Comparison of Rapid Tests for Evaluation of Chloride Resistance of Concretes with Supplementary Cementitious Materials

Abstract

In this research, the performance of three rapid methods for evaluation of chloride resistance of concrete, including the rapid chloride penetration test (RCPT), rapid chloride migration test (RCMT), and electrical resistance test, are compared. Because the ability of the RCPT method to evaluate of concrete mixes containing supplementary cementitious materials has been questioned by some researchers, the mixes studied included the control mix and mixes containing 2.5, 5, 7.5, and 10% silica fume (SF); 7.5 and 15% fine fly ash (VFA); 15 and 30% fly ash (FA); 15 and 30% pumice (PU); and 15, 30, and 50% slag (SL). The results of all three methods show a considerable decrease in chloride permeability of mixes containing silica fume at the ages of 28 and 90 days and mixes containing other supplementary cementitious materials at 90 days. However, the RCPT test considerably overestimated the improvement compared to the other two methods, mainly as a result of the temperature rise effect in this test. Despite the simplicity and speed of the electrical resistance test, its results correlate well with those of the RCMT test.