通过模拟火灾现场材料表面实际升温曲线，对普通混凝土板及不同掺量聚丙烯纤维混凝土板进行火灾实验，结果表明：不同于高性能混凝土中常出现的高温爆裂现象，普通混凝土在经历高温与冷却的过程后，内外部温度梯度应力使其出现很大的裂缝。而通过掺加聚丙烯纤维可有效地缓解裂缝宽度，降低高温对普通混凝土的损伤。同时，通过测试高温前后混凝土板底面及侧面回弹值发现，由于混凝土板内部与侧面温度值在空间内分布不同，进而造成混凝土材料回弹值的损失也不一样，使得混凝土板残余力学性能呈空间分布，且与温度场有着直接的关系。%The fire tests of the normal concrete slab and polypropylene fiber reinforced concrete slab with different contents of polypropylene fiber are carried out through simulating the practical heating curve of material surface in the fire site. The results show that normal concrete has cracks due to the temperature gradient inside or outside the concrete dur-ing cooling after continuous heating, which is different from the spalling of high strength concrete at elevated temperatures, and the polypropylene fiber in the concrete can effectively restrain the crack development. The rebound hammer tests car-ried out on the post-fire concrete slabs shows that the spatial distribution of residual mechanical property inside the slabs correlates with the temperature field.
展开▼
