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对超高韧性水泥基复合材料(UHTCC)进行单轴压缩疲劳试验,研究其压缩疲劳寿命、疲劳变形特征、纤维破坏形态以及疲劳寿命方程。结果表明:在单轴压缩疲劳荷载作用下,UHTCC材料的三阶段变形特征与普通混凝土以及钢纤维混凝土类似,所不同的是,该材料在疲劳荷载作用下的变形明显大于其静载包络线,具有更优异的变形能力,在疲劳破坏时呈现更显著的延性特征;疲劳破坏后,疲劳破坏面上的纤维受到严重挤压,其形态不同于纤维初始形态以及单调荷载作用下纤维的破坏形态。UHTCC材料的压缩疲劳寿命服从威布尔分布,p-S-N双对数方程可根据威布尔参数拟合得到。该研究结果可为UHTCC材料的工程应用提供参考。
The uniaxial compression fatigue test of ultrahigh toughness cementitious matrix composites (UHTCC) was conducted to study the compression fatigue life, fatigue deformation characteristics, fiber failure morphology and fatigue life equation. The results show that under the uniaxial compression fatigue load, the three-stage deformation characteristics of UHTCC are similar to ordinary concrete and steel fiber reinforced concrete. The difference is that the deformation of UHTCC under fatigue load is obviously larger than that of static load envelope , Which has more excellent deformability and exhibits more ductile characteristics when fatigue failure occurs. After fatigue failure, the fibers on the fatigue failure surface are severely compressed, and the morphology is different from the initial morphology of fibers and the failure morphology of fibers under monotonic loading . The compressive fatigue life of UHTCC material obeys Weibull distribution, and p-S-N double logarithm equation can be fitted according to Weibull parameter. The results of this study can provide reference for the engineering application of UHTCC materials.