PRELIMINARY STUDY OF COATINGS AND IMPREGNANTS FOR UPGRADING FROST-SENSITIVE AGGREGATES

Laboratory tests carried out to evaluate the potential of various types of coatings and impregnants as means of upgrading frost-sensitive aggregates are described. Although some of the materials tested would probably not be economical for commercial application, they were chosen to represent classes of materials that might include some that could be economically feasible. The impregnants tested were epoxy (diluted with a solvent), methyl methacrylate, boiled linseed oil, polyethylene glycol, and sulfur. The coatings included epoxy and linseed oil emulsion. Two aggregates were used that were known to be highly frost-suceptible, but for different reasons. One was a chert river gravel of moderately high absorption but very low permeability. Its mode of failure under freezing and thawing conditions is internal fracturing and dilation of the aggregate particles as a result of the development of excessive hydraulic pressures. The aggregate was treated by impregnation because of the high capillary potentials offered by the small pore sizes. The second aggregate was a vesicular, highly porous and andesite with very large pore sizes. Its primary mode of failure in concrete under freezing conditions involves the expulsion of water to the paste phase ahead of the advancing frost zone. Because of the large absorptive capacity of this aggregate, an attempt was made to block the pores by using external surface coatings. Triplicate sets of specimens were used in the freeze-thaw tests for each aggregate-treatment combination in accordance with ASTM C682. Both coatings and all impregnants except sulfur were found to render the test aggregates non-frost- susceptible. Specimens containing untreated (control) aggregates failed early in freeze-thaw tests. (Authors)

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 53-56
  • Monograph Title: Corrosion, Cathodic Protection, Aggregate Upgrading, Concrete Density, and Pavement Markings
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00331047
  • Record Type: Publication
  • ISBN: 0309031044
  • Files: TRIS, TRB
  • Created Date: Jun 12 1981 12:00AM