Research

16 pages, 4107 KiB

Open AccessArticle

Design Method for Reinforced Concrete Based on Bond-Slip Energy Consumption

by Jianhui Yang, Nianxu Yang, Xinyan Lin, Shuren Wang, Tom Cosgrove and Peter Hughes

Buildings 2022, 12(12), 2065; https://doi.org/10.3390/buildings12122065 - 25 Nov 2022

Cited by 3 | Viewed by 1306

To reveal the energy consumption characteristics of a steel bar and all-lightweight shale ceramsite concrete (ALWSCC), focusing on hot rolled crescent ribbed bars (CRB) and hot rolled plain steel bars (PSB), a series of pull-out tests were carried out. The bonding failure modes, [...] Read more.

To reveal the energy consumption characteristics of a steel bar and all-lightweight shale ceramsite concrete (ALWSCC), focusing on hot rolled crescent ribbed bars (CRB) and hot rolled plain steel bars (PSB), a series of pull-out tests were carried out. The bonding failure modes, the contribution of the ribs to bond-slip failure and the energy consumption characteristics were analyzed based on the curves of pull-out load F-slip displacement S and energy consumption W–slip displacement S. Results show that the splitting failure is the main failure of the CRB specimen, and the pulling out failure is the main failure of the PSB one. The ratio of the total energy dissipation of splitting failure to that of the pulling out failure is less than 30%. The mechanical bite force between CRB and concrete contributes more than 95% to the bond strength. The pull-out force is divided into four stages, such as the chemical adhesive force stage (elastic and micro-elastic strain stage), the common-effect stage of mechanical bearing force and static frictional force (plastic development stage), and the frictional force stage (crushed stage). The new design is proposed to guarantee the ductility of the reinforced concrete structure, which is based on the bond-slip energy consumption rather than the traditional strength design. The conclusions provide a reference to the reinforced concrete practice. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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18 pages, 4163 KiB

Open AccessArticle

Optimization of Graphene Oxide Incorporated in Fly Ash-Based Self-Compacting Concrete

by Veerendrakumar C. Khed, Vyshnavi Pesaralanka, Musa Adamu, Yasser E. Ibrahim, Marc Azab, M. Achyutha Kumar Reddy, Ahmad Hakamy and Ahmed Farouk Deifalla

Buildings 2022, 12(11), 2002; https://doi.org/10.3390/buildings12112002 - 17 Nov 2022

Cited by 4 | Viewed by 1754

Abstract

Self-compacting concrete (SCC) was developed to overcome the challenges of concrete placement in dense or congested reinforcement structure, where the concrete can flow under its own weight to fill the densely reinforced structure. However, production of SCC mostly involves the use of high [...] Read more.

Self-compacting concrete (SCC) was developed to overcome the challenges of concrete placement in dense or congested reinforcement structure, where the concrete can flow under its own weight to fill the densely reinforced structure. However, production of SCC mostly involves the use of high cement to achieve the desired strength. Therefore, to reduce the needed amount of cement, pozzolanic materials such as fly ash can be used to partially replace cement. However, fly ash has been reported to decrease the strengths of concrete especially at early ages. In this study, a self-compacting concrete (SCC) was developed with fly ash as a basic replacement material considering the efficiency of fly ash and incorporating graphene oxide (GO) as a cement additive to counteract the negative effect of fly ash. Response surface methodology (RSM) was utilized for designing the experiments, investigating the effects of fly ash and GO on SCC properties, and developing mathematical models for predicting mechanical properties of SCC. The ranges of fly ash and graphene oxide were 16.67 to 35% and zero to 0.05%, respectively. Statistical analysis was performed by using Design Expert software (version 11.0, Stat Ease Inc., Minneapolis, MS, USA). The results showed that fly ash had a positive effect while GO had a negative effect on the workability of SCC. The incorporation of fly ash alone decreased the compressive strength (CS), splitting tensile strength (STS) and flexural strength (FS), and additionally, increased the porosity of SCC. The addition of GO to fly ash-based SCC reduced its porosity and enhanced its mechanical strengths which was more pronounced at early ages. The developed models for predicting the mechanical strengths of fly ash-based SCC containing GO have a very high degree of correlation. Therefore, the models can predicts the strengths of SCC using fly ash and GO as the variables with a high level of accuracy. The findings show that based on the EFNARC guidelines, up to 35% of fly ash can be used to replace cement in SCC to achieve a mix with satisfactory flowability and deformability properties Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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25 pages, 7547 KiB

