Leaching from Granular Waste Materials Used in Highway Infrastructures During Infiltration Coupled with Freezing and Thawing

Many secondary materials are being considered for use as substitutes for natural aggregates in highway applications due to suitable engineering and economic properties. The durability of aggregate materials against the forces of weathering is an important consideration in the selection of the material. A primary exposure of concern is alternate freezing and thawing. Current test methods for evaluating the soundness of aggregates that undergo freezing and thawing are based only upon meeting physical test criteria and do not integrate environmental material performance. However, during the design life of the application, materials are exposed to freeze/thaw cycles coupled with intermittent infiltration/wetting by precipitation events. In such a scenario, leaching of material constituents is a primary pathway for environmental impact. Material freeze/thaw durability and its impact on flow mechanisms may then be of concern. The objective of the research reported here was to study the effect of freezing and thawing processes on flow mechanisms and constituent leaching from granular materials used in highway infrastructures. Scenarios considered included water percolating through the material and run-off (flow-around), both of which are important routes in the highway environment for leaching of constituent of potential concern present in recycled materials. The effect of material moisture content at the time of freezing, the number of freeze/thaw cycles, and material gradation were investigated.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 190p

Subject/Index Terms

Filing Info

  • Accession Number: 01531734
  • Record Type: Publication
  • Files: TRIS, ATRI, USDOT
  • Created Date: Jul 18 2014 1:15PM