Experimental study on effects of reactive RHA and curing conditions on GeoPolymer concrete

Abstract

The cement used in construction leads to one of the largest production of carbon-di-oxide, creating upto 8% of the worldwide emissions of the gas. The carbon-di-oxide emission for the production of concrete is directly proportional to the amount of cement used in the concrete mix. Geopolymer concrete is more environmental friendly construction material, containing silicon and aluminium compounds and alkaline activating solution which polymerizes the compounds to form a network of molecular chains creating hardened binder. The category of geopolymer concrete adopted for study is alkali activated fly ash based geopolymer concrete. Researches have estimated that 1 percent of replacement of cement with fly ash results in 7 percent reduction in energy consumption for the production of concrete. This paper studies the properties of geopolymer concrete adopting 8 molarity NaoH solution and an alkaline solution to fly ash ratio of 0.45. The formation of the binder gel can be assisted by application of heat. This effect of curing temperature on the strength of geopolymer concrete is also studied at temperatures of 60 degrees and 90 degrees comparing to strength at ambient temperatures. The scope of the study also includes the effect of addition of rice husk ash to fly ash in 5 percent and 10 percent replacement for fly ash. The compressive strength of geopolymer concrete is tested at 7, 14 and 28 days. Tests are carried out to investigate the effect of curing conditions on the compressive strength, effect of alkaline solution on compressive strength and effect of addition of rice husk ash with fly ash on the compressive strength of the geopolymer concrete.