Abstract Super-fine stainless wires (SSWs) with micron diameter and large specific surface area can simultaneously strengthen and toughen reactive powder concrete (RPC) at low volume fraction, so SSW reinforced RPC composites have potential for developing infrastructures bearing fatigue load or with aseismic requirements. In this paper, the uniaxial compressive fatigue characteristics of such composites under high stress levels were investigated, and the modification mechanisms of SSWs to RPC were revealed through failure state and microstructure analyses. The results showed that incorporating only 0.5 vol% SSWs into RPC enables the fatigue life and energy dissipation capacity to increase by 252.0% and 262.3%, meanwhile, the fatigue limit strength of composites at the failure probability of 50% reaches up to 76.6% of static uniaxial compressive strength, due to the improvement effect on microstructure compactness, inhibiting effect on flaw initiation, and the ability to convert single main crack into radial multiple micro cracks centered on SSWs. Furthermore, the average maximum fatigue strain and residual strain of composites are improved by 73.7% and 87.2%, respectively, which can be ascribed to the bridging, debonding and being pulled-off effect of SSWs. It can be therefore concluded that the incorporation of SSWs endows RPC with excellent fatigue performance, thus further enlarging the application of composites.

中文翻译：

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超细不锈钢丝活性粉末混凝土单轴压缩疲劳行为

摘要 具有微米直径和大比表面积的超细不锈钢丝（SSWs）可以在低体积分数下同时增强和增韧反应性粉末混凝土（RPC），因此 SSW 增强 RPC 复合材料具有开发承受疲劳载荷或抗震要求的基础设施的潜力. 在本文中，研究了这种复合材料在高应力水平下的单轴压缩疲劳特性，并通过失效状态和微观结构分析揭示了 SSWs 对 RPC 的改性机制。结果表明，仅在 RPC 中加入 0.5 vol% SSWs，疲劳寿命和耗能能力分别提高了 252.0% 和 262.3%，同时，复合材料在失效概率为 50% 时的疲劳极限强度达到了 76。6%的静态单轴抗压强度，由于对微观结构致密性的改善作用，对裂纹萌生的抑制作用，以及将单个主裂纹转变为以SSWs为中心的径向多微裂纹的能力。此外，复合材料的平均最大疲劳应变和残余应变分别提高了 73.7% 和 87.2%，这可以归因于 SSW 的桥接、脱粘和拉脱效应。因此可以得出结论，SSWs的加入赋予了RPC优异的疲劳性能，从而进一步扩大了复合材料的应用。复合材料的平均最大疲劳应变和残余应变分别提高了 73.7% 和 87.2%，这可以归因于 SSW 的桥接、脱粘和拉脱效应。因此可以得出结论，SSWs的加入赋予了RPC优异的疲劳性能，从而进一步扩大了复合材料的应用。复合材料的平均最大疲劳应变和残余应变分别提高了 73.7% 和 87.2%，这可以归因于 SSW 的桥接、脱粘和拉脱效应。因此可以得出结论，SSWs的加入赋予了RPC优异的疲劳性能，从而进一步扩大了复合材料的应用。