Influence of Supplementary Cementitious Materials on Reduction and Variation of Charge Passed

This study presents the variation of charge passed computed from two different models that utilizes the electrical resistivity data from three different instruments. The instruments are surface resistivity (SR) meter for using the SR data and two bulk conductivity meters: one for using the bulk conductivity data at a constant frequency of 325 Hz, and the other one for using the bulk resistivity (BR) data at wide range of frequencies of 10 Khz, 1 Khz, 0.1 Khz, and 0.01 Khz. Fifty mixtures are investigated, where the majority of them are ternary mixtures along with Ordinary Portland Cement (OPC) and binary mixtures. They are categorized in several groups based on the supplementary cementitious material (SCM) as a second component in ternary and binary based concrete mixtures. The variation and distribution of the charge passed in individual group is investigated and the influence of varying replacement level of silica fume and metakaolin to the charge passed reduction is explored in ternary mixtures. Results from statistical analysis show that charge passed in each group varies significantly and the addition of SCM and its varying replacement level influences the reduction of charge passed remarkably over extended time period. Depending on the source and availability of SCM, the results provide very helpful data to identify the type and amount of second SCM in ternary mixtures in order to obtain the high-durability concrete mixtures. Overall, this study could provide promising options for computation of the charge passed in light to its ease of measurement, repeatability, and shorter amount of time than conventional time consuming Rapid Chloride Permeability Test (RCPT).