Plastic foam in a road acts as thermal insulation, reducing frost heave in the subgrade and thus in the pavement. There are two types of commercial polystyrene foam, bead board of variable quality and extruded board of uniform quality. Since insulation in a road is subjected to mechanical action and a very wet environment, stresses in it must be investigated by long-term field tests. A Swedish test road has yielded results over 5-6 years. Insulation effect depends chiefly on moisture conditions. Field tests show that after 5 years bead board has a moisture content of 20%, while extruded board only 2%. Laboratory results are in close agreement. Results of field and laboratory tests on conductivity also agree. Water absorption may be due to infiltration from above, the moist atmosphere on both sides of the board, and changes in temperature gradient from summer to winter. Owing to good agreement between laboratory and field results, tests can in future be made shorter. Frost damaged roads can be repaired easiest by laying insulation on the existing pavement and a new pavement on top of this. Insulation thickness depends on desired degree of protection; this is an economic consideration. Effects on subgrade are to be investigated. /TRRL/

  • Corporate Authors:

    Royal Norwegian Council for Scientif & Ind Res

    Gaustadalleen 25
    Oslo 3,   Norway 
  • Authors:
    • Gandahl, R
  • Publication Date: 1973


  • Swedish

Media Info

  • Features: Figures; Photos; References;
  • Pagination: 8 p.
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00096767
  • Record Type: Publication
  • Source Agency: Swedish National Road and Traffic Research Institute
  • Files: ITRD, TRIS
  • Created Date: Jul 15 1975 12:00AM