 11 | Viewed by 3130

Abstract

Crumb rubber, as a recycled material used in asphalt mixture, has gained more attention in recent years due to environmental benefits and the advantages of its pavement, such as excellent resistance to cracking, improved durability, less road maintenance, lower road noise, etc. However, [...] Read more.

Crumb rubber, as a recycled material used in asphalt mixture, has gained more attention in recent years due to environmental benefits and the advantages of its pavement, such as excellent resistance to cracking, improved durability, less road maintenance, lower road noise, etc. However, the high-temperature performance of mixture with crumb rubber does not perform well. In order to improve the performance, this paper examined the effect of additives on the laboratory performance of asphalt rubber Stone Matrix Asphalt (AR-SMA) with additives. Three groups of AR-SMA: no additives, Styrene–Butadiene–Styrene (SBS) and Granular Polymer Durable additive (GPDa) were included, with no additives as a control group. Each group was investigated at three asphalt rubber content (ARC): 6.4%, 6.9%, 7.4% with regard to high-temperature and fatigue properties. The results show that with increasing ARC, the high-temperature performance of mixture without additive decreases, and the high-temperature performance increases first and then decreases for SBS and GPDa. Moreover, the rutting resistance of AR-SMA with GPDa at 6.9% ARC performs best. Under the condition of mixtures with appropriate ARC, AR-SMA with GPDa has higher fatigue life and sensitivity to fatigue cracking than the control group. Simultaneously, the fatigue performance of AR-SMA with GPDa is not as significant as that without additive with increasing ARC. In a word, GPDa is a good choice to improve the performance of AR-SMA. However, it should be noted that optimal asphalt content of AR-SMA mixtures with GPDa is higher than that of traditional mixtures. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 9845 KiB

Open AccessArticle

Hemp-Straw Composites: Gluing Study and Multi-Physical Characterizations

by Marie Viel, Florence Collet, Sylvie Prétot and Christophe Lanos

Materials 2019, 12(8), 1199; https://doi.org/10.3390/ma12081199 - 12 Apr 2019

Cited by 14 | Viewed by 3312

Abstract

In order to meet the requirement of sustainable development, building materials are increasingly environmentally friendly. They can be partially or fully bio-based or recycled. This paper looks at the development of fully bio-based composites where agro-resources are valued as bio-based aggregates (hemp) and [...] Read more.

In order to meet the requirement of sustainable development, building materials are increasingly environmentally friendly. They can be partially or fully bio-based or recycled. This paper looks at the development of fully bio-based composites where agro-resources are valued as bio-based aggregates (hemp) and as binding materials (wheat). In a previous work, a feasibility study simultaneously investigated the processing and ratio of wheat straw required to ensure a gluing effect. In this paper, three kinds of hemp-straw composites are selected and compared with a hemp-polysaccharides composite. The gluing effect is analyzed chemically and via SEM. The developed composites were characterized multi-physically. They showed sufficiently high mechanical properties to be used as insulating materials. Furthermore, they showed good thermal performances with a low thermal conductivity (67.9–69.0 mW/(m

\cdot

K) at 23

^{°}

C, dry). Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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18 pages, 3347 KiB

Open AccessArticle

Research on Internal Force Detection Method of Steel Bar in Elastic and Yielding Stage Based on Metal Magnetic Memory

by Caoyuan Pang, Jianting Zhou, Ruiqiang Zhao, Hu Ma and Yi Zhou

Materials 2019, 12(7), 1167; https://doi.org/10.3390/ma12071167 - 10 Apr 2019

Cited by 19 | Viewed by 3069

Abstract

Based on the metal magnetic memory effect, this paper proposed a new non-destructive testing method for the internal tensile force detection of steel bars by analyzing the self-magnetic flux leakage (SMFL) signals. The variation of the SMFL signal of the steel bar with [...] Read more.

Based on the metal magnetic memory effect, this paper proposed a new non-destructive testing method for the internal tensile force detection of steel bars by analyzing the self-magnetic flux leakage (SMFL) signals. The variation of the SMFL signal of the steel bar with the tensile force indicates that the curve of the SMFL signal has a significant extreme point when the tensile force reaches about 65% of the yield tension, of which the first derivative curve has extreme points in the elastic and yielding stages, respectively. To study the variation of SMFL signal with the axial position of the steel bar under different tensile forces, a parameter reflecting the fluctuation of the SMFL signal along the steel bar is proposed. The linear relationship between this parameter and the tensile force can be used to quantitatively calculate the tensile force of steel bar. The method in this paper provides significant application prospects for the internal force detection of steel bar in the actual engineering. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 5182 KiB

Open AccessArticle

Preparation and Short-Term Aging Properties of Asphalt Modified by Novel Sustained-Release Microcapsules Containing Rejuvenator

by Xin Yan, Guotao Ning, Xiaofeng Wang, Tao Ai, Peng Zhao and Zhenjun Wang

Materials 2019, 12(7), 1122; https://doi.org/10.3390/ma12071122 - 04 Apr 2019

Cited by 10 | Viewed by 3366

Abstract

Aged asphalt can enormously affect the performance of asphalt pavement and cause serious environmental hazards. Microcapsule-modified asphalt is one of the effective means to improve the anti-aging ability of asphalt. In this work, novel sustained-release microcapsules containing rejuvenator were prepared by the solvent [...] Read more.

Aged asphalt can enormously affect the performance of asphalt pavement and cause serious environmental hazards. Microcapsule-modified asphalt is one of the effective means to improve the anti-aging ability of asphalt. In this work, novel sustained-release microcapsules containing rejuvenator were prepared by the solvent evaporation method. The morphology of the microcapsules was characterized by scanning electron microscopy (SEM). The sustained-release properties of the microcapsules were investigated by static thermogravimetric analysis. The physical properties such as penetration, ductility, softening point, and Brookfield viscosity of the original asphalt and microcapsule-modified asphalt were studied. In addition, the viscoelasticity of the original asphalt and microcapsule-modified asphalt was investigated by means of a dynamic shear rheometer (DSR). The results show that the prepared microcapsules have a smooth surface and a complete encapsulation with an average particle size of 60 μm. After the heating treatment (above 140 °C), a large number of micropores were formed on the shell surface of microcapsules, which provided a structural basis for the sustained-release of rejuvenator. The release rate of the rejuvenator was obviously slowed down by the microcapsules. The aging behavior of sustained-release microcapsules containing rejuvenator-modified asphalt can be greatly improved. The enhanced anti-aging properties of sustained-release microcapsule-modified asphalt are attributed to the functions of the rejuvenator which can be slowly released from the micropores on the microcapsules’ surface, after which the light components lost in the original asphalt can be supplemented. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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18 pages, 6097 KiB

