摘   要：配制了芳纶纤维（具有阻燃性）高性能混凝土，研究了在0、100 ℃、500 ℃、900 ℃和1 200 ℃环境下加热2 h后不同放置时间对芳纶纤维混凝土抗压强度的影响，并结合扫描电镜方法分析了混凝土的微观结构变化规律。结果表明，芳纶纤维能够提高混凝土的耐火性；随着芳纶纤维掺量的增加，混凝土的抗压强度呈先增大后减小的趋势，且纤维最佳掺量为5%；随着温度的升高，试件的抗压强度均呈线性下降趋势；低温环境下（0、100 ℃），试件放置0 d、7 d、14 d和28 d后的抗压强度基本相同；中高温环境下（500 ℃和900 ℃），放置时间对纤维混凝土的抗压强度有明显影响；高温环境下（1 200 ℃），纤维混凝土被烧坏，其抗压强度随着放置时间的延长基本不变化。

Abstract: The high performance concrete with aramid fiber (flame retardant) was prepared, and the effect of different storage time on the compressive strength of aramid fiber concrete after heating at 0, 100 ℃, 500 ℃, 900 ℃ and 1 200 ℃ for 2 hours was studied, and the scanning electron microscopy(SEM) method was used to analyze the microstructure changes of concrete. The results show that aramid fiber can improve the fire resistance of concrete, and with the content of aramid fiber increases, the compressive strength of concrete increases first and then decreases, and the optimal content of aramid fiber is 5%. With the increase of ambient temperature, the compressive strength of the specimens shows a linear downward trend. At low temperature(0, 100 ℃), the compressive strength of the specimens after 0 d, 7 d, 14 d and 28 d is basically the same. At medium and high temperature(500 ℃, 900 ℃), the storage time has a significant effect on the compressive strength. At high temperature(1 200 ℃), the fiber concrete is burned out, and the compressive strength basically does not change with the prolongation of the storage time.