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

Abstract

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 high-performance 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.