The ultra-high-strength engineering cementitious composites demonstrates pseudo strain hardening behavior when subjected to uniaxial tension, making it a promising material for enduring repeated or fatigue loads. Extensive research has been conducted on the quasi-static, dynamic, and fatigue behavior of this composites. However, due to the challenges of conducting direct tensile testing on concrete, investigations into the tensile fatigue behavior of ECC, particularly for ultra-high-strength ECC, remain limited. The fatigue behavior of concrete can be influenced by various factors. This study focuses on the impact of loading frequency. Several series of tensile fatigue tests were conducted under different loading frequencies and stress levels. The test results revealed that fatigue life increases with higher applied loading frequencies and decreases with increasing stress levels. The analysis of the test results includes the examination of failure modes, fatigue life, deformation, and secondary strain rates. A probabilistic model of fatigue failure, considering the discreteness of the initial static strength, was proposed based on the fatigue life. This model aligned well with the experimental results, providing valuable insights into the behavior of ultra-high-strength ECC under tensile fatigue conditions.

中文翻译：

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加载频率对超高强度工程水泥基复合材料拉伸疲劳行为的影响


超高强度工程水泥基复合材料在受到单轴拉伸时表现出伪应变硬化行为，使其成为承受重复载荷或疲劳载荷的有前途的材料。已经对这种复合材料的准静态、动态和疲劳行为进行了广泛的研究。然而，由于对混凝土进行直接拉伸试验的挑战，对 ECC 的拉伸疲劳行为的研究，特别是对于超高强度 ECC，仍然有限。混凝土的疲劳行为会受到各种因素的影响。本研究侧重于加载频率的影响。在不同的载荷频率和应力水平下进行了几个系列的拉伸疲劳试验。测试结果表明，疲劳寿命随着施加载荷频率的增加而增加，而疲劳寿命随着应力水平的增加而缩短。测试结果的分析包括对失效模式、疲劳寿命、变形和二次应变率的检查。基于疲劳寿命，提出了一种考虑初始静态强度离散性的疲劳失效概率模型。该模型与实验结果非常吻合，为超高强度 ECC 在拉伸疲劳条件下的行为提供了有价值的见解。