Experimental Study on Mechanical Properties of Desert Sand Concrete Under Freeze–Thaw Cycles

This study aims to explore the mechanical behavior of Desert Sand Concrete (DSC) under freeze-thaw (F-T) cycles. By adjusting the number of F-T cycles, the research analyzed the impact of various desert sand replacement ratios on the frost resistance of concrete. The study focused on the dynamic changes in mass loss of concrete specimens, relative dynamic elastic modulus, cubic compressive strength, splitting tensile strength, and axial compressive strength. Scanning electron microscopy was employed to analyze the micro-morphology of specimens after F-T cycles. This analysis aimed to predict the service life of DSC and provide practical recommendations for the maximum compressive strength loss rate within the designed service life. The results indicated that although the frost resistance of DSC was similar to that of ordinary concrete before 50 F-T cycles, it subsequently exhibited a nonlinear degradation trend correlated with increasing desert and replacement ratios, with both frost resistance and compactness reaching optimal levels at a 40% replacement rate. Additionally, the F-T damage model proposed in this study demonstrated high applicability and fitting accuracy. This model provided effective theoretical support for understanding and predicting the mechanical behavior of DSC.