Influence of High reactive Metakaolin (HRM) on flexural strength of Concrete in combination with self-curing agents

Abstract

The present study is directed to understand contribution of High reactive Meta kaolin in combination with self-curing agents on flexural strength of concrete of higher strength. Earlier studies revealed that ordinary Portland cement can be replaced by HRM and optimum replacement level is 10 %. It was also observed that compressive was found improved at the same replacement level. This optimum replacement level may get vary and mainly depends on the water cent ratio of mix. This study include experimental program to find out compressive strength of concrete of low water cement ratios varies in between 0.32 to 0.42.Result showed that the water cement ratios, it was found that w/c 0.38 provides compressive strength nearly equals to target mean strength and observed declined for other w/c ratios. The concrete produced of low water cement ratios likely to shrink in early days; this is because of insufficient water for hydration process. This is the reason due to which strength obtained for 0.32, 0.34, and 0.36 is not up to the mark. Hence in this research attempt was made to enhance strength of such low water cement ratios by addition of super absorbent polymers like Poly acrylic acid. No external curing is employed. The poly acrylic acid (PAA) is white granular powder has been tried as self -curing agent. It absorbs water, swells and releases water slowly during hydration process. From the experimentation it was observed that due to the addition of PAA, the compressive as well as flexural Strength of such low water cement is get enhanced and is about 90% of strength of control mix (water cured). Study also proposes relation between avg. flexural strength and w/c for different curing conditions with degree of confidence more than 90 %. Hence research promotes internal curing method for high strength concrete for low water cement ratios.