THE WHITEWATRER EXPERIMENTAL PROJECT: AN INSTRUMENTED ROADWAY TEST SECTION TO STUDY HYDROGENESIS

THE PURPOSE IS TO DETERMINE THE SOURCE OF FREE WATER PRESENT UNDER ROADWAY IN WESTERN COLOADO. TWO INSTRUMENTED TEST SECTIONS WERE ESTABLISHED IN SPRING 1968 IN A SHALE MAT. A PLASTIC MEMBRANE WAS USED TO PROTECT THE SUBGRADE FROM MOISTURE TRANSFERRED FROM THE SUBBASE. IN THE CONTROL SECTION NO PROTECTIVE MEMBRANE WAS PROVIDED. THERE WAS A DISTINCT MOISTURE BUILDUP IN THE CONTROL SECTION TWO TO THREE WEEKS FOLLOWING A SURFACE PRECIPITATION. MOISTURE PENETRATES THE SURFACE AND ENTERS THE SUBBASE AND EVENTUALLY THE SUBGRADE BY EITHER (1) SEEPAGE, OR (2) THE BAROMETRIC PRESSURE VARIATION ALLOWING THE STRUCTURE TO "BREATHE" IN SATURATED AIR FROM THE ATMOSPHERE (HYDROGENESIS). HYDROGENESIS, RESULTING FROM A DIFFENENTIAL TEMPERATURE, DID NOT HAVE A SIGNIFICANT EFFECT ON THE MOISTURE BUILDUP IN THE SUBBASE OR SUBGRADE. AFTER ONE YEAR, THE SUBBASE AND SUBGRADE BECAME SATURATED AND FURTHER MOISTURE VARIATION COULD NOT BE DETECTED. THE MOISTURE CONTENT OF THE SUBBASE WAS NOW APPROXIMATELY 4 TO 5% AND THE SUBGRADE NEAR 19% IN THE CONTROL SECTION. THE PLASTIC MEMBRANE BEGAN TO DECAY RESULTING IN A MOISTURE INCREASE IN THE TEST SECTION SUBGRADE. THE RESULTS INDICATED THAT UNDER EXPERIMENTAL CONDITIONS, A SMALL AMOUNT OF SURFACE MOISTURE WAS SUFFICIENT TO CREATE FREE WATER AT THE BASE OF THE OPEN GRADED SUBBASE. UNLESS SUCH WATER IS PREVENTED FROM ENTERING THE SUBGRADE, CONSIDERABLE STRENGTH LOSS AND/OR SWELLING MAY OCCUR RESULTING IN A PAVEMENT STRUCTURAL FAILURE. /FHWA/

  • Corporate Authors:

    Colorado Department of Highways

    4201 East Arkansas Avenue
    Denver, CO  United States  80222

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00233741
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Aug 8 1971 12:00AM