Harnessing Raw Materials in Cement Plants for the Production of Limestone Calcined Clay Cement

Abstract

Reliance on kaolinite clay in limestone calcined clay cement (LC3) can create availability issues. This study compared a kaolinitic clay obtained from an industrial pit with four other clays used as sources of silica in cement plants, exploring their potential for LC3 production. Three cements were prepared; gray, white, and a composite cement with slag, to investigate the interaction and synergy between the clinker and clay in LC3. Inert quartz was used to replace the clay, limestone, or both components of the mixtures, to evaluate their separate and combined effects on strength, mineralogy, and heat evolution. Several of the LC3 mortars made with the non-kaolinite clays had higher 1-7 d strengths, by up to 60 %, than the LC3 with gray cement and kaolinite which reached similar to 48 MPa strength at 28 d). Carboaluminate formation depends on clinker type, while its quantity is influenced more by the type of calcined clay.