Optimization of Steam-Curing Regime for Recycled Aggregate Concrete Incorporating High Early Strength Cement-A Parametric Study

This paper investigates the properties of steam cured recycled aggregate concrete (RAC), in an attempt to determine the optimum conditions of the steam-curing cycle for RAC, and incorporating high early strength cement (HESC). Varying conditions of steam curing were employed. The steam-curing cycle was set based on the peak temperature, and the duration for which the peak temperature was maintained. Three peak temperatures were used for steam curing, 50 degrees C, 60 degrees C, and 70 degrees C, maintained for up to two hours. The compressive strength results indicated that the steam-curing cycle employing the peak temperature of 50 degrees C maintained for one hour with a total duration of four hours was the optimum for strength development, both at the early and late stages of hydration. Determining the optimum steam-curing temperature and duration will help reduce the associated curing cost, thus further economizing the production cost of recycled aggregate concrete.