Evaluation and prediction of fatigue life for ceramsite lightweight concrete considering the effects of ceramsite aggregate size and content

Ceramsite concrete is currently one of the most widely used types of lightweight concrete. Although its durability (in terms of permeability, shrinkage, etc.) has been extensively demonstrated, fatigue resistance has not been addressed in previous studies, particularly the impact of ceramsite characteristics on fatigue resistance. Hence, in this study, the fatigue life of ceramsite concrete at different stress levels is investigated using four-point bending fatigue tests. The Weibull distribution test reveal, the effects of ceramsite size and content on the equivalent fatigue life under different failure probabilities. The effects of ceramsite on fatigue resistance are also analysed using SEM. Finally, a uniform fatigue equation considering the ceramsite content, ceramsite size, and stress level is established to predict the fatigue life of ceramsite concrete. The results show that: the equivalent fatigue life of ceramsite concrete increases with 5 – 10 mm and 10 – 20 mm ceramsite contents, especially for 5 – 10 mm ceramsite. Concerning 20 – 30 mm ceramsite, it has a negative impact on the fatigue resistance of ceramsite concrete, particularly at low stress levels. Ceramsite size and content have less influence on fatigue life under stress level variation. The propose fatigue prediction equation concurrently considers the effects of ceramsite content, ceramsite size, and stress level on the fatigue life. The R2 values of the prediction equation for different failure probabilities exceed 0.94, thereby proving the reliability of the proposed fatigue equation.