Open AccessArticle

The Effect of Elevated Curing Temperatures on High Ye’elimite Calcium Sulfoaluminate Cement Mortars

by Yeonung Jeong, Craig W. Hargis, Hyunuk Kang, Sung-Chul Chun and Juhyuk Moon

Materials 2019, 12(7), 1072; https://doi.org/10.3390/ma12071072 - 01 Apr 2019

Cited by 36 | Viewed by 3912

Abstract

This study investigated the material properties and hydration characteristics of calcium sulfoaluminate cement (CSA) based mortars cured under 3 different initial curing temperatures. Two CSA cements with different M-values were selected. Obtained experimental results of mechanical properties, dimensional stability, and heat release were [...] Read more.

This study investigated the material properties and hydration characteristics of calcium sulfoaluminate cement (CSA) based mortars cured under 3 different initial curing temperatures. Two CSA cements with different M-values were selected. Obtained experimental results of mechanical properties, dimensional stability, and heat release were explained by hydration characteristics from X-ray diffraction, thermal gravimetric analysis, porosimetry, and thermodynamic modeling. Decomposition of ettringite decreased compressive strength but re-formation of ettringite after additional curing at 30 °C helped to recover the strength in CSA cement with a high amount of calcium sulfate. CSA cement with a low amount of calcium sulfate which was designed to predominantly have monosulfate as the main hydration product, showed increased 1-day strength after higher temperature curing but this occurred was at the expense of decreased 28-day strength. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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14 pages, 3971 KiB

Open AccessArticle

Improvement of Compressibility and Thaw-Settlement Properties of Warm and Ice-Rich Frozen Soil with Cement and Additives

by Mingtang Chai and Jianming Zhang

Materials 2019, 12(7), 1068; https://doi.org/10.3390/ma12071068 - 01 Apr 2019

Cited by 14 | Viewed by 3201

Abstract

The warm and ice-rich frozen soil (WIRFS) that underlies roadway embankments in permafrost regions exhibit large compression and thaw deformation, which can trigger a series of distresses. Cement and additives were used in this study to improve the compressibility and thaw-settlement properties of [...] Read more.

The warm and ice-rich frozen soil (WIRFS) that underlies roadway embankments in permafrost regions exhibit large compression and thaw deformation, which can trigger a series of distresses. Cement and additives were used in this study to improve the compressibility and thaw-settlement properties of WIRFS. We, therefore, selected optimum additives and studied the improvement effect on the frozen soil with 30% water content based on our previous research. Given constant load and variable temperatures, compression coefficients, thaw strains, and water content changes were obtained at temperatures of −1.0 °C, −0.5 °C, and 2.0 °C to evaluate the effect of improvements. A scanning electron microscope (SEM) was then used to observe the microstructure of improved soils and analyze causal mechanisms. Data show that hydration reactions, physical absorptions, cement, and additives formed new structures and changed the phase of water in frozen soil after curing at −1.0 °C for 28 days. This new structure, cemented with soil particles, unfrozen water, and ice, filled in the voids of frozen soil and effectively decreased the WIRFS compression coefficient and thaw strain. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 4309 KiB

Open AccessArticle

Experimental Studies on the Effect of Properties and Micro-Structure on the Creep of Concrete-Filled Steel Tubes

by Rongling Zhang, Lina Ma, Qicai Wang, Jia Li, Yu Wang, Huisu Chen and Valeriia Samosvat

Materials 2019, 12(7), 1046; https://doi.org/10.3390/ma12071046 - 29 Mar 2019

Cited by 9 | Viewed by 3044

Abstract

To study different lateral restraints, different constituents of expansion agents, the influence of different steel ratios, and concrete creep properties, we carried out experiments with lateral restraint and without lateral restraint conditions separately on 12 specimens with the expansion agent content accounting for [...] Read more.

To study different lateral restraints, different constituents of expansion agents, the influence of different steel ratios, and concrete creep properties, we carried out experiments with lateral restraint and without lateral restraint conditions separately on 12 specimens with the expansion agent content accounting for 4%, 8%, and 12% respectively. In addition, the creep tests were performed on specimens with different steel ratios of 0.0%, 3.8%, 6.6%, and 9.2%. The test results show that the lateral restraint improves the strength of the system (concrete-filled steel tubes) which resists further load after the concrete ultimate strength is surpassed and reduces the creep. The creep degree of the concrete-filled steel tube with lateral restraint is about 0.09–0.30 times smaller than that of the tube without lateral restraints. The creep degree of the concrete-filled steel tube increases as the steel ratio decreases. Creep tests with different amounts of expansion agent indicate that the creep degree of the concrete structure increases as expansion agent content decreases. To study the internal mechanism of the creep of concrete-filled steel tubes with different lateral restraints and different expansion agent concentrations, a microscopic pore structure test on the steel core concrete was conducted using the RapidAir457 pore structure instrument. Microscopic studies show that the air content and the length of the bubble chord of the laterally restrained core concrete are lower than those without lateral restraint core concrete. The amount of air content and the length of the bubble chord of core concrete specimens increase as the expansion agent content in the core concrete specimens decreases from 12% to 4%. Under the same external loading conditions, as steel ratio increases, the lateral restraint causes a further reduction of creep. The results of this study suggest that the creep of concrete can be reduced by selecting appropriate lateral restraint conditions and an optimal amount of expansion agent in the mix design of concrete for concrete-filled steel tubes. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 8124 KiB

Open AccessArticle

Additive Manufacturing of Geopolymers Modified with Microalgal Biomass Biofiller from Wastewater Treatment Plants

by Emanuele Agnoli, Riccardo Ciapponi, Marinella Levi and Stefano Turri

Materials 2019, 12(7), 1004; https://doi.org/10.3390/ma12071004 - 27 Mar 2019

Cited by 12 | Viewed by 4326

Abstract

This paper deals with the additive manufacturing of metakaolin-based geopolymers and with the use of microalgal biomass from wastewater treatment plants as biofiller in this kind of cementitious material. The study was developed following the evolution stages of the material, which was prepared [...] Read more.

