Reduced Zinc Leaching from Scrap Tire during Pavement Applications


Large quantities of scrap tires have been generated and accumulated over the years. However, a significant amount of them are stocked due to the lack of environmentally-friendly methods for disposing of, or reusing them. Because tires contain approximately 1-2% zinc by weight, leaching of zinc from scrap tires could be an environmental concern. In this research, we investigated the leaching of zinc from tire particles that are used with asphalt for pavement applications. The effects of tire particle size and pH on zinc leaching were also examined. Our results indicated that asphalt treatment significantly reduced zinc leaching from tires, and that it was also reduced by increasing the tire particle size and pH. The leaching of zinc was quantified by using a speciation-based modeling approach. The model parameters, namely, the total leachable zinc mass and the adsorption constant, can be used to predict the leaching of zinc under different conditions. The reduction in zinc leaching from asphalt-treated tire particles was due to the physical blocking of the tire surface by the asphalt. Results also indicated that, while the leaching of zinc and other selected toxic elements from untreated tire particles using simulated acid rain was not significant compared to the drinking water regulations, asphalt treatment during the pavement application further improved the environmental performance of the tire particles.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Acid rain; Asphalt; Chemicals removal (water treatment); Environmental management; Environmental regulations; Leaching; Particle size; Pavements; Potable water; Tires; Zinc; Adsorption constant; Environmental concerns; Environmental performance; Model approach; Model parameters; Scrap tires; Simulated acid rains; Water regulation; Zinc scrap; Speciation-based model

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2018 Elsevier, All rights reserved.

Publication Date

01 Nov 2018