Innovative materials for constructing sustainable and smart cities: performance of fiber-reinforced geopolymer composites (FRGC)

Geopolymers have been reported as a key solution to decrease the amount of greenhouse gas emissions generated by the cement industry. Geopolymers offer the industry a promising and sustainable substitute for ordinary Portland cement. In this study, the effectiveness of incorporating fibers into geopolymer composites to enhance their mechanical properties was investigated. The influence of fiber type [basalt (BSF), polyvinyl alcohol, and polyethylene], fiber volume ratio (0.5, 1.0, and 1.5%), and fiber length (6, 12, and 19 mm) on the compressive strength, flexural strength, and workability of FRGC was investigated. The results showed that adding fiber significantly improved the mechanical properties of geopolymer composites. PVA fiber with a length of 12 mm and BSF fiber with a length of 6 mm at a fiber volume of 0.5% increased the compressive strength of FRGC by 22.20% and 15.70%, respectively. While PVA fiber with a fiber volume of 1.0% and a length of 19 mm improved the flexural strength of FRGC by 72.92%. Also, it was found that the workability of FRGC was reduced by adding fibers. Furthermore, it was observed that the highest workability was obtained with basalt fiber at a fiber volume of 0.5% and a length of 6 mm. It was concluded that the fiber volume ratio is the most influential factor in the compressive strength and workability of FRGC, while the fiber type is the most significant factor in the flexural strength of FRGC. Finally, the findings of this study demonstrate the potential of FRGC as a sustainable and durable alternative to conventional construction materials in the context of smart cities.