Article
Construction & Building Technology
Yuzhu Guo, Xudong Chen, Bo Chen, Rongkun Wen, Peng Wu
Summary: This study analyzed the pore structure characteristics of three different density foamed concrete using X-CT technology, showing that there is a relationship between porosity, pore size distribution, pore sphericity, and density. The basic mechanical properties of foamed concrete were also analyzed based on pore parameters.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Tao Meng, Huadong Wei, Dawang Dai, Jianping Liao, Sara Ahmed
Summary: This study used non-destructive X-ray computed tomography technology to observe the influence of brick aggregates on the properties of mixed recycled aggregate concrete. It was found that the presence of brick aggregates caused changes in the internal properties and surface areas of the concrete, leading to a change in the failure mode.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Sizhe Du, Yu Zhang, Jie Zhang, Nina Selyutina, Ivan Smirnov, Gang Ma, Xiang Zhang, Beibei Li, Yanchun Miao, Yuanzhen Liu, Wenjing Wang
Summary: High temperatures can significantly affect the internal pore structure of concrete and therefore degrade its mechanical properties. This study examined the impact of high temperatures on the microstructural characteristics and residual mechanical properties of recycled aggregate concrete mixed with glazed hollow beads (RATIC). The results showed that the addition of glazed hollow beads can slow down heat propagation in the concrete and improve its resistance to heat-induced damage. Additionally, a quantitative relationship was established between pore characteristic parameters and the residual compressive strength of RATIC.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Blas Cantero, Miguel Bravo, Jorge de Brito, Isabel Fuencisla Saez del Bosque, Cesar Medina
Summary: The study found that concrete with ground recycled concrete (GRC) had lower resistance to corrosive agents due to its higher porosity, but still exhibited good quality with oxygen and carbon dioxide permeability within certain limits. Incorporating 25% GRC increased the penetration of carbon dioxide and chloride ions, while reinforcement passivity could still be guaranteed in such recycled materials over a 100 year service life.
APPLIED SCIENCES-BASEL
(2021)
Article
Construction & Building Technology
Yiwen Wu, Chao Liu, Huawei Liu, Huimin Hu, Chunhui He, Lin Song, Wei Huang
Summary: This study investigates the pore structure, carbonation, and chloride ion permeability of recycled aggregate-powder concrete (RAPC) prepared with recycled coarse aggregates and recycled powder. The results show that the carbonation depth and chloride ion permeability of RAPC increase with the increase of recycled aggregate replacement rate. The incorporation of 15% recycled powder refines and partitions the pores in the mortar, resulting in reduced average pore diameter and carbonation depth. However, the incorporation of 30% and 45% recycled powder is detrimental to the pore structure and carbonation resistance. The addition of 0-45% recycled powder successfully reduces the chloride ion permeability of RAPC, with the best result achieved at 15% replacement rate.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Songsong Lian, Tao Meng, Hongqi Song, Zhongjia Wang, Jiabin Li
Summary: This study investigated the relationship between percolation mechanism and pore characteristics for recycled permeable bricks with different porosities using X-ray computed tomography (X-CT). The results showed a linear and then quadratic curve relationship between effective porosity and permeability coefficient, with nonlinear channels in permeable bricks being larger and fewer compared to linear percolation channels. Additionally, the overall percolation state of the permeable bricks changed from linear to nonlinear when the area and number ratios of linear and nonlinear percolation channels reached 80% and 10%, respectively.
REVIEWS ON ADVANCED MATERIALS SCIENCE
(2021)
Article
Construction & Building Technology
Stefano Silva, Luis Evangelista, Jorge de Brito
Summary: An extensive experimental study was conducted to investigate the durability performance of concrete made with recycled coarse aggregates from multiple recycling cycles. The results show that as the number of recycling cycles increases, the properties of the recycled coarse aggregates decrease, leading to poorer durability and shrinkage performance of the resulting concrete. Moreover, the decrease in performance tends to slow down with the increase of recycling cycles, showing an asymptotic behavior.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Dongya Ren, Jie Xu, Shaonan Su, Gangsheng Tian, Xu Chen, Allen Zhang, Changfa Ai
Summary: This study uses 3D X-ray computed tomography technology to analyze the digital images of three typical asphalt mixtures with different porosities, and quantitatively and statistically analyzes several pore structure parameters at a micro level. The results show that as the total pores content increases, the difference between the pore fraction and open pores fraction decreases. The porosity of porous asphalt mixtures is high, but mainly composed of interconnected pores with only a small proportion of closed pores. The coordination number determines the connectivity and thus the porosity of the asphalt mixture, and larger open pore channels lead to larger pore diameters and greater permeability.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Ana Carrico, Sofia Real, Jose Alexandre Bogas
Summary: Concrete produced with thermoactivated recycled cement obtained from waste materials showed improved durability properties compared to non-treated waste materials. Even concretes with up to 100% recycled cement exhibited comparable durability to reference concretes.
