Study on the role of n-SiO2 incorporation in thermo-mechanical and microstructural properties of ambient cured FA-GGBS geopolymer matrix

The effect of Nano silica (seed) addition on the early period of geopolymer formation in the alkali mediated FA + GGBS reaction, was analyzed by Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Experimentation on different dosages of NS (0-3%), in the 80% FA and 20% GGBS (precursor material) activated through NaOH and Na2SiO3 (MR:1.1). The seed (NS) added in the system triggering the nucleation that reduce the induction period by formation of more geo polymeric gel in the early period of 12-72 h that was evident from ATR-FTIR results and it was pronounced at the NS dose of 2.5% that yield rapid increase in strength development to an extend of 50% gain as curing age increased from 1 day to 3 days, thereafter at slower rate upto 365 days. The weight change and strength characteristics of mortars after heat treatment in the temperature range of 30-800 °C studied showed that seeded mortar did not show any visible cracks/deterioration. Thermal conductivity and thermal stability using TGA/DTA and SEM microscopic examination studied.