The compressive fatigue performance of cementitious composites largely depends on the generation and connection of fatigue nano/micro-cracks in the composites. These types of cracks are beyond the scope that traditional fibers can restrain, but can be effectively eliminated and inhibited by incorporating nano-materials, especially those with fiber shape, such as carbon nanotube (CNT). Unfortunately, the effect of CNT and its physical and chemical characteristics on the compressive fatigue performance of cementitious composites remains unclear. Therefore, this paper systematically investigated the effect of CNT with different contents and sizes, functional groups and coating layers on the compressive fatigue performance of cementitious composites, including fatigue life, strength, deformation behavior and cracking characteristics. The morphology of the fatigue fracture surface of cementitious composites shows that CNT can refine pore structure, bridge nano/micro-cracks and result in the generation of the multi-directional and network-like fatigue micro-cracks as well as the appearance of the fatigue striation around aggregates. Consequently, by increasing the integrity among each phase of cementitious composites, CNT significantly maximizes the compressive fatigue life (in logarithmic form), strength and failure strain of cementitious composites by 160 %, 43.4 % and 20.6 %, respectively, showing great potential for extending the service life of concrete structures.

水泥基复合材料的压缩疲劳性能很大程度上取决于复合材料中疲劳纳米/微米裂纹的产生和连接。这些类型的裂纹超出了传统纤维可以抑制的范围，但可以通过掺入纳米材料，特别是碳纳米管（CNT）等具有纤维形状的材料来有效消除和抑制。不幸的是，碳纳米管及其物理和化学特性对水泥复合材料压缩疲劳性能的影响仍不清楚。因此，本文系统研究了不同含量和尺寸的碳纳米管、不同官能团和涂层对水泥基复合材料压缩疲劳性能的影响，包括疲劳寿命、强度、变形行为和开裂特性。水泥基复合材料的疲劳断口形貌表明，碳纳米管可以细化孔隙结构，桥接纳米/微裂纹，导致多向网状疲劳微裂纹的产生和疲劳的出现。聚集体周围的条纹。因此，通过提高水泥复合材料各相之间的完整性，CNT显着提高了水泥复合材料的抗压疲劳寿命（以对数形式）、强度和破坏应变，分别提高了160%、43.4%和20.6%，显示出巨大的扩展潜力。混凝土结构的使用寿命。桥接纳米/微米裂纹，导致多向网状疲劳微裂纹的产生以及骨料周围疲劳条纹的出现。因此，通过提高水泥复合材料各相之间的完整性，CNT显着提高了水泥复合材料的抗压疲劳寿命（以对数形式）、强度和破坏应变，分别提高了160%、43.4%和20.6%，显示出巨大的扩展潜力。混凝土结构的使用寿命。桥接纳米/微米裂纹，导致多向网状疲劳微裂纹的产生以及骨料周围疲劳条纹的出现。因此，通过提高水泥复合材料各相之间的完整性，CNT显着提高了水泥复合材料的抗压疲劳寿命（以对数形式）、强度和破坏应变，分别提高了160%、43.4%和20.6%，显示出巨大的扩展潜力。混凝土结构的使用寿命。