CEMENT & CONCRETE COMPOSITES
(2021)
Article
Construction & Building Technology
Song Gao, Xin Guo, Shunli Ban, Yanxuan Ma, Qi Yu, Shiyu Sui
Summary: This study investigates the influence of fly ash, slag powder, and silica fume on the performance of recycled aggregate concrete (RAC) from a microscopic perspective. The results demonstrate that supplementary cementitious materials (SCMs) can enhance the compressive strength and chloride resistance of RAC, refine the pore structure of the interface transition zone (ITZ), and modify the phases around ITZ. Moreover, the SCMs fill the voids in the cement paste and promote the compactness of the ITZ structure, thereby improving the macroscopic performance of RAC.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Fengming Xu, Xiaoshan Lin, Annan Zhou
Summary: The study investigates the application of recycled ceramic aggregate (RCA) in concrete construction and reveals the mechanism underlying the role RCA plays in regulating hydration heat output and permeability of HPC for the first time. Microscopic tests are conducted to investigate the porosities and pore distributions of three types of RCA, and the internal structures of HPC with different types of RCA are analyzed. Hydration heat tests and chloride ion penetration experiments are carried out to measure the temperature during exothermic process and the permeability of HPC, respectively. The results show that RCA can lower the temperature during exothermic reaction, prolong the cement hydration process, and increase the permeability of HPC.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Ligang Peng, Yuxi Zhao, Jiaxing Ban, Yuzhou Wang, Peiliang Shen, Jian-Xin Lu, Chi-Sun Poon
Summary: By using waste glass powder (GP), the corrosion resistance of recycled aggregate concrete (RAC) was enhanced due to the alkali-rich and pozzolanic characteristics of GP. The results showed that partially replacing cement with GP improved the steel corrosion resistance of RAC, surpassing that of conventional concrete prepared with natural aggregates. Additionally, the presence of 20% GP significantly enhanced the chloride penetration resistance without sacrificing compressive strength. The use of GP in low-carbon cement can compensate for the inferior durability of RAC, making it a promising option in the construction sector.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Jiuwen Bao, Yunwei Wang, Peng Zhang, Xinyu Zhang, Yifei Cui
Summary: This paper experimentally investigated the compressive strength, transport properties behavior, and microstructure of recycled aggregate concrete (RAC) modified with nano-SiO2 (NS). The effects of different NS dosages on water absorption and chloride penetration resistance were studied. It was found that the addition of 3% NS improved the compressive strength and reduced the water absorption and chloride diffusion coefficient of RAC. The microstructure analysis showed that NS optimized the ITZ structures and compacted the mortar matrix, enhancing the mechanical and durability-related properties of RAC.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Wen Huang, Xudong Chen, Lu Feng, Tao Ji, Yingjie Ning, Jie Wang
Summary: Foamed concrete, with its lightweight and high-strength properties, has advantages as a roadbed material. However, its mechanical properties are influenced by density and microstructure. This study conducted tests and analyses on foamed concrete samples of varying densities to understand their mechanical and microstructural characteristics, and found a significant correlation between density, compressive strength, and microstructure.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Article
Construction & Building Technology
Junli Liu, Shuai Li, Chamila Gunasekara, Kate Fox, Phuong Tran
Summary: Sustainable 3D concrete printing has gained attention recently, with one method being the replacement of natural river sand with recycled glass. This study focused on the flexural properties of 3D-printed concrete with different gradations of recycled glass, finding that glass addition can impact flexural strength and microstructural properties. The research showed that the location and morphology of pores related to the addition of glass particles influence crack propagation and ultimate strength.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Xi Xiao, Ashley C. Y. Tan, Cise Unluer, En-Hua Yang
Summary: This paper presents the development of a new type of functionally graded reactive magnesia cement-based bacteria spores (RMC-B) capsule for self-healing concrete. The capsule is designed with a gradient structure consisting of a dense shell and a porous and low alkaline core to protect and enhance the viability of bacteria spores. The addition of the RMC-B capsules maintains the strength of the matrix and enables self-healing of cracks. The inclusion of these capsules does not negatively affect hydration and fresh properties of the paste, while improving the compressive strength and crack healing performance.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
