The hardening of middle east petroleum asphalts (bitumens) in pavement surfacings

The results of a study commenced in 1969 on the hardening of asphalts in pavement surfacings under the climatic conditions encountered in the different regions of Australia are given. The asphalts were derived from some of the principal asphaltic crude petroleums produced in the middle east. The mechanism of hardening in the field and the relationship between level of hardening and surfacing distress for different climatic conditions is discussed and an outline of the development of a laboratory durability test to predict hardening in the field indicated. Details of seven road trials and how they were sampled and monitored for asphalt hardening are then given and the correlation between durability test results and asphalt hardening in the six 'spray and chip' sealing trials indicated. In the dense hot mix (ac) surfacing trial, hardening was found to be dependent on the degree of compaction achieved in the layer by traffic action (as indicated by air void content) as well as on the intrinsic resistance of the asphalt to hardening. Methods for improving resistance of asphalts to hardening in service are then considered. In refinery processing, vacuum residues which are hard enough for paving purposes will have intrinsic durabilities depending on crude petroleum source. Where these residues are too soft, hardening by blending with propane precipitated asphalts from the residue is preferred to high temperature air blowing (a).

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    Melbourne, Victoria  Australia 
  • Authors:
    • Dickinson, E J
  • Publication Date: 1979-11


  • English

Media Info

  • Pagination: 45P
  • Serial:
    • Issue Number: AIR 118-5

Subject/Index Terms

Filing Info

  • Accession Number: 01439802
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Aug 24 2012 10:33PM