Article
Construction & Building Technology
M. H. Lai, S. A. M. Binhowimal, A. M. Griffith, L. Hanzic, Qing Wang, Zhouyi Chen, J. C. M. Ho
Summary: Concrete shrinkage needs to be carefully considered in the design of reinforced concrete structures, with factors such as water-to-cementitious material ratio, dosage of superplasticizer, concrete strength, and cementitious paste volume playing key roles. The authors proposed using wet packing density to account for the combined effect of water-to-cementitious material ratio and superplasticizer on concrete shrinkage, leading to better prediction of shrinkage behavior. The shrinkage design model developed by the authors can predict concrete shrinkage at different ages more accurately than existing standards.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
M. H. Lai, S. A. M. Binhowimal, A. M. Griffith, L. Hanzic, Zhouyi Chen, Qing Wang, J. C. M. Ho
Summary: This paper investigates the shrinkage of concrete and proposes a method of reducing concrete shrinkage through wet packing density. It is suggested that the shrinkage of concrete is negatively correlated to wet packing density, taking into account the volume of cementitious paste.
STRUCTURAL CONCRETE
(2022)
Article
Chemistry, Multidisciplinary
Jesus Diaz, Jaime C. Galvez, Marcos G. Alberti, Alejandro Enfedaque
Summary: This paper discusses the packing models essential for the design of ultra-high-performance concrete (UHPC), focusing on continuous and discrete models, and highlights the variation in compressive strength values of mixtures with different cement contents and proportions of additions at seven and 28 days.
Article
Engineering, Chemical
S. H. Chu, W. L. Lam, L. Li, Chi Sun Poon
Summary: The particle packing of cementitious materials is crucial for the performance of paste, especially in 3D printable concrete and ultra-high performance concrete. However, the scientific understanding of particle packing in these materials is insufficient. This study used the wet packing method to measure the wet packing density of ternary particle systems and determined the optimum system. Comparison with existing models showed the limitations of the current model. A design approach based on packing density will advance particle packing-oriented cement and concrete science for sustainable design.
Article
Engineering, Chemical
J. J. Chen, G. X. Guan, P. L. Ng, A. K. H. Kwan, S. H. Chu
Summary: The study demonstrated that adding powder waste as paste and aggregate replacements can increase the packing densities and strength of concrete while reducing cement and aggregate consumption. Additionally, separately optimizing the paste phase and aggregate phase is an effective way to optimize concrete mix design.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Automation & Control Systems
Swamy Naga Ratna Giri Pallapothu, Rathish Kumar Pancharathi, Rakesh Janib
Summary: This study presents an innovative approach using machine learning techniques and particle packing theories to predict concrete compressive strength, offering a more efficient and reliable method compared to traditional empirical models. The results demonstrate significant advancements in accurately estimating concrete strength, with the potential to revolutionize concrete mix design and improve construction practices.
ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE
(2023)
Article
Construction & Building Technology
Mianheng Lai, Kaijie Wu, Xiaoling Ou, Mengru Zeng, Chengwei Li, Johnny Ching Ming Ho
Summary: River sand has been widely used as fine aggregate in concrete production, but the decreasing supply calls for alternative sources. Manufactured sand, produced by mechanical crushing, is gaining popularity as a replacement. This article investigates the mechanical performance of concrete-filled-steel-tube columns with manufactured sand and highlights the significant impact of wet packing density on their strength.
STRUCTURAL CONCRETE
(2022)
Article
Construction & Building Technology
Nan Zhang, Ming Xia, Jay Sanjayan
Summary: The study introduces a Short-duration Near-Nozzle Mixing (SDNNM) technique using a customized high shear mixer to address the rheological demands for buildability and pumpability during 3D concrete printing. The research investigates the impact of sand characteristics on mixing energy consumption, flowability, compressive strength, and microstructure, highlighting the importance of sand packing density in achieving the optimal mix for comparable compressive strength. Results show that the SDNNM technique using a 90-second mixing time can achieve high flowability and compressive strength in printable concrete. Three 3D printing trials were conducted to verify the feasibility of the SDNNM technique.
