Ground Bottom Ash Application for Conventional Mortar and Geopolymer Paste

Abstract

The present study investigates the possibility of using ground bottom ash (GBA) as an alternative to cement to produce geopolymer concrete. The process of geopolymerization includes the reaction of a solid precursor and an alkali-activated solution made of diluted sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). Several studies have been reported in the past, which used fly ash as the solid precursor material for producing geopolymer paste and concrete. The main objective of this study was to produce geopolymer paste and conventional ordinary portland cement (OPC) mortar using GBA and demonstrate its effectiveness in comparison to fly ash (FA)-based geopolymer paste. The effect of an increase in the ratio of Na2SiO3:NaOH from 1.5∶1 to 3.0∶1 based on the strength of geopolymer paste was studied. The results showed that the GBA geopolymer paste cube was stronger than the ones made of ground fly ash (GFA) (obtained from the same source), even those of a finer particle size. The results also showed that with the increase in the ratio of Na2SiO3:NaOH, the compressive strength of geopolymer paste increased. When different combinations of FA and GBA were used, the results showed that geopolymer paste with higher GBA content produced better results.