Early Age Properties of Pozzolanic Mortars under Hot Weather

Abstract

Properties of natural pozzolanic mortars in the fresh state are investigated under normal‐ and hot‐weather conditions. Varius levels of pozzolans (0%, 15%, and 25% by weight) are used as cement replacement in this study. The investigation included the study of flow, setting times, and temperature changes during hydration of mortars. Flow of mortars was measured at different time intervals by using the flow table described by ASTM C230. Setting times were estimated using both ASTM C403 and the ultrasonic pulse velocity methods. Temperature . changes during hydration of mortars were also measured, plotted, and then used to estimate setting times. The setting time results obtained by the three different methods were compared. This study concluded that the use of natural pozzolans under normal conditions would result in a retarding effect on the workability and setting times of mortars, whereas under hot weather conditions it would result in an accelerating effect. These effects are proportional to the amount of the pozzolan used.