THE EFFECTS OF SPRING THAW SUBGRADE CONDITIONS ON THE LOAD-CARRYING CAPACITY OF FLEXIBLE AIRFIELD PAVEMENTS IN COLD REGIONS

The greatest variation in the bearing capacity of a flexible airfield pavement occurs in pavements on frost-susceptible subgrades where frost penetration is deep. The very high bearing capacity in winter, due to frost, changes to a very low value during the spring thaw when the top of the subgrade is saturated. A study was made of seasonal variations in the strength of a normal flexible runway pavement in scandinavian climatic conditions. Based on deflectometer tests, the strains in pavement and subgrade were computed and the annual "failure ratio" for different seasons and loads calculated; this is the ratio of the number of strain applications due to repetitions of the same load, to the total number causing fatigue failure. The two important conclusions to be drawn from the results are that 1. If bearing capacity is expressed by one single safe load applicable for the whole year, then this load is very greatly dependent on the failure ratio; 2. If safe load for the spring thaw period is made lower, then that for the remainder of the year can be considerably increased. The latter method will lead to greater utilisation of flexible pavements in cold regions. /TRRL/

  • Corporate Authors:

    Swedish National Road and Transport Research Institute (VTI)

    Olaus Magnus vaeg 35
    Linkoeping,   Sweden  SE-581 95
  • Authors:
    • Oerbom, B
  • Publication Date: 1975

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 16 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00125150
  • Record Type: Publication
  • Source Agency: Swedish National Road and Traffic Research Institute
  • Report/Paper Numbers: No. 60A R&D Rept.
  • Files: ITRD, TRIS
  • Created Date: Nov 18 1975 12:00AM