A modified colorimetric method to determine the chloride profile from the ponding test

The ponding test has been used in recent years to evaluate the durability of concrete. However, the process of collecting the powder from various depths for the chloride analysis is difficult and exhausting. This paper presents a simplified procedure for measuring the chloride diffusion coefficient of concrete and the chloride profile using the modified colorimetric method (MCM). The MCM uses a depth of penetration approach and the surface chloride content to determine the chloride profile. The depth of penetration of chloride at 0.01% concentration is obtained from the colorimetric penetration depth by using regression analysis. The results show that the chloride diffusion coefficients and the profiles obtained from the MCM are very close to those yielded by conventional ponding. The MCM is a rapid and accurate method to determine the chloride profile of concrete during ponding tests.