Effect of parameters on the compressive strength of fly ash based geopolymer concrete

Geopolymer concrete is an inorganic polymer composite which has the potential to build an eco-friendly and sustainable construction by replacing the existing conventional concrete. Herein, cement is totally replaced by mineral admixtures rich in aluminosilicates such as fly ash and is formed by the alkali activation using alkaline activator solutions, such as sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Fly ash, a waste material from industry, can be incorporated in the manufacture of geopolymer concrete. The replacement of cement by fly ash in geopolymer concrete reduces the huge energy consumption and restricts carbon dioxide emission to the atmosphere during its production. In this paper, experimental investigations have been carried out involving the variation of total aggregate content (viz., 74, 76, 78, 80, and 82%), NaOH concentration (8, 10, 12, and 14M), and curing temperature (60, 70, 80, 90, and 100 degrees C) on the strength of geopolymer concrete by keeping a constant alkaline liquid to fly ash ratio of 0.45 and a 24-hour rest period. It is concluded that 76% of total aggregate content is suitable for producing geopolymer concrete without hindering the workability. Further, strength of geopolymer concrete has been found to be increased at 90 degrees C having 12M NaOH concentration.