Sustainable Approach for the Confinement of Concrete Cylinders Using Fiber‐Reinforced Polymers With Bio‐Based Hemp and Halloysite Nano Tubes

Minimizing environmental impact and adopting renewable alternatives are essential in sustainable construction materials development. This research investigates the effectiveness of hemp fiber‐reinforced polymer (HFRP) with halloysite nanotube (HNT) incorporation utilizing epoxy resin as a matrix for concrete cylinder confinement. FRP composites were fabricated using the manual lay‐up method, and incorporation of 1% by weight (wt.%) of HNT yielded significant enhancement in mechanical properties. Marked improvements were witnessed in the composite laminates' ultimate tensile strength, resistance to cracking and bending. Epoxy multiscale composites demonstrated a 5°C increase in glass transition temperature ( T g ) with respect to hemp fiber composites. Compressive stress and ultimate axial strain of 1% HNT‐incorporated three‐layer HFRP confinement were found 22% and 9% higher, respectively, than those of a three‐layer HFRP confined cylinder. Confinement is carried out on pre‐loaded reinforced concrete (RC) cylinders in order to analyze the real‐time behavior. When compared to a three‐layer HFRP confined pre‐loaded RC cylinder, the HNT‐incorporated HFRP confined RC cylinder exhibited 15% and 28% higher axial stress and strain, respectively. The HNT‐incorporated three‐layer HFRP confinement system manifests excellent energy absorption and ductility.