This paper deals with the additive manufacturing of metakaolin-based geopolymers and with the use of microalgal biomass from wastewater treatment plants as biofiller in this kind of cementitious material. The study was developed following the evolution stages of the material, which was prepared and printed as a soft paste and then hardened thanks to an inorganic polymerization reaction (geopolymerization). Thus, the characterization techniques adopted encompassed rheometry, mechanical tests performed on the hardened material, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury intrusion porosimetry (MIP). Microalgal biomass addition, evaluated in this study at 1, 3 and 5 php with respect to the powder weight, affected both the properties of the fresh and of the hardened material. Regarding the former aspect, biomass reduced the yield stress of the pastes, improving the ease of the extrusion process, but potentially worsening the ability to build structures in height. When hardened, geopolymers containing microalgae showed mechanical properties comparable to the unfilled material and a microstructure characterized by smaller pores. Finally, a printing test was successfully performed with a larger printer to assess the feasibility of producing large-scale structures. Taking into account these results, this study demonstrates the possibility of using microalgal biomass as biofiller in geopolymers for additive manufacturing. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 2800 KiB

Open AccessArticle

Ternary Blended Binder for Production of a Novel Type of Lightweight Repair Mortar

by Milena Pavlíková, Lucie Zemanová, Martina Záleská, Jaroslav Pokorný, Michal Lojka, Ondřej Jankovský and Zbyšek Pavlík

Materials 2019, 12(6), 996; https://doi.org/10.3390/ma12060996 - 26 Mar 2019

Cited by 38 | Viewed by 4061

Abstract

The goal of the paper was development and testing of a novel type of ternary blended binder based on lime hydrate, metakaolin, and biomass ash that was studied as a binding material for production of lightweight mortar for renovation purposes. The biomass ash [...] Read more.

The goal of the paper was development and testing of a novel type of ternary blended binder based on lime hydrate, metakaolin, and biomass ash that was studied as a binding material for production of lightweight mortar for renovation purposes. The biomass ash used as one of binder components was coming from wood chips ash combustion in a biomass heating plant. The raw ash was mechanically activated by grinding. In mortar composition, wood chips ash and metakaolin were used as partial substitutes of lime hydrate. Silica sand of particle size fraction 0–2 mm was mixed from three normalized sand fractions. For the evaluation of the effect of biomass ash and metakaolin incorporation in mortar mix on material properties, reference lime mortar was tested as well. Among the basic physical characterization of biomass ash, metakaolin and lime hydrate, specific density, specific surface, and particle size distribution were assessed. Their chemical composition was measured by X-Ray fluorescence analysis (XRF), morphology was examined using scanning electron microscopy (SEM), elements mapping was performed using energy dispersive spectroscopy (EDS) analyser, and mineralogical composition was tested using X-Ray diffraction (XRD). For the developed mortars, set of structural, mechanical, hygric, and thermal properties was assessed. The mortars with ternary blended binder exhibited improved mechanical resistance, lower thermal conductivity, and increased water vapor permeability compared to the reference lime mortar. Based on good functional performance of the produced mortar, the tested biomass ash could potentially represent a novel sustainable alternative to other pozzolans commonly used in construction industry. Moreover, reuse of biomass ash in production of building materials is highly beneficial both from the environmental and economic reasons especially taking into account circular economy principles. The ternary blended binder examined in this paper can find use in both rendering and walling repair mortars meeting the requirements of culture heritage authorities and technical standards. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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11 pages, 2870 KiB

Open AccessArticle

Aging Mechanism of a Diatomite-Modified Asphalt Binder Using Fourier-Transform Infrared (FTIR) Spectroscopy Analysis

by Peng Zhang, Qinglin Guo, Jinglin Tao, Dehua Ma and Yedan Wang

Materials 2019, 12(6), 988; https://doi.org/10.3390/ma12060988 - 26 Mar 2019

Cited by 28 | Viewed by 4262

Abstract

In this paper, Fourier-transform infrared (FTIR) spectroscopy was used to evaluate the effects of diatomite on aging properties of an asphalt binder. The modified asphalts included 5%, 10%, and 15% diatomite, and were prepared in the laboratory. The changes in functional groups of [...] Read more.

In this paper, Fourier-transform infrared (FTIR) spectroscopy was used to evaluate the effects of diatomite on aging properties of an asphalt binder. The modified asphalts included 5%, 10%, and 15% diatomite, and were prepared in the laboratory. The changes in functional groups of asphalt were employed to investigate the aging mechanisms of the modified and control asphalts. Effects of diatomite on the anti-aging properties of asphalt were analyzed via the changes in intensity of the absorption peaks. Results showed that there were no new functional groups generated after diatomite mixing with asphalt. This indicated that the process of diatomite modification was just physical mixing. Furthermore, parts of saturates and aromatics were volatilized in the aging process of modified asphalt. Polar molecules reacted with oxygen in aging. Meanwhile, carbonyl (C=O) and sulfoxide (S=O) were also generated. The aging resistance of modified asphalt was the best when the diatomite content was 10%. The work of this paper may provide a new perspective to evaluate asphalt aging. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 4556 KiB

Open AccessArticle

Preparation and Physical Properties of High-Belite Sulphoaluminate Cement-Based Foam Concrete Using an Orthogonal Test

by Chao Liu, Jianlin Luo, Qiuyi Li, Song Gao, Zuquan Jin, Shaochun Li, Peng Zhang and Shuaichao Chen

Materials 2019, 12(6), 984; https://doi.org/10.3390/ma12060984 - 25 Mar 2019

Cited by 14 | Viewed by 3595

Abstract

Prefabricated building development increasingly requires foam concrete (FC) insulation panels with low dry density (ρ_d), low thermal conductivity coefficient (k_c), and a certain compressive strength (f_cu). Here, the foam properties of a composite foaming [...] Read more.

