Enhancement of Mechanical Properties of Geopolymer Ferrocement through Incorporation of a Novel Binder and through Optimization of Alkaline Activator Ratios

Abstract

Geopolymer ferrocement is geopolymer mortar, reinforced with wire mesh. The ratios of binder composition and alkaline activator, with which the geopolymer has been prepared, have profound influence on the mechanical performance of geopolymer ferrocement. In this study the influence of a binder material Alccofine and variation in ratios of alkaline activators have been studied for their effect on mechanical properties of geopolymer ferrocement. Alccofine was replaced with varying proportions of Ground Granulated Blast-Furnace Slag (GGBS). The molarities of NaOH and NaOH/Na₂SiO₃ ratios were also variated to find their influence on strength and crack control of ferrocement, when combined with single, double, and triple-layers of ferro mesh configurations. Tests such as direct shear test, three-point bending, and four-point flexural tests were conducted to to measure shear strength, flexural strength and to estimate region of pure bending. It was observed that the mix with 20% Alccofine and 80% GGBS, an A/B ratio of 0.5, and a NaOH/Na₂SiO₃ ratio of 1.5 yielded a compressive strength of 50 MPa at 90 days of geopolymer ferrocement. Also the triple-layer mesh configuration exhibited the best results, achieving 10 N/mm² in shear strength and 12 N/mm² in flexural strength, compared with other configurations. These findings indicate that by incorporation of Alccofine, optimizing binder composition, activator ratios and reinforcement, the strength parameters of geopolymer ferrocement can be significantly improved.