Drying Shrinkage and Heat of Hydration of Ternary Blended Concrete Incorporating Coal bottom Ash as Fine Aggregate Substitute

Abstract This study evaluated the effects of metakaolin (MK), palm oil fuel ash (POFA), along with coal bottom ash (CBA) as partial fine aggregate replacement on drying shrinkage and heat of hydration (HOH) of concrete. Optimal proportions of MK, hybrid blend of MK and POFA, and the best combination of CBA with MK and POFA were determined based on the compressive strength. The optimization process showed that 15% MK is the optimal blend, a hybrid blend of 15% MK and 20% POFA is the best blend, and 10% CBA is the optimal addition when mixed with the blend of MK and POFA. The findings indicated that the incorporation of MK and POFA in concrete with or without CBA reduced the drying shrinkage. Additionally, concrete blended with MK and POFA with or without CBA reduced the temperature rise due to hydration. However, CBA mixed with combined MK and POFA resulted in a higher initial temperature compared to the reference concrete. In conclusion, MK, POFA and CBA can minimize the formation of cracks due to decreased shrinkage and HOH.