Article
Construction & Building Technology
N. Algourdin, Q. N. A. Nguyen, Z. Mesticou, A. Si Larbi
Summary: The study highlighted the characterisation of recycled fine mortars under frost action. Although there was no macroscopic damage after 96 freeze-thaw cycles, changes were observed at a microscopic level, such as increased pore diameter and decreased size of rehydrated cement products. The critical period of structural degradation for recycled mortar was found to be during the first 24 freeze-thaw cycles in this experimental study.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Chunyu Qiao, Xu Chen, Prannoy Suraneni, W. Jason Weiss, David Rothstein
Summary: Chloride-based deicers, such as CaCl2 and MgCl2, can damage cementitious materials by forming mineral phases like calcium oxychloride and brucite. The study found that deicer exposure resulted in the formation of calcium oxychloride and leaching of calcium hydroxide, leading to reduced physical and mechanical properties of the mortar and increased ingress of external deicer solutions. Furthermore, deicer application also filled airvoids with calcium oxychloride and secondary ettringite, compromising freeze-thaw durability.
CEMENT & CONCRETE COMPOSITES
(2021)
Article
Chemistry, Physical
Riccardo Maddalena
Summary: There is a growing concern for finding alternative solutions to construction materials in order to minimise their environmental impact as well as enhancing their service life. This study investigated the durability of cementitious mortars prepared by replacing fine aggregate (sand) with recycled tyre shreds and crumbs, aiming at providing an alternative outlet to tyre waste disposal. The results showed that the mortar containing tyre crumbs at lower particle sizes resulted in negligible shrinkage, improved freeze/thaw resistance, a reduced water absorption by up to 52% and an improved thermal resistivity.
Article
Engineering, Civil
Enxi Qiu, Qiaoling He, Qiuling Chen, Xiwang Sun, Rui Zhang, Mengfei Qu, Xusheng Wan
Summary: The changes in mechanical properties of soil due to freeze-thaw cycles pose significant threats to transportation systems in moraine deposit areas. A series of uniaxial compression tests were conducted to study the mechanical mechanism and deformation characteristics of moraine soils. The results showed that the stress-strain curves of moraine soils exhibited four deformation stages, and the acoustic emission (AE) counts were closely related to rock content. The mechanical strength of moraine soils decreased continuously after freeze-thaw cycles, with the most significant reduction occurring at the optimal water content for uniaxial compressive strength (UCS). Water content and rock content were found to be the most critical factors affecting the elastic modulus and UCS, respectively.
TRANSPORTATION GEOTECHNICS
(2023)
Article
Construction & Building Technology
Qingpei Wu, Fuyuan Gong, Dian Zhi, Yuxi Zhao
Summary: The study suggests an innovative method for modifying recycled aggregate, involving the use of freeze-thaw cycles to remove attached mortar and the introduction of high temperature drying to improve spalling efficiency. The results show that high temperature drying increases the likelihood of mortar peeling off during subsequent freeze-thaw cycles, and optimal combination of methods can quickly remove all attached mortar, thereby improving the performance of recycled aggregate.
STRUCTURAL CONCRETE
(2022)
Article
Green & Sustainable Science & Technology
Miras Mamirov, Jiong Hu, Tara Cavalline
Summary: Recycling offers benefits in minimizing waste, but the use of recycled concrete aggregate (RCA) is limited due to the absence of effective characterization. This study aims to develop a testing protocol to characterize RCA and has achieved a better understanding of its properties. The success of the study will encourage the use of RCA in concrete production.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Construction & Building Technology
Yonggui Wang, Meng Xie, Juan Zhang
Summary: This study used nano-silica and surface-modified basalt fiber as reinforcement materials to improve the freeze-thaw resistance of recycled concrete. The results showed that the addition of nano-silica and surface-modified basalt fiber reduced the degree of damage and mass loss, and improved the mechanical properties and relative dynamic elastic modulus of the modified recycled concrete, thus enhancing its anti-freezing capability.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
Yi Wang, Junhui Li, Tamon Ueda, Dawei Zhang, Jun Deng
Summary: Low water-to-cement ratio specimens showed stable strength and modulus after freeze thaw cycles, while high water-to-cement ratio specimens degraded gradually. The connectivity of specimens had limited increase in frost damage incurred with higher NaCl concentrations, mainly due to the reversible formation of Friedel's salt.