Open AccessArticle

Performance of Polyethylene Vapor Barrier Systems in Temperate Climates

by Torben Valdbjørn Rasmussen, Tessa Kvist Hansen, Yvonne Shashoua, Lisbeth M. Ottosen, Louise Green Pedersen, Jens Kromann Nielsen and Frederik R. Steenstrup

Buildings 2022, 12(10), 1768; https://doi.org/10.3390/buildings12101768 - 21 Oct 2022

Cited by 2 | Viewed by 2007

Abstract

The performance of nine different vapor barrier systems comprising polyethylene (PE) membranes were assessed. The vapor barrier systems comprised membranes of virgin PE, 100% new PE, regenerated PE and multilayered virgin and regenerated PE. Membranes were joined either with tape suited to the [...] Read more.

The performance of nine different vapor barrier systems comprising polyethylene (PE) membranes were assessed. The vapor barrier systems comprised membranes of virgin PE, 100% new PE, regenerated PE and multilayered virgin and regenerated PE. Membranes were joined either with tape suited to the individual system or an adhesive base on butyl rubber. The vapor barrier systems were evaluated and compared using standard laboratory tests. Chemical analytical techniques and physicomechanical tests were used. Mechanical properties were assessed using laboratory tests recommended by the harmonized standard EN 1385. Chemical analyses followed standard laboratory protocols performed with specialized equipment and visual examination. Chemical and mechanical properties were determined before and after exposure to an aging regime comprising 168 days at 70 °C in total. The chemical stability of the plastic present in each membrane was further evaluated after an additional exposure to an aging regime comprising 50 days followed by another 30 days at 70 °C. Additional aging indicated chemical changes in the membrane material with time. However, it was not possible to distinguish between aging properties for membranes containing virgin PE, 100% new PE, regenerated PE or multilayered virgin and regenerated PE. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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23 pages, 6177 KiB

Open AccessArticle

Thermal Modeling of a Historical Building Wall: Using Long-Term Monitoring Data to Understand the Reliability and the Robustness of Numerical Simulations

by Simone Panico, Marco Larcher, Alexandra Troi, Cristina Baglivo and Paolo Maria Congedo

Buildings 2022, 12(8), 1258; https://doi.org/10.3390/buildings12081258 - 17 Aug 2022

Cited by 5 | Viewed by 1392

Abstract

Thermal modeling of building components plays a crucial role in designing energy efficiency measures, assessing living comfort, and preventing building damages. The accuracy of the modeling process strongly depends on the reliability of the physical models and the correct selection of input parameters, [...] Read more.

Thermal modeling of building components plays a crucial role in designing energy efficiency measures, assessing living comfort, and preventing building damages. The accuracy of the modeling process strongly depends on the reliability of the physical models and the correct selection of input parameters, especially for historic buildings where uncertainties on wall composition and material properties are higher. This work evaluates the reliability of building thermal modeling and identifies the input parameters that most affect the simulation results. A monitoring system is applied to a historic building wall to measure the temperature profile. The long-term dataset is compared with the result of a simulation model. A sensitivity analysis is applied for the determination of the influential input parameters. A two-step optimization is performed to calibrate the numerical model: the first optimization step is based on an optimized selection of the database materials, while the second optimization step uses a particle swarm algorithm. The results indicate that the output of the simulation model is largely influenced by the coefficients describing the coupling with the boundary conditions and by the thermal conductivities of the materials. Very good results are obtained already after the first optimization step (

R M S E = 0.75 ° C)

while the second optimization step improves further the agreement (

R M S E = 0.48 ° C)

. The parameter values reported in the datasheets do not match those found through optimization. Even with extensive optimization using an algorithm, starting with monitoring data is insufficient to identify material parameter values. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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20 pages, 7671 KiB

Open AccessArticle

Effect of Foaming Agent, Binder and Density on the Compressive Strength and Thermal Conductivity of Ultra-Light Foam Concrete

by Jacek Gołaszewski, Barbara Klemczak, Aneta Smolana, Małgorzata Gołaszewska, Grzegorz Cygan, Christoph Mankel, Ignacio Peralta, Frank Röser and Eduardus A. B. Koenders

Buildings 2022, 12(8), 1176; https://doi.org/10.3390/buildings12081176 - 06 Aug 2022

Cited by 15 | Viewed by 2701

Abstract

The study is focused on ultra-light foam concrete (FC) aimed as a thermal insulation material. Two important properties of such material were investigated: compressive strength and thermal conductivity. In the conducted tests, the influence of the air-dry density (200–500 kg/m³), type [...] Read more.

