materials-logo

Journal Browser

Journal Browser

Advanced and Emerging Materials-2022

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (30 April 2023) | Viewed by 25751

Special Issue Editors


E-Mail Website
Guest Editor
1. Department of Biomedical Engineering, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 2B6, Canada
2. Faculty of Dentistry and Oral Health Sciences, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
Interests: cell-biomaterial interactions; LbL self-assembly systems; theranostic devices for gene/protein therapy and tissue engineering; nanostructured interface by surface molecular engineering; microfluidic platforms for biorecognition systems and Lab-on-a-chip devices; real-time monitoring of cellular activities; characterization of biomaterials debris in biological tissues; polymer synthesis and characterization
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Chemical Engineering, Materials and Environment, Sapienza University of Rome, 00184 Rome, Italy
Interests: fatigue and fracture behavior of materials; mechanical characterization; structural integrity of conventional and innovative materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue represents a collection of original research on the topic of  Advanced and Emerging Materials. Nowadays new manufacturing techniques allow us to develop and to employ a wide range of functional materials and structures. This Special Issue will cover this topic in a broad way  focusing on materials characterization; nanotechnology in material sciences and engineering; materials processing and manufacturing; soft and biomaterials; fibers and membranes; optical, electrical and magnetic materials. Authors are cordially invited to contribute and submit the details of their original and cutting-edge research in the field of materials science to this thematic issue. The aim is to provide an updated state of the art discussing new trends and possibilities in the challenging field of emerging materials.

 

Prof. Dr. Maryam Tabrizian
Prof. Dr. Filippo Berto
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (12 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

11 pages, 1458 KiB  
Article
Carbonation of a Synthetic CAF Compound by CO2 Absorption and Its Effect on Cement Matrix
by Woong-Geol Lee, Seung-Min Kang and Myong-Shin Song
Materials 2023, 16(23), 7344; https://doi.org/10.3390/ma16237344 - 25 Nov 2023
Viewed by 862
Abstract
In the field of construction materials, the development of fundamental technologies to reduce energy consumption and CO2 emissions, such as manufacturing process improvement and the expanded use of alternative materials, is required. Technologies for effectively reducing energy consumption and improving CO2 [...] Read more.
In the field of construction materials, the development of fundamental technologies to reduce energy consumption and CO2 emissions, such as manufacturing process improvement and the expanded use of alternative materials, is required. Technologies for effectively reducing energy consumption and improving CO2 absorption and reduction that can meet domestic greenhouse gas reduction targets are also required. In this study, calcium–aluminate–ferrite (CAF), a ternary system of CaO·Al2O3·Fe2O3, was sintered at a low temperature (1100 °C) to examine the possibility of CO2 adsorption, and excellent CO2 absorption performance was confirmed, as the calcite content was found to be 11.01% after 3 h of the reaction between synthetic CAF (SCAF) and CO2. In addition, the physical and carbonation characteristics were investigated with respect to the SCAF substitution rate for cement (10%, 30%, 50%, 70%, and 100%). It was found that SCAF 10% developed a compressive strength similar to that of ordinary Portland cement (OPC 100%), but the compressive strength tended to decrease as the SCAF substitution rate increased. An increase in the SCAF substitution rate led to the rapid penetration of CO2, and carbonation was observed in all the specimens after 7 days. As carbonation time increased, the CO2 diffusion coefficient tended to decrease. This is because the diffusion of CO2 in the cement matrix follows the semi-infinite model of Fick’s second law. SCAF can contribute to reduced energy consumption and CO2 emissions because of the low-temperature sintering and can absorb and fix CO2 when a certain amount is substituted. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

