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This study focused on the plastic shrinkage and cracking of 3D printed mortar mixed with recycled sand as fine aggregates. The test methods for free and restrained plastic shrinkage were designed and improved to simulate the plastic shrinkage of 3D printed mortar. The shrinkage and the development of cracks under constraints were measured by image processing, and the effect of recycled sand was evaluated. 3D printed natural sand mortar and 3D printed recycled sand mortar with replacement ratios of 25%, 50%,75%, and 100% were tested and analyzed. Results showed that the plastic shrinkage of the 3D printed mortar increased with the increase of recycled sand content. With the higher replacement ratio of recycled sand, the plastic cracking of 3D printed mortar under restraint conditions showed a higher cracking depth. It can be concluded that the 3D printed mortar mixed with recycled sand shows a minor plastic shrinkage rate under a 50% replacement ratio. When a 100% replacement ratio of recycled sand is reached, the 3D printed recycled sand mortar needs additional consideration of shrinkage compensation design to avoid early-age cracking in the plastic stage.
Hanghua Zhang; Jianzhuang Xiao. Plastic shrinkage and cracking of 3D printed mortar with recycled sand. Construction and Building Materials 2021, 302, 124405 .
AMA StyleHanghua Zhang, Jianzhuang Xiao. Plastic shrinkage and cracking of 3D printed mortar with recycled sand. Construction and Building Materials. 2021; 302 ():124405.
Chicago/Turabian StyleHanghua Zhang; Jianzhuang Xiao. 2021. "Plastic shrinkage and cracking of 3D printed mortar with recycled sand." Construction and Building Materials 302, no. : 124405.
3D concrete printing technique offers a novel approach to build new infrastructure. However, the microstructure of 3D printed concrete has rarely been studied so far. This study presents the microstructural characterization of 3D printed concrete by using MIP and X-ray CT. The void size distribution reported in this study covers a wide spectrum. The mechanical performance of the 3D printed concrete, along different directions, is also investigated. This study reveals that a higher amount of macropores and large voids are present in the 3D printed samples, attributed to the movement of the printhead, elimination of vibration, and rapid moisture loss. Moreover, the morphologies of the voids are more irregular and elongated. This is more pronounced at the interlayer than in the filament. As a result, the strength of 3D printed samples is lower than that of mould-cast specimens.
Shiwei Yu; Ming Xia; Jay Sanjayan; Lin Yang; Jianzhuang Xiao; Hongjian Du. Microstructural characterization of 3D printed concrete. Journal of Building Engineering 2021, 44, 102948 .
AMA StyleShiwei Yu, Ming Xia, Jay Sanjayan, Lin Yang, Jianzhuang Xiao, Hongjian Du. Microstructural characterization of 3D printed concrete. Journal of Building Engineering. 2021; 44 ():102948.
Chicago/Turabian StyleShiwei Yu; Ming Xia; Jay Sanjayan; Lin Yang; Jianzhuang Xiao; Hongjian Du. 2021. "Microstructural characterization of 3D printed concrete." Journal of Building Engineering 44, no. : 102948.
Huixia Wu; Chaofeng Liang; Jianzhuang Xiao; Jianguang Xu; Zhiming Ma. Early‐age behavior and mechanical properties of cement‐based materials with various types and fineness of recycled powder. Structural Concrete 2021, 1 .
AMA StyleHuixia Wu, Chaofeng Liang, Jianzhuang Xiao, Jianguang Xu, Zhiming Ma. Early‐age behavior and mechanical properties of cement‐based materials with various types and fineness of recycled powder. Structural Concrete. 2021; ():1.
Chicago/Turabian StyleHuixia Wu; Chaofeng Liang; Jianzhuang Xiao; Jianguang Xu; Zhiming Ma. 2021. "Early‐age behavior and mechanical properties of cement‐based materials with various types and fineness of recycled powder." Structural Concrete , no. : 1.
