Autogenous healing of cracked mortar using modified steady-state migration test against chloride penetration

Abstract

Concrete is a popular building material all over the world, but because of different phys-iochemical processes, it is susceptible to crack development. One of the primary deterioration processes of reinforced concrete buildings is corrosion of steel bars within the concrete through these cracks. In this regard, a self-healing technique for crack repair would be the best solution to reduce the penetration of chloride ions inside concrete mass. In this study, a rapid chloride migration (RCM) test was conducted to determine the self-healing capacity of cracked mortar. With the help of the RCM test, the steady-state migration coefficient of cracked and uncracked specimens incorporating expansive and crystalline admixtures was calculated. Based on the rate of change of the chloride ion concentrations in the steady-state condition, the migration coefficient was calculated. Furthermore, bulk electrical conductivity tests were also conducted before and after the migration test to understand the self-healing behavior. It was evident from the test results that the self-healing of cracks was helpful to reduce the penetration of chloride ions and that it enhanced the ability of cracked mortar to restrict the chloride ingress. Using this test method, the self-healing capacity of the new self-healing technologies can be evaluated. The RCM test can be an acceptable technique to assess the self-healing ability of cement-based materials in a very short period, and the self-healing capacity can be characterized in terms of the decrease of chloride migration coefficients.