高性能混凝土抗火性能试验及数值模拟

Test and numerical simulation on fire resistance of high performance concrete

对掺加聚丙烯纤维的高性能混凝土进行高温力学性能试验及数值模拟分析,结果表明:掺加聚丙烯纤维可较大提升高性能混凝土强度,其强度在达到峰值强度后都急剧下降,在200~600℃范围内,不掺加聚丙烯纤维的峰值强度下降大约56.36%,而掺加的下降58.56%;基于最小耗能原理对高温混凝土损伤准则进行推导,该准则考虑了温度对于弹性模量和泊松比影响,也考虑了热流密度矢量和温度梯度的增大对混凝土强度的影响,将该准则代入到FLAC^3D中进行高温混凝土加载试验的模拟,得出的试验值与模拟值变化规律吻合度较高,证明了基于最小耗能原理的高温混凝土损伤准则的正确性。

The high temperature mechanical performance test and numerical simulation analysis are carried out for the high performance concrete added with polypropylene fiber. The result shows that, adding the polypropylene fiber can substantially increase the strength of high performance concrete, when reaching a peak strength, the concrete strength decreases sharply. In the range of 200-600 ℃, the peak strength of concrete without addition of polypropylene fiber decreases by about 56. 36%, while that of concrete with addition of polypropylene fiber decreases by 58. 56%. The concrete damage criterion of high temperature concrete is derived based on the minimum energy dissipation. The influence of temperature on the elastic modulus and Poisson' s ratio is considered in the damage criterion, and the in fluence of the increase of heat flux density vector and temperature gradient on concrete strength is also considered. The damage criterion is substituted in FLAC^3Dto simulate the high temperature concrete loading test, the variation law of the obtained experimental value is in good agreement with that of the simulated value, which proves the correctness of the high temperature concrete damage criterion based on the principle of minimum energy consumption.