同济大学学报（自然科学版）2023，Vol.51Issue(12)：1813-1821,9.DOI:10.11908/j.issn.0253-374x.23100
钢纤维对超高性能混凝土徐变损伤与失效行为的影响
Influence of Steel Fibers on Creep Damage and Failure Behaviors of UHPC
摘要
Abstract
To study the influence of steel fibers on damage and failure behaviors of ultra-high-performance concrete(UHPC)at short-term high sustained stress loading,an experimental program on creep damage and failure was proposed by using UHPC and normal concrete at the age of 28 days.The stress-strain relationship of each specimen was measured during the whole loading processing.The failure modes,irreversible strain,creep strain,and nominal Poisson's ratio were analyzed according to the tested results.Based on the non-destructive ultrasonic test and scanning electron microscopy test(SEM),the expansion of internal micro-cracks within UHPC specimens and the bond damage between steel fibers and matrix were characterized.The results show the high sustained stress of UHPC and normal concrete lead to the development of internal micro-cracks and lateral expansion of specimens,and finally result in the creep failure of specimens.The bridging and confinement effects provided by steel fibers can control the development of internal micro-cracks,and reduce the lateral expansion of specimens.Before sustained loading,UHPC and normal concrete have similar nominal Poisson's ratios of 0.18～0.19.After sustained loading,the nominal Poisson's ratio of UHPC becomes 0.28,whereas the normal concrete specimens have a higher nominal Poisson's ratio of 0.6.When the sustained stress was higher than 0.70 fc,creep damage of UHPC specimens occurs,which lead to the reductions in strength and elastic modulus at cycle of reloading.With the increment in sustained stress,the bond between steel fibers and matrix is damaged,and the steel fibers fail to confine the development of internal micro-cracks.As a results,the specimens are continuedly damaged and finally fail.关键词
超高性能混凝土(UHPC)/内部微裂缝/徐变损伤/徐变失效/钢纤维Key words
ultra-high-performance concrete(UHPC)/internal micro-cracks/creep damage/creep failure/steel fibers分类
交通工程引用本文复制引用
徐腾飞,张子飏,卞香港,刘志峰..钢纤维对超高性能混凝土徐变损伤与失效行为的影响[J].同济大学学报（自然科学版）,2023,51(12):1813-1821,9.基金项目
国家自然科学基金(52378315) （52378315）
