Abstract
The use of industrial by-products is extending steadily in concrete admixtures. However, the effects of these mineral admixtures on the chloride binding in concrete have been insufficiently studied. In this study, the chloride binding effect of various mineral admixtures is evaluated and the results can be drawn as follows. The resistance to chloride penetration was greatly improved when ground granulated blast-furnace slag (GGBS) and silica fume (SF) was used in concrete. The chloride penetration resistance of concrete used fly ash (FA) was improved after 91 days. The chloride penetration depth of concrete used GGBS was lowest and concrete used SF showed second-lowest penetration depth. Concrete used FA having the effect of long-term strength development by pozzolanic reaction showed the lowest resistance to chloride penetration. In case of concrete used only ordinary portland cement, chloride migration coefficient reduced approximately 40.3% when compressive strength increased 10%. Chloride migration coefficients of concrete used FA, SF and GGBS was reduced 24.9%, 23.0% and 14.1%, respectively. Soluble chloride content was various with types and replacements of mineral admixtures in range of 41% to 77% of total chloride content. The chloride binding effect of concrete used FA was highest because concrete used FA was not denser than concrete used GGBS or SF and chloride ion penetrated inside more. However, concrete used GGBS or SF was dense and chloride ion concentrated inner surface portion of specimen. It caused lower chloride binding effect of concrete used GGBS or SF.
