Clay Deposits from the Northeastern of Cuba: Characterization, Evaluation, and Use as a Source of Supplementary Cementitious Materials

Three clay deposits from northeastern Cuba were characterized by X-ray fluorescence, X-ray diffraction, and thermogravimetric analysis. The clay deposits present high content of aluminum oxide and loss on ignition. Kaolinite was identified as a main clay mineral, and iron and aluminum phases as impurities. The clays were preliminarily selected by chemical and mineralogical criteria and then activated by stationary calcination at 750 °C. The pozzolanic reactivity was determined by strength activity index in standardized mortars. Three blended cements containing calcined clay, limestone, clinker, and gypsum were formulated and assessed. Formulated cements were used to produce hollow blocks of concrete and hydraulic tiles. Finally, it is concluded that the three clayey deposits are presented with high potential for use as source of supplementary cementitious materials. Chemical criteria and kaolinite content are a useful tool to predict the potential of clay deposits to be used as source of supplementary cementitious materials. Samples with higher kaolinite content present the best pozzolanic activity. Ternary cements assessed can replace Portland cement in the manufacture of hollow concrete blocks and hydraulic tiles.