Metakaolin may be calcined without grinding and suitably activated by Ca(OH)2, NaSO4, CaSO4 (beta anhydrite) andjor NaOH. The best strengths, 50 ΜΡα from mortar cubes at 18 months, were obtained using Ca(OH), and CaSO4 activators. The handling and set properties are similar to those of Portland cement; aluminous C-S-H gel is the best binder. All compositions contain K+ derived from mineral impurities in kaolin, thus the performance and activation of kaolins may depend partly on their alkali content. The micro-structures of the cured products are described, and the importance of good space filling by the hydrates is emphasized. Since the precursor minerals are widely distributed, kaolin deserves more investigation as the principal component of low-energy binder systems.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below