The study is focused on ultra-light foam concrete (FC) aimed as a thermal insulation material. Two important properties of such material were investigated: compressive strength and thermal conductivity. In the conducted tests, the influence of the air-dry density (200–500 kg/m³), type of foaming agent (synthetic and protein) and binder type (ordinary Portland cement—OPC; calcium sulphoaluminate cement—CSA; metakaolin; siliceous fly ash—SFA; calcareous fly ash—CFA) on the mentioned properties were examined. The results confirmed the dependence of compressive strength and thermal conductivity on the FC density but also indicated the important effect of the nature of the foaming agent and the binder type. The best thermo-mechanical properties were obtained for the foam concrete made of protein-based foaming agent, OPC and metakaolin. Simultaneously, the use of CSA mixed with metakaolin and foam based on the synthetic foaming agent also shows satisfactory properties. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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19 pages, 10737 KiB

Open AccessArticle

Effects of Natural Weathering on the Performance of High Solar Reflective Index Paint Surfaces Exposed in Harsh Climatic Conditions of United Arab Emirates

by Tirumala Uday Kumar Nutakki and Waqar Ullah Kazim

Buildings 2022, 12(7), 1002; https://doi.org/10.3390/buildings12071002 - 13 Jul 2022

Cited by 3 | Viewed by 2230

Abstract

The solar reflective index (SRI) is one of the important parameters in the analysis of a building’s energy and thermal performance, especially for “cool” reflective paints or coatings and also for cool roof membranes. However, there exists less information on the typical performance [...] Read more.

The solar reflective index (SRI) is one of the important parameters in the analysis of a building’s energy and thermal performance, especially for “cool” reflective paints or coatings and also for cool roof membranes. However, there exists less information on the typical performance of the cool materials exposed for long term in the Middle East and more specifically in the United Arab Emirates (UAE). In this study, we determined values of reflectance, emittance, solar reflective index (SRI), and color difference, for three different high-SRI white-paint-coated panels exposed naturally on low- and high-sloped racks for three years. After 3 years, reflectance values of exposed sample panels significantly decreased with an increased color difference in comparison with original unexposed paint surfaces. The emissivity of the paint changed very little for all of the exposed samples, but SRI, determined from both the reflectance and emittance, initially ranged between 95 and 110 and decreased to 60–90 after three years of exposure. This appeared to be related to exposure to high temperatures, UV radiation, and adhesion of airborne contaminants in conjunction with low precipitation. Macroscopically, panels exposed on a low slope were the most discolored with the greatest presence of dust infusion and reduction in increase in surface temperatures, which was demonstrated through thermal imaging. Such natural weathering research study is necessary for the development of standard exposure tests and for the determination of various control elements to increase the durability of cool materials in hot and arid climatic conditions of the UAE. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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19 pages, 4409 KiB

Open AccessArticle

Predicting Compressive Strength of Blast Furnace Slag and Fly Ash Based Sustainable Concrete Using Machine Learning Techniques: An Application of Advanced Decision-Making Approaches

by Syyed Adnan Raheel Shah, Marc Azab, Hany M. Seif ElDin, Osama Barakat, Muhammad Kashif Anwar and Yasir Bashir

Buildings 2022, 12(7), 914; https://doi.org/10.3390/buildings12070914 - 29 Jun 2022

Cited by 13 | Viewed by 2334

Abstract

The utilization of waste industrial materials such as Blast Furnace Slag (BFS) and Fly Ash (F. Ash) will provide an effective alternative strategy for producing eco-friendly and sustainable concrete production. However, testing is a time-consuming process, and the use of soft machine learning [...] Read more.

