Heat evolution during the hydration of Portland cement in the presence of fly ash, calcium hydroxide and super plasticizer

Rate of heat evolution during the hydration of OPC, OPC-20 wt% FA, OPC-5 wt% CH and OPC-20 wt%FA-5 wt% CH in the presence of 0.2 and 0.5 wt% super plasticizer has been studied at 35 and 45 °C with the help of TAM Air isothermal calorimeter for 60 h. The results have shown that hydration retarded in the presence of super plasticizer. Higher the concentration of super plasticizer, higher is the retardation. However hydration accelerated with the increase of temperature. Mechanism of hydration is discussed in this manuscript.

► Rate of heat evolution of cement increases with temperature.
► In the presence of CH, hydration of OPC-FA is increased.
► Super plasticizer retards the hydration.