Abstract: Compared with the traditional steel guardrail, bamboo reinforced composite guardrail has many advantages, such as light weight, low cost, corrosion resistance, environment friendly and renewable. But surface of bamboo fiber had complex composition which influence the interfacial properties of the composites. In this paper, bamboo was used as a reinforcing material to reinforce epoxy vinyl resin to make the bamboo composite by using vacuum assisted molding method. The effects of chemical modification by alkali treatment with silane coupling agent and the number of bamboo layer on bending strength and impact toughness in composite were studied. And, the failure mode of impact section of unidirectional composites was analyzed. The results show that the bending strength of modified bamboo reinforced composite increased by 31.95%, 46.72%, 29.58% under different layer structure conditions, and the impact toughness increased respectively by 25.62%, 29.74%, 28.61%, but the flexural and impact properties of unidirectional composites is the best. When the number of bamboo layer is: 15 layers in the unidirectional composites, impact absorbing energy is 13.55J, tensile strength is 270MPa, bending strength is 340MPa, which can meet the highway guardrail requirements on the raw Q-235 on the main performance. The failure mode of impact section is bamboo fiber pull-out fracture, matrix crack, fiber/matrix interfacial debonding and shear layer, as found by SEM in unidirectional composite. The results have some significance for guiding the preparation of highway anti-collision guardrail made of composites.

Key words: bamboo, composite materials crash barrier, surface modification, layer structure, impact performance, crashworthy mechanism