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试验分析了高温后活性粉末混凝土(RPC)的外观、质量损失和抗压强度随温度的变化情况;利用扫描电镜(SEM)研究了经历不同高温后的RPC微观结构变化和物相组成.结果表明:经历温度低于400℃时,水泥水化反应和火山灰反应互相促进,RPC微观结构得到改善,抗压强度较常温时有所提高;经历温度为400～800℃时,C-S-H凝胶由连续块状变为尺寸较小的分散相,钢纤维与基体粘结界面处的裂纹逐渐形成并扩展,聚丙烯纤维融化后的孔道加剧了RPC的内部缺陷,RPC微观结构不断恶化,抗压强度逐渐降低.
The appearance, mass loss and compressive strength of RPC after high temperature were analyzed with the change of temperature, and the changes of microstructure and phase composition of RPC after high temperature were studied by scanning electron microscope (SEM) : When the temperature is lower than 400 ℃, the cement hydration reaction and volcanic ash reaction promote each other, the microstructure of RPC is improved and the compressive strength is higher than that at room temperature. When the temperature is 400 ~ 800 ℃, CSH gel consists of continuous block Shape into a smaller dispersed phase, the crack at the interface between the steel fiber and the matrix gradually formed and expanded. The pores after melting the polypropylene fiber aggravated the internal defects of the RPC. The microstructure of the RPC deteriorated continuously and the compressive strength gradually decreased .