高温后钢材及再生混凝土的力学性能试验研究

为了研究高温后钢材及再生混凝土的力学性能,设计了再生粗骨料取代率为100%的再生混凝土立方体试块并加工了钢材标准试件,对其进行常温、200~800℃(级差为100℃)的模拟火灾高温后的受力性能试验,细致观察了高温后再生混凝土、钢材的表观变化,获取了高温后再生混凝土的破坏形态和强度、钢材的屈服及极限强度等力学性能指标;分析火灾温度对钢材及再生混凝土剩余强度的影响,并提出高温后再生混凝土的剩余强度计算式。研究结果表明:随着温度的升高,钢材的屈服强度呈先上升后下降的变化趋势,极限强度在600℃以下时变化不大,在600℃以上则显著降低;随着温度的升高,其抗压强度逐渐降低。

EXPERIMENTAL STUDY OF MECHANICAL BEHAVIOR OF STEEL AND RECYCLED AGGREGATE CONCRETE AFTER HIGH TEMPERATURE

In order to reveal mechanical behavior of steel and recycled coarse aggregate concrete after high temperature,the recycled coarse aggregate replacement ratio of 100% recycled concrete cubic block and the artifactitious steel specimens were designed,which were put at normal temperature and at 200 ~ 800 ℃( differential varying by 100 ℃)to do mechanical tests of high temperature simulation fire. The appearance after high temperature of recycled coarse aggregate concrete and steel was observed,and the damage process,failure mode of recycled coarse aggregate concrete and yield strength and ultimate strength of steel were observed. The effect of high temperature on their residual strengths was analyzed and the formula to calculate their residual strengths was also proposed. The results showed that with the increasing of temperature,the yield strength of steel was in the change trend of decline after rising first. Temperature under 600 ℃ had little influence on ultimate strength,while the effect of temperature above 600 ℃ was significant.With the increasing of temperature,compressive strength decreased gradually.