A 25-YEAR EVALUATION OF CONCRETE CONTAINING REACTIVE KANSAS-NEBRASKA AGGREGATES

Durable concretes made with reactive aggregates require compatible ingredients, properly blended and cured. Initially, accelerated tests were used to evaluate materials; however, seldom is the opportunity available, as it is here, to reassess the original concretes after many years of weathering. The concrete slabs, exposed out-of-doors for 25 years, which were inspected for soundness and measured initially, have now been inspected to determine dimensional stability. Concretes contained aggregates which had varying potential for reacting with alkalis in the cements. Methods tried for alleviating effects of reactive expansion included use of various additive aggregates, pozzolans, and portland cements, both with and without entrained air. Fundamental conclusions from initial accelerated tests were confirmed. These require the use of cements having very low alkali content or 45 percent crushed limestone additive with the reactive aggregate. However, use of palliatives such as pozzolan and granite or crushed quartzite aggregate additives delay, but do not prevent, reactive expansion and cracking.

  • Corporate Authors:

    Bureau of Reclamation

    Engineering and Research Center, Bldg 67, Denver Federal Center
    Denver, CO  United States  80225
  • Authors:
    • Porter, L C
  • Publication Date: 1978-10

Media Info

  • Pagination: 89 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00305180
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: REC-ERC-78-5
  • Files: TRIS
  • Created Date: Feb 11 1980 12:00AM