CEMENT AND CONCRETE RESEARCH
(2022)
Article
Construction & Building Technology
Ye Shi, Guangcheng Long, Xiaohui Zeng, Youjun Xie, Huihui Wang
Summary: GUHPC, with very low cement content, shows good mechanical performance and low environmental impact. Enhancing chemical effects through nanomaterials and chemical activator, along with multi-scale particles system, can improve the initial packing density of GUHPC.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Ye Shi, Guangcheng Long, Xiaohui Zeng, Youjun Xie, Huihui Wang
Summary: The development of Green Ultra-High Performance Concrete (GUHPC) has attracted attention in the construction industry, with the potential to achieve high mechanical performance and low environmental impact by adding nanomaterials and chemical activator. Experimental results show that GUHPC with good mechanical properties and low environmental impact can be prepared with low cement content.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Engineering, Chemical
Xiang Zhou, Youjun Xie, Guangcheng Long, Xiaohui Zeng, Jiangteng Li, Fan Wang
Summary: In this study, the passing ability of self-compacting concrete (SCC) was simulated using three-dimensional discrete element method (DEM), and the reliability of the model was verified through laboratory tests. The results showed that particle size has a significant effect on the passing rate, and the passing rate is related to the ratio and difference between the bar spacing and the maximum aggregate size.
Article
Engineering, Chemical
Mingrui Dong, Zhongzheng Wang, Yixiang Gan
Summary: This study adopts the discrete element method (DEM) to propose a strategy for tailoring packing structures by controlling the cohesive forces between particles. By comparing the results with previous experiments, the effectiveness of this strategy is demonstrated, and it is found that larger clusters tend to form looser packing structures. The study also reveals that the effect of cohesion varies throughout different stages of packing, which sheds light on the understanding of wet granular packing.
Article
Construction & Building Technology
Fayez Moutassem, Samir E. Chidiac
Summary: This paper proposes a mathematical model approach to improve the sustainability of the concrete industry and investigates the link between packing density, concrete mixture, rheological properties, and compressive strength. The results show that packing density provides a consistent and reliable link, and the concrete mixture composition can be designed to achieve the target performance and ensure quality control.
ACI MATERIALS JOURNAL
(2023)
Article
Construction & Building Technology
Donguk Choi, Kyungchan Hong, Munkhtuvshin Ochirbud, Didar Meiramov, Piti Sukontaskuul
Summary: This study investigates the use of recycled sand in the fabrication of ultra-high performance concrete (UHPC) and ultra-high performance fiber-reinforced concrete (UHPFRC). The mechanical characteristics, autogenous shrinkage development, and microstructure of the UHPC/UHPFRC are studied through experiments and tests. The results show that the green concrete has high strength and elastic modulus, low environmental impact, and good economic performance.
INTERNATIONAL JOURNAL OF CONCRETE STRUCTURES AND MATERIALS
(2023)
Article
Engineering, Chemical
Zhongzheng Wang, Jean-Michel Pereira, Yixiang Gan
Summary: In this study, the packing of wet monodisperse spheres with controlled falling height was experimentally investigated, showing a decrease in packing fraction with smaller grain size and free fall height. A model was developed to describe the effects of interparticle force and falling height on packing fraction, resulting in the observation of a universal law applicable to both wet particles and dry powders. This study deepens the understanding of packing of cohesive spheres and provides a simple experimental method for generating granular media with tailored packing fraction.
Article
Construction & Building Technology
Jinxu Mo, Fengming Ren, Shiyu Tian, Qing Wang, Johnny Ching Ming Ho
Summary: This paper investigates the impact of crumb rubber (CR) particle size on the mechanical and microstructure properties of crumb rubber concrete (CRC). The results show that as the size of CR decreases, the workability of CRC significantly improves, and the apparent density and strength exhibit a trend of initial decrease followed by an increase. The presence of CR greatly improves the brittleness of the concrete, with smaller-sized CR showing greater effectiveness.
