DO 'TENDER' BITUMENS REALLY EXIST?

Recently a number of cases of bitumen exhibiting 'tenderness' have been reported in South Australia and Victoria. In sprayed seal work, significant bleeding and loss of aggregate is associated with this condition whilst,in asphalt work, shoving under normal compaction and heavy bleeding and rutting under traffic occurs. Laboratory work was undertaken in Australia to identify those properties which separated 'tender' bitumens from 'normal' ones. Various physical and chemical tests were carried out which showed only that a significant change in the chemical composition of bitumen had occurred over the past 20 years. The laboratory testing failed to show sufficiently large differences in flow and deformation properties to convincingly explain the differences in field performance between 'tender' and 'normal' bitumens. Victorian experience suggests that construction practice may be a major contributing factor. It is proposed that the tendernessproblem encountered in Australia is a complex phenomenon. Increased freight traffic, higher loadings and, particularly, higher tyre pressures may have substantially reduced the safety margin associated with the design and construction of thin surfacings and may account for the prevalence of distress in recent years. (a) For the covering abstract of this conference see IRRD abstract no. 861222.

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 91-106

Subject/Index Terms

Filing Info

  • Accession Number: 00669754
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ITRD, ATRI
  • Created Date: Dec 23 1994 12:00AM