15 pages, 3731 KiB  
Article
Torsional Vibrations in the Resonance of High-Speed Rotor Bearings Reduced by Dynamic Properties of Carbon Fiber Polymer Composites
by Zuzana Murčinková, Jozef Živčák and Dominik Sabol
Materials 2023, 16(9), 3324; https://doi.org/10.3390/ma16093324 - 24 Apr 2023
Viewed by 1397
Abstract
The present study deals with the harmful torsional resonance vibrations of textile rotor bearings, the amplitudes of which are reduced mainly by the use of high-capacity damping materials, characterized by an internal hierarchical structure and macroshape, added into the machine mechanical system. The [...] Read more.
The present study deals with the harmful torsional resonance vibrations of textile rotor bearings, the amplitudes of which are reduced mainly by the use of high-capacity damping materials, characterized by an internal hierarchical structure and macroshape, added into the machine mechanical system. The additional materials are polymer matrix composites reinforced either by carbon nanofibers or carbon chopped microfibers and either aramid or carbon continuous fibers. The macroshape is based on a honeycomb with internal cavities. Torsional vibrations arise in mechanical systems as a result of fluctuations in the low-level pressing load of the flat belt driving the rotor-bearing pin and the changing of kinematic conditions within it, which, in the resonance area, leads to cage slip and unwanted impulsive torsional vibrations. Moreover, this occurs during high-frequency performance at around 2100 Hz, i.e., 126,000 min−1. The condition, before the redesign, was characterized by significantly reduced textile rotor-bearing life due to significant impulse torsional vibrations in the resonance area. The study showed a significant reduction in average and maximum torsional amplitudes in the resonance area by 33% and 43%, respectively. Furthermore, the paper provides visualization of the propagation of a stress wave at the microscale obtained by the explicit finite element method to show the dispersion of the wave and the fibers as one of the sources of high damping. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

20 pages, 24058 KiB  
Article
Evolution of Microstructure, Mechanical Properties, and Corrosion Resistance of Mg–2.2Gd–2.2Zn–0.2Ca (wt%) Alloy by Extrusion at Various Temperatures
by Hüseyin Zengin, Soner Ari, Muhammet Emre Turan and Achim Walter Hassel
Materials 2023, 16(8), 3075; https://doi.org/10.3390/ma16083075 - 13 Apr 2023
Cited by 4 | Viewed by 1545
Abstract
The current investigation involved casting the Mg–2.2Gd–2.2Zn–0.2Ca (wt%) alloy (GZX220) through permanent mold casting, followed by homogenization at 400 °C for 24 h and extrusion at 250 °C, 300 °C, 350 °C, and 400 °C. Microstructure investigations revealed that α-Mg, Mg–Gd, and Mg–Gd–Zn [...] Read more.
The current investigation involved casting the Mg–2.2Gd–2.2Zn–0.2Ca (wt%) alloy (GZX220) through permanent mold casting, followed by homogenization at 400 °C for 24 h and extrusion at 250 °C, 300 °C, 350 °C, and 400 °C. Microstructure investigations revealed that α-Mg, Mg–Gd, and Mg–Gd–Zn intermetallic phases were present in the as-cast alloy. Following the homogenization treatment, a majority of these intermetallic particles underwent partial dissolution into the matrix phase. α-Mg grains exhibited a considerable refinement by extrusion due to dynamic recrystallization (DRX). At low extrusion temperatures, higher basal texture intensities were observed. The mechanical properties were remarkably enhanced after the extrusion process. However, a consistent decline in strength was observed with the rise in extrusion temperature. The corrosion performance of the as-cast GZX220 alloy was reduced by homogenization because of the lack of corrosion barrier effect of secondary phases. A significant enhancement of corrosion resistance was achieved by the extrusion process. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

11 pages, 4610 KiB  
Article
Preparation of Flexible Calcium Carbonate by In Situ Carbonation of the Chitin Fibrils and Its Use for Producing High Loaded Paper
by Sang Yun Kim, Sun Young Jung, Yung Bum Seo and Jung Soo Han
Materials 2023, 16(8), 2978; https://doi.org/10.3390/ma16082978 - 9 Apr 2023
Cited by 1 | Viewed by 1356
Abstract
Flexible calcium carbonate (FCC) was developed as a functional papermaking filler for high loaded paper, which was a fiber-like shaped calcium carbonate produced from the in situ carbonation process on the cellulose micro-or nanofibril surface. Chitin is the second most abundant renewable material [...] Read more.
Flexible calcium carbonate (FCC) was developed as a functional papermaking filler for high loaded paper, which was a fiber-like shaped calcium carbonate produced from the in situ carbonation process on the cellulose micro-or nanofibril surface. Chitin is the second most abundant renewable material after cellulose. In this study, a chitin microfibril was utilized as the fibril core for making the FCC. Cellulose fibrils for the preparation of FCC were obtained by fibrillation of the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) treated wood fibers. The chitin fibril was obtained from the β-chitin from the born of squid fibrillated in water by grinding. Both fibrils were mixed with calcium oxide and underwent a carbonation process by the addition of carbon dioxide, thus the calcium carbonate attached on the fibrils to make FCC. When used in papermaking, both the FCC from chitin and cellulose gave a much higher bulk and tensile strength simultaneously than the conventional papermaking filler of ground calcium carbonate, while maintaining the other essential properties of paper. The FCC from chitin caused an even higher bulk and higher tensile strength than those of the FCC from cellulose in paper materials. Furthermore, the simple preparation method of the chitin FCC in comparison with the cellulose FCC may enable a reduction in the use of wood fibers, process energy, and the production cost of paper materials. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

