Durability of Gangue Concrete under Freeze-thaw and Dry-wet Cycles

Objective In order to study the influence mechanism of changing the number of freeze-thaw cycles and the coarse aggregate replacement rate on the mechanical properties, frost resistance and sulfate erosion resistance of ordinary concrete and coal gangue concrete, Methodthis article focuses on analyzing key indicators such as the loss rate of compressive strength, mass loss rate and dynamic elastic modulus loss rate. Result Compressive strength of coal gangue concrete decreases significantly with an increase in the number of freeze-thaw cycles, specifically decreasing by an average of 30% for every 50 freeze-thaw cycles. Compared to ordinary concrete, coal gangue concrete exhibits more pronounced degradation effects at freeze-thaw action. The freeze-thaw damage model constructed based on the dynamic elastic modulus loss rate demonstrates higher fitting accuracy and effectively characterises the evolutionary patterns of the macro-mechanical properties of coal gangue concrete. ConclusionIn dry-wet cycle tests, all specimens exhibited progressive damage characteristics. As the coal gangue content increased, the durability performance showed a regular decline. At the same number of dry-wet cycles, adding more gangue reduces durability. Specifically, R60, R80, and R100 were deemed structurally damaged when their compressive strength and corrosion resistance coefficients decreased to 75% after 60 dry-wet cycles.