LAUSR

Abstract Performance of polymer reinforced with continuous long natural and man-made fibers was extensively investigated in literature. However, using yarns made of short discrete natural fibers needs to be investigated as a source of sustainable reinforcement for composites. In this study, long yarns made of short flax and jute fibers were selected to reinforce polyester bars. Infusion technique was implemented to produce natural yarns reinforced polyester (NYRP) bars having various fiber volume fraction ratios. Microscopic images showed good fibers distribution and resin-fibers impregnation across the of NYRP bars. In addition, polyester bars reinforced with selected natural yarns lead to remarkable enhancement of their tensile strength, stiffness and ductility. Moreover, concrete slabs reinforced with surface treated NYRP bars performed compatibly until failure. Despite low stiffness of the produced NYRP bars, their use for reinforcing normal and lightweight concrete slabs enhanced their ductility and toughness as well as increased their flexural capacity up to six-fold.