Consideration is given to the impurities which generally occur in aggregates used for the different layers of the pavement or in concrete. A distinction is made between inorganic and organic impurities. Among the former are clays found in limestone materials. Certain siliceous rocks when washed develop some superficial acidity which impairs adhesion of bitumen. In pyritic or feldspathic rocks; aggregates can become impregnated with ferrous hydroxides. The most harmful inorganic impurities are fines. Those which are below 20 microns are usable in roadbases, but not for wearing courses. Among organic impurities are calcium produced by the decomposition of humus, and fragments of shells in alluvial and marine terrains. /TRRL/

  • Corporate Authors:

    Asociacion Argentina de Carreteras

    Paseo Colon
    Buenos Aires,   Argentina  823 P70
  • Authors:
    • Colombo, J
  • Publication Date: 1975-1-3


  • Spanish

Media Info

  • Features: Figures; References;
  • Pagination: p. 31-32
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00163123
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Mar 14 1978 12:00AM