冻融循环下沙漠砂混凝土单轴受压细观模拟OA

To analyze the temperature conduction of desert sand concrete(DSC)during freeze-thaw cy-cles and its mechanical behavior after freeze-thaw,considering its heterogeneity,this study treated DSC as a composite material composed of coarse aggregate,mortar,and interfacial transition zone.A two-dimensional mesoscopic model was established using ABAQUS,and the temperature field and temperature stress of DSC with circular and polygonal aggregates under freeze-thaw cycles were simu-lated using a thermal-mechanical coupling method,and the variation patterns of temperature and stress were obtained.The uniaxial compressive failure process of DSC after freeze-thaw was simulat-ed.After comparison and validation with experimental results,the effects of porosity and interfacial phase strength on its frost resistance were investigated,and the intrinsic relationship between the com-pressive strength of DSC,interfacial phase strength ratio,and the number of freeze-thaw cycles was established.The results showed that the temperature transfer in DSC exhibited a delayed effect.The temperature at the specimen surface changed faster than that at the center,and the internal tempera-ture of circular aggregate concrete model changed faster than that of the polygonal aggregate concrete model.During freeze-thaw cycles,the temperature stress in the outer layer of DSC was higher than that in the inner layer,making the outer layer more susceptible to freeze-thaw damage.The tempera-ture stress showed an initial increase followed by a decrease as the number of freeze-thaw cycles in-creased.Under the same number of freeze-thaw cycles,both the frost resistance and mechanical prop-erties of concrete with a 50%desert sand replacement rate were superior to those with a 0%replace-ment rate.Enhanced interfacial phase properties had a positive effect on the frost resistance of DSC,while an increase in porosity had a negative effect.