Shrinkage Behavior of Cements Containing 2:1 Metaclays

Abstract

The use of 2:1 metaclays as supplementary materials in composite cements can significantly reduce CO ₂ emissions. Research has focused almost exclusively on LC3 cements, whereas publications on cements containing 2:1 metaclays remain scarce. For characterization of these systems and for modeling and predicting the properties of mortars and concretes produced with 2:1 metaclay‐based cements, detailed knowledge of shrinkage deformations, their development, and underlying mechanisms is essential. Clay minerals can be activated thermally or mechanically. Depending on the activation route, the physicochemical properties of activated clay minerals (metaclays) differ significantly. While thermally activated clays have been extensively investigated, systematic studies on mechanically activated clay minerals are still largely lacking. Against this background, the shrinkage behaviour of cement pastes containing thermally and mechanically activated 2:1 metaclays was investigated experimentally and compared with a reference cement paste based on ordinary Portland cement. The results show that cement pastes incorporating mechanically activated 2:1 metaclays exhibit significantly different shrinkage deformations compared with those containing thermally activated 2:1 metaclays and the reference cement paste.