Probabilistic Prediction Model of Fatigue Life of RC Structures Considering the Meso-scale Inhomogeneity of Concrete

A 3D microscopic numerical model for chloride diffusion in fatigue-damaged concrete was established, where the concrete was treated as a three-phase composite consisting of coarse aggregate, mortar matrix and ITZ to consider its inhomogeneity. Results showed that the chloride concentration in concrete increases significantly with the increase of fatigue stress level, water-cement ratio, temperature and exposure time, in which the chloride concentration at the same depth is different. According to the K-S test, the chloride concentration at a certain concrete depth follows the mixed normal distribution at a 5% significance level, based on which, a probabilistic fatigue life prediction model is proposed. It was found that the failure probability increases with the increase of fatigue life, but decreases with the decrease of fatigue stress level, water-cement ratio, temperature and exposure time. Hence it was suggested that RC structure should be maintained a fatigue stress level of below 0. 4 (failure probability of 10% and 2 million cycles of fatigue life)during its service . In addition, based on the proposed model, the fatigue life of RC structures in four coastal cities was predicted and the related durability recommendations were given. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.