Prefabricated building development increasingly requires foam concrete (FC) insulation panels with low dry density (ρ_d), low thermal conductivity coefficient (k_c), and a certain compressive strength (f_cu). Here, the foam properties of a composite foaming agent with different dilution ratios were studied first, high-belite sulphoaluminate cement (HBSC)-based FCs (HBFCs) with 16 groups of orthogonal mix proportions were subsequently fabricated by a pre-foaming method, and physical properties (ρ_d, f_cu, and k_c) of the cured HBFC were characterized in tandem with microstructures. The optimum mix ratios for ρ_d, f_cu, and k_c properties were obtained by the range analysis and variance analysis, and the final optimization verification and economic cost of HBFC was also carried out. Orthogonal results show that foam produced by the foaming agent at a dilution ratio of 1:30 can meet the requirements of foam properties for HBFC, with the 1 h bleeding volume, 1 h settling distance, foamability, and foam density being 65.1 ± 3.5 mL, 8.0 ± 0.4 mm, 27.9 ± 0.9 times, and 45.0 ± 1.4 kg/m³, respectively. The increase of fly ash (FA) and foam dosage can effectively reduce the k_c of the cured HBFC, but also leads to the decrease of f_cu due to the increase in mean pore size and the connected pore amount, and the decline of pore uniformity and pore wall strength. When the dosage of FA, water, foam, and the naphthalene-based superplasticizer of the binder is 20 wt%, 0.50, 16.5 wt%, and 0.6 wt%, the cured HBFC with ρ_d of 293.5 ± 4.9 kg/m³, f_cu of 0.58 ± 0.02 MPa and k_c of 0.09234 ± 0.00142 W/m·k is achieved. In addition, the cost of HBFC is only 39.5 $/m³, which is 5.2 $ lower than that of ordinary Portland cement (OPC)-based FC. If the surface of the optimized HBFC is further treated with water repellent, it will completely meet the requirements for a prefabricated ultra-light insulation panel. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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13 pages, 5233 KiB

Open AccessArticle

Regulating the Expansion Characteristics of Cementitious Materials Using Blended MgO-Type Expansive Agent

by Peng Liu, Zhiyang Chen and Min Deng

Materials 2019, 12(6), 976; https://doi.org/10.3390/ma12060976 - 25 Mar 2019

Cited by 13 | Viewed by 2800

Abstract

To promote the application of MgO-type expansive agents (MEAs), the expansion stresses produced by compacted MEAs with different activities cured in water at 40 °C were measured using a self-designed expansion stress test apparatus. Based on these, different MEAs were divided into the [...] Read more.

To promote the application of MgO-type expansive agents (MEAs), the expansion stresses produced by compacted MEAs with different activities cured in water at 40 °C were measured using a self-designed expansion stress test apparatus. Based on these, different MEAs were divided into the early-type MgO expansive agent and the late-type MgO expansive agent classifications according to the stress curves of compacted MEAs. The two types of MEAs were blended with each other at different ratios and added into cement pastes. Results indicated that the expansion of the cement pastes added with blended MEAs lasted from the beginning to 200 days later, and the expansion characteristics can be regulated by adjusting the blending ratio of MEAs and the choice of types of MEAs. The results suggest that the expansion of MEAs can be improved by using blended MEAs in practical applications. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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16 pages, 1296 KiB

Open AccessArticle

Microstructural Characterization of Porous Clay-Based Ceramic Composites

by Lorena Freitas Dutra, Monica E. Freitas, Anne-Cécile Grillet, Nathan Mendes and Monika Woloszyn

Materials 2019, 12(6), 946; https://doi.org/10.3390/ma12060946 - 21 Mar 2019

Cited by 10 | Viewed by 3279

Abstract

Clay-based materials are the most traditional components of buildings. To improve their performance in a sustainable way, agents can be mixed to fired clay acting as a pore-forming factor. However, firing temperatures highly influence their microstructure which is closely linked to a material’s [...] Read more.

Clay-based materials are the most traditional components of buildings. To improve their performance in a sustainable way, agents can be mixed to fired clay acting as a pore-forming factor. However, firing temperatures highly influence their microstructure which is closely linked to a material’s final performance as a ceramic block. To highlight the influence of the firing temperature on microstructure, and more specifically on the pore size distribution of clay-based materials, three innovative porous materials were manufactured. These materials were produced by mixing clay and pore-forming agents. They were characterized by optical and scanning electronic microscopy, x-ray diffraction, mercury intrusion and nitrogen adsorption. These techniques allow the phase identification of materials, show sample microstructure and quantify the pore size distribution at different scales. Furthermore, geometric parameters of sample microstructure such as grain diameter and roundness are estimated by using computer software. To conclude, results provide an enlightenment about the influence of material microstructure on the pore size distribution at two firing temperatures. These results can be useful to allow the tune of porous characteristics and, therefore, contribute to the production of more sustainable construction materials. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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24 pages, 6926 KiB

Open AccessArticle

Reactivity and Hydration Property of Synthetic Air Quenched Slag with Different Chemical Compositions

by Hui Wang, Yali Wang, Suping Cui and Jianfeng Wang

Materials 2019, 12(6), 932; https://doi.org/10.3390/ma12060932 - 20 Mar 2019

Cited by 11 | Viewed by 3865

Abstract

Air quenched slag is processed by a fast air cooling method which is developed with the advantages of recovering heat from molten slag and water conservation compared to the water quenching method. Air quenched slags with different chemical compositions are synthesized in the [...] Read more.

Air quenched slag is processed by a fast air cooling method which is developed with the advantages of recovering heat from molten slag and water conservation compared to the water quenching method. Air quenched slags with different chemical compositions are synthesized in the lab by designing three chemical composition ratios: (CaO + MgO)/(SiO₂ + Al₂O₃), CaO/MgO and SiO₂/Al₂O₃, which are donated as CM/SA, C/M and S/A, respectively. The effect of different chemical compositions on the phase compositions of synthetic air quenched slag, the strength and hydration properties of slag blends were investigated by using various characterization techniques. The results show that the amorphous content of air quenched slag decreased with the increasing basicity CM/SA of slag. The S/A ratio of slag was the dominant factor for the compressive strength of slag blends at 28 days and negatively correlated with strength. Decreasing the S/A ratio of slag increased the reactivity of slag and its reaction degree indicated by higher hydration heat release, lower CH content, greater chemical combined water amount and denser microstructure. Moreover, thermodynamic modelling revealed that a higher S/A of slag leads to the increase of C-(A)-S-H and AFt contents, whilst decreasing the amounts of Ht, AFm-SO₄ phases and the total volume of hydrates. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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12 pages, 2145 KiB

Open AccessArticle

Evaluation and Selection of De-Icing Salt Based on Multi-Factor

by Guoju Ke, Jun Zhang and Bo Tian

Materials 2019, 12(6), 912; https://doi.org/10.3390/ma12060912 - 19 Mar 2019

Cited by 14 | Viewed by 3298

Abstract

De-icing salts can greatly ease traffic congestion but introduce corrosion of concrete and damage to plant growth. The decision of which de-icing salt to use becomes a crucial issue. In this study, several representative de-icing salts were investigated, and the effects of de-icing [...] Read more.