S. H. Chu, E. H. Yang, C. Unluer
Summary: Nanofiber reinforced reactive magnesia-based composites (nano-FRMC) with varying nanofiber contents and water to binder ratios were studied for their fresh properties and mechanical performance. The inclusion of nanofibers improved the shape stability and acceleration of leveling. An optimum nanofiber content was found to enhance the compression strength through fiber bridging and networking effects. Thermogravimetric analysis and scanning electron microscopy revealed the enhanced formation of hydrate and carbonate phases and microstructural evolution. A thixotropy index successfully modeled the variation of slump and flow diameter. The study deepened the understanding of nano-FRMC for 3D printing applications.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Materials Science, Ceramics
Yufeng Song, Xiaoqian Qian, Dongming Yan, Cise Unluer, Yu Peng, Deyu Kong, Chuanlin Hu, Su Wang, Shaoqin Ruan
Summary: In this study, different types and contents of seeds were introduced in reactive magnesia cement (RMC) systems. The results showed that seeded RMC samples exhibited accelerated hydration/carbonation, resulting in faster strength development. Among the seeds, magnesite performed the best due to its more homogenous microstructures. Further experiments confirmed the nucleation effects of seeds in RMC formulations, and it was found that seeds had a higher affinity for Mg2+ ions, making them effective accelerators for curing RMC-based concrete products on a large scale.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Construction & Building Technology
Tangwei Mi, En-Hua Yang, Cise Unluer
Summary: This study characterizes and investigates the effects of MgO properties on the performance of Reactive MgO cement (RMC) powders. The results show that hydration progress is highly dependent on the reactivity of RMC, while the purity influences the early stages of the reaction. Additionally, the agglomeration ratio is strongly correlated with strength after 7 days of carbonation curing and 28 days of hydration. A regression analysis is used to propose a model for predicting strength based on the initial properties of RMC powder. The findings can serve as a guideline for selecting suitable RMC-based binders for different building applications.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Chenyu Pan, Yufeng Song, Jiaze Wang, Shulin Zhan, Cise Unluer, Shaoqin Ruan
Summary: In this study, the strength development of CO2-cured RMC-RCA was explored for the first time, and the strength variation among groups was interpreted by microstructural analyses. The initial results show that the strength of RMC-RCA is higher compared to samples with natural aggregates, which could be attributed to its refined microstructures and larger carbonation depths. The presence of porous ITZs in RCA contributes to better CO2 diffusion, as described in the proposed revised CO2 diffusion model. Overall, this preliminary study could pave the path for the upcycling of RCAs in RMC concrete on a large scale while enabling a pronounced CO2 capture potential.
CEMENT AND CONCRETE RESEARCH
(2023)
Review
Engineering, Multidisciplinary
Yiming Peng, Cise Unluer
Summary: This paper systematically reviews the recent advances in the use of key alternative binders in the context of 3D printing, including geopolymers/alkali-activated systems, aluminate cements, MgO-based cements, gypsum-based materials, and limestone-calcined clay-based cementitious materials. The paper provides a detailed discussion on the progress, challenges, and potential solutions in the development of 3D-printed components using these alternative binders. It also includes a comprehensive evaluation of the key properties controlling the performance of 3D-printed components prepared with different mixture proportions and curing conditions.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Engineering, Environmental
Yiming Peng, Cise Unluer
Summary: By building a comprehensive database with 607 records, the complex functional relationship between key parameters of recycled aggregate concrete (RAC), such as recycled aggregate properties, mix proportion, and compressive strength, was explored. Two standard algorithms (artificial neural network and support vector regression) and two optimized hybrid models (Particle Swarm Optimization based support vector regression and grey Wolf optimizer based support vector regression) were used. Additionally, two interpretable algorithms (Partial Dependence Plot and SHapley Additive exPlanations) were applied to assess the global and local approaches independent of machine learning models. Results showed that the hybrid models outperformed the conventional models, with the coefficient of determination (R2) of the optimized hybrid models reaching above 0.89.