This paper presents an investigation on the effects of recycled coarse aggregate (RCA) replacement ratio and recycled rubber particle (RRP) size on the hysteretic energy and damping variation of recycled aggregate concrete (RAC) under various cyclic compression loadings. The hysteretic energy and damping of RAC v. s. The same stress amplitude and strain amplitude were compared and analyzed, and the mechanism of hysteretic energy and damping variation of RAC were discussed. The results show that the hysteretic energy of RAC increases with increasing RCA replacement ratio and RRP size under the same stress amplitude, while an opposite phenomenon is observed under the same strain amplitude. The incorporated RRPs and RCAs improve the hysteretic energy and damping of RAC in the elastic stage under the same stress amplitude. The hysteretic energy and damping variation of RAC are closely related to the damage evolution and dynamic modulus degradation with increasing levels of applied loading. The hysteretic energy follows a power function of the applied stress amplitude or strain amplitude, and the energy dissipation within the RAC defects is the main damping mechanism of RAC. The damping variation of RAC under the same stress amplitude is mainly affected by the hysteretic energy as the stress evolves; however, the damping variation under the same strain amplitude is primarily impacted by the dynamic modulus as the strain evolves.
Chaofeng Liang; Jianzhuang Xiao; Chunhui Wang; Zhiming Ma. Hysteretic energy and damping variation of recycled aggregate concrete with different cyclic compression loading levels. Journal of Building Engineering 2021, 44, 102936 .
AMA StyleChaofeng Liang, Jianzhuang Xiao, Chunhui Wang, Zhiming Ma. Hysteretic energy and damping variation of recycled aggregate concrete with different cyclic compression loading levels. Journal of Building Engineering. 2021; 44 ():102936.
Chicago/Turabian StyleChaofeng Liang; Jianzhuang Xiao; Chunhui Wang; Zhiming Ma. 2021. "Hysteretic energy and damping variation of recycled aggregate concrete with different cyclic compression loading levels." Journal of Building Engineering 44, no. : 102936.
Recycled aggregate concrete with seawater and sea sand (SSRAC) was tested under uniaxial compressive loading with five strain rates (from 10−5 to 10−1 /s). The peak stress, elastic modulus, peak strain (strain at the peak stress) and ultimate strain of tested stress–strain curves as well as the failure patterns were analyzed. The test results indicate that strain rates have significant effects on the peak stress and elastic modulus of SSRAC. Compared with quasi-static state, the peak stress and the elastic modulus was increased by 26.29% and 64.69% for M-SSRAC (SSRAC with medium shell particle contents), and 34.23% and 74.98% for H-SSRAC (SSRAC with high shell particle contents) at a strain rate of 10−1/s, respectively. Furthermore, the dynamic increase factors (DIFs) of SSRAC were evaluated based on a comparison analysis with those of the recycled aggregate concrete (RAC) and ordinary concrete reported in the literature. When the strain rate is 10−1/s, the DIFs of peak stress for M-SSRAC and H-SSRAC are 1.26 and 1.34, and the DIFs of elastic modulus are 1.65 and 1.75, respectively. Finally, based on an analysis of the pore structures by computed technology (CT) scanning, the shell particles decrease the porosity and contribute to the compressive strength and elastic modulus of H-SSRAC specimens, which therefore leads to the lower peak strain and ultimate strain.
Jianzhuang Xiao; Kaijian Zhang; Qingtian Zhang. Strain rate effect on compressive stress–strain curves of recycled aggregate concrete with seawater and sea sand. Construction and Building Materials 2021, 300, 124014 .
AMA StyleJianzhuang Xiao, Kaijian Zhang, Qingtian Zhang. Strain rate effect on compressive stress–strain curves of recycled aggregate concrete with seawater and sea sand. Construction and Building Materials. 2021; 300 ():124014.
Chicago/Turabian StyleJianzhuang Xiao; Kaijian Zhang; Qingtian Zhang. 2021. "Strain rate effect on compressive stress–strain curves of recycled aggregate concrete with seawater and sea sand." Construction and Building Materials 300, no. : 124014.
3D concrete printing technology has been well developed and applied in various engineering fields. Anisotropy is one of the most important properties for the 3D printed cementitious material. Like fiber reinforced composite matters, if the material property is symmetric in only one plane, then the material is called as monoclinic with 13 independent elastic moduli in its constitutive law. In this study, multiscale finite element analysis of the monoclinic 3D printed cementitious material is made. Both material and geometrical randomness and uncertainty are quantified and investigated. At micro scale the material randomness is explored using nanoindentation technique. In addition, the geometrical uncertainty is analyzed through multiscale finite element method at meso scale. Then a stochastic finite element numerical experiment of 3D printed concrete simple supported beam under vertical loading is made based on the 13 independent stochastic elastic constants at macro scale. Computational methods proposed in this paper could be widely applied in 3D concrete printing industry.