CEMENT & CONCRETE COMPOSITES
(2021)
Article
Construction & Building Technology
Yizhou Yao, Chao Liu, Huawei Liu, Wei Zhang, Tianfeng Hu
Summary: Recycled powder has the potential to replace cement as a supplementary cementitious material with great environmental benefits. This study focused on the deterioration mechanism of recycled powder concrete (RPC) under sulfate freeze-thaw cycles. The results showed that RPC's physical-mechanical properties deteriorated with the increase in freeze-thaw cycles, and the replacement rate of recycled powder was the most important factor affecting the amount of damage. The research provides theoretical support for the engineering application of RPC.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Crystallography
Yu Liu, Jinghai Zhou, Di Wu, Tianbei Kang, Aixia Liu
Summary: The study found that freeze-thaw cycles can reduce the bond strength between recycled fiber recycled concrete (RFRC) and reinforcement, but the addition of recycled fibers can improve the bond strength. A simplified two-phase bond-slip model was established to correlate well with the experimental results, providing a theoretical basis for the application of RFRC in building structures in cold areas.
Article
Construction & Building Technology
Zefeng Tao, Yu Zhang, Xinran Chen, Xiaoming Gu
Summary: The stability and durability of the subgrade structure in seasonally frozen areas can be enhanced by adding cement and fiber to silty clay. Results show that the mechanical properties of the composite treated soil change significantly after the first freeze-thaw process, but tend to stabilize after six cycles. Different types and dosages of fiber have an impact on the performance of the composite treated soil, with polypropylene fiber showing better results than basalt fiber.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Multidisciplinary Sciences
Merve Akbas, Recep Iyisan, Asli Y. Dayioglu, Mustafa Hatipoglu
Summary: This study focuses on the impact of freeze-thaw cycles on recycled concrete aggregates (RCAs), finding that RCAs from Istanbul, Turkey are suitable for use as unbound base or subbase course materials. The highest resilient modulus was obtained after 5 F-T cycles, indicating the potential for maintaining stiffness properties even after exposure to freeze-thaw cycles.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Gaohang Cui, Zhiqiang Liu, Shu Xian Ma, Zhuo Cheng
Summary: This study investigated the dynamic characteristics of carbonate saline soil under traffic load through a low-temperature dynamic cyclic triaxial test. The impact of salt content and the number of freeze-thaw cycles on the characteristics of saline soil was explored. It was found that saline soil exhibited typical nonlinear and strain-hardening characteristics, with higher salt content or more freeze-thaw cycles resulting in smaller dynamic shear modulus and larger damping ratio of the remodeled soil. The findings of this study provide valuable reference for the design and construction of structures in regions with seasonal freezing.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Lifang Mei, Haoyu Gu, Jun He, Tianbao Cheng
Summary: In seasonally frozen regions, the bearing capacity of soil decreases and deteriorates after freeze-thaw cycles. A proposed solution is to use expanded polystyrene (EPS) particles lightweight soil as frost-resistant filling material. Tests show that EPS particle lightweight soil has good frost resistance and can be used in cold regions. The compressive strength depends on the EPS and cement contents, with EPS reducing and cement increasing the strength. Shear strength and cohesion decrease with freeze-thaw cycles and EPS content, while the internal friction angle decreases with EPS content. An empirical formula for the compressive strength of EPS particle lightweight soil under freeze-thaw cycles is proposed. This study provides insights for engineering design and applications in cold regions.
Article
Multidisciplinary Sciences
Yongcheng Ji, Hongrui Zhang
Summary: This study investigated the degradation law mechanism of recycled brick aggregates concrete in the cold region by using treated red brick aggregates as a substitute for natural aggregates. The experiments showed that the mass of the specimens decreased after freeze-thaw cycles, with the highest mass loss observed for specimens with 50% and 75% brick substitution rates.
