Mechanical and microstructural characterization of recycled aggregate geopolymer concrete having high strength and recycled tire steel wire fibers

The mechanical and microstructural properties of recycled aggregate geopolymer concrete (RAGC) that contains high-strength steel wire fibers (HSWF), recycled tire steel fibers (RTF), or a mix of the two as hybrid fibers are investigated in this study. Using scanning electron microscopy (SEM) analysis, the study examines microstructure, flexural toughness, compressive strength, and stress–strain response. By volume, metallic fiber additions ranged from 0.5 % to 1.5 %. Results showed that the HSWF1.5 mix achieved the highest mechanical strength of 56.27 MPa at 28 days, a 16.18 % increase over the mix having no fibers i.e., the Control mix. Toughness increased by 59 % in the mix with 1.5 % hybrid fibers i.e., HF1.5 mix, underscoring the significant durability enhancement from fibers.