高温作用后聚丙烯纤维混凝土氯离子渗透性能研究

Research on chloride ion permeability of polypropylene fiber reinforced concrete after high temperature

采用RCM试验研究分析了高温作用后聚丙烯纤维混凝土的渗透性能,在fick第二扩散定律的基础上,建立了考虑高温影响的聚丙烯纤维混凝土氯离子扩散模型。研究表明：经历200℃高温后,混凝土的氯离子扩散系数为常温下的2～3倍;经历600℃高温后,混凝土的氯离子扩散系数为常温状态下的7～8倍。未经历高温时,聚丙烯纤维的掺入提高了混凝土的抗渗性能,且纤维掺量越大,氯离子扩散系数越小;经历高温作用后,聚丙烯纤维未能改善混凝土的抗渗性,当纤维掺量过大时,反而会对混凝土的抗渗性产生不利影响。

The permeability of polypropylene fiber reinforced concrete after the high temperature was analyzed by RCM test.Based on the tick second diffusion theory and experimental results, construct a polypropylene fiber concrete chloride ion diffusion model which considered the impact of high temperature.Research shows that after 200 degrees high temperature, the chloride ion diffusion coefficient of concrete is 2-3 times higher than normal temperature.After 600 degrees high temperature, the chloride ion diffusion coefficient of concrete is 7-8 times higher than normal temperature.Before the high temperature,the impermeability of concrete is improved by polypropylene fibers,and the amount of fiber is greater,the chloride ion diffusion coefficient will be smaller.After the high temperature,the polypropylene fiber can not improve the impermeability of concrete, when the fiber content is too large, it will have an adverse effect on the anti permeability of concrete.