SCIENTIFIC REPORTS
(2022)
Article
Construction & Building Technology
Diego J. De Souza, Leandro F. M. Sanchez, Juarez Hoppe Filho, Marcelo H. F. Medeiros
Summary: This paper evaluates the physical and chemical properties of mortar mixtures with different binders and exposed to different sulphate solutions. A theoretical approach to describe the susceptibility of cementitious mixtures against sulphate attack is proposed. The results show that the amount of portlandite and the potential of ettringite formation are well correlated with the expansion and damage caused by sulphate attack.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Yu Chen, Hossein Rahmani, Erik Schlangen, Og uzhan Copurog
Summary: This study presents a method to accelerate the production of limestone-calcined clay-based cementitious materials using Ca(NO3)2 solution in 3D printing, and investigates the effects of adding Ca(NO3)2 solution on the material's properties. The results show that adding Ca(NO3)2 solution can improve buildability, accelerate initial setting, and increase compressive strength.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Jing Xu, Xianzhi Wang, Wu Yao, Qing Chen, Hehua Zhu, Surendra P. Shah
Summary: Concrete cracks in marine engineering are caused by the hostile seawater environment, leading to serious deterioration of infrastructures. Microbial induced carbonate precipitation (MICP) is an effective and environmentally friendly approach for self-healing of concrete cracks. However, the formation and structure of MICP products for crack healing in seawater are still unclear, which hinders the application of MICP in marine structures.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Zhenbo Wang, Peng Sun, Yurun Fan, Yudong Han, Yudong Hu
Summary: This study investigates the potential use of engineered cementitious composites (ECCs) with strain-hardening and self-healing characteristics as a cover material in wet coral sand exposure. The results show that ECCs can effectively close cracks, reduce water permeability, and restore the load-carrying capacity of structures. Additionally, lower strain levels are associated with decreased rebar corrosion.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Zhengxian Yang, Xiaoli Xiong, Kang Li, Bruno Briseghella, Giuseppe Carlo Marano, Shanghong Chen
Summary: This study investigates the long-term volume stability and strength development of engineered cementitious composites (ECC) containing high-volume steel slag (SS). It is found that the strength of ECC with SS starts to decline after 90 days, while the decline is more significant compared to the matrix. The expansion of SS reduces the fracture toughness of the matrix, leading to an increase in toughness and ductility of the ECC. The introduction of ground granulated blast furnace slag (GGBFS) and PVA fibers can reduce the volume expansion and strength loss caused by SS expansion.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Bin Xi, Zhewen Huang, Salam Al-Obaidi, Liberato Ferrara
Summary: This study investigates the self-healing capabilities of Ultra-High Performance Concrete (UHPC) under the combined influence of mechanical and environmental factors. The results reveal that UHPC with narrow cracks exhibits a higher degree of self-healing, especially when exposed to tap water. Furthermore, prolonged exposure mitigates the inhibitory effect of aggressive ions on self-healing.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Zhichao Xu, Huayang Sun, Yanlin Huo, Minjie Jia, Zhitao Chen, Yingzi Yang
Summary: In this study, MXene was used to modify the surface of polyethylene fiber, improving the interfacial properties and tensile properties of strain hardening cementitious composites. The MXene-coated fiber showed increased tensile stress and strain, reduced crack width and spacing, and enhanced frictional bond strength between the fiber and matrix.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Bao Lu, Yeqiang Zhou, Lei Jiang, Zhensen Liu, Guihua Hou
Summary: This study investigated the leaching rate of Ca2+ from magnesium slag (MS) and developed a leaching-carbonation method to convert MS into high-purity vaterite and supplementary cementitious materials. The wet carbonation process with glycine as a crystal modifier successfully produced spherical vaterite with high purity and surface area. The leachate solid residue (LSR) obtained from the leaching process of MS showed a smaller size destruction and higher surface area compared to Portland cement, leading to accelerated hydration process and improved compressive strength and pore structure development. This work provides a novel treatment method for MS and enables its high value-added utilization.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Gustavo Henrique Nalon, Jose Carlos Lopes Ribeiro, Leonardo Goncalves Pedroti, Roberto Marcio da Silva, Eduardo Nery Duarte de Araujo, Gustavo Emilio Soares de Lima
