文献类型：期刊文献

英文题名：Quantifying the effects of CO2 enhancement on the microstructure and damage constitutive behavior of fiber-reinforced RAC using In-situ CT analysis

作者：Wang, Changqing[1,4];Jiao, Jiaqi[1];Zhang, Youchao[2];Wu, Huixia[3];Ma, Zhiming[2,3]

机构：[1]Shanghai Univ, Sch Mech & Engn Sci, Dept Civil Engn, Shanghai 200444, Peoples R China;[2]Yangzhou Univ, Coll Civil Sci & Engn, Yangzhou 225127, Peoples R China;[3]Shaoxing Univ, Sch Civil Engn, Shaoxing 312000, Peoples R China;[4]Tongji Univ, Dept Bldg Engn, Coll Civil engn, Shanghai 200092, Peoples R China

年份：2025

卷号：491

外文期刊名：CONSTRUCTION AND BUILDING MATERIALS

收录：SCI-EXPANDED(收录号：WOS:001542047200003)、、WOS

基金：The authors wish to acknowledge the financial support from the National Natural Science Foundation of China (NSFC) through Grant No. (51608383) , China Postdoctoral Science Foundation through Grant Nos. (2014M550247) and (2015T80449) , Natural Science Foundation of Shanghai Municipality through Grant No. (25ZR1401128) , and the Key Projects of Science & Technology Pillar Program of Henan Province (152102310027) .

语种：英文

外文关键词：Carbonated fiber-reinforced recycled aggregate concrete (CFR-RAC); In-situ CT; Micromechanical behavior; Damage constitutive model; Micro-fibers; Micro-fibers

外文摘要：This study systematically investigates the synergistic effects of carbonation and micro-fiber reinforcement on the mechanical properties, microstructural evolution, and damage mechanisms of recycled aggregate concrete. Using 4D computed tomography (CT) and three-dimensional reconstruction, the internal crack and pore evolution under different fiber volume fractions and carbonation conditions were quantitatively analyzed. Results show that increasing the fiber content from 1 % to 2 % reduces the internal crack volume fraction from 0.8 % to 0.2 % and controls porosity within 0.1 %-0.3 %, significantly improving the compactness, toughness, and durability of the concrete. Steel fibers effectively inhibit crack propagation at the microscale, while carbonation refines the interfacial transition zone (ITZ) by filling pores and densifying the matrix. A damage constitutive model based on stiffness degradation and microstructural parameters was established, accurately capturing the nonlinear stress-strain response with peak stress and elastic modulus prediction errors below 2 %. Under cyclic loading, 2 % fiber content was identified as optimal for minimizing damage accumulation, as validated by a robust damage evolution model. This research establishes a comprehensive link between multi-scale microstructure, damage mechanism, and macroscopic constitutive behavior, providing theoretical and quantitative support for the design and engineering application of green, high-performance recycled concrete.