Utilization of palm oil boiler ash (POBA) as geopolymer material for Industrialized Building System (IBS) application

The increment of palm oil waste from palm oil extraction increased every year in Malaysia. Palm oil boiler ash (POBA) or bottom ash is one of the waste material from the palm oil industry where it was obtained from the burning process of solid waste such as empty fruit bunch, shell and fiber. The production of POBA was estimated about 4 million tonnes/year where it was usually used as fertilizer. Geopolymer or alkali-activated binder is produced by synthesizing aluminosilicate source materials with an alkaline activator solution. This study has been conducted to produce POBA geopolymer paste and brick and IBS brick by using geopolimerization process. The parameters for the geopolymer paste production included the NaOH concentration, ratios of S/L as well as Na2SiO3/NaOH and curing temperature. Then, the effect of each parameter towards production of geopolymer paste was evaluated using compressive strength, XRD, FTIR, and SEM. Meanwhile, for mix design of geopolymer brick and IBS brick, the optimum ratio (NaOH concentration, ratio of S/L and Na2SiO3/NaOH and curing temperature) from the geopolymer paste production has been used to produce the bricks. The ratio of POBA-to-sand for geopolymer brick and IBS brick for this study was 1:3. The performance of geopolymer brick and IBS brick were analyzed in term of compressive strength, water absorption and density at different aging period, which is 1st, 3rd, 7th, 28th and 60th days.