文献类型：期刊文献

英文题名：Synergistic effects of steel fiber reinforcement and strain rate on dynamic constitutive behavior of UHPFRC

作者：Li, Yao[2];Li, Mei[1];Tang, Baijian[1];Shi, Yanchao[3];Cui, Jian[3];Ding, Kaiyao[1]

机构：[1]Suzhou Univ Sci & Technol, Sch Civil Engn, 1701 Binhe Rd, Suzhou 215011, Jiangsu, Peoples R China;[2]East China Univ Sci & Technol, Sch Mat Sci & Engn, Shanghai 200237, Peoples R China;[3]Tianjin Univ, Sch Civil Engn, Tianjin 300072, Peoples R China

年份：2026

卷号：89

外文期刊名：STRUCTURES

收录：;EI(收录号：20262320838470);WOS:【SCI-EXPANDED(收录号:WOS:001787739900001)】；

基金：Funding: This research was financially supported by the National Natural Science Foundation of China with grant numbers 52278518 and 52478538, and The Natural Science Foundation of the Jiangsu Higher Education Institutions of China with grant number 24KJB560021.

语种：英文

外文关键词：Ultra-high-performance concrete; Dynamic strength; Strain rate effect; Steel fiber volume; Dynamic constitutive relation

摘要：This study investigates the coupled effects of fiber reinforcement and strain rate on the dynamic compressive behavior of ultra-high performance fiber-reinforced concrete (UHPFRC). Split Hopkinson pressure bar (SHPB) tests were conducted on UHPFRC specimens with various volume fractions (0%-1.8%). The results reveal that steel fibers significantly enhance dynamic strength and energy dissipation through the fiber bridging effect. A key finding clarifies the previously inconsistent reports on peak strain: while fiber reinforcement nearly doubles the peak strain compared to the plain matrix, a saturation phenomenon is observed. Once the strain rate exceeds 150 s-1 , the peak strain stabilizes within a narrow range of 0.008-0.010 regardless of fiber content. The dynamic increase factor (DIF) exhibits a synergistic dependence on both strain rate and fiber content, yet the strengthening efficiency diminishes at a fiber volume fraction of 1.8%. This attenuation is attributed to a kinetic competition mechanism, where rapid matrix fragmentation outpaces the activation of fiber bridging, compounded by microstructural heterogeneities induced by excessive fiber dosage. To bridge the modeling gap, the mesoscale model was established and validated to explicitly capture fiber-matrix interactions. Based on integrated experimental and numerical data, a novel dynamic strength model incorporating a unified enhancement factor and a Weibull-based damage evolution law is proposed. The model accurately predicts the nonlinear coupled strengthening effects, offering a practical tool for the impact-resistant design of UHPFRC structures.