Abstract
Sodium silicate is a complementary source used in the geopolymerization reaction. However, this reagent is produced at high temperature or in an autoclave at high pressure, which generates a significant environmental impact. Aiming the production of greener geopolymers, an alternative sodium silicate (ASW) from the dissolution of silica present in rice husk ash (RHA) was produced. Geopolymers were prepared at SiO2/Al2O3 molar ratios of 3.0, 3.5, and 4.0, and concentrations of 8 and 10 M NaOH. The specimens were subjected to compressive strength (7 and 28 days), FTIR and XRD tests. The mechanical performance of ASW-produced geopolymers was similar to those made with commercial sodium silicate. Analysis of the mechanical behavior and infrared spectra suggested that there was a greater dissolution of RHA with increasing SiO2/Al2O3 molar ratio and alkali concentration.
Keywords:
geopolymer; rice husk ash; sodium silicate; alkaline source
