Microstructure and Service-Life Prediction Models of Aeolian Sand Concrete Under Freeze–Thaw Damage

In this study, aeolian sand was used as fine aggregate to partially replace natural river sand in the range of 25 to 100% to prepare aeolian sand concrete (ASC). The ASC under freeze–thaw conditions in chloride environment was studied. Based on the compressive strength loss rate and the relative dynamic modulus of elasticity (the relative DME) obtained from the study as damage variables and combined with the Weibull distribution model, the freeze–thaw damage model of ASC was established to predict the service life of ASC in China’s northwestern cold regions. The microstructure of ASC under freeze–thaw conditions was also observed and studied. The results showed that 100% ASC had the best frost resistance, and the compressive strength loss rate and relative dynamic elastic modulus after 200 freeze–thaw cycles were 18.2 and 90.8%, respectively. These evaluation indexes show that the concrete has not reached the freeze–thaw damage state. The linear damage evolution model can accurately predict the durability of ASC in a cold environment, and predict that the service life of 100% ASC in 3.5% chloride solution is more than 25 years, which meets the requirements of concrete in water conservancy projects in Northwest China.