Volume 3, Issue 3 (March 2006)
Enhancing the Reliability of Evaluating Chloride Ingress in Concrete Using the ASTM C 1202 Rapid Chloride Penetrability Test
The rapid chloride penetrability test (RCPT-ASTM C 1202) is commonly used to evaluate the resistance of concrete to chloride ions ingress owing to its simplicity and rapidity. However, it has been criticized for various shortcomings such as giving favorable results to supplementary cementitious materials (e.g., silica fume), and bias against calcium nitrite corrosion inhibitors (CNI). Based on the ASTM C 1202 induced voltage concept, this study aims at enhancing the reliability of rapidly evaluating concrete resistance to chloride ions ingress. It is proposed that upon test termination, not only the passing charges are recorded, but the depth of chloride front migrating into concrete is also measured. Concrete mixtures herein were prepared incorporating selected materials (silica fume and CNI) that have been known to cause misleading results for the RCPT test. The effects of silica fume and CNI dosages on RCPT results were investigated and correlated to porosity trends evaluated by mercury intrusion porosimetry (MIP). The study reveals that measuring the migrating chloride front in concrete subsequent to the ASTM C 1202 test can eliminate the bias induced by electrolysis conductivity resulting from silica fume and/or CNI. This improves the reliability of assessing concrete resistance to chloride ions penetration using the RCPT procedure.