USE OF ASPHALT MEMBRANES TO REDUCE EXPANSION IN CERTAIN TYPES OF EXPANSIVE SOILS

NINETEEN EXPERIMENTAL TEST SECTIONS WERE BUILT IN AN INTERSTATE HIGHWAY SECTION TO DETERMINE THE SUCCESS OF A MEMBRANE CONSTRUCTED FROM 50-60 PENETRATION CATALYTICALLY BLOWN ASPHALT CEMENT PLACED ON MANCOS SHALE SOIL TO PREVENT INTRUSION OF MOISTURE INTO THE SUBGRADE AND KEEP THE EXPANSIVE CLAYS IN EQUILIBRIUM. THE MEMBRANE MERELY NEEDS TO ACT AS A LID OR ROOF TO PREVENT MOSITURE FROM ENTERING OR ESCAPING AT THE SURFACE. THE MANCOS SHALE IN SITU IS A HIGHLY CONSOLIDATED MATERIAL WITH A DRY DENSITY OF 130-150 LBS/CU FT. THIS EXPERIMENT IS INTENDED TO BE A FIVE YEAR STUDY. THIS REPORT IS MADE AFTER TWO AND ONE-HALF YEARS OF INSTALLATION. CONCLUSIONS REACHED ARE: (1) SOME MECHANISM CAUSES FREE WATER TO BE ACCUMULATED OR GENERATED IN THE GRANULAR MATERIALS UNDER ASPHALT PAVEMENTS, EVEN IN DESERT AREAS WHERE THERE IS NO WATER TABLE, (2) AS USED, HYDRATED LIME DOES NOT EFFECTIVELY PREVENT SWELLING OF MANCOS SHALE, (3) AIR PERMEABLE GRANULAR SUBBASE AND BASES ARE APPARENTLY RESPONSIBLE FOR HYDROGENESIS, SUGGESTING THAT DENSE GRADED BITUMINOUS BASES MAY ACT AS VAPOR BARRIERS WHEN PLACED DIRECTLY ON THE SUBGRADE, (4) ASPHALT MEMBRANES CONSTRUCTED FROM CATALYTICALLY BLOWN ASPHALTS CAN BE EFFECTIVE IN PREVENTING MOISTURE FROM INTRUDING INTO SUBGRADE SOILS, AND (5) WITH PROPER ENGINEERING CONTROL, IT SEEMS THAT PAVEMENT STRUCTURAL SECTIONS MAY BE THINNED DOWN IF THE SUBGRADE MOISTURE CAN BE KEPT STATIC.

  • Supplemental Notes:
    • 19 Pp, 4 FiG, 6 PHOT, 4 REF
  • Authors:
    • Brakey, B A
  • Publication Date: 0

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00231194
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 15 2004 2:41AM