COMPARATIVE ANALYSIS OF STEEL REBAR AND POLYESTER FIBER REINFORCED GEOPOLYMER CONCRETE: MECHANICAL PROPERTIES AND FAILURE MECHANISMS

This article presents a study of the mechanical properties of geopolymer concrete reinforced with steel rebar and polyester fibers and compares their performance under different loading conditions. Geopolymer concrete, known for its environmental benefits due to its low CO₂ emissions, has been enhanced with micro silica as an activator and sodium silicate to accelerate the curing process. In this study, non-destructive ultrasonic testing (UT) was used to evaluate the compressive strength, dynamic and static Young's modulus, shear modulus, and pore characteristics. Steel rebar is more suitable for applications requiring high load-bearing capacity, but polyester fibers increase the ductility and resistance of geopolymer concrete to sudden failure by absorbing more energy. The optimum content of polyester fibers is 6%, which ensures the highest flexural load (10,080 kN) and displacement (2.6 mm). Failure analysis revealed shear cracks in samples with steel rebar and vertical cracks in polyester fiber-reinforced samples, indicating different failure mechanisms. The study highlights the trade-off between flexural load and ductility, providing insights for individual applications in sustainable construction. The SADRA algorithm and UT methods have proven their effectiveness in predicting mechanical properties, confirming the potential of geopolymer composites in modern engineering.