This report reviews eleven field and laboratory studies that have been performed to address concerns about the use of recycled concrete aggregate in pavement foundations. Performance concerns have centered on the possible impairment of drainage systems by deposits of calcium carbonate precipitate and other fines derived from the recycled concrete base materials. Environmental concerns have focused on the relatively high pH of the effluent produced by drainage systems that remove water from untreated recycled concrete aggregate foundation layers. The studies considered in this report demonstrate that all recycled concrete aggregates are capable of producing various amounts of precipitate, with the precipitate potential being directly related to the amount of freshly exposed cement mortar surface. It appears that selective grading and blending with virgin aggregates are techniques that should significantly reduce precipitate potential. One study suggests that washing recycled concrete products will reduce accumulations of crusher dust and other fines in and around the pavement drains. Others indicate that the use of filter fabrics with sufficiently high initial permittivity will allow the accumulation of precipitate and other fines without significantly impairing drainage function. This report discusses study results related to environmental concerns and provides recommendations for revisions to current specifications.

  • Corporate Authors:

    Snyder (Mark B), Consulting Engineering

    1216 Driving Park Road
    Stillwater, MN  United States  55082-3718

    Minnesota Department of Transportation

    Transportation Building, 395 John Ireland Boulevard
    St Paul, MN  United States  55155
  • Authors:
    • Snyder, M B
  • Publication Date: 1995-3


  • English

Media Info

  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 55 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00725560
  • Record Type: Publication
  • Report/Paper Numbers: MN/RC-96/12, Final Report
  • Contract Numbers: 72603
  • Created Date: Sep 12 1996 12:00AM