钢纤维混凝土的高温动态强度特性

Strength Property of Steel Fiber Reinforced Concrete at Elevated Temperature

本文采用自主研制的高温SHPB试验系统,对高温条件下钢纤维混凝土(SFRC)的动态压缩强度进行了试验研究。结果表明:高温下SFRC的动态抗压强度同时存在加载速率强化效应和温度强弱化效应。加载速率越大,SFRC的动态抗压强度越高;200℃以前,以温度强化效应为主,200℃以后则以温度弱化效应为主,400℃后低于常温下的动态抗压强度,600℃后低于常温下的静压强度,到800℃时强度已变得很小。钢纤维的加入可以显著提高混凝土在不同温度和加载速率下的动态抗压强度,且纤维掺量越大,相应增加幅度越高;当纤维体积掺量为1.0%时,SFRC的动态抗压强度增长因子高于素混凝土。

The dynamic compressive strength of steel fiber reinforced concrete （SFRC） at elevated temperature is investigated using self-designed high temperature SHPB system. The results show load rate strengthening effect and temperature strengthening-weakening effect on the dynamic compressive strength of SFRC. The dynamic compressive strength increases with load rate. It increases before 200 ℃ and decreases after 200 ℃. After 400 ℃, the dynamic compressive strength is lower than that at room temperature and after 600 ℃, temperature reaches 800 ℃, the it is lower than the static strength at room temperature. When strength becomes quite small. Steel fiber can effectively enhance the the dynamic compressive strength of concrete at different temperature and load rate. The increase ratio increases with the fiber volume fraction. The dynamic increase factor of SFRC at 1% is higher than plain concrete.