Permeability properties of concretes with high reactivity metakaolin and calcined impure kaolin

This study reports the findings of an experimental study carried out on transport properties of the concretes modified with different calcined non purified kaolins (CK) and commercially available high reactivity metakaolin (MK). CK used in this study were obtained by calcining impure ground kaolins from four different quarries located on kaolin beds of different morphological and geological formations in Turkey. However, commercially available MK produced by thermal treatment of high purity kaolin from Czech Republic was used as reference material. In concrete mix design, the cement was replaced with 5, 10, 15, and 20 % by weight of CK or MK. The gas permeability, water permeability, water sorptivity, and chloride permeability tests were performed at the end of 28 and 90 days of curing periods. The results indicated that the concretes incorporated with different types of calcined kaolins had comparable performance in permeability with MK modified concrete, depending mainly on the type and amount of the mineral admixture used. Moreover, all of the concretes incorporation MK or CK had considerably better permeability than plain concrete regardless of the replacement level.