A comprehensive review on material characterization and thermal properties of geopolymers: Potential of various fibers

Because of their brittleness, traditional Portland cement-based composites are inherently weaker under tensile loads. This issue becomes worse in geopolymer (GPL) composites by the pozzolanic action of precursors such as fly ash and GGBFS. When selecting building materials, fire resistance is essential since structures may experience fire hazards at some point in their lifetime. Although it is widely accepted that concrete is naturally fire-resistant, high temperatures can change the material's performance, compromising its strength, durability, and chemical and physical characteristics. This may result in cracking and spalling, which can result in financial losses and, in extreme circumstances, fatalities. Fiber reinforcement has long been used in traditional Portland cement concrete to address this problem. It not only greatly improves the material's mechanical and durability qualities but also successfully changes the brittle nature of the concrete into a more ductile or quasi-ductile state. To enhance performance and prolong service life, efforts have been made to incorporate fiber reinforcement into GPL composites, considering the global trend towards the partial or total replacement of Portland cement-based products in the construction industry and the emergence of these composites as viable alternatives. Given the recent development of fiber-reinforced geopolymer composites (FRGPL), the goal of this research is to advance knowledge and assessment of the function of fibers in improving GPL materials. This work performs an extensive literature evaluation of FRGPL research that has been published, classifying publications according to the fiber types used. The physical, mechanical, microstructural, and thermal characteristics of GPL composites are thoroughly examined in this paper. The review emphasizes that fiber additions significantly improve GPL characteristics, and FRGPL shows great promise as a sustainable option for structural applications. To completely investigate their performance across a variety of applications, more investigation is necessary.