Investigation of Best Options for Using Scrap Tires in Highway Noise Barriers

摘要

In Colorado, approximately 60 million scrap tires have been stockpiled and approximately 4.5 million scrap tires are generated annually. While CDOT does not generate these scrap tires, CDOT does have goals and policies to promote sustainability/recycling and receives requests for more traffic noise barriers than can be funded. CDOT identified an opportunity to combine these two topics by investigating new ways to incorporate scrap tires into highway noise barriers. This research project reviewed potential noise barrier materials made from scrap tires, selected a material for field testing, designed and built a test barrier at the designated site using the material, and monitored barrier performance for one year. The material selected was a railroad tie replacement made from scrap tire treads. Although not originally developed as a noise barrier material, the railroad ties were found to be effective. The ties provided a substantial noise reduction, consumed a number of scrap tires, had substantial internal strength that is a plus as a building material, and were easily assembled in a post-and-panel barrier design. The barrier performed well over its first year. The material and the wall design are recommended for consideration by CDOT on other projects. Some challenges were identified through the project: the ties were not a low-cost alternative for reasons stated in the body of the report; the finish stain method may need adjusting for a better long-term appearance; rust will appear on the steel components; and a few minor construction/finish improvements were identified.