Development of geopolymer mortar from metakaolin blended with agricultural and industrial wastes

Geopolymer is greener alternative cement produced from the reaction of pozzolans and strong alkali solutions. Generally, the cement industry is one of largest producers of CO2 that caused global warming. For geopolymer mortar usage, Portland cement is not utilized at all. In this research, geopolymer mortars were prepared by mixing fly ash with metakaolin and various wastes (bagasse ash and rice husk ash) varied as 80:20, 50:50 and 20:80, 15M NaOH, Na2SiO3 and sand. The influence of various parameters such as metakaolin to ashes ratios and pozzolans to alkali ratios on engineering properties of metakaolin blended wastes geopolymer mortar were studied. Compressive strength tests were carried out on 25 x 25 x 25 mm3 cube geopolymer mortar specimens at 7, 14, 21, 28 and 91 air curing days. Physical and chemical properties were also investigated at the same times. The test results revealed that the highest compressive strength was 80% fly ash - 20% metakaolin geopolymer mortar. When the curing times increases, the compressive strength of geopolymer mortar also increases. The mixing of fly ash and bagasse ash/rice husk ash presented lower compressive strength but higher water absorption and porosity. For FTIR results, the geopolymer chain such as the H-O-H, Si-OH and Al-O-Si were found. Moreover, the geopolymer mortar could easily plastered on the wall.