含粗骨料超高性能混凝土高温性能的研究进展

Research Progress on High Temperature Performance of Ultra High Performance Concrete with Coarse Aggregate

与高性能混凝土类似,含粗骨料超高性能混凝土(Ultra High Performance Concrete with Coarse Aggregate,UHPC-CA)经历高温后残余力学性能会发生变化,甚至出现高温爆裂行为。为了推进UHPC-CA的实际应用进程,结合现有文献分析了含湿量、纤维、加热速率、骨料、加载应力和混凝土强度等因素对UHPC-CA高温爆裂的影响;分析了高温后UHPC-CA的残余抗压强度、残余劈拉强度和残余断裂能等残余力学性能的变化;分析了UHPC-CA高温性能的改善措施。结果表明:随着含湿量、加热速率、加载应力和混凝土强度的增加,UHPC-CA的高温爆裂程度均呈现加重趋势,加入粗骨料与纤维后可减轻UHPC-CA的高温爆裂;随目标温度的升高,UHPC-CA的残余抗压强度与残余劈拉强度均呈现先增大后减小的趋势,残余断裂能逐渐下降;热水—干热组合养护可避免UHPC-CA的高温爆裂,显著改善其高温性能。

Similar to high performance concrete,the residual mechanical properties of ultra high performanceconcrete with coarse aggregate(UHPC-CA)will change after high temperature,and even appear high temperature cracking behavior.In order to promote the practical application of UHPC-CA,the influence of moisture content,fiber,heating rate,aggregate,loading stress and concrete strength on the high temperature cracking of UHPC-CA was analyzed.The residual mechanical properties of UHPC-CA such as residual compressive strength,residual splitting tensile strength and residual fracture energy were analyzed.The improvement measures of UHPC-CA high temperature performance were analyzed.The results showthat with the increase of moisture content,heating rate,loading stress and concrete strength,the high tem-perature burst degree of UHPC-CA presents an increasing trend,and the addition of coarse aggregate andfiber can reduce the high temperature burst of UHPC-CA.With the increase of the target temperature,the residual compressive strength and the residual splitting tensile strength of UHPC-CA increase firstand then decrease,and the residual fracture energy decreases gradually.The combination of hot water anddry heat curing can avoid the high temperature burst of UHPC-CA and significantly improve its hightemperature performance.