In the present study, the mechanical properties of polyvinyl alcohol (PVA)-basalt hybrid fiber reinforced engineered cementitious composites (ECC) after exposure to elevated temperatures were experimentally investigated. Five temperatures of 20, 50, 100, 200 and 400 °C were set to evaluate the residual compressive, tensile and flexural behaviors of hybrid and mono fiber ECC. It was shown that partial replacement of PVA fibers with basalt fibers endowed ECC with improved residual compressive toughness, compared to brittle failure of mono fiber ECC heated to 400 °C. The tension tests indicated that the presence of basalt fibers benefited the tensile strength up to 200 °C, and delayed the sharp reduction of strength to 400 °C. Under flexural load, the peak deflections corresponding to flexural strengths of hybrid fiber ECC were found to be less vulnerable ranging from 20 to 100 °C. Further, the scanning electron microscopy (SEM) results uncovered that the rupture of basalt fiber at moderate temperature and its pullout mechanism at high temperature was responsible for the mechanical evolution of hybrid fiber ECC. This work develops a better understanding of elevated temperature and basalt fiber impact on the residual mechanical properties and further provides guideline for tailoring ECC for improved fire resistance.

在本研究中，通过实验研究了聚乙烯醇 (PVA)-玄武岩混合纤维增强工程水泥基复合材料 (ECC) 在暴露于高温后的机械性能。设置了 20、50、100、200 和 400 °C 五个温度来评估混合纤维和单纤维 ECC 的残余压缩、拉伸和弯曲行为。结果表明，与加热到 400°C 的单纤维 ECC 的脆性破坏相比，用玄武岩纤维部分替代 PVA 纤维使 ECC 具有改进的残余压缩韧性。拉伸试验表明，玄武岩纤维的存在有利于高达 200 °C 的拉伸强度，并将强度的急剧下降延迟到 400 °C。在弯曲载荷下，发现与混合纤维 ECC 的弯曲强度相对应的峰值挠度在 20 到 100 °C 的范围内不易受到影响。此外，扫描电子显微镜（SEM）结果表明，玄武岩纤维在中等温度下的断裂及其在高温下的拉拔机制是混合纤维 ECC 机械演化的原因。这项工作更好地了解高温和玄武岩纤维对残余机械性能的影响，并进一步为定制 ECC 以提高耐火性提供指导。