STRUCTURAL CONCRETE
(2023)
Article
Construction & Building Technology
Qing Wang, Zihao Xiong, Jun Zhang, Zhaosong Fang, Mianheng Lai, Johnny Ho
Summary: This study investigates the full life-cycle shrinkage of polyvinyl alcohol fiber reinforced engineered cementitious composite (PVA-ECC) through experimental testing and simulation analysis. The results show that PVA fiber has a significant restraint effect on the shrinkage behavior of PVA-ECC, and a shrinkage model considering fiber influence coefficient can effectively simulate the shrinkage characteristics.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
F. M. Ren, S. Y. Tian, L. Gong, J. L. Wu, J. X. Mo, C. L. Lai, M. H. Lai
Summary: This paper investigates the seismic performance of the ring beam joint connecting FTCES column and RC/ESRC frame beam. The proposed joint provides reliable connection and exhibits favorable seismic performance.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
M. H. Lai, W. C. Lao, W. K. Tang, L. Hanzic, Q. Wang, J. C. M. Ho
Summary: Superplasticizer (SP), especially poly-carboxylate based, improves the strength and workability limits of cement powder paste by reducing water demand for hydration. However, it also increases viscosity at high shear flow, leading to impaired pumpable distance and mixing uniformity.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
M. H. Lai, Z. H. Chena, J. Cuia, J. P. Zhonga, Z. R. Wua, J. C. M. Ho
Summary: Tests were conducted on 360 specimens to investigate the post-fire behavior of slag concrete containing supplementary cementitious material (SCM) consisting of fly ash (FA) or silica fume (SF) upon exposure to elevated temperatures. The study revealed that using basic oxygen furnace slag coarse aggregate (BSSCA) in concrete mix design improved the post-fire residual strength. Additionally, replacing a portion of cement with FA/SF had no detrimental effect on the residual strength, indicating that the combined use of BSSCA and SCM could produce more sustainable and robust concrete after fire exposure.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Qing Wang, Yuxuan Zhou, Linhui Huang, Mianheng Lai, Johnny Ho
Summary: In this study, basalt fiber was selected to replace polyvinyl alcohol (PVA) fiber as reinforcement due to its high temperature resistance. The visual observations and strength deterioration of high strength engineered cementitious composites (HSECC) were evaluated after heating. The incorporation of basalt fiber has shown potential in improving the flexural behavior of HSECC under elevated temperatures, with an effective enhancement of the interfacial transition zone (ITZ) at 200 and 400 degrees Celsius.
Article
Construction & Building Technology
Z. C. Huang, J. C. M. Ho, J. Cui, F. M. Ren, X. Cheng, M. H. Lai
Summary: This study investigates the influence of steel slag on concrete at elevated temperatures, showing that concrete containing steel slag coarse aggregate and/or ground granulated blast furnace slag (GGBFS) can enhance its thermal resistance. Adding GGBFS effectively mitigates the reduction in post-fire relative strength of concrete containing steel slag. Additionally, the EC2 Model was proven to be conservative in estimating the post-fire residual strength of steel slag concrete.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Engineering, Civil
S. Y. Tian, J. L. Wu, J. X. Mo, C. L. Lai, F. M. Ren, M. H. Lai
Summary: Fiber-reinforced polymer (FRP) tube-concrete-encased steel (FTCES) column exhibits excellent strength, stiffness, and ductility, but its practical application is limited due to a lack of knowledge on the behavior of the entire structural system, especially the beam-column joint. To address this gap, a demountable beam-column joint using high-strength bolts was proposed. Experimental results showed that this joint provided an effective and simple connection with favorable seismic performance. Additionally, an analytical model was proposed, which accurately predicted the peak load of the joint.
Proceedings Paper
Construction & Building Technology
Y. H. Lin, Y. Y. Jin, J. C. M. Ho, M. H. Lai
Summary: Steel slag, a waste by-product in the steel industry, is increasingly being used as a replacement for natural aggregates in making concrete, providing a sustainable solution to environmental problems. Research shows that steel slag concrete has superior strength and stiffness. However, its unique chemical composition may cause instability in concrete. To solve this problem, a steel slag concrete-filled-steel-tube (SSCFST) column was proposed, which enhances the overall behavior of the column by confining the concrete with a steel tube.
