随机分布多边形骨料沙漠砂混凝土高温后抗压强度研究

Study on compressive strength of desert sand concrete after high temperature based on random polygon aggregate

为了对火灾后沙漠砂混凝土(DSC)力学性能进行研究,将DSC看作由粗骨料、沙漠砂砂浆基质及两者间界面过渡区(ITZ)组成三相复合材料。基于瓦拉文式,提出一种二维含界面过渡区随机分布多边形粗骨料投放方法,利用ANSYS对高温后DSC单轴受压破坏过程进行数值模拟,分析试件尺寸、沙漠砂替代率(DSRR)、粒径大小、界面过渡区厚度和强度及粗骨料体积分数对高温后DSC抗压性能影响。结果表明:模拟结果与试验结果吻合良好。高温后DSC抗压强度尺寸效应明显;抗压强度随界面过渡区厚度增加呈逐渐减小趋势;随着界面过渡区强度增加,抗压强度基本呈线性增长趋势;当DSRR为40%时,抗压强度最优。研究结果可为DSC工程应用提供理论依据。

In order to study the mechanical behaviors of desert sand concrete(DSC)after fire,DSC was considered as a three-phase composite consisting of coarse aggregate,desert sand mortar and interface transition zone(ITZ).Based on Walraven′s formula,a two-dimensional numerical simulation of uniaxial compressive failure process of DSC after high temperature was establish by ANSYS to analyze the effects of specimen size,desert sand replacement rate(DSRR),particle size,ITZ thickness,ITZ strength and coarse aggregate volume content on the compressive performance of DSC after high temperature.The results showed that the simulation results agreed well with test results.The compressive resistance of DSC after high temperature had obvious size effect,which tended to decrease with increasing thickness of ITZ.The compressive resistance basically showed a linear growth trend with ITZ strength.When the DSRR was equal to 40%,the compressive resistance was optimal,which provide a theoretical basis for the application of DSC.