De-icing salts can greatly ease traffic congestion but introduce corrosion of concrete and damage to plant growth. The decision of which de-icing salt to use becomes a crucial issue. In this study, several representative de-icing salts were investigated, and the effects of de-icing ability, salt freezing corrosion on concrete, and plant growth were comprehensively tested. Finally, the decision of de-icing salt was made based on analytic hierarchy process (AHP). Results show that de-icing salts achieving the best de-icing effect are not the same at different concentrations. De-icing salts of 3% concentration have the greatest corrosion to concrete. Notably, magnesium chloride and calcium magnesium acetate have the least impact on plants among all studied de-icing salts. Using AHP, ethylene glycol and calcium magnesium acetate are selected as optimal items under different priorities. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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9 pages, 4360 KiB

Open AccessArticle

Construction Materials from Vitrified Lignite Fly Ash in Plasmatron Plasma Reactor

by Jakub Szałatkiewicz

Materials 2019, 12(6), 905; https://doi.org/10.3390/ma12060905 - 19 Mar 2019

Cited by 5 | Viewed by 2969

Abstract

This article presents results of an investigation of vitrified (melted) fly ash samples from lignite (brown coal) in a plasmatron plasma reactor, to determine its mechanical and chemical properties. The XRF elemental analysis results of sample tests, from before the vitrification process and [...] Read more.

This article presents results of an investigation of vitrified (melted) fly ash samples from lignite (brown coal) in a plasmatron plasma reactor, to determine its mechanical and chemical properties. The XRF elemental analysis results of sample tests, from before the vitrification process and after the vitrification process are shown. The experiments were carried out in a plasma plasmatron reactor with a total power of 65 kW, enabling testing on a quarter technical scale. During the tests, samples of fly ash of about 4 kg mass were processed under selected process conditions. Produced samples of vitrified materials were analyzed in accordance to the requirements for building/construction materials. Results from this investigation confirm its quality to be used as concrete and cement filler, as an addition, and as synthetic aggregate, safe for the environment and neutral for cements. Also the most important leaching of heavy metals to water was analyzed which confirmed meeting of all of requirements necessary to use this material in building materials. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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15 pages, 3610 KiB

Open AccessArticle

Mechanical Performance of Warm-Mixed Porous Asphalt Mixture with Steel Slag and Crumb-Rubber–SBS Modified Bitumen for Seasonal Frozen Regions

by Yongchun Cheng, Chao Chai, Chunyu Liang and Yu Chen

Materials 2019, 12(6), 857; https://doi.org/10.3390/ma12060857 - 14 Mar 2019

Cited by 23 | Viewed by 3799

Abstract

In this paper, the performance of a warm-mixed porous asphalt mixture (PAM) with steel slag as aggregate and crumb-rubber–SBS (styrene-butadiene-styrene) modified bitumen as a binder was studied. Two kinds of warming additives were used, namely ethylene bis stearic acid amide (EBS) and stearic [...] Read more.

In this paper, the performance of a warm-mixed porous asphalt mixture (PAM) with steel slag as aggregate and crumb-rubber–SBS (styrene-butadiene-styrene) modified bitumen as a binder was studied. Two kinds of warming additives were used, namely ethylene bis stearic acid amide (EBS) and stearic acid amide (SA). The mixtures were investigated for their permeability, Marshall stability, low-temperature crack resistance, and underwent a rutting test, water sensitivity evaluation and Cantabro particle loss test. Then, the viscoelastic and dynamic characteristics of the mixtures were also analyzed. The results showed that the addition of the warming additives allowed the decrease of the manufacturing temperature by 10 °C. Thus, the addition of warming additives significantly improves the low-temperature crack resistance and slightly reduces the water sensitivity, weakly increases the permeability, and has little effect on the resilient modulus. Since the addition of SA significantly improves the low-temperature crack resistance and rutting resistance of the PAM, SA is therefore recommended for pavement engineering in seasonal frozen regions. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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31 pages, 2832 KiB

Open AccessArticle

Environmental Assessment of Ultra-High-Performance Concrete Using Carbon, Material, and Water Footprint

by Husam Sameer, Viktoria Weber, Clemens Mostert, Stefan Bringezu, Ekkehard Fehling and Alexander Wetzel

Materials 2019, 12(6), 851; https://doi.org/10.3390/ma12060851 - 13 Mar 2019

Cited by 43 | Viewed by 8140

Abstract

There is a common understanding that the environmental impacts of construction materials should be significantly reduced. This article provides a comprehensive environmental assessment within Life Cycle Assessment (LCA) boundaries for Ultra-High-Performance Concrete (UHPC) in comparison with Conventional Concrete (CC), in terms of carbon, [...] Read more.

There is a common understanding that the environmental impacts of construction materials should be significantly reduced. This article provides a comprehensive environmental assessment within Life Cycle Assessment (LCA) boundaries for Ultra-High-Performance Concrete (UHPC) in comparison with Conventional Concrete (CC), in terms of carbon, material, and water footprint. Environmental impacts are determined for the cradle-to-grave life cycle of the UHPC, considering precast and ready-mix concrete. The LCA shows that UHPC has higher environmental impacts per m³. When the functionality of UHPC is considered, at case study level, two design options of a bridge are tested, which use either totally CC (CC design) or CC enhanced with UHPC (UHPC design). The results show that the UHPC design could provide a reduction of 14%, 27%, and 43% of carbon, material, and water footprint, respectively. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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11 pages, 1250 KiB

Open AccessArticle

Effective Medium Method for Chloride Diffusion Coefficient of Mature Fly Ash Cement Paste

by Hong Zhou, Xin-Zhu Zhou, Jian Zhang and Jian-Jun Zheng

Materials 2019, 12(5), 811; https://doi.org/10.3390/ma12050811 - 08 Mar 2019

Cited by 8 | Viewed by 3211

Abstract

The chloride diffusion coefficient of concrete plays an essential role in the durability assessment and design of concrete structures built in chloride-laden environments. The purpose of this paper is to present an effective medium method (EMM) for evaluating the chloride diffusion coefficient of [...] Read more.