PROCEEDINGS OF THE 17TH EAST ASIAN-PACIFIC CONFERENCE ON STRUCTURAL ENGINEERING AND CONSTRUCTION, EASEC-17 2022
(2023)
Proceedings Paper
Construction & Building Technology
J. H. Mo, M. R. Zeng, S. J. Yang, J. C. M. Ho, M. H. Lai
Summary: Manufactured sand (MS), as a river sand (RS) substitute, has been investigated for its application in concrete-filled-steel-tube (CFST) columns. Experimental study found that replacing RS with MS altered the fresh and hardened properties of concrete. CFST columns failed due to local buckling and the irregularity of local buckling increased with the MS replacement ratio. Additionally, the load-strain behavior of CFST columns changed with the MS replacement ratio. Wet packing density (WPD) of concrete is a better indicator than MS replacement ratio for concrete strength and CFST column load-carrying capacity.
PROCEEDINGS OF THE 17TH EAST ASIAN-PACIFIC CONFERENCE ON STRUCTURAL ENGINEERING AND CONSTRUCTION, EASEC-17 2022
(2023)
Proceedings Paper
Construction & Building Technology
X. L. Ou, J. C. M. Ho, M. H. Lai
Summary: CFST column, with advantages of superior strength, stiffness and ductility, has been widely used in construction. However, current design codes fail to accurately predict the load-carrying capacity of CFST columns, especially when material strengths exceed their limitations. This study evaluates the applicability of current design codes through a comprehensive analysis of 177 test results, and finds that EC4 provides the most accurate prediction.
PROCEEDINGS OF THE 17TH EAST ASIAN-PACIFIC CONFERENCE ON STRUCTURAL ENGINEERING AND CONSTRUCTION, EASEC-17 2022
(2023)
Article
Construction & Building Technology
Qi Jiang, Wei Liu, Shaopeng Wu, Xuanwen Gou
Summary: This study analyzes the erosion mechanisms of NaCl solution on asphalt concrete and finds that NaCl solution softens asphalt and promotes the intrusion of crystalline salt into it. Salt crystallization alters the surface roughness of aggregates, resulting in a decrease in skid resistance but an improvement in compressive strength. Additionally, the concentration of NaCl solution initially has no significant impact on the mechanical performance of asphalt concrete, but its domination gradually increases with the intensification of cyclic effects.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Lili Kan, Lan-qing Dai, Ning Kong, Bin Peng, Fei Wang
Summary: This paper investigates the effect of freezing and thawing cycles on the tensile behavior of cracked ultra-high performance concrete (UHPC). The results show that long-term freezing and thawing action deteriorates the cracking strength, tensile strength, tensile strain, and strain energy of cracked UHPC. On the other hand, the action of water generally favors the development of tensile properties of UHPC. The crack distribution tends to be unsaturated under freezing and thawing environment, and the re-hydration reaction is hindered. The pore structure near the crack varies under different environments.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Xin Xiao, Jingwei Li, Qingke Meng, Xiangshan Hou, Yanhui Liu, Xujiang Wang, Wenlong Wang, Shengtao Lu, Yuzhong Li, Yanpeng Mao, Tong Li
Summary: Preparing gypsum-based self-leveling mortar (GSLM) using beta-hemihydrate gypsum and solid wastes-derived sulfoaluminate cement (WSAC) can improve the mechanical performance of the mortar, but phosphorus impurities can weaken the hydration speed and degree.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Sihang Bao, Junzhen Di, Yanrong Dong, Ziqing Gao, Qing Gu, Yuanfang Zhao, Hongyu Zhai
Summary: Tailings dam break and leakage accidents pose a threat to the safety of people in mining areas and cause severe environmental pollution. This study focuses on solidifying tailing sand using microbial induced calcite precipitation (MICP) to improve strength and fix heavy metals. The curing time of MICP bio-cemented tailings is found to significantly impact the strength of tailings, while its effect on heavy metal fixation is minimal. The optimized MICP curing time is 10 days, resulting in improved strength and cementation of tailings particles.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Ferhat Benmahiddine, Fares Bennai, Achraf Charaka, Ameur El Amine Hamami, Abdelkader Tahakourt, Rafik Belarbi
Summary: This paper studied the effects of hysteresis on the hygrothermal behavior at the building scale. Through laboratory validation and numerical simulations, it was found that hysteresis has a significant impact on the relative humidity and total heat fluxes in buildings, while it does not have a noticeable effect on temperature variations.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
You Gao, Wei He, Xiayang Zhang, De'an Sun, Pei Li
Summary: This study determined the boundary line between the swelling and compression deformation zone in lateritic clay through wetting tests, and proposed a simple bimodal SWRC model. It also found that the existing strength model underestimated the tested values in the medium to high suction range, therefore a segmented strength equation was introduced for enhanced predictions of the strength properties of lateritic clay.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Prabhath Ranjan Kumar Soda, Asheer Mogal, Kalyan Chakravarthy, Nikhil Thota, Nimish Bandaru, Sanjay Kumar Shukla, K. M. Mini
