同济大学学报（自然科学版）2023，Vol.51Issue(12)：1835-1844,10.DOI:10.11908/j.issn.0253-374x.23102
纤维协同效应下超高性能混凝土的弯曲性能
Flexural Properties of Ultra-high Performance Concrete Under Fiber Synergistic Effect
摘要
Abstract
To study the effect of steel-polypropylene crude fiber on the bending and tensile properties of ultra-high performance concrete(UHPC),a four-point bending test was conducted to obtain different volume contents(the content of steel fiber and polypropylene crude fiber being 0,0.5%,1.0%,and 1.5%).The load-deflection curve under the combination is described from the failure form,flexural strength,flexural toughness,etc.,of the specimen,and a model with high feasibility is derived from the fitting formula of the single-doped fiber to analyze the synergistic effect of the hybrid fiber.Finally,the microstructure of the hybrid fiber UHPC was observed and analyzed by scanning electron microscopy(SEM).The test results show that the incorporation of steel-polypropylene crude fiber significantly improves the flexural strength of UHPC,with an increase range of 17.8%to 101.2%.At the same time,using the proposed method,it is found that the synergistic effect of hybrid fibers showed a positive synergistic effect when the total fiber volume content is between 1.5%and 2.0%,and the best positive synergistic effect is obtained in S10P10.In addition,compared with the specimens without fiber,the initial crack toughness of matrix specimens increases by 51.8%to 98.2%and 33.9%to 48.2%respectively with the addition of steel fiber and polypropylene crude fiber.When the content of steel fiber is 1.0%and the volume content of polypropylene crude fiber is 1.0%,the improvement to the bending toughness of UHPC is the best,which further verifies the evaluation model of fiber synergy effect.Finally,the synergistic effect and the toughening mechanism of the hybrid fiber are revealed at the micro level.关键词
超高性能混凝土/混杂纤维/弯曲韧性/协同效应Key words
ultra-high performance concrete(UHPC)/hybrid fibers/bending toughness/synergistic effect分类
建筑与水利引用本文复制引用
李福海,刘耕园,刘梦辉,杨宗驰,穆勃江,苏君豪,姜怡林..纤维协同效应下超高性能混凝土的弯曲性能[J].同济大学学报（自然科学版）,2023,51(12):1835-1844,10.基金项目
国家重点研发计划(2021YFB2600900) （2021YFB2600900）
四川省科技厅项目(2021YJ0545,2021JDTD0012) （2021YJ0545,2021JDTD0012）
国家自然科学基金(U2034205) （U2034205）
