Following promising results from laboratory investigations, the effect of small concentrations of ZDC on the rate of hardening of Kuwait bitumens in pavement service was investigated. Spray seal trails were laid in Queensland, Victoria and western Australia during period 1969-1970 with concentrations of ZDC of up to 4 percent by weight in the bitumen. The rate of hardening of the bitumen has been monitored by periodically taking samples from the seals and recovering the bitumen adhering to the underside of seal stones plucked from these samples. The viscosity of the recovered bitumens was measured. Estimates of the precision of these procedures are given in the appendix. In the Queensland and Victoria trails the bitumens were 'cut-back' with kerosene and evidence was obtained that this diluent precipitated some of the ZDC from solution in the 85/100 pen grade bitumens. No cutter was used in the western Australian trail. Results from the trails indicate that most of the ZDC originally dissolved in the bitumen is decomposed after one or two years of pavement service and that there is no permanent effect on the rate of hardening of the bitumen in the seal. The bitumen used in the Queensland trial has hardened much more rapidly than the bitumens used in the other trials. After six years service, all the sections require maintenance treatment and the bitumen has reached the "critical" viscosity level associated with seal cracking. The queensland trial is sited in a hot dry climate area, the road is lightly trafficked and the bitumen used showed a high rate of hardening in the ARRB durability test. Observations of the hardening of the bitumen in the Victoria and western Australian trails will be continued. /TRRL/

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  • Corporate Authors:


    Melbourne, Victoria  Australia 
  • Authors:
    • Dickinson, E J
  • Publication Date: 1976-7


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 17 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00145298
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • ISBN: 0-86910-000-9
  • Report/Paper Numbers: Rpt. No 64
  • Files: ITRD, TRIS
  • Created Date: Apr 13 2003 12:00AM