Bamboo Reinforced Composite Materials Development And Research Of Highway Guardrail

As the global energy crisis is aggravated and environment issue grows increasingly, people can not satisfy their demands for road safety in the low life, bad crashworthiness, and big damage to our bodies and the disadvantage like this triggered by the metal highway crash barrier. However, people pay more attentions to bamboo wood a kind of clean and renewable energy in the bamboo reinforced composites for its good crashworthiness, big mechanical strength and extensive sources. This laid a certain foundation for developing new crashworthy guardrail of the mankind. This topic presented by enterprises related, researched the properties of highway crash barrier made by the bamboo composite materials to meet the impact resistance of the metal raw material of Q-235B steel requirements. The impact resistance of its products declines because of bamboo wood’s good hydrophilicity and bad cohesiveness with resin interface bonding. Therefore, the research focus on improving the interface properties between bamboo and resin, choosing the best layer structures of bamboo composite materials, and then studying the impact of the bamboo composite properties.In this paper, we select the position of raw materials by measuring mechanical properties of different parts of the natural bamboo. Using alkali of different concentration and KH550to dispose bamboo, we study how surface modification effect the tensile strength of bamboo and the effect on the interface property between bamboo and resin by optimizing experimental scheme to choose the best modification method. We confirm the enhance fiber and resin integrating theory with practice though comparing and analyzing to get the forming process and each volume fraction of composite material. After choosing the best layer structure by studying interface properties of three layer structure (unidirectional, orthogonal and oblique) composite materials, we study its impact property and test. Analyzing the crashworthy mechanism of the notched fracture surface of the crash barrier material though scanning electron microscopy (SEM).The result reveals that mechanical properties of the upper bamboo were better than those of the middle and lower parts; As the concentration of alkali increased, the tensile strength of bamboo had a downward trend after rising first. When the concentration of alkali treatment reached15%, tensile properties of bamboo was the best. As the concentration of the silane coupling agent increased, the tensile strength of bamboo was damaged in different degrees. When the concentration of silane coupling agent treatment was1%, the tensile strength of bamboo was damaged to a minimum. By analyzing and comparing the alkali treatment, coupling agent treatment and the combination of them, the three modification methods, the method using coupling agent after using alkali treatment is better than using alkali treatment and coupling agent respectively, which has the best surface modification. Comparing the composite material sample composed by untreated surface bamboo, in different layer structures, the shear strength of samples got by the bamboo treated by alkali(concentration is15%)and silane coupling agent (concentration is1.0%) increased by82.74%,90.78%and90.78%, respectively. The bending strength increased by31.95%,46.72%and46.72%, respectively. Impact toughness increased by25.62%,29.74%and29.74%respectively. After analyzing the three different layer structure shear properties of composite materials, the bending property and impact property, we can see the shear, bending, impact properties of unidirectional composites are the highest. Therefore in this paper the bamboo reinforced composites highway crash barrier layer is single layer. In terms of unidirectional composite material, as the number of the layer of composite material increases, the impact toughness did not increase significantly. However, the shock absorption function significantly increased. When the unidirectional composite material layer was15, the impact absorbing energy was13.55J. This can meet the main properties of the raw material of Q-235B for the highway crash barrier. The collision mechanism of crash barrier material shows the fracture, matrix fracture, pull fiber/matrix interface debonding and shear delamination of the bamboo fiber. It is the pull fracture, fracture and matrix of fiber/matrix interface debonding and shear delamination combination of the bamboo fiber that makes the material have a better impact strength and better ability to absorb collision energy.