EFFECTS OF METAKAOLIN ON COMPRESSIVE STRENGTH AND PERMEABILITY PROPERTIES OF PERVIOUS CEMENT CONCRETE

This paper presents the experimental results on the effect of metakaolin (MK) as a replacement of cement in pervious cement concrete based on compressive strength, void ratio and permeability test. Metakaolin was used to replace Portland Cement Composite (PCC) in pervious concrete by 10% (by wt.). The results show that pervious concrete sample containing 10% metakaolin with 1% superplasticizer exhibited 4 times higher compressive strength at 7 days when compared to normal cement concrete. In addition, the continuous voids of 10%MK concrete sample was found higher than PCC only, indicating the effectiveness of metakaolin in improving the interfacial bond of the binders due to micro-filler effect of metakaolin and the additional CSH gel formation. The continuous voids of pervious concrete with 10% MK is 17%, which is higher than the percentage of continuous voids in normal pervious concrete. This finding is also supported by the infiltration rate of concrete samples. Furthermore, the microstructure analysis through Backscattered Electron Imaging and X-Ray Diffraction reported denser matrix and CH reduction in polished paste samples due to 10%MK addition.