21 pages, 4181 KiB  
Article
Zeolite Composite Materials from Fly Ash: An Assessment of Physicochemical and Adsorption Properties
by Jakub Mokrzycki, Wojciech Franus, Rafał Panek, Maciej Sobczyk, Piotr Rusiniak, Justyna Szerement, Renata Jarosz, Lidia Marcińska-Mazur, Tomasz Bajda and Monika Mierzwa-Hersztek
Materials 2023, 16(6), 2142; https://doi.org/10.3390/ma16062142 - 7 Mar 2023
Cited by 10 | Viewed by 2219
Abstract
Waste fly ash, with both low (with the addition of vermiculite) and high contents of unburned coal, were subjected to hydrothermal syntheses aiming to obtain zeolite composite materials—zeolite + vermiculite (NaX–Ver) and zeolite + unburned carbon (NaX–C). The composites were compared with parent [...] Read more.
Waste fly ash, with both low (with the addition of vermiculite) and high contents of unburned coal, were subjected to hydrothermal syntheses aiming to obtain zeolite composite materials—zeolite + vermiculite (NaX–Ver) and zeolite + unburned carbon (NaX–C). The composites were compared with parent zeolite obtained from waste fly ash with a low content of unburned carbon (NaX–FA). In this study, the physicochemical characteristics of the obtained materials were evaluated. The potential application of the investigated zeolites for the adsorption of ammonium ions from aqueous solutions was determined. Composite NaX–Ver and parent zeolite NaX–FA were characterized by comparable adsorption capacities toward ammonium ions of 38.46 and 40.00 mg (NH4+) g−1, respectively. The nearly 2-fold lower adsorption capacity of composite NaX–C (21.05 mg (NH4+) g−1) was probably a result of the lower availability of ion exchange sites within the material. Adsorbents were also regenerated using 1 M NaCl solution at a pH of 10 and subjected to 3 cycles of adsorption–desorption experiments, which proved only a small reduction in adsorption properties. This study follows the current trend of waste utilization (fly ash) and the removal of pollutants from aqueous solutions with respect to their reuse, which remains in line with the goals of the circular economy. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

13 pages, 3967 KiB  
Article
Nanosilica Modification of Epoxy Matrix in Hybrid Basalt-Carbon FRP Bars—Impact on Microstructure and Mechanical Properties
by Karolina Ogrodowska and Marek Urbański
Materials 2023, 16(5), 1912; https://doi.org/10.3390/ma16051912 - 25 Feb 2023
Cited by 1 | Viewed by 1429
Abstract
This article focuses on the effect of nano-silica on an epoxy matrix of hybrid basalt-carbon fiber reinforced polymers (FRP) composites. Usage of this type of bar continues to grow in the construction industry. The corrosion resistance, strength parameters, and easy transport to the [...] Read more.
This article focuses on the effect of nano-silica on an epoxy matrix of hybrid basalt-carbon fiber reinforced polymers (FRP) composites. Usage of this type of bar continues to grow in the construction industry. The corrosion resistance, strength parameters, and easy transport to the construction site are significant parameters compared to traditional reinforcement. The research for new and more efficient solutions resulted in the intensive development of FRP composites. In this paper, scanning electron microscopy (SEM) analysis of two types of bars is proposed: hybrid fiber-reinforced polymer (HFRP) and nanohybrid fiber-reinforced polymer (NHFRP). HFRP, in which 25% of the basalt fibers were replaced with carbon fibers, is more mechanically efficient than basalt fiber reinforced polymer composite (BFRP) alone. In HFRP, epoxy resin was additionally modified with a 3% SiO2 nanosilica admixture. Adding nanosilica to the polymer matrix can raise the glass transition temperature (Tg) and thus shift the limit beyond which the strength parameters of the composite deteriorate. SEM micrographs evaluate the surface of the modified resin and fiber–matrix interface. The analysis of the previously conducted tests—shear and tensile at elevated temperatures—correlate with the microstructural SEM observations with the obtained mechanical parameters. This is a summary of the impact of nanomodification on the microstructure–macrostructure of the FRP composite. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