Yu-Ching Wu; Qianfan Yang; Xiangrui Kong; Peng Zhi; Jianzhuang Xiao. Uncertainty quantification for the representative volume element of geometrically monoclinic 3D printed concrete. International Journal of Solids and Structures 2021, 226-227, 111102 .
AMA StyleYu-Ching Wu, Qianfan Yang, Xiangrui Kong, Peng Zhi, Jianzhuang Xiao. Uncertainty quantification for the representative volume element of geometrically monoclinic 3D printed concrete. International Journal of Solids and Structures. 2021; 226-227 ():111102.
Chicago/Turabian StyleYu-Ching Wu; Qianfan Yang; Xiangrui Kong; Peng Zhi; Jianzhuang Xiao. 2021. "Uncertainty quantification for the representative volume element of geometrically monoclinic 3D printed concrete." International Journal of Solids and Structures 226-227, no. : 111102.
Recycling hardened cement paste powder (HCPP) as an alternative binder is a high-efficiency approach to reducing the amount of hardened cement paste waste. In this work, the performance of the cement-based materials doped with HCPP from various sources is investigated. The results show that the HCPP particle is irregular, and a CO2-curing treatment makes HCPP denser through changing unstable CH into stable CaCO3 and silica gel. Substituting HCPP for 50% cement results in a 13.3% increase in the drying shrinkage, and the blended HCPP is unfavorable to the mechanical strength and transport properties. For example, the 28-d compressive strength and sorptivity coefficient of recycled mortar including 30% HCPP are approximately 27.6% lower and 55.3% higher than those of plain mortar without HCPP. Original hardened cement paste with low w/c ratio or blended with SCMs (fly ash, silica fume and mineral powder) improves the properties of preparing HCPP and its mortar, but the cement grade in original hardened cement paste has little influence on the properties of preparing HCPP and its mortar. Employing CO2-curing treatment on HCPP improves the properties of prepared cement-based materials; for instance, the 28-d compressive strength and sorptivity coefficient of recycled mortar with 30% carbonated HCPP are 12.6% higher and 34.8% lower compared with recycled mortar including 30% un-carbonated HCPP. Recycled mortar including 30% carbonated HCPP, as well as incorporating 30% HCPP from SCM-blended paste, shows water transport properties similar to plain mortar.
Huixia Wu; Chaofeng Liang; Jianzhuang Xiao; Zhiming Ma. Properties and CO2-curing enhancement of cement-based materials containing various sources of waste hardened cement paste powder. Journal of Building Engineering 2021, 44, 102677 .
AMA StyleHuixia Wu, Chaofeng Liang, Jianzhuang Xiao, Zhiming Ma. Properties and CO2-curing enhancement of cement-based materials containing various sources of waste hardened cement paste powder. Journal of Building Engineering. 2021; 44 ():102677.
Chicago/Turabian StyleHuixia Wu; Chaofeng Liang; Jianzhuang Xiao; Zhiming Ma. 2021. "Properties and CO2-curing enhancement of cement-based materials containing various sources of waste hardened cement paste powder." Journal of Building Engineering 44, no. : 102677.
Currently, construction projects are getting more complex, applying more information and communication technologies (ICT), while few studies use real-time data to dynamically optimize construction. The purpose of this article is to study the current development status of the optimization applied dynamically in the construction phase and their potential for applying real data collected by ICT. This article reviews 72 relevant optimization methods and identified some of the ICT research studies that can provide them with dynamic data. The dynamic triggering mode of each research is first analyzed, then its dynamic way, dynamic data, data resource, optimization object, and method are identified and formulated. The results reveal the great value of dynamic optimization in dealing with the complicated and uncertain contextual conditions in construction. Different dynamic triggering modes have different affinities with real data. Then, through the analysis of ICT articles, the huge potential of these dynamic optimization methods in applying real data is shown. This paper points out the most practical dynamic mode for engineers or managers to continuously apply optimization methods to solve dynamic problems in construction, and put forward scientific questions for related researchers: How does one combine ICT with the event dynamics or uncertain parameters? Based on this, the research gap of this area is identified a conceptual solution is proposed.
Boda Liu; Bin Yang; Jianzhuang Xiao; Dayu Zhu; Binghan Zhang; Zhichen Wang; Miaosi Dong. Review of Optimization Dynamically Applied in the Construction and the Application Potential of ICT. Sustainability 2021, 13, 5478 .
