Metakaolin sand – a promising addition for Portland cement

Abstract

The kaolin sand resource at the Vyšný Petrovec quarry in Slovakia comes to a total of 20 megatonnes. The metakaolin material obtained by heating kaolin sand at 650 ºC contains from 31.5 to 40% (wt) metakaolinite, as well as illite, muscovite, quartz and feldspar. The aim of this study was to verify whether this calcined sand (MK1) is a pozzolanic material and characterize the cements and mortars prepared with it. The hydration reactions taking place in the blends were assessed with conduction calorimetry, X-ray diffraction (XRD) and differential thermal analysis-thermogravimetry (DTA-TG). Blend and mortar strength development and pore structure were also evaluated. The results obtained showed that this metakaolin sand (MK-1) is a pozzolanic material apt for use as a cement addition and for making mortars.

Keywords

• cement
• mortar
• metakaolin sand
• pozzolanic activity
• hydration