Performance Evaluation of Novel 3D Printed Hemp-PLA Composites for Sustainable Concrete Reinforcement (2026-04)¶

Safe and sustainable materials are increasingly required in construction applications. This study investigates the mechanical behavior, processing characteristics, and reinforcement potential of novel 3D-printed biodegradable hemp-reinforced polylactic acid (HRPLA) composites as sustainable alternatives to conventional polymer components. Three formulations were examined: pure PLA (H0PLA100) and two hemp-reinforced composites containing 7 wt% (H7PLA93) and 10 wt% (H10PLA90) industrial hemp. Standardized tensile testing revealed monotonic improvements in stiffness, ultimate strength, and strength-to-weight performance with increasing hemp content. The H7PLA93 and H10PLA90 specimens achieved relative strengths of 4.61 MPa/g and 5.04 MPa/g, respectively, compared to 3.12 MPa/g for pure PLA, corresponding to improvements of approximately 48% and 62%. The elastic modulus increased from 8.30 GPa for PLA to 12.65 GPa and 15.32 GPa for the 7 wt% and 10 wt% hemp composites, confirming the stiffening contribution of short natural fibers even at low weight fractions. Minor sensitivities related to extrusion temperature, fiber clustering, and interlayer bonding were observed during printing, although dimensional repeatability and mechanical consistency remained stable under controlled conditions. To contextualize the strengthening trend, an exploratory extrapolation toward higher fiber fractions was performed. This extrapolation is purely hypothetical and intended only as a trend reference; it does not represent experimentally validated performance. The findings highlight the potential of hemp–PLA composites for sustainable lightweight reinforcement applications and outline future research directions including interface engineering, high-fiber-fraction manufacturing, and durability assessment in alkaline environments.