AMA StyleBoda Liu, Bin Yang, Jianzhuang Xiao, Dayu Zhu, Binghan Zhang, Zhichen Wang, Miaosi Dong. Review of Optimization Dynamically Applied in the Construction and the Application Potential of ICT. Sustainability. 2021; 13 (10):5478.
Chicago/Turabian StyleBoda Liu; Bin Yang; Jianzhuang Xiao; Dayu Zhu; Binghan Zhang; Zhichen Wang; Miaosi Dong. 2021. "Review of Optimization Dynamically Applied in the Construction and the Application Potential of ICT." Sustainability 13, no. 10: 5478.
3D printed concrete (3DPC) has become increasingly popular in the last decade. However, the mechanical and microstructural evolution of the 3DPC under extremely high-temperature environments has not been fully understood. The purpose of this study is to experimentally investigate the influence of recycled sand and polyethylene (PE) fiber on the mechanical properties and pore structure of the 3DPC under high temperatures. A series of compressive, flexural, and CT scanning tests were conducted for 3DPC specimens under 20 °C, 200 °C, 400 °C, 600 °C, and 800 °C, respectively. It shows that there is a similar degradation trend of the compressive and flexural strengths of 3D printed and mold-casted specimens with the same mixture at elevated temperatures. 3DPC specimens delaminated through the interface between layers and strips in the layer at 600 °C and 800 °C, respectively, due to the weak adhesion between layers and strips. The addition of recycled sand and PE fiber into the 3DPC could modify its pore structure and mitigate the risks of explosive spalling.
Jianzhuang Xiao; Nv Han; Lihai Zhang; Shuai Zou. Mechanical and microstructural evolution of 3D printed concrete with polyethylene fiber and recycled sand at elevated temperatures. Construction and Building Materials 2021, 293, 123524 .
AMA StyleJianzhuang Xiao, Nv Han, Lihai Zhang, Shuai Zou. Mechanical and microstructural evolution of 3D printed concrete with polyethylene fiber and recycled sand at elevated temperatures. Construction and Building Materials. 2021; 293 ():123524.
Chicago/Turabian StyleJianzhuang Xiao; Nv Han; Lihai Zhang; Shuai Zou. 2021. "Mechanical and microstructural evolution of 3D printed concrete with polyethylene fiber and recycled sand at elevated temperatures." Construction and Building Materials 293, no. : 123524.
This research assessed the shrinkage of mortar containing recycled powder generated from aerated blocks and bricks by replacing cement with a ratio of 30%. Five mix proportions were formulated to prepare mortar plate specimens. AP represents the mixes with aerated block powder and BP represent the mixes with sintered brick powder. Among all of the mixes, AP1 and BP1 was formulated at the same water binder ratio as that of the reference mix, and the same fluidity as the reference was maintained in AP2 and BP2 by adjusting the water content. Digital image correlation (DIC) technique was used to evaluate the strain distribution during the plastic shrinkage stage. The results showed that the mortar containing the aerated block powder presented a higher risk of cracking. On the contrary, the brick powder had a lower water requirement, as a result, a lower risk of cracking. The aerated block powder particles contain pores of 2–3 μm size, which seriously reduces the fluidity of the mortar and causes a tremendous shrinkage.
Qiong Liu; Jianzhuang Xiao; Amardeep Singh. Quantification of plastic shrinkage and cracking in mortars containing different recycled powders using digital image correlation technique. Construction and Building Materials 2021, 293, 123509 .
AMA StyleQiong Liu, Jianzhuang Xiao, Amardeep Singh. Quantification of plastic shrinkage and cracking in mortars containing different recycled powders using digital image correlation technique. Construction and Building Materials. 2021; 293 ():123509.
Chicago/Turabian StyleQiong Liu; Jianzhuang Xiao; Amardeep Singh. 2021. "Quantification of plastic shrinkage and cracking in mortars containing different recycled powders using digital image correlation technique." Construction and Building Materials 293, no. : 123509.
A probabilistic sustainability design method for quantifying the benefits from sustainable structural strategies under climate change is put forward in this study. To help curb the vicious circle of increasing structural and environmental degradation, the sustainable probability is defined as a conditional probability, and the interaction between structural reliability and environmental impacts is quantified. Global warming potential (GWP) is adopted as the key indicator for environmental impacts. By analyzing the trends of climate change, the GWP limit is set to match the prediction of structural resistance degradation. A new environmental impact allocation rule based on time-dependent resistance is put forward to characterize the environmental benefits of the reuse strategy. With help of the durability life prediction method for reusable components and the stochastic model for time-dependent resistance, the calculation method for sustainable probability is established, catering for both reusable and non-reusable structural components. With the Monte Carlo simulation, the proposed sustainability design process is implemented in a numerical example. Results show that the reusable structural concrete component design can simultaneously satisfy the current and future safety and environmental requirements, meeting the demand for sustainable development.
