干湿循环作用下混凝土裂缝区域氯离子的传输状态

Transport State of Chloride Ion in Concrete Crack Area under Dry-Wet Cycle

研究了干湿循环作用下混凝土裂缝区域的氯离子浓度分布和裂缝影响区域。制备了不同宽度横向裂缝的混凝土试件,采用干湿循环加速氯离子对混凝土的侵蚀,定期检测不同侵蚀周期试件破型后裂缝侧面以及试件上表面至钢筋方向的氯离子浓度。试验结果表明:氯离子浓度随着传输深度增加而降低,在20 mm处基本稳定。随着干湿循环的进行,在20个干湿循环周期后,裂缝宽度为0.1~0.5 mm的试件,裂缝侧面30 mm处氯离子浓度都大于0.1%,钢筋在裂缝左右30 mm范围内有锈蚀的危险。并且由于二维传输的互相影响,裂缝宽度越大,相同传输深度氯离子浓度也越高。

The chloride ion concentration distribution and crack-influenced area in concrete crack area under dry-wet cycle are studied. Concrete samples with different widths of transverse crack are exposed in the chloride dry-wet cycle environment for accelerating chloride ion erosion into concrete. The chloride ion concentration in the side of the crack and from the surface of the specimen to the steel bar of different erosion cycles is regularly detected. The test results show that chloride concentration decreases with the increase of transmission depth, and achieves stability at 20 mm. With the dry-wet cycle progressing, after 20 dry-wet cycle periods, chloride concentration in specimen with crack width from 0. 1 mm to 0. 5 mm is over 0. 1% on the side of crack by 30 mm, which means the steel in this section is in danger of corrosion. Meanwhile, because of the influence of two dimensional transmissions, the greater crack width, the higher chloride concentration of same transmission depth is.