Experimental and numerical investigation of the usability of nonwoven hemp as a reinforcement material

This study presents experimental and numerical investigations on the use of chemically untreated and recyclable hemp fibers as reinforcement for outer wrapping in reinforced concrete beams. Hemp fibers, recognized as an alternative to Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP), were utilized in three forms: unwashed hemp, washed hemp, and hemp rope. The materials underwent distinct tensile tests, compression tests on cylinder specimens (15x30 cm), and 4-point bending tests on reinforced concrete beams (15x25x200 cm) wrapped with CFRP, GFRP, Glass Fiber Chopped Strand, Geotextile, and NFRP (Unwashed hemp, washed hemp, and hemp rope). Additionally, the epoxy used in wrapping underwent adhesive and tensile tests. Despite swelling during adhesion, untreated hemp demonstrated effectiveness in load-carrying capacity, positioning it as a viable alternative to costly petroleum-derived materials. A finite element model compared the experimental results, confirming the efficacy of untreated hemp fibers in reinforced concrete applications. This study contributes not only to the exploration of sustainable construction materials but also underscores the potential of untreated hemp fibers in meeting the demand for eco-conscious alternatives in structural reinforcement.