SUMMARY
This paper presents an experimental investigation for testing the effect of elevated temperature on the hydration heat and mechanical properties of blended cement mortars. Two tests on mortars were made. The first set of mortars is tested of mechanical properties at various temperatures of 20, 35 and 50°C and the second test consists to determine the hydration heat by a semi-adiabatic calorimeter at isothermal temperature of 20, 35 and 50°C during seven days. The new empirical equation has been proposed to estimate the compressive strength depending on the hydration heat for blended cement preserved in constant temperature at early. The results founded from this relationship illustrate a good accuracy with the experimental ones and reflect the best choice to be used to predict the compressive strength depending on the heat of hydration at early age (7 days).