New method development for evaluation concrete chloride ion permeability

Abstract

This paper describes the development of a very rapid test method which can evaluate the permeability of concrete against chloride ions. The test involves saturating a concrete specimen with a 23% NaCl solution before measuring the conductivity of the sample. By saturating specimens with a highly conductive solution, they showed virtually the same pore solution conductivity. Different concrete samples yield different conductivity primarily due to differences in their pore structure. In order to evaluate the performance of the presented method (MRCPT), different concrete mixtures consisting ordinary and blended cement of silica fume and nano silica were examined. Two standard test methods of RCPT (ASTM C1202) and surface resistivity (AASHTO TP 95) were also applied to all of the samples. The results obtained from the experiments demonstrated that for concretes containing silica fume and nano silica, the MRCPT is less sensitive towards the variations in the pore solution conductivity in comparison with RCPT and surface resistivity tests. It seems that this procedure is a suitable tool for the assessment of the performance and durability of different concretes containing supplementary cementitious materials.