15 pages, 4144 KiB  
Article
Super Hydrophobic SiO2/Phenolic Resin-Coated Filter Screen and Its Application in Efficient Oil–Water Separation
by Yan Zhao, Zhongmin Xiao, Ziming Feng, Qing Luo, Xiaoping Liu and Wei Cui
Materials 2022, 15(23), 8395; https://doi.org/10.3390/ma15238395 - 25 Nov 2022
Cited by 2 | Viewed by 1480
Abstract
The discharge of industrial liquid waste continues to cause more and more environmental problems. The current research aims at developing a durable and highly efficient filter screen for oil-water separation. In this paper, hydrophobic nano-SiO2 and phenolic resin were used as raw [...] Read more.
The discharge of industrial liquid waste continues to cause more and more environmental problems. The current research aims at developing a durable and highly efficient filter screen for oil-water separation. In this paper, hydrophobic nano-SiO2 and phenolic resin were used as raw materials. Hydrophobic SiO2 particles were fixed on the surface of the coated filter screen by heating and curing the anchored particles. The surface morphology, element composition, surface roughness and water contact angle of the prepared super hydrophobic SiO2/phenolic resin-coated filter screen were analyzed and discussed by using SEM, EDS, AFM, OCA and other instruments. The results showed that the prepared filter screen contained Si, O, C elements, which proved that the resin coating film had adhered to the filter screen surface. When the aperture of the phenolic resin-coated filter screen was 400 meshes, the drainage angle reached a maximum value of 153.8° ± 0.8°. When two layers of hydrophobic SiO2 phenolic resin were coated on the screen, the surface of the filter screen had a sufficient nano-porous structure and high roughness. The tests showed that the minimum water contact angle of the filter screen exceeded 150°, which indicated excellent chemical resistance. Through the analysis of oil-water separation efficiency of isooctane, gasoline, n-hexane, dodecane, edible oil, dichloromethane and trichloromethane, it was concluded that the lowest separation efficiency for edible oil was 97.2%, and the highest separation efficiency for n-hexane was 99.4%. After 50 cycles of separation, the oil-water separation efficiency for n-hexane was still at 99%. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

23 pages, 7424 KiB  
Article
Material Characterisation and Computational Thermal Modelling of Electron Beam Powder Bed Fusion Additive Manufacturing of Ti2448 Titanium Alloy
by Qiushuang Wang, Wenyou Zhang, Shujun Li, Mingming Tong, Wentao Hou, Hao Wang, Yulin Hao, Noel M. Harrison and Rui Yang
Materials 2021, 14(23), 7359; https://doi.org/10.3390/ma14237359 - 30 Nov 2021
Cited by 5 | Viewed by 2059
Abstract
Ti-24Nb-4Zr-8Sn (Ti2448) is a metastable β-type titanium alloy developed for biomedical applications. In this work, cylindrical samples of Ti2448 alloy have been successfully manufactured by using the electron beam powder bed fusion (PBF-EB) technique. The thermal history and microstructure of manufactured samples are [...] Read more.
Ti-24Nb-4Zr-8Sn (Ti2448) is a metastable β-type titanium alloy developed for biomedical applications. In this work, cylindrical samples of Ti2448 alloy have been successfully manufactured by using the electron beam powder bed fusion (PBF-EB) technique. The thermal history and microstructure of manufactured samples are characterised using computational and experimental methods. To analyse the influence of thermal history on the microstructure of materials, the thermal process of PBF-EB has been computationally predicted using the layer-by-layer modelling method. The microstructure of the Ti2448 alloy mainly includes β phase and a small amount of α″ phase. By comparing the experimental results of material microstructure with the computational modelling results of material thermal history, it can be seen that aging time and aging temperature lead to the variation of α″ phase content in manufactured samples. The computational modelling proves to be an effective tool that can help experimentalists to understand the influence of macroscopic processes on material microstructural evolution and hence potentially optimise the process parameters of PBF-EB to eliminate or otherwise modify such microstructural gradients. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