Bing Xia; Jianzhuang Xiao; Tao Ding; Kaijian Zhang. Probabilistic sustainability design of structural concrete components under climate change. Structural Safety 2021, 92, 102103 .
AMA StyleBing Xia, Jianzhuang Xiao, Tao Ding, Kaijian Zhang. Probabilistic sustainability design of structural concrete components under climate change. Structural Safety. 2021; 92 ():102103.
Chicago/Turabian StyleBing Xia; Jianzhuang Xiao; Tao Ding; Kaijian Zhang. 2021. "Probabilistic sustainability design of structural concrete components under climate change." Structural Safety 92, no. : 102103.
This paper investigates the time-dependent reliability of recycled aggregate concrete (RAC) beams made with 50% incorporation of recycled coarse aggregates. A basic method based on the series system model is adopted to calculate the reliability index, and the case studies show that the reliability index decreases with the service time: the reliability indices decrease from the values of 3.27 and 3.70 to 3.02 and 3.55 for RAC beams and normal aggregate concrete (NAC) beams during the service period of 50 years (target reliability index is 3.2 according to Chinese code) in the first case study, also indicating that the reliability index of RAC beams is lower than that of the NAC beams. Then, influencing factors such as the compressive strength, reinforcement ratio, thickness of concrete cover, carbonation rate and corrosion rate are analyzed based on a parametric study. All these factors affect the time to surface cracking and the time to reach the limit crack width of concrete cover. Finally, this investigation concludes that the methods, such as increasing the compressive strength or appropriately increasing the strength of concrete and reinforcement ratio at the same time, are feasible methods for meeting the requirements of the time-dependent reliability of concrete beams.
Kaijian Zhang; Jianzhuang Xiao. Time-dependent reliability analysis of recycled aggregate concrete beams. Journal of Building Engineering 2021, 43, 102659 .
AMA StyleKaijian Zhang, Jianzhuang Xiao. Time-dependent reliability analysis of recycled aggregate concrete beams. Journal of Building Engineering. 2021; 43 ():102659.
Chicago/Turabian StyleKaijian Zhang; Jianzhuang Xiao. 2021. "Time-dependent reliability analysis of recycled aggregate concrete beams." Journal of Building Engineering 43, no. : 102659.
An experimental study with 72 specimens was conducted to determine the effects of various factors on the mechanical behaviours of grouted sleeve connections, including an increase in temperature from 20 °C to 600 °C, the loading regime (uniaxial tensile loading or cyclic loading), and the grout compressive strength (83.1–91.1 MPa). After the specimens were exposed to elevated temperatures of up to 600 °C and then uniaxial tensile loading or cyclic loadings, the experimental results indicated that the sleeve was still elastic and the grout had a compressive strength of more than 83.1 MPa, which was beneficial for maintaining the mechanical behaviours of the specimens. In this study, the sleeve region was equal to the gauge length, which consisted of the length of the sleeve and three times the diameter of the rebar from each end of the sleeve. Moreover, a bilinear model was formulated to calculate the yield and ultimate loads of the heat-damaged grouted sleeve connections after different loading regimes. Finally, the constitutive relationship of the heat-damaged grouted sleeve connection was investigated. These findings will be helpful in the fire safety design of precast concrete structures.
Lianglin Liu; Jianzhuang Xiao; Tao Ding; Lei Zhang. Mechanical behaviours of heat-damaged grouted sleeve connections. Fire Safety Journal 2021, 122, 103345 .
AMA StyleLianglin Liu, Jianzhuang Xiao, Tao Ding, Lei Zhang. Mechanical behaviours of heat-damaged grouted sleeve connections. Fire Safety Journal. 2021; 122 ():103345.
Chicago/Turabian StyleLianglin Liu; Jianzhuang Xiao; Tao Ding; Lei Zhang. 2021. "Mechanical behaviours of heat-damaged grouted sleeve connections." Fire Safety Journal 122, no. : 103345.
