This study investigates the effects of matrix strength, synthetic fiber content, and heating duration on the explosive spalling resistance and residual compressive and flexural properties of high-performance fiber-reinforced cementitious composites (HPFRCCs). Three different matrix strengths, ranging from 100 to 180 MPa; four different volume fractions of synthetic fibers, i.e., polypropylene (PP) and nylon (Ny) fibers, ranging from 0% to 0.6%; and three different fire durations of 1, 2, and 3 h under the ISO standard fire curve were adopted. Scanning electron microscope (SEM) images were obtained to evaluate the microstructural states of HPFRCCs and a mercury intrusion porosimetry (MIP) analysis was conducted to determine pore size distribution characteristics before and after fire exposure. The test results indicate that the addition of PP and Ny fibers is effective at enhancing the explosive spalling resistance, and higher amounts are required for higher strength matrices. The compressive strength of HPFRCCs decreased by more than 75% after the fire (≥950 °C), and higher residual compressive strengths were obtained with shorter fire durations and higher amounts of added PP and Ny fibers. The toughness was decreased by the fire more than the flexural strength, and the residual flexural performance were enhanced with higher amounts of synthetic fibers and matrix strengths. In particular, the residual flexural performance significantly decreased when the fire duration increased from 1 to 2 h, and only a minor change was observed thereafter. The effectiveness of higher amounts of synthetic fibers at improving the residual performance diminished with longer fire durations.

这项研究调查了基质强度，合成纤维含量和加热时间对高性能纤维增强水泥基复合材料（HPFRCC）的抗爆炸剥落性和残余压缩和弯曲性能的影响。三种不同的基体强度，范围从100到180 MPa；合成纤维的四种不同体积分数，即聚丙烯（PP）和尼龙（Ny）纤维，范围从0％至0.6％；并采用了ISO标准着火曲线下的1、2和3小时三种不同的着火时间。获得了扫描电子显微镜（SEM）图像以评估HPFRCC的微观结构状态，并进行了压汞法（MIP）分析，以确定着火前后的孔径分布特征。测试结果表明，添加PP和Ny纤维可有效提高抗爆炸剥落性，而更高强度的基体则需要更高的用量。火灾（≥950°C）后，HPFRCC的抗压强度降低了75％以上，并且随着燃烧时间的缩短和PP和Ny纤维添加量的增加，获得了更高的残余抗压强度。着火后韧性比弯曲强度下降得更多，而残余弯曲性能则随着合成纤维含量和基体强度的增加而提高。特别地，当燃烧持续时间从1小时增加到2小时时，残余挠曲性能显着下降，此后仅观察到很小的变化。