Predicting the chloride content from the color analysis for various cement-based materials

The rate of chloride content is of great importance for the performance of reinforced concrete structures exposed to chloride-contaminated environments. The chlorides are known to cause corrosion of metals embedded in cement-based materials. Thus, an important criterion for the evaluation of reinforced concrete structures is the measurement of the chloride content. This is normally done using time consuming standard methods. This paper presents the determination of the apparent chloride content of various cement-based materials using color analysis, which provides the advantages of a fast measurement and the potential for on-site application. The surface can be scanned, or depth profiles are available from cores. Measurements can be performed directly on the sample surface and the results are available in near real time. The results of color analysis method are compared with the results of the Volhard, ion-meter, and Scanner Electron Microscope methods.