Metakaolin is a high quality pozzolonic material, which is
blended with Portland cement in order to improve the durability
of concrete and mortars. Metakoalin removes chemically
reactive calcium hydroxide from the hardened cement paste.
Metakaolin reduces the porosity of hardened concrete. It
densifies and reduces the thickness of the interfacial zone,
thus improving the adhesion between the hardened cement
paste and particles of sand or aggregate.