FROST TENTING (POSTULATION AND EXPERIMENTATION)

A MECHANISM OF DIFFERENTIAL HEAVING IN THE VICINITY OF JOINTS AND CRACKS IN HIGHWAY PAVEMENTS DURING THE FREEZING MONTHS (TERMED "TENTING" DUE TO THE TENT-LIKE STRUCTURE PRODUCED) IS THEORIZED. THE DEVELOPMENT OF THE THEORY IS FOUNDED ON MANY OF THE PRINCIPLES AND CONDITIONS ASCRIBED TO THE GENERAL FROST HEAVE CASE. LIMITED LABORATORY TESTING SUBSTANTIATES THE PROPOSED THEORY, DEMONSTRATING THAT THE TENTING MECHANISM IS A FUNCTION OF MANY PARAMETERS, THE MOST IMPORTANT BEING THE THERMAL CONDITIONS, AMOUNT OF SOIL FINES, AND THE AVAILABILITY OF WATER CONTAINING SODIUM CHLORIDE IN SOLUTION. THE SALT WATER TENDS TO MIGRATE INTO STRATA BENEATH THE JOINT OR CRACK (APERATURE) DECREASING IN CONCENTRATION WITH DISTANCE FROM THE APERATURE. THUS, A DISH SHAPED EQUAL SALT CONCENTRATION CONDITION IS DEVELOEPED BELOW THE APERATURE. WITH SUCH A CONDITION OF SALT CONCENTRATION OF THE SOIL TENDS TO FREEZE UPWARD IN THE PROXIMITY OF THE TENTING AREA, EVEN THOUGH THE SURFACE OF THE SOIL IS AT A LOWER TEMPERATURE THAN THE SOIL BELOW. THIS UPWARD PROGRESSING FROST LINE (ALSO DISH SHAPED) CAN PRODUCE ICE LENSES IF THE PROPER CONDITIONS PREVAIL. THE UPWARD FREEZING CONDITION PREVENTS THE ICE LENSES FROM BEING SHUT OFF FROM THEIR SUPPLY OF SALT WATER (MELT WATER) AND PERMITS CONTINUED ICE LENS GROWTH WHICH IS ASSUMED TO BE THE CAUSE OF THE TENTING PROBLEM. /AUTHOR/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 57 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00206010
  • Record Type: Publication
  • Files: TRIS, STATEDOT
  • Created Date: Jul 17 1972 12:00AM