AgNO3 spray tests: advantages, weaknesses, and various applications to quantify chloride ingress into concrete. Part 2: Non-steady-state migration tests and chloride diffusion coefficients

This paper forms the second part of a series devoted to the analysis of the capabilities of AgNO3 spray tests, in view of using them for various issues, within the framework of the evaluation and the prediction of chloride-induced corrosion risks. More precisely, the Maultzsch procedure (spraying of 0.1-N AgNO3 solution + K2CrO4) and the use of AgNO3 alone have been investigated on a broad range of concretes. In this second part, the feasibility of colorimetric techniques on saturated specimens cast in laboratory, after non-steady-state migration tests carried out in various conditions is discussed. Colorimetric methods have been applied to the determination of the average penetration depth. In addition, the detection threshold of these techniques has been investigated. Moreover, colorimetric methods have been applied to the calculation of apparent and effective chloride diffusion coefficients from non-steady-state diffusion and migration tests. The results then obtained have been compared to the values obtained by other types of methods.