Authors : Hidayati Asrah, Abdul Karim Mirasa, Nurmin Bolong, Md Abdul Mannan and Muhammad Madi
Abstract: This study presents the effect of Ultrafine Palm Oil Fuel Ash (UPOFA) in controlling the Alkali-Silica Reaction (ASR) expansion in mortar bar through pozzolanic reactivity, alkali binding, reduction of aggregate dissolution and change in the Alkali Silica Gel (ASG) composition. The expansion of mortar bar was investigated using the Accelerated Mortar Bar (AMBT) by replacing 10-40% of cement with UPOFA. The effects of how UPOFA reduced the ASR were then studied by conducting the pozzolanic activity test, Thermo Gravimetric Analysis (TGA), aggregate dissolution and Scanning Electron Microscopy (SEM). It was found that 20-40% UPOFA has the ability to reduce the ASR expansion in a mortar. The higher the amount of replacement, the lower the ASR expansion recorded. Strength activity index at 7 and 28 days showed higher pozzolanic reactivity indicating the formation of Extra Calcium Silica Hydrate (CSH) through pozzolanic reaction and this was supported by the TGA analysis of the CSH and Calcium Hydroxide (CH) content. The aggregate dissolution was reduced with an increment of POFA replacement level. The change in the chemical composition of the ASG indicates the transformation of the ASG characteristic from hard to soft and less vicious gel which explains the lower ASR expansion when ultrafine UPOFA was used as supplementary cementitious material in mortar bar.
Hidayati Asrah, Abdul Karim Mirasa, Nurmin Bolong, Md Abdul Mannan and Muhammad Madi, 2017. Reduction of Alkali-Silica Reaction Expansion using Ultrafine Palm Oil Fuel Ash. Journal of Engineering and Applied Sciences, 12: 4820-4825.