A chemical analysis method for determining blast-furnace slag content in hardened concrete

This research presents the results of the study on the estimation of blast-furnace slag content in hardened concrete by chemical analysis method. To determine slag content in the mixture, there are two steps of investigation. The fraction of sand content in the mortar extracted from concrete has to be determined, and then the chemical composition of cement paste phase can be calculated. Thereafter, slag content in the mixture can be estimated by the relationship of chemical composition among in cement paste, Portland cement and slag. Artificially made mortars and concrete mixes with slag content of 30%, 50% and 70% by mass exposed to different curing durations were investigated. The results suggest that the techniques have potential for estimation of blast-furnace slag content in already hardened concrete with acceptable accuracy.