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通过弯曲疲劳试验研究了超高韧性水泥基复合材料(UHTCC)的弯曲疲劳寿命、疲劳变形以及破坏特征等。试验结果表明:疲劳荷载作用下,UHTCC也会产生多条裂缝,随应力水平降低,裂缝数目减少,使得其变形能力减弱;疲劳破坏后,试件断面可分为3个不同区域,且不同应力水平下,纤维的拔出破坏和拉断破坏比例不同。UHTCC疲劳寿命服从双参数的威布尔分布,根据威布尔参数拟合的S-N双对数方程呈明显的双线性特征,原因是在低周与高周疲劳荷载循环作用下UHTCC中PVA纤维发挥作用的程度有所不同。
The bending fatigue life, fatigue deformation and failure characteristics of ultrahigh toughness cementitious composites (UHTCC) were studied by bending fatigue test. The results show that under the action of fatigue load, UHTCC will also produce a number of fractures. With the decrease of stress level, the number of fractures will decrease and the deformation ability will be weakened. After fatigue failure, the fracture surfaces of the specimens can be divided into three different zones with different stresses Under the level of pull out of the fiber damage and pull off the destruction of different proportions. The UHTCC fatigue life obeys the two-parameter Weibull distribution, and the SN double logarithmic equation fitting to Weibull’s parameters shows a distinct bilinear characteristic due to the PVA fiber in UHTCC being affected by low-cycle and high-cycle fatigue load cycles The degree of difference is different.