This article presents the results of an experimental investigation on the mechanical behavior of hybrid fiber reinforced Strain Hardening Cementitious Composites (SHCC) subjected to monotonic and cyclic loadings. For the study, PVA, ultra-high molecular weight polyethylene (UHMWPE) and steel fibers were used in a constant volume fraction of 2.0%. To study the synergetic effects between the fibers, hybrid compositions were also produced by replacing PVA and polyethylene by steel fibers in 0.5% and 1.0% volume fractions. The mechanical response was measured under direct tension tests, four-point bending tests on plates and three-point bending tests on notched specimens while the crack pattern was investigated using optical microscopy. To study the mechanical performance of the materials when subjected to loading/unloading cycles, cyclic three-point bending tests were also carried on. The partial replacement of PVA and polyethylene fibers by steel fibers increased the strength and post-cracking stiffness but reduced the ductility of the composites. The hybrid SHCCs presented a good mechanical performance when subjected to cyclic loadings, since the load bearing capacity and the multiple cracking behavior were maintained even for high crack opening values. The stiffness degradation and the dissipated energy over the loading/unloading cycles varied when different fibers combinations were used.

本文介绍了单调和循环载荷下混合纤维增强应变硬化水泥复合材料（SHCC）力学性能的实验研究结果。为了进行研究，使用了PVA，超高分子量聚乙烯（UHMWPE）和钢纤维，体积分数为2.0％。为了研究纤维之间的协同作用，还通过用钢纤维以0.5％和1.0％的体积分数代替PVA和聚乙烯来生产杂化组合物。在直接拉伸试验，在板上的四点弯曲试验和在有缺口的样品上的三点弯曲试验下测量机械响应，同时使用光学显微镜研究裂纹图案。为了研究材料在加载/卸载循环后的机械性能，还进行了循环三点弯曲测试。用钢纤维部分替代PVA和聚乙烯纤维可以提高强度和开裂后的刚度，但会降低复合材料的延展性。混合型SHCC在承受周期性载荷时表现出良好的机械性能，因为即使对于较高的开裂值，也能保持承重能力和多次开裂行为。当使用不同的纤维组合时，在加载/卸载循环中的刚度降低和耗散能量发生变化。混合型SHCC在承受周期性载荷时表现出良好的机械性能，因为即使对于较高的开裂值，也能保持承重能力和多次开裂行为。当使用不同的纤维组合时，在加载/卸载循环中的刚度降低和耗散能量发生变化。混合型SHCC在承受周期性载荷时表现出良好的机械性能，因为即使对于较高的开裂值，也能保持承重能力和多次开裂行为。当使用不同的纤维组合时，在加载/卸载循环中的刚度降低和耗散能量发生变化。