Stochastic Fatigue Damage Behavior and Modeling of Seawater Sea-Sand Concrete Under Uniaxial Compression

This paper presents the first study on the fatigue damage behavior of seawater sea-sand concrete (SSC) and its modeling. Experimental tests were conducted on cylindrical specimens subjected to uniaxial compression, investigating the effects of maximum stress level and material variability. The results indicate that the maximum stress-fatigue life curve for SSC can be well represented by a straight line, while the secant stiffness of SSC degrades in a two-phase process: initially in a decelerating manner, followed by an accelerating degradation until failure. Compared to ordinary concrete, SSC exhibits a significantly longer fatigue life. Due to material variability, the fatigue life of SSC shows considerable randomness, which can be effectively modeled using a Weibull distribution. A modification was made to a recently proposed damage model by the author and Li to capture the stochastic fatigue damage evolution behavior of SSC. The modified model successfully simulates both the maximum stress-fatigue life curve and the secant stiffness degradation curve, including their inherent randomness. Future research should explore the underlying specific factors contributing to the significantly longer fatigue life of SSC compared to ordinary concrete.