高温后不同沙漠砂替代率砂浆单轴受压力学性能试验研究

Study on the uni-axial compression performance of mortar with different desert sand replacement rates after elevated temperature

为得到高温后不同沙漠砂替代率砂浆单轴受压力学性能,设置目标温度分别为100,200,300,500,700℃,对高温后不同沙漠砂替代率砂浆进行单轴受压试验,得到应力-应变曲线,分析温度和沙漠砂替代率对砂浆峰值应力、峰值应变、弹性模量、泊松比和质量损失率的影响,建立高温后不同沙漠砂替代率砂浆单参数受压本构方程。试验结果表明:随着温度的升高,不同沙漠砂替代率砂浆表面颜色均经历灰色→泛红→发白的变化过程;随着沙漠砂替代率增加,经历不同温度后砂浆的峰值应力和弹性模量均呈现先增大后减小的变化趋势,沙漠砂替代率为40%时峰值应力和弹性模量达到最大值;随着温度的升高,不同沙漠砂替代率砂浆泊松比呈现先降低后增大的变化趋势。通过回归分析,得到砂浆峰值应力、峰值应变、弹性模量、泊松比与温度、沙漠砂替代率之间的关系方程,并建立高温后不同沙漠砂替代率砂浆单参数受压本构方程,为配制沙漠砂混凝土以及沙漠砂混凝土的工程应用提供理论依据。

In order to obtain the uni-axial compression performance of mortar with different desert sand replacement rates after elevated temperature, the target temperatures were set to 100, 200, 300, 500, 700℃ respectively. The uni-axial compression tests of mortar with different desert sand replacement rates after elevated temperature were carried out and the stress-strain curve was obtained. The effects of temperature and desert sand replacement rate on the compressive strength, peak strain, elastic modulus, Poisson’s ratio and mass loss rate of mortar were analyzed. A single-parameter compression constitutive equation of mortar with different desert sand replacement rates after elevated temperature was established. The test results show that the surface color of mortar with different desert sand replacement rates changes from gray, reddish and to whitening with the increase of temperature. With the increase of desert sand replacement rate, the compressive strength and elastic modulus of mortar after elevated temperature increase first, and then decrease. When the desert sand replacement rate is equal to 40%, the compressive strength and elastic modulus of mortar after elevated temperature reached the maximum value. With the increase of temperature, the Poisson’s ratio of mortar with different desert sand replacement rates decreases first, and then increases. On the basis of regression analysis, the relationship between compressive strength, peak strain, elastic modulus, Poisson’s ratio of mortar and temperature, desert sand replacement rate was obtained. At the same time, the single-parameter compression constitutive equation of mortar with different desert sand replacement rates after elevated temperature was established, and provide reference for the preparation of desert sand concrete and desert sand concrete engineering applications.