高温作用后钼尾矿混凝土单轴受压性能试验研究

Test on uniaxial compressive behavior of molybdenum tailings concrete exposed to high temperature

为研究钼尾矿混凝土高温后的单轴受压力学性能,进行了不同目标温度(20,200,300,400,600,800℃)条件下钼尾矿混凝土的轴心抗压强度、峰值应变、弹性模量、泊松比、破坏形态及质量变化的试验研究。结果表明:钼尾矿混凝土试件的质量损失率随温度的升高而增加,在800℃时质量损失率平均为6.52%;轴心抗压强度随温度的升高而逐渐降低,800℃时与常温相比平均降低70.04%,且随钼尾矿掺量的增加而降低;而峰值应变随温度的升高先减后增;弹性模量和泊松比都随温度的升高而降低,在800℃时弹性模量和泊松比平均比常温降低88.22%和35.66%。对于弹性模量,大体上随着钼尾矿掺量的增大而减小;而对于泊松比,钼尾矿掺量100%的混凝土略大于掺量50%的混凝土。根据试验结果,建立了钼尾矿混凝土高温后的单轴受压应力-应变本构方程。

In order to study the mechanical properties of molybdenum tailing concrete under uniaxial compression at high temperature,the axial compressive strength,peak strain,elastic modulus,Poisson's ratio,failure mode and mass changes of molybdenum tailing concrete specimens at different target temperatures(20,200,300,400,600,800℃)were tested.The results showed that the mass loss rate of molybdenum tailing concrete specimens increased with the increase of temperature,and the average mass loss rate was 6.52%at 800℃.The axial compressive strength gradually decreases with the increase of temperature,with an average decrease of 70.04%at 800℃compared with room temperature,and decreases with the increase of molybdenum tailings admixture.While the peak strain decreases first and then increases with the increase of temperature.Both the modulus of elasticity and Poisson's ratio decreased with the increase of temperature,and the modulus of elasticity and Poisson's ratio decreased by 88.22%and 35.66%on average at 800℃compared with room temperature.For the modulus of elasticity,it generally decreased with the increase of molybdenum tailing admixture,while for Poisson's ratio,the concrete with 100%molybdenum tailing admixture was slightly larger than the concrete with 50%admixture.According to the test results,the uniaxial compression stress-strain constitutive equation of molybdenum tailing concrete after high temperature is established.