采用三维彩色扫描技术和线性极化电阻测试方法研究了盐水浸烘条件下表面涂覆迁移性阻锈剂(PCI-2015)对含氯盐混凝土中钢筋锈蚀状况的影响,计算了浸烘前后钢筋腐蚀电流密度(I_(corr)),运用逆向工程软件获得了剖开锈蚀钢筋表面积、截面积等参数,并对钢筋沿纵向各截面积进行统计分析。结果表明:表面涂覆400 g/m~2的PCI-2015及防水剂的混凝土试件,浸烘循环后I_(corr)平均值为0.17μA/cm~2,平均锈蚀面积9.58%,未涂覆的空白组I_(corr)平均值为1.04μA/cm~2,平均锈蚀面积为71.75%;氯盐致钢筋不均匀锈蚀的横截面积服从三参数Weibull分布,涂覆组与空白组横截面积分布的阈值参数分别为27.67和27.49,形状参数分别为1.15和2.24,涂覆组钢筋截面均匀且腐蚀较少,钢筋腐蚀累积损伤程度较低;用三维彩色扫描技术量化表征氯盐致混凝土中钢筋不均匀锈蚀是一种较为可行的方法。
Effect of surface painting migrating corrosion inhibitor (MCI) on the steel bar corrosion in chloride contaminated concrete was investigated by wet-dry cycling tests in chloride solution. The corrosion current density (Icorr) of steel bar in concrete was examined by a linear polarization resistance method. A colored three-dimensional scanner was used to scan the steel bars removed from concrete. The geometry parameters of steel bars, such as rusted surface area and cross-sectional area, were calculated by a reverse engineering software. The data of cross-sectional area were analyzed via a statistics software. The results show that after four wet-dry cycling tests, the average current density Icorr of steel bar is 0.17 μA/cm2 and the average corrosion ratio is 9.58% after painting 400 g/m2 PCI-2015 and water-proofing agent. The average 1tort of steel bar is 1.04 μA/cm2 and the average corrosion ratio is 71.75% in a controled group. The variation of steel bar cross-sectional area data in concrete painted PCI-2015 and water-proofing agent is less than that in the controled group. The steel bar cross-sectional area data in concrete painted PCI-2015 and water-proofing agent follow the three-parameter Weibull distribution, in which the shape parameter is i. 15 and the threshold parameter is 27.67. The shape parameter and threshold parameter are better than those in the controlled group (i.e., 2.24, 27.49), indicating that the random corrosion cumulative damage degree of steel bars in concrete surface-painted PCI-2015 is much lower than that in the controled concrete. It is indicated that the parameters drawing from the 3D color scanning technique are suitable for the quantitative characterization and evaluation of the non-uniform corrosion of steel bar in chloride-contaminated concrete.