Reinforcement of Silica Particles in Bentonite Clay Based Porous Geopolymeric Material

Positive effect of silica reinforcement in bentonite clay based geopolymer has been observed in the present investigation. In this research, heat treated bentonite clay with varying percentages of silica reinforcing particles (low, medium and high concentration) were used to prepare geopolymer mortars. While a constant quantity (25%) of sodium hydroxide and sodium silicate mixture was used. The effect of reinforcing silica particles on the physical and mechanical integrity of heat treated bentonite clay based geopolymer mortar has been elaborated in this research. After geopolymerization and de-hydroxylation, density (bulk and apparent) and porosity were measured for the all geopolymeric samples. Various techniques like FTIR (to confirm degree of geopolymerization), XRD (to determine the mineral phases), TGA (to measure the weight loss), and SEM (to study the microstructure) were used for the characterization of samples. The sample with low percentage of silica particles showed higher degree of polymerization. A compressive strength upto 57 MPa was achieved for the sample having high concentration (90%) of silica. The evaluation of various samples demonstrated that heat-treated bentonite-silica particles reinforced geopolymers were viable and eco-friendly alternative to fly ash geopolymers.