A STUDY OF THE CLAY MINERALOGY OF LOESS IN KANSAS IN RELATION TO ITS ENGINEERING PROPERTIES

AN APPARENT CORRELATION BETWEEN THE PRESENCE OF THE BURIED SANGAMON SOIL IN THE SUBGRADE AND THE LOCATION OF FAILURES IN LIGHT TYPE BITUMINOUS PAVEMENT SURFACES HAS BEEN OBSERVED IN NORTH CENTRAL KANSAS. FIELD STUDIES INDICATED THAT THE SANGAMON SOIL IS LESS PERMEABLE THAN THE OVERLYING PEORIA LOESS AND THEREFORE ACTS AS A ZONE OF RESTRICTION TO DOWNWARD MOVING WATER RESULTING IN A MOISTURE BUILDUP AT THE TOP OF THE BURIED SOIL WHICH MAY CAUSE A WEAKENED SUBGRADE CONDITION. FIELD STUDIES REVEALED THAT FAILED SECTIONS HAD A GREEN PLASTIC SOIL MATERIAL DERIVED FROM THE PEORIA LOESS C HORIZON AT THE BASE OF THE MAT. PRELIMINARY INVESTIGATIONS OF THE CONDITIONS UNDER FAILED AND NON-FAILED SECTIONS OF LIGHT TYPE BITUMINOUS PAVEMENT SURFACES INDICATED THAT CERTAIN TYPES OF SUBGRADE MATERIALS ARE POSSIBLY ALTERING TO CLAY OR CHANGING IN CLAY MINERAL COMPOSITION DURING OR AFTER CONSTRUCTION. THIS WAS INVESTIGATED TO DETERMINE THE DIFFERENCES IN TEXTURE AND COMPOSITION OF SUBGRADE MATERIAL AND THE LATERAL AND VERTICAL VARIATIONS IN THE PROPERTIES OF UNITS STUDIED. RESULTS REVEAL THAT LOESSIAL SUBGRADE MATERIALS IN CONTACT WITH ASPHALT MATS WERE UNDERGOING CHANGES IN STRUCTURE, COLOR, AND AMOUNT OF LESS-THAN-TWO MICRON CLAY, STRUCTRUE WAS CHANGING FROM MASSIVE OR SINGLE GRAIN TO WEAK SUBANGULAR BLOCKY. THESE CHANGES WERE BROUGHT ABOUT BY MICROOGANISMS UTILIZING THE ASPHALT AS AN ENERGY SOURCE. THE GREEN COLOR OF THE GREEN PLASTIC SOIL WAS DUE TO A REDUCTION OF THE IRON IN THE SUBGRADE MATERIAL AT ITS CONTACT WITH THE ASPHALT MAT.

  • Supplemental Notes:
    • 69 Pp, 8 FiG, 11 TAB
  • Corporate Authors:

    Kansas State Highway Commission

    State Office Building
    Topeka, KS  United States  66612
  • Authors:
    • Crumpton, C F
    • Badgley, W A
  • Publication Date: 1965

Subject/Index Terms

Filing Info

  • Accession Number: 00237345
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 28 1994 12:00AM