Pozzolanic Reactivity of the Calcination Products Obtained from Yaguajay Clay Deposit

Abstract

The influence of calcination temperature and mineralogical composition on the pozzolanic reactivity of calcination products obtained from Yaguajay clay deposit is assessed in this research. The samples were characterized by ATG, DRX and petrography. The pozzolanic reactivity of calcination products was evaluated by compressive strength (NC95:2011, NC506:2013, NC-TS527:2013, NC-TS528:2013) and its influence in the hydrate kinetics by isothermal calorimetry in pastes with 30% of cement substitution for calcined clay. All identified technological types present quartz, calcite, goethite and kaolinite like main mineral phases. The kaolin contents oscillate among 40% (Types A and B) and 50% (Type C). The calcite contents are lower than 5%; except in the layer B, with 20%. The pozzolanic reactivity of the calcination products of all the technological types is strongly influenced by the activation temperature, being reached the best reactivity at 800 °C. Other factors that could affect negatively the pozzolanic reactivity are high calcite contents (Type B) and high contact degree between the calcite and the kaolinite (Type C). For a sustainable exploitation of the deposit, it is recommended that the composite dedicated to the industrial production has an approximate composition of 37.5% Type A, 25% Type B and 37.5% Type C.