INSULATION OF SUBGRADE - THIRD YEAR SUMMARY

AN EXPERIMENTAL EVALUATION WAS CONDUCTED ON THE EFFECTIVENESS OF STYROFOAM INSULATION IN REDUCING FROST HEAVING OF THE ROADWAY. THERMOCOUPLES WERE USED TO MEASURE TEMPERATURES, NUCLEAR PROBES TO MEASURE SOIL WATER CONTENT, TRANSIT SURVEYS TO DETERMINE THE AMOUNT OF HEAVE OF THE PAVEMENT SURFACE WITH PERIODIC VISUAL INSPECTIONS TO LOCATE CRACKS AND DETERMINE THE CONDITION OF THE PAVEMENT. THE INSULATION WAS PLACED DIRECTLY ON THE SUGBRADE SOILS EXCEPT IN ONE SECTION WHICH WAS UNDERCUT. DATA ARE PRESENTED FROM THE THIRD WINTER OF TESTS. THE FREEZING INDEX FOR THE WINTER WAS 1284, BUT THE TEMPERATURE UNDER THE CENTER OF THE STYROFOAM REMAINED WARMER THAN 32F. DURING THE WINTER MOST OF THE HEAT LOSS BY THE INSULATED SECTIONS WAS AROUND THE EDGES OF THE STYROFOAM BLANKET, BUT IN SUMMER MOST OF THE HEAT ABSORBED PASSED THROUGH THE CENTER OF THE PAVEMENT AND INTO THE SOILS BELOW THE INSULATION. THE THERMAL REGIME OF THE INSULATED SECTIONS WAS PERMANENTLY ALTERED BOTH ABOVE AND BELOW THE INSULATION, BUT THE DATA DO NOT SUPPORT THE HYPOTHESIS THAT THE TEMPERATURE OF ANY GIVEN POINT BENEATH THE INSULATION WILL BECOME INCREASINGLY COLDER AND COLDER. THE PAVEMENT OF THE INSULATED SECTIONS WAS SHOWN TO CONTAIN FEWER CRACKS THAN THAT OF THE UNINSULATED SECTIONS. THIS IS ATTRIBUTED TO THE LESSER OVERALL MOVEMENT OF THE SOILS IN THE INSULATED AREAS AS SUPPORTED BY THE SURVEY DATA.

• Supplemental Notes:
  • Hpr-pr-1/3/, STATE 510
• Corporate Authors:

  Maine State Highway Commission

  Materials and Research Division, Bureau of Highways
  Augusta, ME  United States  04330

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • Bigelow, N
• Publication Date: 1968-2

Subject/Index Terms

• TRT Terms: Electric insulating materials; Freezing; Frost heaving; Insulating materials; Nuclear engineering; Pavements; Plastic foams; Soil water; Subgrade (Pavements); Temperature measurement; Thermocouples
• Old TRIS Terms: Freezing index; Frost heave; Highway pavement; Nuclear applications; Styrofoam
• Subject Areas: Geotechnology; Highways; Materials; Pavements;

Filing Info

• Accession Number: 00215882
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS
• Created Date: Jun 18 1994 12:00AM