Strain hardening geopolymer composites with hybrid POM and UHMWPE fibers: Analysis of static mechanical properties, economic benefits, and environmental impact

With unique ultra-high toughness, strain-hardening cementitious composite (SHCC) has attracted considerable attention. However, environmental and economic concerns have hindered its engineering application due to the high consumption of Portland cement and expensive highperformance fibers. To address this issue, geopolymer concrete and polyoxymethylene (POM) fibers are adopted to replace Portland cement and ultrahigh molecular weight polyethylene (UHMWPE) fibers, respectively, to prepare strain-hardening geopolymer composite with hybrid POM and UHMWPE fibers (POM/PE-SHGC). Static mechanical properties, economic benefits, and environmental impact of POM/PE-SHGC with different POM fiber replacement ratios are investigated. Axial compression and tensile tests on POM/PE-SHGC with different POM fiber replacement ratios (0%, 25%, 50%, 75%, 100%) are conducted to investigate the effect of different POM fiber replacement ratios on the static failure mode, tensile crack development, compression behavior, and strain-hardening behavior of POM/PE-SHGC. In addition, Carbon emissions and energy consumption of POM/PE-SHGC were estimated and compared with SHCC. An evaluation method that comprehensively considers environmental and economic benefits and mechanical properties is proposed. The results indicated that under the condition of a total fiber volume fraction of 2%, POM/PE-SHGC with a POM fiber replacement ratios under 75% exhibited good strain-hardening behavior. The compressive strength, ultimate compressive strain, and ultimate tensile strain of POM/PE-SHGC reached a maximum at a POM replacement ratios of 50%, except for a decrease in its tensile strength. Furthermore, the cost, carbon emissions and energy consumption of POM/PE-SHGC was significantly lower than that of SHCC. This study verified the feasibility of producing green, high-performance SHGC and promoted the engineering application of this material.