Mechanical and microstructural properties of basalt fiber reinforced underwater geopolymer mortar

This study aims to examine the mechanical and microstructural characterization of underwater geopolymer mortar. The study assessed the efficacy of basalt fiber in underwater geopolymer mortar manufactured using Ground granulated blast-furnace slag (GGBS). This work generated basalt fiber-reinforced GGBS-based geopolymer mortar samples. 0 %, 0.25 %, 0.50 %, and 0.75 % basalt fiber ratios were used to produce basalt fiberreinforced GGBS-based geopolymer mortar. The basalt fiber-free and the basalt fiber-reinforced GGBS-based geopolymer mortar samples were cast and cured in river water. This research tested fresh mixes and hardened samples in two test groups. pH and slump tests were done on fresh mixes. Porosity, flexural strength, and compressive strength tests were also performed on the hardened GGBS-based geopolymer cube and prism samples. In addition, various microstructural experiments were conducted for the microstructural evaluation of the hardened GGBS-based geopolymer. Incorporating fiber into the underwater geopolymer mortar samples resulted in enhanced compressive and flexural strength. After 28 days, the compressive strength of the sample with 0.75 basalt fiber increased by 14.76 % compared to the reference sample, while the flexural strength increased by 56.85 %. In addition, Thermogravimetric analysis revealed that the presence of basalt fibers reduced the mass loss in the geopolymer samples.