【摘要】 通过试验分析了一定冻融循环损伤对陶粒混凝土高温后的荷载变形及弹性模量等性能参数的影响,及掺入聚丙烯腈纤维对陶粒混凝土经历冻融损伤及高温试验后力学性能的影响.试验结果表明,未掺入聚丙烯腈纤维,陶粒混凝土的峰值荷载超过200℃高温后就开始出现明显下降;掺入聚丙烯腈纤维后,纤维组织的增韧阻裂效应不仅在常温~400℃温度范围内能有效减缓峰值荷载的下降,还能缓解峰值荷载状态下陶粒混凝土的脆性破坏特性.一定冻融循环损伤后,陶粒混凝土的峰值荷载和弹性模量在各温度段升温试验后均出现不同程度降低;掺入聚丙烯腈纤维后,在一定程度上可减缓峰值荷载和弹性模量的降低,超过400℃后,纤维熔融蒸发并在陶粒混凝土内部产生孔洞,导致峰值荷载和弹性模量开始下降明显.更多还原

【Abstract】 Experiment on the influence of freeze-thaw cycling on the load-deformation performance of ceramsite lightweight aggregate concrete(LWAC) after elevated temperature was conducted. And the effect of the mixing of polyacrylonitrile fiber(PANF) was discussed. The results indicate that, without the PANF mixing, the peak load of LWAC clearly reduces after 200 ℃ test. Because of the effect of flexibility and crack-stopping, the mixing of PANF not only slows up the reducing of the peak load of LWAC from the room temperature to 400 ℃, it also releases the brittle failure performance at the peak loading state. After a certain degree of freeze-thaw cycling, there are varying degrees of reduction of the peak loads and elastic modulus of LWAC after elevated temperature. After mixing the PANF, there is a certain effect to slow up the reduction of the peak load and elastic modulus. Exceeding 400 ℃, because of the fusion and evaporation of PANF,the peak load and elastic modulus begin clearly to reduce.更多还原