Experimental study on fatigue damage of self-compacting concrete of CRTS III slab track

To study fatigue performances and establish the fatigue damage model of self-compacting concrete (SCC) of China Railway Track System (CRTS) III slab track under different stress levels, static and fatigue tests were conducted. In the static test, the flexural strength of SCC was obtained. In the fatigue test, fifteen specimens were divided into five groups. The maximum stress levels were 0.65, 0.70, 0.75, 0.80, and 0.85 for each group, and the minimum stress level was 0.10 for every group. The S-N curve of SCC is obtained and shows that the fatigue life of SCC decreases with the increase of the maximum stress level. The strain evolution and elastic modulus degradation can be divided into 'Fast-Slow-Fast' three stages. With the maximum stress level increases, the proportion of elastic modulus degradation increases and decreases in the first and third stages, respectively. The fatigue damage model derived from the improved elastic modulus method and the Chaboche fatigue damage model can reflect the damage evolution of SCC under different stress levels. Moreover, the proposed model can provide theoretical guidance for the further numerical simulation of SCC for ballastless tracks under the fatigue load.