Compressive strength of mortar containing natural pozzolan under various curing temperature

A first set of mortar specimens was made with 0%, 10%, 20%, 30% and 40% of natural pozzolan replacement and cured under constant curing temperature of 20, 40 and 60 degrees C with saturated humidity. The second set incorporating only 20% of natural pozzolan was exposed to elevated temperatures for 1, 3 and 7 days and then cured in saturated environment under a temperature of 20 degrees C. This paper presents the experimental results of the mortar properties such as the ultimate strength, the half age of strength and the activation energy. The introduction of the pozzolan enhances the ultimate compressive strengths and increases the activation energy which indicates the slow reactivity. The effect of the temperature on the ultimate strengths is evaluated by a new model. By using the equivalent time method, we could estimate the strength at 28 and. 90 days of the second set mortar. This method satisfactorily predicts the strength of concrete cured at any temperature history. (C) 2007 Elsevier Ltd. All rights reserved.