Comprehensive Analysis of Mechanical, Economic, and Environmental Characteristics of Hybrid PE/PP Fiber-Reinforced Engineered Geopolymer Composites

Engineered Geopolymer Composites (EGCs), known for their excellent tensile properties and lower carbon emissions, have gained widespread attention in the field of fiber-reinforced concrete. However, the high cost of high-performance synthetic fibers, a crucial component of EGCs, limits their practical engineering applications. In this study, by using low-cost PP fibers hybridized with PE fibers and adjusting the fly ash/ground granulated blast furnace slag (FA/GGBS) ratio, cost-effective, high-performing hybrid PE/PP-reinforced engineered geopolymer composites (H-EGCs) were developed. This study conducted axial compressive and tensile tests on H-EGCs with different FA/GGBS ratios (7:3, 6:4, and 5:5) and PP fiber replacement ratios (0%, 25%, 50%, 75%, and 100%), investigated the influence of FA/GGBS and PP fiber replacement ratio on static mechanical behavior, and evaluated the economic and environmental benefits based on mechanical performance indicators. The result indicated that the compressive strength of H-EGCs can reach 120 MPa when the FA/GGBS ratio is 5:5; however, an increase in FA/GGBS and PP fiber replacement ratio leads to a loss in compressive strength and elastic modulus. The incorporation of PP fibers in moderate amounts enhances ultimate tensile strain by reducing crack control ability, and the maximum tensile deformation capacity (7.82–9.66%) was obtained for H-EGCs with a PP fiber replacement ratio of 50%. The optimal economic and environmental benefits of H-EGCs are observed when the FA/GGBS ratio is 5:5 and the PP fiber replacement ratio is set at 50%.