Summary: This study investigates the use of encapsulated bacteria to improve the self-healing ability of concrete. Through various tests, it is found that using 20% cement-coated alginate beads (CCAB) and 5% nanosilica (NS) can achieve optimal strength and healing. This research is significant for enhancing the durability of concrete.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Shizhe Wang, Haiping Wu, Wen Yang, Wei Wang, Zhibo Zhu, Kun Nie, Luoxin Wang, Hua Wang, Jing Wu
Summary: In this study, photothermal-heat storage concrete (PHSC) was developed with excellent photothermal conversion performance and heat storage capacity. By absorbing and storing solar energy during the day and releasing it at night, PHSC can effectively reduce energy consumption in buildings.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Robin Deb, Jialuo He, Geetika Mishra, Yaghoob (Amir) Farnam
Summary: Incorporation techniques of phase change materials in cementitious composites have a significant influence on thermal properties. This study investigated the thermal behavior of low-temperature PCM when subjected to varying temperature change rates and pore confinement inside the porous network of lightweight aggregates. The results showed that ramp rates affect the nucleation and crystallization growth process during the phase transition, and the pore structure of the aggregates affects the supercooling phenomenon and confinement pressure of the PCM.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Eduardo Ferreira, Payam Sotoudeh, Dagmar Svecova
Summary: This study investigates the fatigue behavior of concrete under different stress reversal conditions. The results indicate that stress reversal generally causes more severe damage and reduces the cycles to failure compared to tensile fatigue. Additionally, adding some level of compression contributes to the energy required for failure under stress reversal fatigue. Specimens with higher concentration of fractured aggregates achieve longer fatigue lives.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Mag Raj Gehlot, Sandeep Shrivastava
Summary: This study evaluates the compatibility relationship between plaster bonds and the substrate under an accelerated aging environment, and finds that incorporating an appropriate amount of granite cutting waste can improve the strength parameters and adhesion of the cement mortar.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Min Zhang, Qirui Luo, Mingke Deng, Shixing Zhao
Summary: This study investigated the bond behavior between carbon FRCM composites with added short fibers and concrete substrates. The effects of different factors were considered and 36 specimens were tested and discussed. The experimental results were analyzed in terms of failure mode, load-slip curve, and characteristic parameters, and the contribution of weft yarns was taken into account in the developed bondslip model.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Dengkai Liu, Hongniao Chen, Ray Kai Leung Su
Summary: The susceptibility of building stones to fire and high temperature was investigated in this study by examining their physical and mechanical properties. The results show that both compressive and tensile properties of stones are affected by temperature changes. The tensile strength is particularly sensitive to temperature changes, requiring special attention to the components subjected to tensile stress in stone buildings. Principal component analysis was used to predict the mechanical properties of stones, providing a new method for calculating the residual mechanical properties after high temperature or fire.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Joso Maria Raposo, Eduardo Cavaco, Luis Costa Neves, Eduardo Julio
Summary: This paper investigates the correlation between the friction coefficient and the surface roughness of concrete-to-concrete interfaces. Experimental tests were performed on specimens with different surface treatments, and the surface roughness parameters were analyzed and correlated with the shear strength and friction coefficient. The results showed that certain roughness parameters had a strong positive correlation with the friction coefficient, while others had little or no correlation. A novel combined roughness parameter with optimized correlation was proposed.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Chiara Riccardi, Massimo Losa
Summary: The interest in using bio materials in asphalt pavements is growing due to economic reasons and environmental benefits. This study aimed to review the use of bio extenders as additives in binders, with a focus on replacements greater than 20% of fossil binder. The properties of bio-extended binders were found to vary substantially depending on the biomass source and production process.
CONSTRUCTION AND BUILDING MATERIALS
(2024)