Commingled Plastic Guardrail Post

Abstract

There has been an increased interest in the use of recyclable materials due to environmental and economic concerns. As a result, the use of recycled materials in roadside safety features is being explored. In the present paper, a guardrail post manufactured from recycled plastic and steel is evaluated for possible use along highways. Tests were carried out on two cross-sectional configurations. A static cantilever bending test shows that although the plastic posts have less stiffness and strength than a standard wooden post, their energy absorption is approximately three times as large as their wooden counterpart. The plastic posts behaved essentially as rigid elements and sustained no permanent damage in standard in-situ tests. A large pendulum was used to impact the posts in an in-situ condition, and also with a fixed base and a variation of post temperature. Comparison of performance with standard posts was favorable. Finally, a full-scale crash test using a 20-kN (4,500-lb) automobile traveling at 96 km/h (mi/h) and making contract at a 25° angle shows that the commingled plastic post and W-beam guardrail can successfully contain and redirect an errant vehicle.