氯盐与冻融共同作用下引气高性能混凝土氯离子渗透性

Chloride penetration of air-entrained high-performance concrete subjecdted to chloride and freeze-thaw

通过引气高性能混凝土在3%Na Cl溶液中自然浸泡及盐水快速冻融试验,测试了不同冻融次数后混凝土中氯离子含量分布和相对动弹性模量的变化;利用损伤力学原理,研究了冻融损伤与氯离子扩散系数、冻融循环次数的关系。研究表明:冻融循环导致混凝土性能劣化,增大了混凝土氯离子扩散系数,当冻融300次时混凝土的冻融损伤度为5%,氯离子扩散系数增大了1倍;混凝土冻融损伤度与氯离子扩散系数、冻融循环次数之间均符合指数关系。

Naturally immersion in 3% Na Cl solution and fast freeze-thaw were tested for the air-entrained high-performance concrete. Contents of chloride ion in concrete and relative dynamic elastic modulus after different freeze-thaw cycles were investigated. According to the principle of damage mechanics,the relationship between the freeze-thaw damage and chloride diffusion coefficient,freeze-thaw cycles are studied. Test result indicates that the freeze-thaw cycle leads to degradation, and increases the chloride diffusion coefficient of concrete. The diffusion coefficient is 1 time of undamaged concrete when the damage degree is 5%. The relationship between the damage degree of freeze-thaw,chloride diffusion coefficient and freeze-thaw cycles conforms to the exponential relationship.