Summary: The mechanical behavior of mortar joints is crucial for masonry's structural performance. This study investigated the effects of different lime/cement ratios and carbon black nanoparticles content on the properties of mortars. The results showed that increasing lime content decreased mortar strength but increased self-sensing properties at the end of the percolation zone.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Yifei Wang, Lei Lei, Caijun Shi
Summary: The effects of DEIPA and EDIPA at dosages of 0.02% and 0.05% on the hydration and strength development of cement-fly ash-limestone ternary blend were investigated. It was found that both dosages of DEIPA and EDIPA promote the chemical effect of limestone and the hydration of aluminates from cement and fly ash. The hydration of silicates was accelerated by 0.02% of DEIPA or EDIPA but delayed by 0.05% due to excessive aluminates hydration. DEIPA and EDIPA also refine the pore structure and increase compressive strength of the blend mortar.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Du Pan, Ditao Niu, Zongjin Li
Summary: A thick-walled cylinder model was developed in this study to analyze the cracking behavior of seawater sea-sand concrete (SSC) cover. Damage variables were introduced to determine the extent of damage for each cracked ring, and a predictive model for the cracking time of SSC cover was established. The accuracy of the model was verified using the Digital Image Correlation (DIC) technique.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Jiangyu Wu, Hong S. Wong, Hao Zhang, Qian Yin, Hongwen Jing, Dan Ma
Summary: This study explores a method of strengthening cemented rockfill by using well-graded gangue and partially replacing Portland cement with fly ash and a premixed low-alkalinity activator. The research investigated the effects of activator dosage and curing time on the mechanical properties, composition, and microstructure of cemented rockfill. Results show improved performance with low cement content and the use of a low-cost activator. The addition of premixed activator to fly ash enhanced the formation of specific minerals and caused densification of the microstructure. The study reveals an effective and low-cost method for recycling mining wastes and reducing cement.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Juntao Dang, Xiaosong Tang, Jianzhuang Xiao, Aihong Han
Summary: This study proposes a solution to improve the fresh stability and thermal insulation of alkali-activated foamed concrete by adding recycled brick powder. The study investigates the effects of activator modulus and Na2O concentration on the properties of alkali-activated foamed concrete with different bases. The presence of alkaline activator negatively affects the foamability and foam stability, but adjusting the activator concentration can achieve shorter initial setting time and higher fluidity loss. In addition, the increased activator concentration resulted in changes in the pore structure of the foamed concrete.
CEMENT & CONCRETE COMPOSITES
(2024)
Article
Construction & Building Technology
Jiandong Zuo, Bo Wu, Biqin Dong, Feng Xing, Jun Ma, Guanqi Wei
Summary: Nitrite ion intercalated Ca-Al and Mg-Al layered double hydroxides (LDHs) were successfully synthesized using two modified methods. The Ca-Al LDH synthesized by hydrothermal method (H-C-LDH) exhibited the best properties. The intercalated LDHs improved the mechanical properties, chloride penetration resistance, and permeability resistance of cement mortars without affecting the fluidity. Additionally, the intercalated LDHs provided better corrosion resistance.
CEMENT & CONCRETE COMPOSITES
(2024)
Review
Construction & Building Technology
Jingbin Yang, Zhenping Sun, Nele De Belie, Didier Snoeck
Summary: This review paper provides an overview of internal curing mechanism, common internal curing agents, and the most promising agent-superabsorbent polymers in alkali-activated materials (AAM) systems. The introduction of voids by internal curing agents typically has a negative impact on mechanical properties, but continuous water release during internal curing counteracts this effect by promoting hydration. While the effect of internal curing in reducing autogenous shrinkage of AAM systems has been well-established, the impact on drying shrinkage varies widely in different studies.
CEMENT & CONCRETE COMPOSITES
(2024)