The utilization of waste industrial materials such as Blast Furnace Slag (BFS) and Fly Ash (F. Ash) will provide an effective alternative strategy for producing eco-friendly and sustainable concrete production. However, testing is a time-consuming process, and the use of soft machine learning (ML) techniques to predict concrete strength can help speed up the procedure. In this study, artificial neural networks (ANNs) and decision trees (DTs) were used for predicting the compressive strength of the concrete. A total of 1030 datasets with eight factors (OPC, F. Ash, BFS, water, days, SP, FA, and CA) were used as input variables for the prediction of concrete compressive strength (response) with the help of training and testing individual models. The reliability and accuracy of the developed models are evaluated in terms of statistical analysis such as R², RMSE, MAD and SSE. Both models showed a strong correlation and high accuracy between predicted and actual Compressive Strength (CS) along with the eight factors. The DT model gave a significant relation to the CS with R² values of 0.943 and 0.836, respectively. Hence, the ANNs and DT models can be utilized to predict and train the compressive strength of high-performance concrete and to achieve long-term sustainability. This study will help in the development of prediction models for composite materials for buildings. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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21 pages, 3092 KiB

Open AccessArticle

Structural Performance of GFRP Bars Based High-Strength RC Columns: An Application of Advanced Decision-Making Mechanism for Experimental Profile Data

by Muhammad Kashif Anwar, Syyed Adnan Raheel Shah, Marc Azab, Ibrahim Shah, Muhammad Khalid Sharif Chauhan and Fahad Iqbal

Buildings 2022, 12(5), 611; https://doi.org/10.3390/buildings12050611 - 06 May 2022

Cited by 6 | Viewed by 1636

Abstract

Several past studies have shown the use of glass fibre-reinforced polymer (GFRP) bars to alleviate the reinforced steel rusting issue in different concrete structures. However, the practise of GFRP bars in concrete columns has not yet achieved a sufficient confidence level due to [...] Read more.

Several past studies have shown the use of glass fibre-reinforced polymer (GFRP) bars to alleviate the reinforced steel rusting issue in different concrete structures. However, the practise of GFRP bars in concrete columns has not yet achieved a sufficient confidence level due to the lack of a theoretical model found in the literature. The objective of the current study is to introduce a novel prediction model for the axial capability of concrete columns made with bars of GFRP. For this purpose, two different approaches, such as data envelopment analysis (DEA) and artificial neural networks (ANNs) modelling, are used on a collected dataset of 266 concrete column specimens made with GFRP bars from previous literature works. Eight parameters were used to predict the axial performance of GFRP-based RC columns. The proposed DEA and ANNs predictions demonstrated a good correlation with the testing dataset, having R² values of 0.811 and 0.836, respectively. A comparative analysis of the DEA and ANNs models is undertaken, and it was found that the suggested models are capable of accurately forecasting the structural response of GFRP-made RC column structures. Then, a comprehensive parametric analysis of 266 GFRP-based columns was performed to study the effect of different materials and their geometrical shape. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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23 pages, 10735 KiB

Open AccessFeature PaperArticle

Timber Semirigid Frame Connection with Improved Deformation Capacity and Ductility

by Marek Johanides, Antonin Lokaj, David Mikolasek, Petr Mynarcik, Pavel Dobes and Oldrich Sucharda

Buildings 2022, 12(5), 583; https://doi.org/10.3390/buildings12050583 - 30 Apr 2022

Cited by 8 | Viewed by 2078

Abstract

The present study deals with the innovation and the possibilities of improving the design solution of a frame connection for two selected types of fasteners. All specimens were made of glued laminated timber. Dowel-type mechanical fasteners, a combination of bolts and dowels, and [...] Read more.

The present study deals with the innovation and the possibilities of improving the design solution of a frame connection for two selected types of fasteners. All specimens were made of glued laminated timber. Dowel-type mechanical fasteners, a combination of bolts and dowels, and full-threaded screws were used for the connection. The main goal of this research was to replace the typical solution (common dowel-type fasteners) with a more modern, faster, and easier solution in order to improve the load-carrying capacity, ductility, and deformation capacity of this type of frame connection. This article also aimed to provide a detailed evaluation of the mechanical properties of the used glued laminated timber and fasteners in order to comprehensively evaluate the research task. For the design solution, a frame connection created from a system of two struts and a partition was chosen as the basis of the experimental program. Dowel-type mechanical fasteners, as well as combinations of bolts and dowels, were used for the connection; however, in addition to these standardly used mechanical fasteners, full-threaded screws were used. The article describes the use of static destructive testing to determine the ductility of the connection, considering different variations in the strengthening of the individual segments of the mentioned connection means. In the first variation, the individual components of the frame were not reinforced in any way. In the second, the crossbar was reinforced with two full-threaded bolts. In the third, the webs and the crossbar were reinforced with two full-threaded bolts. In the article, these ductility values were compared with each other and the procedure was set by the currently valid standard. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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17 pages, 4471 KiB