15 pages, 17042 KiB  
Article
Improved Bacteriostatic and Anticorrosion Effects of Polycaprolactone/Chitosan Coated Magnesium via Incorporation of Zinc Oxide
by Hamid Reza Bakhsheshi-Rad, Esah Hamzah, Wong See Ying, Mahmood Razzaghi, Safian Sharif, Ahmad Fauzi Ismail and Filippo Berto
Materials 2021, 14(8), 1930; https://doi.org/10.3390/ma14081930 - 12 Apr 2021
Cited by 16 | Viewed by 2948
Abstract
Magnesium has been recognized as a groundbreaking biodegradable biomaterial for implant applications, but its use is limited because it degrades too quickly in physiological solutions. This paper describes the research on the influence of polycaprolactone (PCL)/chitosan (CS)/zinc oxide (ZnO) composite coating (PCL/CS/ZnO) on [...] Read more.
Magnesium has been recognized as a groundbreaking biodegradable biomaterial for implant applications, but its use is limited because it degrades too quickly in physiological solutions. This paper describes the research on the influence of polycaprolactone (PCL)/chitosan (CS)/zinc oxide (ZnO) composite coating (PCL/CS/ZnO) on the corrosion resistance and antibacterial activity of magnesium. The PCL/CS film presented a porous structure with thickness of about 40–50 μm, while after incorporation of ZnO into the PCL/CS, a homogenous film without pores and defects was attained. The ZnO embedded in PCL/CS enhanced corrosion resistance by preventing corrosive ions diffusion in the magnesium substrate. The corrosion, antibacterial, and cell interaction mechanism of the PCL/CS/ZnO composite coating is discussed in this study. In vitro cell culture revealed that the PCL/CS coating with low loaded ZnO significantly improved cytocompatibility, but coatings with high loaded ZnO were able to induce some cytotoxicity osteoblastic cells. It was also found that enhanced antibacterial activity of the PCL/CS/ZnO coating against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, while less significant antibacterial activity was detected for uncoated Mg and PCL/CS coating. Based on the results, the PCL/CS coatings loaded with low ZnO content may be recommended as a candidate material for biodegradable Mg-based orthopedic implant applications. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Graphical abstract

13 pages, 3000 KiB  
Article
Fly-Ash-Based Geopolymers Reinforced by Melamine Fibers
by Barbara Kozub, Patrycja Bazan, Dariusz Mierzwiński and Kinga Korniejenko
Materials 2021, 14(2), 400; https://doi.org/10.3390/ma14020400 - 15 Jan 2021
Cited by 24 | Viewed by 2652
Abstract
This paper presents the results of research on geopolymer composites based on fly ash with the addition of melamine fibers in amounts of 0.5%, 1% and 2% by weight and, for comparison, without the addition of fibers. The melamine fibers used in the [...] Read more.
This paper presents the results of research on geopolymer composites based on fly ash with the addition of melamine fibers in amounts of 0.5%, 1% and 2% by weight and, for comparison, without the addition of fibers. The melamine fibers used in the tests retain their melamine resin properties by 100% and are characterized by excellent acoustic and thermal insulation as well as excellent filtration. In addition, these fibers are nonflammable, resistant to chemicals, resistant to UV radiation, characterized by high temperature resistance and, most importantly, do not show thermal-related shrinking, melting and dripping. This paper presents the results of density measurements, compressive and flexural strength as well as the results of the measurement of thermal radiation changes in samples subjected to a temperature of 600 °C. The results indicate that melamine fibers can be used as geopolymer reinforcement. The best result was achieved for 0.5% by weight amount of reinforcement, approximately 53 MPa, compared to 41 MPa for a pure matrix. In the case of flexural strength, the best results were obtained for the samples made of unreinforced geopolymer and samples with the addition of 0.5% by weight of melamine fibers, which were characterized by bending strength values above 9 MPa, amounting to 10.7 MPa and 9.3 MPa, respectively. The thermal radiation measurements and fire-jet test did not confirm the increasing thermal and fire resistance of the composites reinforced by melamine fiber. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

