温度-恒载耦合作用下钢纤维混凝土损伤时变规律及其声发射响应

为研究建筑工程发生火灾时钢纤维混凝土和普通混凝土材料性能的变化规律,通过MTS电液伺服材料测试系统及其配套的高温炉,对高温下2类混凝土的应变曲线进行了研究;同时对2类混凝土施加其极限压应力30%的荷载并维持定值,对钢纤维混凝土以及普通混凝土进行了恒定荷载下的高温应变试验,并采用声发射技术对升温及恒温过程进行了全程实时跟踪和在线监测.结果表明:在温度-恒载作用下,钢纤维混凝土在目标温度加温段的应变比普通混凝土小,其抵抗破坏、变形的能力更强;在加载破坏时钢纤维混凝土的应变比普通混凝土大,其延性更好;钢纤维混凝土的振铃累计计数高于普通混凝土,钢纤维的掺入可以有效延缓混凝土的损伤.

Time Varying Law and Acoustic Emission Response of Steel Fiber Reinforced Concrete under Temperature Constant Load Coupling Action

In order to study the variation regularity of the properties of steel fiber reinforced concrete and ordinary concrete when the actual project was in fire, through the MTS electro hydraulic servo material testing system and its supporting high temperature furnace, the strain curves of two types of concrete under high temperature were studied; at the same time, the load of 30% of the limit compressive stress was applied to the 2 types of concrete and the value was maintained, the high temperature strain test of steel fiber reinforced concrete and ordinary concrete under constant load was carried out, the acoustic emission technology was used to perform real time tracking and online monitoring of the temperature increase and constant temperature process. The result shows that under temperature constant load coupling action, the strain of steel fiber reinforced concrete is smaller than that of the ordinary concrete at the heating section of the target temperature, its ability of resisting destruction and deformation is stronger; the strain at loading damage is larger than that of the ordinary concrete, its ductility is better; the ringing accumulative count of steel fiber reinforced concrete is higher than that of the ordinary concrete, the addition of steel fiber can delay the damage of concrete.