荷载和高温对沙漠砂混凝土单轴抗压性能的影响

Influence of loading and high temperature on uniaxial compressive properties of desert sand concrete

为了研究高温后的沙漠砂混凝土力学性能,采用毛乌素沙地砂代替部分中砂制备沙漠砂混凝土,对经历不同荷载和温度作用后的沙漠砂混凝土进行轴心抗压强度试验,测得应力-应变曲线,分析了荷载水平、温度等级和冷却方式对沙漠砂混凝土高温后的质量损失率、超声波速和单轴受压性能的影响。结果表明:随着温度的升高,沙漠砂混凝土质量损失率逐渐增大,轴心抗压强度逐渐减小,峰值应变显著增大,弹性模量不断降低,应力-应变曲线趋于扁平。最后,基于混凝土两阶段本构模型,建立了考虑温度和荷载水平影响的沙漠砂混凝土本构模型。

In order to research on the mechanical properties of desert sand concrete(DSC) after high temperature,desert sand from Mu Us sandy land was used to partially replace medium sand to make DSC.The uniaxial compression experiments of DSC subjected to different loadings and temperatures were carried out to obtain the stress-strain curves.The influences of loading level,temperature and cooling methods on the mass loss rate,ultrasonic velocity and axial compressive properties were analyzed.Experimental results showed that the mass loss rate of DSC gradually increased with the temperature.The uniaxial compressive strength and modulus of elasticity of DSC declined,peak strain increased greatly,and the stress-strain curve gradually became flat.Taking into account of temperature and loading level,the constitutive model was established to simulate the mechanical properties of DSC based on the two-stage constitutive model,which provided technical support for the performance evaluation of DSC after high temperature.