For satisfactory compaction at the lowest cost, the compactibility of bituminous mixtures for different cooling rates and rolling processes must be known, and a quick means of determining the degree of compaction must be available. The nuclear method subjects the pavement to gamma radiation, the amounts absorbed and back-scattered being a measure of density. The instrument tested has a probe containing isotope cs 137, back scatter being detected by GM tubes. Agreement between paraffin and nuclear methods was good, standard deviation being 0.02-0.03 g/cm3. For efficient utilisation of equipment, time available for compaction must be known. This is the interval between stability and stiffness of the asphalt. Lower limit depends on compactibility, rolling process and cooling process. In field tests the temperature was measured by thermistors placed in the pavement. Good agreement was obtained between field results and theoretical analysis. Field tests in 1965 with variable rolling parameters resulted in the following rolling programme: 1. Rolling to start as soon as possible by 2 static rollers in tandem, 2. At least 8 and preferably 12 passes, 3. Speed of approx. 5 km/h. Average degree of compaction was 97-100%, standard deviation 1%. Resistance to wear by studs was improved by 30%. /TRRL/

  • Availability:
  • Corporate Authors:

    Shell International Petroleum Company Limited

    Shell Center
    London SE1 7NA,   England 
  • Authors:
    • Lilja, B
  • Publication Date: 1973

Media Info

  • Features: Figures;
  • Pagination: 4 p.
  • Serial:
    • Shell Bitumen Review
    • Issue Number: 44
    • Publisher: Shell International Petroleum Company Limited
    • ISSN: 0037-3516

Subject/Index Terms

Filing Info

  • Accession Number: 00096768
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Jul 15 2003 12:00AM