The chloride diffusion coefficient of concrete plays an essential role in the durability assessment and design of concrete structures built in chloride-laden environments. The purpose of this paper is to present an effective medium method (EMM) for evaluating the chloride diffusion coefficient of mature fly ash cement paste. In this method, a numerical method is used to estimate the degrees of hydration of cement and fly ash. Fly ash cement paste is then modeled as a two-phase composite material, composed of a solid phase and a pore space. By introducing the percolation theory, the EMM is modified to derive the chloride diffusion coefficient of fly ash cement paste in an analytical manner. To verify the EMM, a chloride diffusion test of fly ash cement paste at a curing age of up to 540 days is conducted. It is shown that, within a reasonable fly ash content, a larger fly ash content and/or curing age results in a smaller chloride diffusion coefficient. The chloride diffusion coefficient decreases with a decreasing water/binder ratio. Finally, the validity of the EMM is verified with experimental results. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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Review

Jump to: Research

20 pages, 3628 KiB

Open AccessReview

A Bibliometric Analysis of Research Trends in Geopolymer

by Jabulani Matsimbe, Megersa Dinka, David Olukanni and Innocent Musonda

Materials 2022, 15(19), 6979; https://doi.org/10.3390/ma15196979 - 08 Oct 2022

Cited by 12 | Viewed by 2608

Abstract

Geopolymer is an inorganic material formed through the chemical reaction of an aluminosilicate precursor and an alkaline or acidic activating solution. It is seen as a green new alternative binder to ordinary Portland cement (OPC) for sustainable infrastructure development. The strength of the [...] Read more.

Geopolymer is an inorganic material formed through the chemical reaction of an aluminosilicate precursor and an alkaline or acidic activating solution. It is seen as a green new alternative binder to ordinary Portland cement (OPC) for sustainable infrastructure development. The strength of the unary or blended geopolymer product is dependent on the composition and properties of the polymeric gel influenced by the ratios of Al₂O₃/SiO₂, CaO/SiO₂, CaO/(SiO₂ + Al₂O₃), Na₂SiO₃/NaOH, SiO₂/Na₂O, and liquid/binder (L/B). Essential scientific inquiry has been progressively addressed by utilizing expert assessment and research metrics. The network visualization of bibliometric co-occurrence and co-citations is of particular significance. The present study aims to highlight the trends and progress of the most influential publication sources, keywords, authors, articles, and countries in geopolymer research in the last 10 years. Bibliometric data were retrieved through Scopus and visualized in VOSviewer to create bibliometric networks. The yearly distribution and growth trends (April 2011–2022) of geopolymer, geopolymer mortar, and geopolymer concrete before (after) applying inclusion criteria were from 754 to 9887 (5186), 47 to 1374 (866), and 145 to 3721 (2253), respectively, attributed to the discoveries in more precursor materials such as laterite and the growing interest in fire and heat-resistant structures, water and wastewater treatment, cement and concrete, and brick manufacturing. The top three journals in terms of prestige for geopolymer publications were the Journal of Hazardous Materials with an impact factor equal to 14.224 and h-index equal to 307, Cement and Concrete Research with an impact factor equal to 11.958 and h-index equal to 239, and the Journal of Cleaner Production with an impact factor equal to 11.072 and h-index equal to 232. The top three journals in terms of average citation per document were Cement and Concrete Research (135.75), Materials and Design (75), and Cement and Concrete Composites (68.35). Keywords such as “geopolymers”, “inorganic polymer”, “geopolymer”, “compressive strength”, “fly ash”, and “geopolymer concrete” had the highest occurrences in publications. John Provis—University of Sheffield, Prinya Chindaprasirt—Khon Kaen University, and Jay Sanjayan—Swinburne University of Technology had the highest total citations of 6377, 5626, and 4311, respectively. The highest number of publications were from China, India, Australia, the United States of America, and Malaysia. The bibliometric findings from this study can act as a tool for academicians and policymakers to exchange research expertise, collaborate on novel geopolymer research, and create innovative joint ventures. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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34 pages, 8808 KiB

Open AccessReview

Geopolymer: A Systematic Review of Methodologies

by Jabulani Matsimbe, Megersa Dinka, David Olukanni and Innocent Musonda

Materials 2022, 15(19), 6852; https://doi.org/10.3390/ma15196852 - 02 Oct 2022

Cited by 29 | Viewed by 5095

Abstract

The geopolymer concept has gained wide international attention during the last two decades and is now seen as a potential alternative to ordinary Portland cement; however, before full implementation in the national and international standards, the geopolymer concept requires clarity on the commonly [...] Read more.

The geopolymer concept has gained wide international attention during the last two decades and is now seen as a potential alternative to ordinary Portland cement; however, before full implementation in the national and international standards, the geopolymer concept requires clarity on the commonly used definitions and mix design methodologies. The lack of a common definition and methodology has led to inconsistency and confusion across disciplines. This review aims to clarify the most existing geopolymer definitions and the diverse procedures on geopolymer methodologies to attain a good understanding of both the unary and binary geopolymer systems. This review puts into perspective the most crucial facets to facilitate the sustainable development and adoption of geopolymer design standards. A systematic review protocol was developed based on the Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and applied to the Scopus database to retrieve articles. Geopolymer is a product of a polycondensation reaction that yields a three-dimensional tecto-aluminosilicate matrix. Compared to unary geopolymer systems, binary geopolymer systems contain complex hydrated gel structures and polymerized networks that influence workability, strength, and durability. The optimum utilization of high calcium industrial by-products such as ground granulated blast furnace slag, Class-C fly ash, and phosphogypsum in unary or binary geopolymer systems give C-S-H or C-A-S-H gels with dense polymerized networks that enhance strength gains and setting times. As there is no geopolymer mix design standard, most geopolymer mix designs apply the trial-and-error approach, and a few apply the Taguchi approach, particle packing fraction method, and response surface methodology. The adopted mix designs require the optimization of certain mixture variables whilst keeping constant other nominal material factors. The production of NaOH gives less CO₂ emission compared to Na₂SiO_3, which requires higher calcination temperatures for Na₂CO₃ and SiO_2. However, their usage is considered unsustainable due to their caustic nature, high energy demand, and cost. Besides the blending of fly ash with other industrial by-products, phosphogypsum also has the potential for use as an ingredient in blended geopolymer systems. The parameters identified in this review can help foster the robust adoption of geopolymer as a potential “go-to” alternative to ordinary Portland cement for construction. Furthermore, the proposed future research areas will help address the various innovation gaps observed in current literature with a view of the environment and society. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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29 pages, 7098 KiB

Open AccessEditor’s ChoiceReview

Survey of Mechanical Properties of Geopolymer Concrete: A Comprehensive Review and Data Analysis

by Azad A. Mohammed, Hemn Unis Ahmed and Amir Mosavi

Materials 2021, 14(16), 4690; https://doi.org/10.3390/ma14164690 - 20 Aug 2021

Cited by 70 | Viewed by 4792

Abstract

Mechanical properties and data analysis for the prediction of different mechanical properties of geopolymer concrete (GPC) were investigated. A relatively large amount of test data from 126 past works was collected, analyzed, and correlation between different mechanical properties and compressive strength was investigated. [...] Read more.

