A Spray Based Crumb Rubber Technology in Highway Noise Reduction Application

Crumb rubber is a commodity made by re-processing (shredding) disposed automobile tires. This article presents a new technology development on the application of crumb rubber in highway noise reduction systems. Advantages and disadvantages of two commonly used manufacturing processes (molding and spray) of crumb rubber panels are analyzed. It is shown that for the intended application, a spraying process is much preferable. Four types of spray devices are further examined. The bonding agent selection and the mix design are investigated. A number of crumb rubber panels are made by the spraying process, and the test of acoustic absorption (ASTM C423-90a) is performed on one type of the panels. The acoustic testing result shows that crumb rubber panels exhibit an excellent noise reduction capability. The future work to continue the current progress is also discussed. The theme of this article is to present the progress made in advancing this technology-product development as well as the feasibility and promise of what it can do for solving two environmental problems, scrap tires and traffic noise, simultaneously. A Spray Based Crumb Rubber Technology ...by Han Zhu and Douglas D. Carlson