thermo-mechanical behavior of high-strength concrete with nylon granule aggregates: experimental evaluation and predictive analysis

In recent years, incorporating polymer trash as a substitute for natural aggregates in cementitious material has emerged as a sustainable approach to minimize environmental impact. despite growing interest, limited studies have addressed the mechanical and microstructural performance of high-strength concrete (hsc) incorporating polymer waste under elevated temperature conditions. this research investigates the residual stress-strain response of hsc incorporating nylon granules (ng) as a partial substitute for natural sand at proportions of 0, 10, and 20%. specimens were subjected to axial compressive loading after exposure to high temperatures of 20, 300, and 600°c. the analysis covered several physical and mechanical characteristics such as loss of weight, compressive strength, splitting tensile strength, elastic modulus, strain at peak stress, ultimate strain, toughness, stress-strain model, visual changes, and microstructure. the experimental findings were benchmarked against established codes and standards, including aci 216, asce, en 1994-1-2, en 1992-1-2, and ceb-fip. results demonstrated that higher temperatures substantially impaired concrete performance, with compressive strength and modulus of elasticity declining by approximately 59% and 75%, respectively, at 600°c. furthermore, the inclusion of ng led to additional reductions in mechanical performance. based on the experimental observations, predictive models were formulated for mechanical properties, and a stress-strain model for ng-modified concrete was developed, which correlated well with the experimental results.