碳化和应力作用对混凝土抗氯离子渗透性能的影响

Effect of Carbonization and Stress on Performance of Concrete Resistance to Chloride Ion Penetration

碳化、氯离子侵蚀、应力三者共同作用对沿海地区混凝土结构耐久性具有重要影响。以C25级普通混凝土为研究对象,针对应力、碳化和氯盐三因素共同作用,借助室内试验手段,对混凝土试样进行加载及快速碳化试验,研究了碳化和应力作用下混凝土中的氯离子迁移规律。研究表明:碳化龄期短的混凝土试件,氯离子扩散系数会有很大程度的下降,随着碳化时间的增加下降速度不断减缓;碳化龄期较长的混凝土试件,氯离子扩散系数会略有升高。随压应力的增大,混凝土碳化深度逐渐减小,氯离子扩散系数也逐渐减小。

Carbonation, chloride ion erosion, and load combination has important effects on concrete structure endurance in coastal areas. Grade C25 ordinary concrete as the research object, for stress, carbonation and chloride salt three factors work together, loading test and rapid carbonization test are used to study the coupling mechanism of concrete under the action of chloride ion migration. Studies have shown that chloride ion diffusion coefficient will be greatly decreased for short time carbonization specimen. With the increase of carbonization time, diffusion coefficient decreasing speed slows down. The chloride ion diffusion coefficient will rise slightly for long time carbonization specimen. Along with the increase of compressive stress, concrete carbonation depth decreases, and the chloride ion diffusion coefficient is also gradually reduced.