THE COOLING OF ASPHALT LAYERS DURING THE COMPACTION OPERATION

This paper was presented at Session 20 - Pavement design 2. Data on current bituminous hot mix primary compaction practice in Victoria indicated that, to give four passes of a light twintandem steel-wheeled roller to a layer, the time elapsing between laydown and completion of the operation would be at least nine minutes. This time could be reduced to seven minutes if a heavier compactor with a greater rollwidth is used. Calculation using an improved heat transfermodel showed that, for layers less than 50 mm thick laid in cool or cold weather, the layer can cool to below the temperature at which compaction is effective before the primary compaction operation can be completed. Rate of cooling is influenced by layer thickness (most important factor), laydown and substrate temperatures, layer conductivity and wind speed. An equation is given for calculating the (approximate) time required for a layer to cool to a nominated compaction cessation temperature in terms of these five factors. An indication is also given of substrate temperatures below which layers of asphalt of different nominal thickness and laydown temperature should not be laid. This applies only to fine, cool and cold weather conditions and substrate temperatures for these conditions at any locality in Australia can be approximately estimated from monthly mean maximum air temperature (MMAT) data. /TRRL/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 247-259
  • Serial:
    • Volume: 9
    • Issue Number: 4

Subject/Index Terms

Filing Info

  • Accession Number: 00303516
  • Record Type: Publication
  • Source Agency: ARRB Group Ltd.
  • Files: ITRD, TRIS, ATRI
  • Created Date: Mar 31 1980 12:00AM