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Leaching Assessment of Eco-Friendly Rubberized Chip Seal Pavement
Transportation Research Record
  • Ahmed Gheni
  • Xuesong Liu
  • Mohamed ElGawady, Missouri University of Science and Technology
  • Honglan Shi, Missouri University of Science and Technology
  • Jianmin Wang, Missouri University of Science and Technology
Abstract

Companies in the United States need to mine billions of tons of raw natural aggregate each year. At the same time, billions of scrap tires are stockpiled every year. As a result, replacing the natural aggregate with recycled aggregate is beneficial to the construction industry and the environment. This paper is part of a comprehensive project that developed, and field implemented, a new eco-friendly rubberized chip seal where the mineral aggregate in chip seal is partially or totally replaced with crumb rubber made of recycled tires. This paper presents an extensive study of the environmental impact of using rubber aggregate in chip seal pavement in terms of leaching under different pH conditions, including simulated acid rain. The results are compared with those of conventional chip seal. Leaching from the constituents of chip seal, that is, rubber aggregate and emulsion, was investigated. Two types of rubber and two types of asphalt emulsions were studied. The leaching performance of rubberized chip seal was also investigated. This study revealed that the toxic heavy metals leached from the rubberized chip seal, for pH ranging from 4 to 10, were below that of the EPA drinking water standards. In addition, a significant reduction of heavy metal leaching was recorded when rubber was used with emulsion in the form of chip seal pavement under different pH conditions. Finally, the metal leaching in all types of samples (including rubber, asphalt emulsion, and chip seal) decreased with the increase in pH value.

Department(s)
Civil, Architectural and Environmental Engineering
Second Department
Chemistry
Keywords and Phrases
  • Acid rain,
  • Aggregates,
  • Asphalt,
  • Construction industry,
  • Emulsification,
  • Environmental impact,
  • Environmental Protection Agency,
  • Heavy metals,
  • Pavements,
  • pH,
  • Potable water,
  • Recycling,
  • Rubber,
  • Scrap metal reprocessing, Asphalt emulsions,
  • Comprehensive projects,
  • Drinking water standards,
  • Mineral aggregate,
  • Natural aggregate,
  • Recycled aggregates,
  • Simulated acid rains,
  • Toxic heavy metals, Leaching
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2018 National Academy of Sciences: Transportation Research Board, All rights reserved.
Publication Date
12-1-2018
Publication Date
01 Dec 2018
Citation Information
Ahmed Gheni, Xuesong Liu, Mohamed ElGawady, Honglan Shi, et al.. "Leaching Assessment of Eco-Friendly Rubberized Chip Seal Pavement" Transportation Research Record Vol. 2672 Iss. 52 (2018) p. 67 - 77 ISSN: 0361-1981; 2169-4052
Available at: http://works.bepress.com/honglan-shi/73/