Performance Degradation and Service Life Prediction of Magnesium Oxychloride Cement Recycled Concrete in Western Saline Soil Environment

Western saline soil areas contain a large amount of chloride and sulfate ions, leading to a reduction in the service life of Portland concrete in this environment. Magnesium oxychloride cement recycled concrete (MOCRC) is mainly prepared with light-burnt magnesia and magnesium chloride, which is more suitable for application in a western saline soil environment than Portland concrete. In this paper, ultrasonic non-destructive testing technology was used to investigate the effects of multiple factors on the deterioration process and service life of MOCRC in a western saline soil environment. The results showed a clear functional relationship between the relative dynamic elastic modulus and the compressive strength or size of MOCRC. On this basis, a multiparameter time-varying degradation model for MOCRC considering the compressive strength, size effect, and environmental error is established. Moreover, a service life prediction model for MOCRC based on the relative dynamic elastic modulus is proposed, using reliability theory and the first-order second-moment method. This study provides a foundational method for the durability examination and service life prediction of MOCRC.