Cementing Efficiency of Flash and Rotary-Calcined Metakaolin in Concrete

The research focuses on strength efficiency of rotary kiln metakaolin and flash metakaolin in concrete. The Smith and Bolomey modified model is used to develop efficiency factor (k) for calculating strength efficiency in reference to pozzolan content and relative strength. The present study shows that as the replacement percentage of metakaolin increases (up to 30%), the efficiency of metakaolin modified concrete decreases. Replacement of ordinary Portland cement (OPC) in both mixtures with up to 30% rotary-calcined metakaolin (RMK) and up to 30% flash-calcined metakaolin (FMK) showed an increase in strength properties as compared to control concrete after curing age of 14 days. The FMK blended concrete resulted in improved values of k as well as enhanced strength properties as compared to RMK blended concrete. Workability for the concrete blended with FMK was higher in comparison to RMK. The significant changes in k values were observed for both the materials after 28 days of curing at all replacement percentages.