3D printed concrete (3DPC) has drawn continuous research attention due to its potential to boost the development of construction industry. In this paper, an on-site experiment has been conducted to investigate the thermal performance of a real 3D printed concrete building. Its potential defects are detected with the infrared thermography technique. Thermal properties of the main wall body of the tested house are calculated with on-site monitoring data. The results identify a highly non-uniform temperature distribution on the exterior wall surface of the 3DPC tested house, which is mainly caused by variations of printing path and cross-section design. Other 3D printing characteristics, such as number of layers per printing, rest time during printing process and lay-by-layer appearance, can also bring side-effect to the thermal performance of 3DPC and generate thermal defects. The calculated average values of thermal resistance (R-value), effective thermal conductivity and thermal transmittance (U-value) are respectively 0.31 m2•K/W, 0.64 W/(m•K) and 2.27 W/(m2•K). The results demonstrate insufficient and unsatisfied thermal insulating performance of the 3DPC envelops as well as the complexity to depict its heat transfer process. Based on the research findings, further detailed studies of 3DPC in thermal aspect are strongly recommended.
Jingting Sun; Jianzhuang Xiao; Zhengrong Li; Xiwen Feng. Experimental study on the thermal performance of a 3D printed concrete prototype building. Energy and Buildings 2021, 241, 110965 .
AMA StyleJingting Sun, Jianzhuang Xiao, Zhengrong Li, Xiwen Feng. Experimental study on the thermal performance of a 3D printed concrete prototype building. Energy and Buildings. 2021; 241 ():110965.
Chicago/Turabian StyleJingting Sun; Jianzhuang Xiao; Zhengrong Li; Xiwen Feng. 2021. "Experimental study on the thermal performance of a 3D printed concrete prototype building." Energy and Buildings 241, no. : 110965.
The flexural properties of 3D printed concrete specimens with recycled sand reinforced by polyethylene (PE) fibres were investigated through four-point bending tests in this research. The use of recycled sand reduced the flexural stiffness and strength of 3D printed specimens loaded in various directions. From curing ages of 7 d to 14 d, the flexural strength and fracture energy of the specimens increased significantly, while the improvements from 14 d to 28 d were relatively limited. By adding PE fibres into the mix, the negative impact of adding recycled sand can be compensated, and the flexural strength of the 3D printed specimen can be obviously improved. Scanning electron microscopy results showed that the loose old cement paste attached to the recycled sand resulted in the higher porosity of the 3D printed specimens with recycled sand compared to that with only natural sand. The mechanical properties of 3D printed concrete specimens can be effectively improved by the strong interfacial bonds between the fibres and the matrix and the high tensile strength of the fibres. In practical applications, if the deformation and stiffness requirements are not strict, the replacement ratio of recycled sand can be increased if an appropriate fibre content is included.
Tao Ding; Jianzhuang Xiao; Shuai Zou; Jiangtao Yu. Flexural properties of 3D printed fibre-reinforced concrete with recycled sand. Construction and Building Materials 2021, 288, 123077 .
AMA StyleTao Ding, Jianzhuang Xiao, Shuai Zou, Jiangtao Yu. Flexural properties of 3D printed fibre-reinforced concrete with recycled sand. Construction and Building Materials. 2021; 288 ():123077.
Chicago/Turabian StyleTao Ding; Jianzhuang Xiao; Shuai Zou; Jiangtao Yu. 2021. "Flexural properties of 3D printed fibre-reinforced concrete with recycled sand." Construction and Building Materials 288, no. : 123077.
This study focuses on the relationship between the internal viscous damping and the stiffness of concrete material and structure having small deformation amplitude. New damping parameters were proposed to describe the energy dissipation capacity and the vibration–amplitude attenuation rate. An improved damping suspension test method for predicting the essential material parameters, elasticity modulus and loss modulus, was developed and validated. The results show that the viscous damping energy dissipation capacity of concrete material and structure having small deformation amplitude is proportional to the product of the loss factor and the stiffness, and the vibration‐amplitude attenuation rate is proportional to the product of the damping ratio and the natural frequency. The variation in dimensionless damping mainly results from the change in the stiffness of concrete material and structure. The porosity shows the smallest elasticity modulus and the largest energy dissipation capacity of nano‐phase in cement paste under constant loading conditions. The improved damping suspension test method is proposed based on theoretical analysis and is validated using an experiment and finite element analysis.
