Geopolymer hybrid fly ash concrete for construction and conservation in peat environment: A review

Abstract

Fly ash is industrial residue from the coal combustion in electric and steam generating plants and recognized as an environmental pollutant. Fly ash contains a high concentration of silica and alumina and can be used as geopolymer concrete. Studies the use of fly ash as a geopolymer concrete mixture has been developing in recent decades. This review focuses on the characteristics of fly ash as hybrid geopolymer concrete, and its resistance is peat environment. The hybrid geopolymer is made by activating fly ash using an alkaline activator and Portland cement. The addition of fly ash geopolymer concrete with Portland cement forms N-A-S-H bond structure from fly ash, and C-S-H hydration bond from Portland cement forms C-A-S-H, which is more solid and stronger against aggressive environment such as peat. In addition, the geopolymer concrete is proven to be able to mobilize heavy metals in fly ash so the concrete has low leaching rate and not harmful to the peat ecosystem. This review proves that hybrid geopolymer concrete using fly ash is a potentially innovative and promising material in the future. The geopolymer hybrid not only has its resistance to peat and acts as conservative material in an environmentally friendly peat environment.