15 pages, 2478 KiB  
Article
Evaluation of Hybrid Melamine and Steel Fiber Reinforced Geopolymers Composites
by Patrycja Bazan, Barbara Kozub, Michał Łach and Kinga Korniejenko
Materials 2020, 13(23), 5548; https://doi.org/10.3390/ma13235548 - 5 Dec 2020
Cited by 24 | Viewed by 2441
Abstract
This study investigated the influence of the steel and melamine fibers hybridization on the flexural and compressive strength of a fly ash-based geopolymer. The applied reinforcement reduced the geopolymer brittleness. Currently, there are several types of polymer fibers available on the market. However, [...] Read more.
This study investigated the influence of the steel and melamine fibers hybridization on the flexural and compressive strength of a fly ash-based geopolymer. The applied reinforcement reduced the geopolymer brittleness. Currently, there are several types of polymer fibers available on the market. However, the authors did not come across information on the use of melamine fibers in geopolymer composites. Two systems of reinforcement for the composites were investigated in this work. Reinforcement with a single type of fiber and a hybrid system, i.e., two types of fibers. Both systems strengthened the base material. The research results showed the addition of melamine fibers as well as steel fibers increased the compressive and flexural strength in comparison to the plain matrix. In the case of a hybrid system, the achieved results showed a synergistic effect of the introduced fibers, which provided better strength results in relation to composites reinforced with a single type of fiber in the same amount by weight. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Figure 1

24 pages, 6525 KiB  
Article
Ultimate Bearing Capacity Analysis of CFRP-Strengthened Shield Segments Using Bonding Slip Behavior Experiments
by Hong-bin Nie and Shuan-cheng Gu
Materials 2020, 13(18), 4200; https://doi.org/10.3390/ma13184200 - 21 Sep 2020
Cited by 4 | Viewed by 2300
Abstract
Shield segments of subway tunnels are often exposed to the combined actions of several hygrothermal factors that could lead to accidents such as water seepage and tunnel collapse. Further, they often break and deform owing to formation pressure. In addition, uncertainties related to [...] Read more.
Shield segments of subway tunnels are often exposed to the combined actions of several hygrothermal factors that could lead to accidents such as water seepage and tunnel collapse. Further, they often break and deform owing to formation pressure. In addition, uncertainties related to the stress relaxation characteristics and bonding performance of carbon-fiber-reinforced plastics (CFRPs) under a hygrothermal environment make their application in subway systems difficult. This study analyzes the effects of the slip-on-bending strength of CFRP-strengthened shield segments in a hygrothermal environment. In the study, the shield segments are damaged at ambient pressure under a combination of humidity (0%, 5%, and 10%) and temperature (20 °C, 25 °C, 30 °C, and 40 °C). An experimental procedure is designed to evaluate a CFRP-reinforced concrete arch. The method predicts the load–slip relationship and maximum shearing stress and strain. Moreover, confined compression tests are conducted on a tunnel segment lining strengthened with CFRP to evaluate the bearing capacity of the CFRP-strengthened shield segments. An equation for the latter’s ultimate bearing capacity is developed based on the elastic layer system theory, stress boundary condition, and bending stress characteristics of axisymmetric elements. It was found that the results from the developed model are compared with the experimental values of CFRP-strengthened shield segments under different humidity values (0%, 5%, and 10%) and a constant temperature. The ultimate strength—the debonding deflection of the CFRP-strengthened shield segment—can be predicted using the proposed ultimate bearing capacity equation with sufficient accuracy. Full article
(This article belongs to the Special Issue Advanced and Emerging Materials-2022)
Show Figures

Graphical abstract

Back to TopTop