Post-fire flexural performance and microstructure of steel fiber-reinforced concrete with recycled nylon granules and zeolite substitution

Polymer wastes are categorized as highly recyclable materials from various aspects. An effective way to recycle these materials is to utilize them in the concrete industry to replace aggregates. Thus, the non-renewable natural
resources are reserved, and the waste disposal problems are partly mitigated. This study investigates the flexural response of steel fiber-reinforced concrete (SFRC) incorporating recycled nylon granules (NG) and natural zeolite after exposure to elevated temperatures. In total, 216 specimens were produced, which contained steel fiber at 0, 0.75, and 1.25% of mix volume, NG at 0, 10, and 20% of sand volume, and a type of zeolitic framework at 10, 15, and 20% of cement weight to examine the effect of each variable on the compressive and flexural strength, stiffness, and load–deflection response of concrete mixes. A concise microstructural analysis was also conducted
to characterize the microscopic properties of the concrete constituent materials using SEM, BSEM, and EDXMA spectr