Open AccessArticle

Influence of Gradation on the Mechanical Properties of Aged Hot-Mix Asphalts

by Saieth Baudilio Chaves-Pabón, Hugo Alexander Rondón-Quintana and Carlos Alfonso Zafra-Mejía

Buildings 2021, 11(12), 632; https://doi.org/10.3390/buildings11120632 - 10 Dec 2021

Viewed by 1985

Abstract

When a hot-mix asphalt (HMA) ages, its mechanical properties, resistance, and durability change. Several studies have been conducted throughout the world to evaluate the effects of aging in HMAs. However, few studies have analyzed the influence of gradation. The main objective of this [...] Read more.

When a hot-mix asphalt (HMA) ages, its mechanical properties, resistance, and durability change. Several studies have been conducted throughout the world to evaluate the effects of aging in HMAs. However, few studies have analyzed the influence of gradation. The main objective of this study was to evaluate the influence of gradation on the mechanical properties of aged HMA mixes. For such purposes, three HMA mixes with different gradations were manufactured (named HMA-10, HMA-19, and HMA-25), which were conditioned in STOA (short-term oven aging) and LTOA (long-term oven aging) by following the guidelines established by the AASHTO R30 specification. Marshall, Indirect Tensile Strength (ITS), resilient modulus, permanent deformation, fatigue (under controlled-stress condition), and Cantabro tests were performed. These tests were carried out to evaluate resistance under monotonic and cyclic load as well as the resistance to moisture damage and abrasion. The best performing mix in the test was HMA-19. There is no clear trend about the influence of gradation over the susceptibility of mixes for aging. This susceptibility changes depending on the test performed and the property measured. Furthermore, in resilient modulus tests, it is observed that the influence of gradation on aging susceptibility changes depending on the test temperature. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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11 pages, 5131 KiB

Open AccessArticle

Physical Tests of Alternative Connections of Different High Roof Purlins Regarding Upward Loading

by Miroslav Rosmanit, Přemysl Pařenica, Oldřich Sucharda and Petr Lehner

Buildings 2021, 11(11), 512; https://doi.org/10.3390/buildings11110512 - 29 Oct 2021

Cited by 4 | Viewed by 1796

Abstract

Thin-walled cold-rolled sections are used in the construction industry, especially in the roofing of large-span halls. The load-bearing capacity of a thin-walled structure depends to a large extent on the load-bearing capacity of the details at the point of attachment to the structure [...] Read more.

Thin-walled cold-rolled sections are used in the construction industry, especially in the roofing of large-span halls. The load-bearing capacity of a thin-walled structure depends to a large extent on the load-bearing capacity of the details at the point of attachment to the structure and the interconnection of the individual thin-walled elements. Therefore, in the case of thin-walled structures, it is necessary to use additional structural elements such as local reinforcement, stabilising elements, supports, and other structural measures such as the doubling of profiles. This paper focused on the behaviour of tall Z300 and Z350 mm thin-walled trusses at the connection to the superstructure regarding upward loading (e.g., wind suction and so on). Two section thicknesses, 1.89 mm and 2.85 mm, were experimentally analysed. Furthermore, two types of connections were prepared, more precisely without and with a reinforced buckle. The experiments aimed to investigate the behaviour and load-carrying capacity of the detail of the roof truss connections to the supporting structure. The resulting load capacity values were compared with normative approaches. Analyses of the details of the bolt in the connection are also presented. The paper presents a practical evaluation of the physical test on real structural members. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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16 pages, 8107 KiB

Open AccessArticle

Dynamic Properties and Energy Dissipation Study of Sandwich Viscoelastic Damper Considering Temperature Influence

by Yeshou Xu, Zhaodong Xu, Yingqing Guo, Xinghuai Huang, Yaorong Dong and Qiangqiang Li

Buildings 2021, 11(10), 470; https://doi.org/10.3390/buildings11100470 - 13 Oct 2021

Cited by 11 | Viewed by 2619

Abstract

Viscoelastic dampers are a kind of classical passive energy dissipation and vibration control devices which are widely utilized in engineering fields. The mechanical properties and energy dissipation capacity of the viscoelastic damper are significantly affected by ambient temperature. In this work, dynamic properties [...] Read more.

