Effect of Metakaolin Content on the Properties of High Strength Concrete

TLDR

This study investigates the effect of incorporating metakaolin (MK) on the mechanical and durability properties of high‑strength concrete at a constant water/binder ratio of 0.3. MK mixtures with 5 %, 10 % and 15 % cement replacement were formulated to achieve a target strength of 90 MPa and a slump of 100 ± 25 mm. The results showed that a 10 % MK replacement produced the optimum compressive strength of 106 MPa, with higher MK contents still exceeding the control and improving durability, while splitting tensile strength and elastic modulus followed the same trend.

Abstract

This study presents the effect of incorporating metakaolin (MK) on the mechanical and durability properties of high strength concrete for a constant water/binder ratio of 0.3. MK mixtures with cement replacement of 5, 10 and 15 % were designed for target strength and slump of 90 MPa and 100 ± 25 mm. From the results, it was observed that 10 % replacement level was the optimum level in terms of compressive strength. Beyond 10 % replacement levels, the strength was decreased but remained higher than the control mixture. Compressive strength of 106 MPa was achieved at 10 % replacement. Splitting tensile strength and elastic modulus values have also followed the same trend. In durability tests MK concretes have exhibited high resistance compared to control and the resistance increases as the MK percentage increases. This investigation has shown that the local MK has the potential to produce high strength and high performance concretes.