高温前后混杂纤维再生混凝土的多轴本构模型
Multiaxial constitutive model of hybrid fiberrecycled aggregate concrete before and after high temperature
郭少龙 1鹿群 2赵丽红 3柳晓科 4仇建春5
作者信息
- 1. 天津城建大学 土木工程学院,天津 300384;河海大学 水利水电学院,江苏 南京 210098
- 2. 天津城建大学 土木工程学院,天津 300384
- 3. 天津市恒德劳动服务有限公司,天津 300350
- 4. 中国市政工程华北设计研究总院有限公司,天津 300381
- 5. 扬州大学 水利科学与工程学院,江苏 扬州 225009
- 折叠
摘要
地震引发的火灾可能导致再生混凝土爆裂,掺入纤维是改善再生混凝土抗爆裂性能的一种有效措施.本文研究了高温前后混杂纤维再生骨料混凝土(hybrid fiber recycled aggregate concrete,HFRAC)在围压作用下的力学性能和多轴本构模型.研究表明围压对HFRAC试块的破坏模式有显著影响.经历过不同温度后的HFRAC试块在单轴压缩后会产生贯穿性裂缝,且裂缝的宽度较大.随着围压的增加,贯穿性斜裂缝逐渐被局部斜裂缝所取代.在多轴应力作用下,高温暴露后HFRAC试块的体积显著缩小.在八面体应力空间中建立了一个考虑温度影响的改进破坏准则.考虑钢纤维掺量、长径比和温度对HFRAC应力-应变关系的影响,提出了一种改进的三轴本构模型.试验表明改进后的本构模型能够更准确地反映HFRAC在单轴和低围压条件下的受压应力-应变关系和损伤演化规律.
Abstract
Fires caused by earthquakes may lead to the cracking of recycled concrete,and adding fibers is an effective measure to improve the anticracking performance of recycled concrete.This article investigates the mechanical properties and multiaxial constitutive model of hybrid fiber recycled aggregate concrete(HFRAC)under confining pressure before and after high temperature.The results show that confining pressure has significant influence on the failure mode of HFRAC test block.HFRAC blocks subjected to different temperatures will produce penetrating cracks after uniaxial compression,and the cracks are larger in width.With the increase of confining pressure,the penetrating oblique fractures are gradually replaced by local oblique fractures.Under the action of multi-axial stress,the volume of HFRAC test block decreased significantly after high temperature exposure.An improved failure criterion considering the effect of temperature is established in the octahedral stress space.Considering the effects of steel fiber content,length-diameter ratio and temperature on the stress-strain relationship of HFRAC,an improved triaxial constitutive model is proposed.The experimental results show that the improved constitutive model can more accurately reflect the stress-strain relationship and damage evolution of HFRAC under uniaxial and low confining pressure conditions.
关键词
混杂纤维/再生混凝土/高温/破坏准则/本构模型Key words
hybrid fibers/recycled concrete/high temperature/destruction criteria/constitutive model引用本文复制引用
基金项目
天津市教委科研计划项目(2022KJ018)
出版年
2024
NETL
NSTL
万方数据