Chaofeng Liang; Jianzhuang Xiao; Yuanfeng Wang; Chunhui Wang; Shengqi Mei. Relationship between internal viscous damping and stiffness of concrete material and structure. Structural Concrete 2021, 22, 1410 -1428.
AMA StyleChaofeng Liang, Jianzhuang Xiao, Yuanfeng Wang, Chunhui Wang, Shengqi Mei. Relationship between internal viscous damping and stiffness of concrete material and structure. Structural Concrete. 2021; 22 (3):1410-1428.
Chicago/Turabian StyleChaofeng Liang; Jianzhuang Xiao; Yuanfeng Wang; Chunhui Wang; Shengqi Mei. 2021. "Relationship between internal viscous damping and stiffness of concrete material and structure." Structural Concrete 22, no. 3: 1410-1428.
The utilization of recycled brick aggregate (RBA) and recycled brick powder (RBP) in cementitious materials helps the reclamation of clay brick waste in construction and demolition waste. This work studied the properties of cementitious materials with RBA as aggregate and RBP as supplementary cementitious material. The RBA has lower apparent density and higher water absorption than natural aggregate, and RBP with an irregular micro-structure contains high content of silicon and aluminum oxides and possesses excellent pozzolanic activity. Incorporating RBP decreases the fluidity and increases the setting time, but the incorporated RBP improves the pore structure and decreases the average pore diameter of cementitious materials, thereby decreasing the permeability. Utilizing RBA increases the drying shrinkage, while the incorporated RBP decreases the drying shrinkage of cementitious materials; the mortar with 50% RBA and 30% RBP has the lower drying shrinkage than the common mortar without RBA and RBP. Incorporating RBA and high-volume RBP decreases the mechanical strength, while there is no obvious decrease in the mechanical strength for the mortar with 50% RBA and 30% RBP. Moreover, the flexural strength to compressive strength ratio increases with RBA and RBP incorporating. Utilizing RBA increases the water transport, while the water transport properties decrease with the RBP incorporation; incorporating appropriate content of RBA and RBP can obtain the cementitious materials with low permeability. Particularly, a significant decrease in chloride ingress occurs with the substitution of RBP.
Huixia Wu; Jianzhuang Xiao; Chaofeng Liang; Zhiming Ma. Properties of Cementitious Materials with Recycled Aggregate and Powder Both from Clay Brick Waste. Buildings 2021, 11, 119 .
AMA StyleHuixia Wu, Jianzhuang Xiao, Chaofeng Liang, Zhiming Ma. Properties of Cementitious Materials with Recycled Aggregate and Powder Both from Clay Brick Waste. Buildings. 2021; 11 (3):119.
Chicago/Turabian StyleHuixia Wu; Jianzhuang Xiao; Chaofeng Liang; Zhiming Ma. 2021. "Properties of Cementitious Materials with Recycled Aggregate and Powder Both from Clay Brick Waste." Buildings 11, no. 3: 119.
This paper investigates the utilization of powder recycled from construction and industrial waste in the construction industry. To alleviate the negative environmental impact of cement industry, recycled concrete powder (RCP) and spontaneous combustion gangue powder (SCGP) were used as supplementary materials to substitute part of the cement. Six recycled mortar mixes were designed with various contents of RCP and SCGP. In this test, the total replacement ratio of the recycled powder (RCP and SCGP) varied from 0 to 50%. The mechanical and durability properties of the recycled mortar were investigated in combination with microstructure analysis. The findings reveal that 15% RCP and 15% SCGP is a suitable combination for the recycled mortar to maintain mechanical properties comparable to those of the control mix. When the total substitution ratio of RCP and SCGP does not exceed 30%, their incorporation leads to better durability properties of the recycled mortar compared to those of the mix containing one type of recycled powder. Consistent with the mechanical and durability analyses, the microstructure analysis reveals that the combination of 15% RCP and 15% SCGP contributes to a dense structure of the mortar, which benefits from the synergetic effect of the relatively high pozzolanic reactivity of SCGP and the filling ability of RCP.
Chang Sun; Lulu Chen; Jianzhuang Xiao; Amardeep Singh; Jiahao Zeng. Compound utilization of construction and industrial waste as cementitious recycled powder in mortar. Resources, Conservation and Recycling 2021, 170, 105561 .
AMA StyleChang Sun, Lulu Chen, Jianzhuang Xiao, Amardeep Singh, Jiahao Zeng. Compound utilization of construction and industrial waste as cementitious recycled powder in mortar. Resources, Conservation and Recycling. 2021; 170 ():105561.