Viscoelastic dampers are a kind of classical passive energy dissipation and vibration control devices which are widely utilized in engineering fields. The mechanical properties and energy dissipation capacity of the viscoelastic damper are significantly affected by ambient temperature. In this work, dynamic properties tests of the sandwich type viscoelastic damper at different environmental temperatures are carried out. The equivalent fractional Kelvin model which can characterize the mechanical behavior of the viscoelastic damper with varying frequencies and temperatures is introduced to describe the dynamic properties and energy dissipation capability of the sandwich viscoelastic damper. The self-heating phenomenon of the sandwich viscoelastic damper is studied with a numerical simulation, and the dynamic properties and energy dissipation variation of the viscoelastic damper with self-heating processes are also analyzed. The results show that the dynamic properties of the viscoelastic damper are significantly affected by temperature, excitation frequency and the internal self-generated heating. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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14 pages, 3451 KiB

Open AccessArticle

Mechanical Behavior and Frost-Resistance of Alkali-Activated Cement Concrete with Blended Binder at Ambient Curing Condition

by Biruk Hailu Tekle, Klaus Holschemacher, Philipp Löber and Björn Heiden

Buildings 2021, 11(2), 52; https://doi.org/10.3390/buildings11020052 - 04 Feb 2021

Cited by 9 | Viewed by 2155

Abstract

Concrete is the most commonly used construction material because of its various advantages, such as versatility, familiarity, strength, and durability, and it will continue to be in demand far into the future. However, with today’s sensitivity to environmental protection, this material faces unprecedented [...] Read more.

Concrete is the most commonly used construction material because of its various advantages, such as versatility, familiarity, strength, and durability, and it will continue to be in demand far into the future. However, with today’s sensitivity to environmental protection, this material faces unprecedented challenges because of its high greenhouse gas emissions, mainly during cement production. This paper investigates one of the promising cement replacement materials, alkali-activated cement (AAC) concrete. Being produced mainly from byproduct materials and having a comparable structural performance to conventional concrete, AAC concrete can transform the construction industry. Mechanical properties such as compressive and flexural strength and the relationship between them are studied. Different source materials such as fly ash (FA), ground granulated blast furnace slag (GGBS), silica fume (SF), and Metakaolin (MK) are used. The effect of the source materials and the activator solutions on the concrete performance is studied. Furthermore, the freeze-thaw resistance of the concrete is studied. The study results showed that the behavior of AAC depends highly on the source material combinations and type used. The effect of the alkaline solution is also dependent on the source material used. Mixes with higher GGBS content showed the highest strength, while mixes with MK showed the highest flexural strength. The freeze-thaw test results showed that proper design of AAC concrete with lower water content is critical to achieving a good resistance. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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26 pages, 2028 KiB

Open AccessArticle

Evaluation of Metaheuristic-Based Methods for Optimization of Truss Structures via Various Algorithms and Lèvy Flight Modification

by Gebrail Bekdaş, Melda Yucel and Sinan Melih Nigdeli

Buildings 2021, 11(2), 49; https://doi.org/10.3390/buildings11020049 - 31 Jan 2021

Cited by 21 | Viewed by 4564

Abstract

Truss structures are one of the major civil engineering members studied in the optimization research area. In this area, various optimization applications such as topology, size, cost, weight, material usage, etc., can be conducted for different truss structure types. In this scope with [...] Read more.

Truss structures are one of the major civil engineering members studied in the optimization research area. In this area, various optimization applications such as topology, size, cost, weight, material usage, etc., can be conducted for different truss structure types. In this scope with the present study, various optimization processes were carried out concerning two different large-scale space trusses to minimize the structural weight. According to this state, three structural models provided via two different truss structures, including 25 bar and 72 bar truss models, were handled for evaluation of six different metaheuristics together with the modification of Lèvy flight for three of the algorithms using swarm intelligence by considering both constant and variable populations, and different ranges for iterations, too. Additionally, the effects of the Lèvy flight function and whether it is successful or not in terms of the target of optimization were also investigated by comparing with some documented studies. In this regard, some statistical calculations were also realized to evaluate the optimization method performance and detection of optimum values for any data stably and successfully. According to the results, the Jaya algorithm can handle the optimization process successfully, including the case, without grouping truss members. The positive effect of Lèvy flight on swarm-based algorithms can be seen especially for the gray wolf algorithm. Full article

(This article belongs to the Special Issue Testing, Modelling, Analysis and Optimization of Building Structures and Materials)

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