The compressive strength and the setting time of partial replacement of fly ash by palm oil fuel ash on geopolymer paste and mortar

Abstract This study replaced fly ash with palm oil fuel (POFA) in geopolymer paste and mortar. The alkaline activator was a mixture of sodium silicate solution hydroxide ratio 2.5. Three variables were evaluated: the raw material combination (100% 25% POFA substituted to ash), mass alkali (60/40, 65/35, 70/30), NaOH molarity (8 M 10 M). mortar utilized based on highest compressive strength paste. fine aggregate binder 65 35. result showed that increased as increased. substitution for from 12.0% 27% at 28 days. material/ 65/35 indicated strength. replacement had longer setting time than 100% ash. 0.66 0.59 70/30 ratios activator, respectively.