To explore the fatigue fracture behavior of self-compacting concrete (SCC), constant amplitude loading tests and incremental amplitude loading tests were carried out. The experimental results of SCC were obtained and analyzed, including P-CMOD curve, fatigue life, effective crack length, fatigue crack growth (FCG) rate, stress intensity factor (SIF). The results show that the P-CMOD curves of SCC beams follow the unique envelope theory. The fatigue damage of SCC under constant amplitude load can be divided into three stages. In the second stage, cracks grow steadily. The critical SIF is the boundary point between the second and the third stages of fatigue damage. When SIF exceeds the critical SIF, cracks develop rapidly. The first stage of fatigue damage is not obvious for incremental amplitude loading tests. With the increase of load amplitude, there are obvious second and third stages of damage. Except for the maximum load stage, the crack opening rate keeps constant generally. Combined with damage mechanics and fracture mechanics, damage evolution equations of SCC under constant amplitude load and incremental amplitude load were established. The parameters of fatigue damage model based on continuous damage mechanics (CDM) were calibrated by test data, and the predicted results were compared with the experimental results. The results show that the model is sensitive to the first stage of damage. The fatigue damage model based on CDM is more suitable to predict fatigue life for incremental amplitude tests and constant amplitude tests with high cycle. The advantage of this model is that it can be applied to predict fatigue life for different load levels.

为了探索自密实混凝土（SCC）的疲劳断裂行为，进行了恒定振幅载荷试验和增量振幅载荷试验。获得并分析了SCC的实验结果，包括P-CMOD曲线，疲劳寿命，有效裂纹长度，疲劳裂纹扩展率（FCG），应力强度因子（SIF）。结果表明，SCC梁的P-CMOD曲线遵循独特的包络理论。恒振幅载荷下SCC的疲劳损伤可分为三个阶段。在第二阶段，裂纹稳定增长。临界SIF是疲劳损伤的第二阶段和第三阶段之间的边界点。当SIF超过临界SIF时，裂纹会迅速发展。对于增量振幅载荷测试，疲劳损伤的第一阶段并不明显。随着负载振幅的增加，有明显的第二和第三阶段破坏。除最大载荷阶段外，裂纹的开度一般保持恒定。结合损伤力学和断裂力学，建立了SCC在恒定振幅载荷和增量振幅载荷下的损伤演化方程。通过试验数据对基于连续损伤力学（CDM）的疲劳损伤模型的参数进行了标定，并将预测结果与实验结果进行了比较。结果表明，该模型对损伤的第一阶段敏感。基于CDM的疲劳损伤模型更适合预测疲劳寿命，适用于高振幅的增量振幅测试和恒定振幅测试。该模型的优点是可以用于预测不同载荷水平下的疲劳寿命。