【摘要】 混凝土在高温下的强度和变形性能随温度和应力的耦合作用而变化。试验确定了不同温度—应力途径下混凝土抗压强度的上、下限，并量测了混凝土的自由膨胀变形，高温下的应力变形、瞬态热应变和短期高温徐变等数据。在此基础上分析了混凝土高温变形的一般规律，建立了温度—应力耦合本构关系。并通过约束混凝土柱的加热试验加以验证。本构关系可为混凝土结构的高温（如抗火）分析提供合理的依据更多还原

【Abstract】 The strength and deformation behaviour of concrete under high temperature are variable considerably due to the coupling action between temperature( T ) and stress( σ ). Based on the test results, the upper and lower bounds of concrete compressive strength under different T σ paths are determined. The thermal strain( σ=0 ) at elevated temperature, stressing strain at T= Const., transient thermal strain, and short term creep at high temperature of concrete are measured from seperate tests. Then, the general regularities of concrete deformation under high temperature are concluded and a temperature stress coupling constitutive model is suggested. The model is demonstrated by a heating test of a restraint column. The constitutive model can be used for thermal analysis or fire resistance of reinforced concrete structures.更多还原