RESOURCES CONSERVATION AND RECYCLING
(2023)
Article
Construction & Building Technology
Chenyu Pan, Yufeng Song, Yuxi Zhao, Tao Meng, Yanlin Zhang, Ruohong Chen, Xiangming Zhou, Shaoqin Ruan
Summary: This study investigates the impact of recycled concrete aggregates (RCA) on the performances of reactive magnesia cement (RMC) formulations. The results suggest that RMC samples with carbonated RCA show the best 28-day strength and a faster strength gain, which is attributed to the refined microstructure.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Engineering, Civil
Songsong Lian, Tao Meng, Yuxi Zhao, Zhicheng Liu, Xiangming Zhou, Shaoqin Ruan
Summary: The diffusion behavior of chloride in recycled concrete was found to be different from that in normal concrete due to the high porosity of recycled aggregates. The maximum chloride concentration in the drying-wetting environment increased rapidly, but the decrease in the chloride diffusion coefficient was slower. The relationship between several parameters related to chloride diffusion was established, and a more sophisticated model considering key indexes was proposed.
Article
Construction & Building Technology
Yiming Peng, Cise Unluer
Summary: The viscoelasticity of reactive magnesia cement (RMC) pastes with different hydration agents (HCl, Mg(CH3COO)2, and MgCl2) was studied. Various measurements were conducted to analyze the hydration reaction and products. The addition of hydration agents accelerated the growth rate of storage modulus/loss modulus over time. MgCl2 showed the strongest acceleration effect and had applications in 3D printing.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Xi Xiao, Cise Unluer, Shaohua Chu, En-Hua Yang
Summary: Self-healing of cracks in concrete can be achieved through microbial induced calcite precipitation. A new approach using single bacteria spore capsule, formed by layer-by-layer self-assembly of poly(dimethyldiallyl ammonium chloride) and silica nanoparticles, is proposed to enhance the consistency of healing and minimize the negative impact on mechanical properties of concrete. The inclusion of the capsules, with a size of 1 μm, does not compromise the compressive strength of the matrix. Cement paste incorporating the capsules shows complete closure of large cracks and recovery of transport property along the entire crack.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Ning Li, Cise Unluer
Summary: In this study, ethylenediamine tetraacetic acid (EDTA)-induced dry and wet carbonation processes were proposed to accelerate the carbonation of steel slag aggregates (SSA). It was found that spraying EDTA on SSA before dry carbonation resulted in a denser carbonated layer and higher specific gravity. Wet carbonation of SSA in EDTA solution promoted both carbonation and hydration, reducing expansion of SSA.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Liyun Pu, Shaoqin Ruan, Chenyu Pan, Yufeng Song, Fangjun Zhou, Junying Lai, Kuangliang Qian, Qiang Li
Summary: This study investigates the impact of carbonation degree on the strength and pore structures of reactive magnesia cement (RMC) concrete by pretreating recycled aggregates using the carbonation technique. The results show that a higher carbonation degree contributes to strength improvement by forming well-developed carbonates and reducing porosity. However, a lower water-to-cement ratio improves mechanical performance by refining pore structures. The correlation between carbonation degree and strength is weaker due to different types of hydrated magnesium carbonates formed. The study also demonstrates that CO2 diffusion in RMC samples occurs through interfacial transition zones (ITZs) rather than capillary pores.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Guangcheng Sun, Zhiguang Wang, Chengkun Yu, Xiaoqian Qian, Ruohong Chen, Xiangming Zhou, Yiwei Weng, Yufeng Song, Shaoqin Ruan
Summary: The producibility of calcium sulphoaluminate cement-based foam concrete (CSA-FC) with nano-clay and industrial by-products through concrete extrusion was confirmed. The use of appropriate amounts of nano-clay and desulfurized gypsum improved the hydration acceleration and extrudability of samples. A suitable mix design of CSA-FC with satisfactory performance, low carbon footprint, and cost was proposed through the extrusion technology.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
Zhiguang Wang, Liyun Pu, Yuchen Yao, Jie Yang, Liping Li, Jinrong Luo, Shengquan Zhu, Qiang Zeng, Shaoqin Ruan
Summary: This study investigated the use of hydrated magnesia carbonates as the binding material for the production of aerated concrete, and studied the impacts of material design on the properties of aerated concrete. The results showed that the selection of Ca/Mg ratio and water/binder ratio in raw materials directly determined the properties of the aerated concrete.
JOURNAL OF BUILDING ENGINEERING
(2023)
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)
