Relation between the chloride migration coefficients of concrete from the colourimetric method and the chloride profile method

Abstract

In this study the electrochemical technique is applied to accelerate chloride ion migration in concrete to determine its transport property. After the accelerated chloride migration test (ACMT; the electrochemical technique is applied to accelerate chloride ion migration), the penetration depths of the colourimetric method were detected by 0.1 N AgNO3 and the chloride penetration profiles of the profile method were obtained from the chloride content of each depth. The chloride migration coefficients were calculated from the modified Fick's second law based on the colourimetric method and the chloride profile method. In order to develop a better understanding of the relationship between the migration coefficient obtained from the colourimetric method and the chloride profile method, the migration coefficient obtained from those two methods are compared. The experimental result shows that the migration coefficients obtained from the colourimetric method and the chloride profile method are linearly correlated, and the concentration of color change boundary, Cd = 0.07 mol/L, can be used to determine the migration coefficient regardless of the concrete type.