Abstract
•High strength alkali activated POFA binder was produced at room temperature.•C-S-H shifted to C-A-S-H when GGBS was added.•C-A-S-H gel showed stronger and more thermally stable properties.
This study focused on production of high strength alkali activated binder by alkali activation of binary mix of palm oil fuel ash (POFA) and ground granulated blast furnace slag (GGBS) at ambient temperature. Compression test was performed to assess mechanical properties of the mixture. Chemical tests were also conducted to investigate the role of calcium and aluminum ions from GGBS in the strength development. Formation of aluminum-substituted calcium silicate hydrate (C-A-S-H) gel with a higher degree of crystallinity was observed when GGBS was added. Replacement of 50% POFA with GGBS increased the strength up to 92MPa at 90days.