Montmorillonite clays in Portland clinker-reduced, non-clinker cements, and cement composites: A review

Clays with various chemical and mineralogical compositions are an increasingly important mineral source for producing sustainable cements, mortars, and concretes. Numerous studies have recently been conducted to expand the scope of widespread and potentially suitable clays, including bentonite clays. The composition and unique structural characteristics of bentonite clay facilitate their application in cement-based materials in raw, activated, and modified forms as a supplementary cementitious material, micro- and nano-pore-forming agent, pore structure and engineering property modifier, and aluminosilicate precursor. This review analyses recent studies on the growing role of montmorillonite (MM) clays in the design and exploration of Portland clinker-reduced cements, non-clinker alternative cements, and various cement composites. In addition, this review presents the advances in the theoretical investigation of MM reactivity enhancement using activation and modification techniques and reagents, and the interactions of MMs and superplasticisers.