Mechanical properties and data analysis for the prediction of different mechanical properties of geopolymer concrete (GPC) were investigated. A relatively large amount of test data from 126 past works was collected, analyzed, and correlation between different mechanical properties and compressive strength was investigated. Equations were proposed for the properties of splitting tensile strength, flexural strength, modulus of elasticity, Poisson’s ratio, and strain corresponding to peak compressive strength. The proposed equations were found accurate and can be used to prepare a state-of-art report on GPC. Based on data analysis, it was found that there is a chance to apply some past proposed equations for predicting different mechanical properties. CEB-FIP equations for the prediction of splitting tensile strength and strain corresponding to peak compressive stress were found to be accurate, while ACI 318 equations for splitting tensile and elastic modulus overestimates test data for GPC of low compressive strength. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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26 pages, 3681 KiB

Open AccessReview

A State of the Art of the Overall Energy Efficiency of Wood Buildings—An Overview and Future Possibilities

by Matheus Roberto Cabral and Pierre Blanchet

Materials 2021, 14(8), 1848; https://doi.org/10.3390/ma14081848 - 08 Apr 2021

Cited by 14 | Viewed by 7429

Abstract

The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review [...] Read more.

The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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17 pages, 1610 KiB

Open AccessReview

Polish Transition towards Circular Economy: Materials Management and Implications for the Construction Sector

by Justyna Tomaszewska

Materials 2020, 13(22), 5228; https://doi.org/10.3390/ma13225228 - 19 Nov 2020

Cited by 25 | Viewed by 3572

Abstract

Poland’s economy as the sixth largest economy in the EU is painfully experiencing the effects of natural resource depletion, which extend to increasing prices and the growing dependence on foreign suppliers. The situation is particularly unfavorable in the construction sector, which is among [...] Read more.

Poland’s economy as the sixth largest economy in the EU is painfully experiencing the effects of natural resource depletion, which extend to increasing prices and the growing dependence on foreign suppliers. The situation is particularly unfavorable in the construction sector, which is among the most resource- and energy-consuming areas of the economy. This paper juxtaposes the situation of Polish construction industry in the context of the national economy with the context of the evolving EU policies promoting green solutions. The resulting changes in Polish legislation, industry and society are identified. The implementation of selected Circular Economy (CE) aspects, outcomes, emerging challenges and future directions are discussed. The social aspects related to this transformation were analyzed based on a survey carried out among construction industry consumers. The results clearly highlight that individuals are aware of the need to protect the environment, but also indicate a strong necessity to educate the populace about the consequences of the excessive exploitation of the environment and the long-term benefits of CE solutions. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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29 pages, 2327 KiB

Open AccessEditor’s ChoiceReview

A Review on Natural Fiber-Reinforced Geopolymer and Cement-Based Composites

by Marfa Molano Camargo, Eyerusalem Adefrs Taye, Judith A. Roether, Daniel Tilahun Redda and Aldo R. Boccaccini

Materials 2020, 13(20), 4603; https://doi.org/10.3390/ma13204603 - 16 Oct 2020

Cited by 69 | Viewed by 5742

Abstract

The use of ecological materials for building and industrial applications contributes to minimizing the environmental impact of new technologies. In this context, the cement and geopolymer sectors are considering natural fibers as sustainable reinforcement for developing composites. Natural fibers are renewable, biodegradable, and [...] Read more.

The use of ecological materials for building and industrial applications contributes to minimizing the environmental impact of new technologies. In this context, the cement and geopolymer sectors are considering natural fibers as sustainable reinforcement for developing composites. Natural fibers are renewable, biodegradable, and non-toxic, and they exhibit attractive mechanical properties in comparison with their synthetic fiber counterparts. However, their hydrophilic character makes them vulnerable to high volumes of moisture absorption, thus conferring poor wetting with the matrix and weakening the fiber–matrix interface. Therefore, modification and functionalization strategies for natural fibers to tailor interface properties and to improve the durability and mechanical behavior of cement and geopolymer-based composites become highly important. This paper presents a review of the physical, chemical and biological pre-treatments that have been performed on natural fibers, their results and effects on the fiber–matrix interface of cement and geopolymer composites. In addition, the degradation mechanisms of natural fibers used in such composites are discussed. This review finalizes with concluding remarks and recommendations to be addressed through further in-depth studies in the field. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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29 pages, 9577 KiB

Open AccessReview

Production of Sustainable Construction Materials Using Agro-Wastes

by Chrysanthos Maraveas

Materials 2020, 13(2), 262; https://doi.org/10.3390/ma13020262 - 07 Jan 2020

Cited by 104 | Viewed by 17907

Abstract

The construction sector, in modern times, is faced by a myriad of challenges primarily due to the increase in the urban population and dwindling natural resources that facilitate the production of construction materials. Furthermore, higher awareness on climate change is forcing companies to [...] Read more.

