Effect on the properties of fresh and hardened concrete made using fly ash geopolymer sand

Abstract

Fly ash-based geopolymer fine aggregate is a potential replacement material for the natural river sand as it has similar physicochemical properties. This paper reports the experimental investigation of a study conducted using this fine aggregate in concrete with a focus on the properties of fresh and hardened concrete. The geopolymer fine aggregate was developed by air curing process and oven curing method. The oven curing method yielded relatively better mechanical properties in concrete specimens. The oven curing results in better behavior at later age also. Laboratory tests were conducted to ascertain the fresh concrete density, slump value, hardened concrete density, compressive strength, tensile strength, and flexural strength of the concrete specimens. The microstructure of the concrete specimens was analyzed using scanning electron microscope which indicated the agglomeration of the fly ash particles with few voids demonstrating the higher water adsorption capacity of the same. The unreacted particles noted in the microstructure later tend to merge with the lime obtained from the hydration of cement so as to develop improved later age mechanical strength. The results on mechanical properties of the concrete indicate much similar results to that of the concrete developed with the normal river sand, which confirms that the geopolymer sand is an ideal replacement choice for natural river sand.

GGBS based alkali activated fine aggregate in concrete - Properties at fresh and hardened state

“…Though comparable studies [35][36][37] were initiated recently in obtaining fine aggregates by geopolymerization of industrial wastes a refinement in the polymerization process was further mandatory for the potential use of the same [38] in concrete. A similar study [39] with flyash for the production of fine aggregate by geopolymerization process also noted the development of adequate strength in concrete.…”