PROGRESS REPORT OF SPECIAL PROJECT ON STRUCTURAL DESIGN OF NONRIGID PAVEMENTS: SURVEY OF SUBGRADE MOISTURE CONDITIONS

INFORMATION ON SUBGRADE MOISTURE CONTENTS, CHIEFLY BELOW FLEXIBLE PAVEMENTS, WAS COLLECTED FROM SEVERAL STATE HIGHWAY DEPARTMENTS, MOST OF THE DATA BEING RECEIVED FROM STATES IN THE MISSISSIPPI VALLEY. AN ATTEMPT HAS BEEN MADE TO ASSEMBLE THIS INFORMATION SO AS TO GIVE A GENERAL PICTURE OF SUBGRADE MOISTURE CONDITIONS AND TO STUDY THE VARIATIONS WHICH OCCUR. THE MOISTURE VALUES ARE EXPRESSED IN THREE DIFFERENT WAYS: PERCENTAGE OF SATURATION, PERCENTAGE OF PLASTIC LIMIT, AND PERCENTAGE OF OPTIMUM MOISTURE CONTENT. IT WAS FOUND THAT THE PERCENTAGE OF SATURATION OF THE SOILS VARIES, IN GENERAL, WITH SOIL TEXTURE, BEING HIGH FOR CLAYS AND PROGRESSIVELY LESS FOR CLAY LOAMS, LOAMS, AND SANDY LOAMS. THE MOISTURE CONTENT OF THE FINE TEXTURED SOILS, SUCH AS CLAYS, GENERALLY EXCEEDS THEIR PLASTIC LIMIT, THAT OF LOESSIAL SILTY SOILS IS USUALLY EQUAL TO OR JUST UNDER THE PLASTIC LIMIT, AND THAT OF SANDY LOAMS RARELY EXCEEDS AND IS GENERALLY LESS THAN THIS CONSTANT. A SUBSTANTIAL PROPORTION OF THE MOISTURE VALUES IN ALL TEXTURAL CLASSES OF SOIL WAS IN EXCESS OF THE OPTIMUM MOISTURE CONTENTS. ONLY ONE PROJECT SHOWED A MARKED CHANGE OF MOISTURE CONTENT OVER A PERIOD OF TIME. IN THIS PROJECT THE BASE AND SURFACE COURSES HAD BEEN PLACED ON A RELATIVELY DRY LOESSIAL SILTY CLAY SOIL. SOME RESULTS OF STUDIES OF THE EFFECT OF TYPE OF SURFACING, TRANSVERSE LOCATION, AND DEPTH ARE ALSO PRESENTED. SUGGESTIONS ARE MADE FOR THE METHOD OF ACQUISITION OF FURTHER DATA.

  • Supplemental Notes:
    • Vol 24, pp 497-513, 3 FIG, 12 TAB
  • Authors:
    • Kersten, M S
    • Lancaster, C M
  • Publication Date: 1945

Media Info

  • Monograph Title: Proceedings of the Twenty-Fourth Annual Meeting of the Highway Research Board (Unassembled)
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00205590
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 5 1994 12:00AM