The construction sector, in modern times, is faced by a myriad of challenges primarily due to the increase in the urban population and dwindling natural resources that facilitate the production of construction materials. Furthermore, higher awareness on climate change is forcing companies to rethink their strategies in developing more sustainable construction materials. Diverse types of agro-waste ranging from rice husk ash (RHA), sugarcane bagasse ash (SCBA), and bamboo leaves ash (BLA) among others have been identified as potent solutions in the development of sustainable construction materials. In this review paper, six different construction materials, made using agro-waste products, are examined. The materials include brick/masonry elements, green concrete, insulation materials for buildings, reinforcement materials for buildings, particleboards, and bio-based plastics. The main criterion adopted in selecting the materials regards their popularity and wide-scale use in modern construction applications. Additionally, as this research emphasizes identifying alternative approaches to develop sustainable construction materials, the focus is directed toward mainstream materials whose continued use has an adverse impact on the environment. The findings obtained from the review showed that the use of agro-waste to develop sustainable construction materials was effective, as the developed materials adhered to established building standards. Therefore, this indicates that agro-waste materials have the potential to replace conventional construction materials and hence achieve economic, environmental, and social sustainability in the long run. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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25 pages, 573 KiB

Open AccessReview

Nanoparticles in Construction Materials and Other Applications, and Implications of Nanoparticle Use

by Abbas Mohajerani, Lucas Burnett, John V. Smith, Halenur Kurmus, John Milas, Arul Arulrajah, Suksun Horpibulsuk and Aeslina Abdul Kadir

Materials 2019, 12(19), 3052; https://doi.org/10.3390/ma12193052 - 20 Sep 2019

Cited by 158 | Viewed by 10749

Abstract

Nanoparticles are defined as ultrafine particles sized between 1 and 100 nanometres in diameter. In recent decades, there has been wide scientific research on the various uses of nanoparticles in construction, electronics, manufacturing, cosmetics, and medicine. The advantages of using nanoparticles in construction [...] Read more.

Nanoparticles are defined as ultrafine particles sized between 1 and 100 nanometres in diameter. In recent decades, there has been wide scientific research on the various uses of nanoparticles in construction, electronics, manufacturing, cosmetics, and medicine. The advantages of using nanoparticles in construction are immense, promising extraordinary physical and chemical properties for modified construction materials. Among the many different types of nanoparticles, titanium dioxide, carbon nanotubes, silica, copper, clay, and aluminium oxide are the most widely used nanoparticles in the construction sector. The promise of nanoparticles as observed in construction is reflected in other adoptive industries, driving the growth in demand and production quantity at an exorbitant rate. The objective of this study was to analyse the use of nanoparticles within the construction industry to exemplify the benefits of nanoparticle applications and to address the short-term and long-term effects of nanoparticles on the environment and human health within the microcosm of industry so that the findings may be generalised. The benefits of nanoparticle utilisation are demonstrated through specific applications in common materials, particularly in normal concrete, asphalt concrete, bricks, timber, and steel. In addition, the paper addresses the potential benefits and safety barriers for using nanomaterials, with consideration given to key areas of knowledge associated with exposure to nanoparticles that may have implications for health and environmental safety. The field of nanotechnology is considered rather young compared to established industries, thus limiting the time for research and risk analysis. Nevertheless, it is pertinent that research and regulation precede the widespread adoption of potentially harmful particles to mitigate undue risk. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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45 pages, 759 KiB

Open AccessFeature PaperReview

Amazing Types, Properties, and Applications of Fibres in Construction Materials

by Abbas Mohajerani, Siu-Qun Hui, Mehdi Mirzababaei, Arul Arulrajah, Suksun Horpibulsuk, Aeslina Abdul Kadir, Md Tareq Rahman and Farshid Maghool

Materials 2019, 12(16), 2513; https://doi.org/10.3390/ma12162513 - 07 Aug 2019

Cited by 82 | Viewed by 7470

Abstract

Fibres have been used in construction materials for a very long time. Through previous research and investigations, the use of natural and synthetic fibres have shown promising results, as their presence has demonstrated significant benefits in terms of the overall physical and mechanical [...] Read more.

Fibres have been used in construction materials for a very long time. Through previous research and investigations, the use of natural and synthetic fibres have shown promising results, as their presence has demonstrated significant benefits in terms of the overall physical and mechanical properties of the composite material. When comparing fibre reinforcement to traditional reinforcement, the ratio of fibre required is significantly less, making fibre reinforcement both energy and economically efficient. More recently, waste fibres have been studied for their potential as reinforcement in construction materials. The build-up of waste materials all around the world is a known issue, as landfill space is limited, and the incineration process requires considerable energy and produces unwanted emissions. The utilisation of waste fibres in construction materials can alleviate these issues and promote environmentally friendly and sustainable solutions that work in the industry. This study reviews the types, properties, and applications of different fibres used in a wide range of materials in the construction industry, including concrete, asphalt concrete, soil, earth materials, blocks and bricks, composites, and other applications. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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20 pages, 4637 KiB

Open AccessReview

Agricultural Solid Waste as Source of Supplementary Cementitious Materials in Developing Countries

by Suvash Chandra Paul, Peter B.K. Mbewe, Sih Ying Kong and Branko Šavija

Materials 2019, 12(7), 1112; https://doi.org/10.3390/ma12071112 - 03 Apr 2019

Cited by 87 | Viewed by 9105

Abstract

Concrete production utilizes cement as its major ingredient. Cement production is an important consumer of natural resources and energy. Furthermore, the cement industry is a significant CO₂ producer. To reduce the environmental impact of concrete production, supplementary cementitious materials such as fly [...] Read more.

Concrete production utilizes cement as its major ingredient. Cement production is an important consumer of natural resources and energy. Furthermore, the cement industry is a significant CO₂ producer. To reduce the environmental impact of concrete production, supplementary cementitious materials such as fly ash, blast furnace slag, and silica fume are commonly used as (partial) cement replacement materials. However, these materials are industrial by-products and their availability is expected to decrease in the future due to, e.g., closing of coal power plants. In addition, these materials are not available everywhere, for example, in developing countries. In these countries, industrial and agricultural wastes with pozzolanic behavior offer opportunities for use in concrete production. This paper summarizes the engineering properties of concrete produced using widespread agricultural wastes such as palm oil fuel ash, rice husk ash, sugarcane bagasse ash, and bamboo leaf ash. Research on cement replacement containing agricultural wastes has shown that there is great potential for their utilization as partial replacement for cement and aggregates in concrete production. When properly designed, concretes containing these wastes have similar or slightly better mechanical and durability properties compared to ordinary Portland cement (OPC) concrete. Thus, successful use of these wastes in concrete offers novel sustainable materials and contributes to greener construction as it reduces the amount of waste, while also minimizing the use of virgin raw materials for cement production. This paper will help the concrete industry choose relevant waste products and their optimum content for concrete production. Furthermore, this study identifies research gaps which may help researchers in further studying concrete based on agricultural waste materials. Full article

(This article belongs to the Special Issue Sustainability in Construction and Building Materials)

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