【摘要】 采用PCK法测量了高强混凝土受火后的吸水率 ,用以表征混凝土受火后的渗透性及高温时的温扩散能力。研究表明 ,随着受火温度升高、恒温时间延长 ,试件吸水率增大 ,且温度的影响更敏感 ;PP纤维掺入后可提高试件的湿扩散能力 ,从而降低爆裂度 ,但也削弱了受火后混凝土抗环境介质渗透的能力 ;硅灰混凝土结构更为密实 ,湿扩散能力低 ,更易爆裂。验证了蒸气压是爆裂的主要原因更多还原

【Abstract】 The water absorption ratio of high strength concrete after fire measured by PCK method was used to evaluate the permeability of concrete after fire and the moisture diffusivity at high temperature. The study shows that the water absorption ratio was increased with the rise of temperature and the fire sustained duration,moreover, the influence of temperature was more sensitive than that of the duration.PP fiber can improve moisture diffusivity, which reduces spalling possibility. But it decreases the resistance to permeation of media from environment. The concrete with silica fume possesses low moisture diffusivity because of its dense structure, which results in its high fire spalling chance.The study verifies indirectly that the main spalling mechanism is water vapor pressure.更多还原