超高性能混凝土高温后动态劈裂抗拉性能  

Dynamic Splitting Tensile Behavior of Ultra-High Performance Concrete after Exposition to Elevated Temperature

作　　者：陈猛[1,2] 冯珺[1] 张通 CHEN Meng;Feng Jun;ZHANG Tong(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China;Engineering Research Center of Frontier Technologies for Low‑Carbon Steelmaking,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819 [2]东北大学低碳钢铁前沿技术研究院,辽宁沈阳110819

出　　处：《建筑材料学报》2025年第2期118-126,共9页Journal of Building Materials

基　　金：国家自然科学基金资助项目(52308395,52178382);博士后创新人才支持计划项目(BX20230063);中国博士后科学基金面上项目(2023M730526);中央高校基本科研业务专项资金资助项目(N2301023);辽宁省博士科研启动基金计划项目(2023-BS-058)。

摘　　要：为了研究高温和应变率对超高性能混凝土(UHPC)劈裂抗拉性能的影响,对不同温度(20、105、200、300、400℃)作用后UHPC的质量损失率、抗压强度、弹性模量、静态和动态(应变率为1.8~6.8 s^(-1))劈裂抗拉强度进行了测试.结果表明:以2~10℃/min的加热速率升温至400℃后,所有试件均在保温期间发生爆裂性剥落;U H P C的抗压强度、弹性模量、静态劈裂抗拉强度均随温度增大而提高,300℃作用后比常温时分别提高了13.2%、19.1%和17.3%;动态劈裂抗拉强度和耗散能均具有明显的应变率效应,当应变率从1.8~2.2 s^(-1)增加到6.3~6.8 s^(-1)时,20~300℃作用后的UHPC动态劈裂抗拉强度和耗散能分别提高了69.1%~74.1%和146.7%~177.6%;高温作用后UHPC中C-S-H表面的吸附水、孔隙内自由水和凝胶结合水先后分解,增大了试件的质量损失率;基体内高温和高压环境促进了水泥水化反应和硅灰火山灰反应,提升了UHPC的致密程度,增强了钢纤维的桥连作用;在冲击荷载作用下,基体开裂速度的加快和由钢纤维拔出所致基体摩擦效应的增强导致耗散能增大.To investigate the effects of elevated temperature and strain rate on the splitting tensile properties of ultra‑high performance concrete(UHPC),the mass loss rate,compressive strength,elastic modulus,static and dynamic splitting tensile tests(strain rate increases from 1.9 s^(-1) to 6.8 s^(-1))were carried out at different temperatures(20,105,200,300,400℃).Results reveal that all specimens experienced explosive spalling during the temperature holding period after heating at a rate of 2-10℃/min to 400℃.The compressive strength,elastic modulus and static splitting strength of UHPC increase with the increase of temperature,and the strength of UHPC at 300℃increases by 13.2%,19.1%and 17.3%,respectively,relative to that at room temperature.The dynamic splitting strength and dissipated energy show an obvious strain rate effect.When the strain rate increases from about 2.0 s^(-1) to 6.5 s^(-1),the dynamic splitting strength and dissipated energy of UHPC increase by 69.1%-74.1%and 146.7%-177.6%,respectively,within the measured temperature range.After exposed to elevated temperatures,the adsorbed water on C-S-H gel surface,the free water in pores and the gel-bound water in UHPC are gradually decomposed,result in increase of the mass loss rate of UHPC.The high-temperature and high-pressure environment in UHPC matrix promotes cement hydration reaction and pozzolanic reaction,improving the density of UHPC matrix and the bridging effect of steel fiber.At the higher strain rate,the crack propagation in UHPC specimen is faster and the friction effect of steel fiber pulling out is enhanced,which leads to the increase of dissipated energy.

关 键 词：超高性能混凝土 高温 动态劈裂抗拉 力学性能 爆裂性剥落 

分 类 号：TU528.572[建筑科学—建筑技术科学]