Chicago/Turabian StyleChang Sun; Lulu Chen; Jianzhuang Xiao; Amardeep Singh; Jiahao Zeng. 2021. "Compound utilization of construction and industrial waste as cementitious recycled powder in mortar." Resources, Conservation and Recycling 170, no. : 105561.
An experimental study on the nonlinear damping behavior of recycled aggregate concrete (RAC) beams is conducted through subjecting dynamic loadings at the different damage stages. The effects of the loading frequency, loading amplitude, damage, recycled aggregate, and replacement percentage on the energy dissipation by damping and the equivalent viscous damping ratio (EVDR) of the RAC beams are analyzed. The experimental results show that the energy dissipation and the EVDR are not directly influenced by the loading frequency, and the EVDR rises with the increasing loading amplitude for the damaged beams. The damage stage is of great significance to the damping mechanism. The EVDR is firstly increased, peaks at the yielding stage, and finally declines with the damage accumulation, and the EVDR at the yielding stage can be increased to 2.6–3.1 times compared to the undamaged RAC beams. The EVDRs are higher for the beams with the incorporation of the recycled aggregates, because of their lower stiffness and higher energy dissipation. The experimental results demonstrate that the commonly applied viscous damping model is not capable of correctly describing the damping behavior of RAC beams, whereas the modified Coulomb damping model performs much better. A shift in the damping mechanism is observed with the damage evolution, and the relationships between the damage indices and the damping parameters are established.
Chunhui Wang; Jianzhuang Xiao; Chaofeng Liang. Study on nonlinear damping behavior of damaged recycled aggregate concrete beams. Structural Concrete 2021, 22, 1429 -1444.
AMA StyleChunhui Wang, Jianzhuang Xiao, Chaofeng Liang. Study on nonlinear damping behavior of damaged recycled aggregate concrete beams. Structural Concrete. 2021; 22 (3):1429-1444.
Chicago/Turabian StyleChunhui Wang; Jianzhuang Xiao; Chaofeng Liang. 2021. "Study on nonlinear damping behavior of damaged recycled aggregate concrete beams." Structural Concrete 22, no. 3: 1429-1444.
Chloride ingress and resulting steel corrosion are the main reasons leading to durability degradation. A body of literature on chloride transport and steel corrosion in recycled aggregate concrete (RAC) is currently available, but a systematic review has been lacking. This paper presents a critical review of chloride transport in RAC, and the induced steel corrosion behaviour and cracking patterns of reinforced RAC are introduced. Related modification methods are further discussed. The results showed that the incorporated recycled aggregate (RA) increased chloride ingress in RAC, and a time-dependent characteristic was observed for the chloride diffusion coefficient. The lower RA properties led to higher chloride ingress in preparing RAC when RA substitution rates were the same; the induced environmental damage accelerated chloride ingress in RAC. Incorporating RA increased the steel corrosion risk and shortened the initial corrosion time of reinforced RAC, and the cracking pattern of reinforced RAC was different from the cracking pattern of reinforced natural aggregate concrete. Removing and enhancing the adhered old mortar of RA improve the properties of RAC, and various modification methods can be employed to improve the resistance to chloride ingress and steel corrosion in RAC. In particular, a CO2-curing treatment, which is eco-friendly, is recommended for improving the RA and RAC properties. The study of chloride ingress and steel corrosion in ultra-high performance RAC and 3D-printed RAC should be a focus in further studies.
Chaofeng Liang; Zhedong Cai; Huixia Wu; Jianzhuang Xiao; Yuming Zhang; Zhiming Ma. Chloride transport and induced steel corrosion in recycled aggregate concrete: A review. Construction and Building Materials 2021, 282, 122547 .
AMA StyleChaofeng Liang, Zhedong Cai, Huixia Wu, Jianzhuang Xiao, Yuming Zhang, Zhiming Ma. Chloride transport and induced steel corrosion in recycled aggregate concrete: A review. Construction and Building Materials. 2021; 282 ():122547.
Chicago/Turabian StyleChaofeng Liang; Zhedong Cai; Huixia Wu; Jianzhuang Xiao; Yuming Zhang; Zhiming Ma. 2021. "Chloride transport and induced steel corrosion in recycled aggregate concrete: A review." Construction and Building Materials 282, no. : 122547.