FUNDAMENTAL MECHANISMS INVOLVED IN EXPANSION OF CLAYS AS PARTICULARY RELATED TO CLAY MINERALOGY

A NEW HYPOTHESIS IS PROPOSED TO EXPLAIN CLAY SWELLING WHICH TAKES INTO ACCOUNT THE OBSERVED RELATION BETWEEN FREE SWELLING AND B-DIMENSION. THIS HYPOTHESIS IS ESSENTIALLY AS FOLLOWS. THE STRUCTURES OF INTERLAYER WATER AND MONTMORILLONITE CONFORM TO EACH OTHER, I.E., EPITAXY OCCURS, BECAUSE OF THE HYDROGEN BONDING THAT EXISTS BETWEEN THEM. AS THE INTERLAYER WATER INCREASES IN THICKNESS, ITS STRUCTURE TENDS TO ASSUME A PREFERRED CONFIGURATION AND THE MONTMORILLONITE STRUCTURE ADJUSTS ACCORDINGLY. THIS ADJUSTMENT CONTINUES UNTIL THE WATER ACHIEVES ITS PREFERRED CONFIGURATION. OR, ALTERNATIVELY, THE MONTMORILLONITE STRUCTURE RELAXES AS STRESSES ACTING ON IT ARE RELIVED BY THE INCLUSION OF WATER, AND THE WATER STRUCTURE CHANGES CONFOMABLY. THIS RELAXATION CONTINUES UNTIL THE WATER STRUCTURE RESISTS FURTHER STRAIN. IN EITHER EVENT, THE B-DIMENSION INCREASES AS THE INTERLAYER WATER INCREASES IN THICKNESS AND ITS FINAL VALUE IS GOVERNED BY THE WATER. HENCE, ITS IS THE SAME FOR EVERY MAXIMALLY SWOLLEN MONTMORILLONITE. THE MUTUAL ADJUSTMENT OF THE MONTMORILLONITE AND WATER STRUCTURES, WHICH ACCOMPANIES THE ABSORPTION OF WATER, NECESSARILY CAUSES A CHANGE IN THEIR STRUCTURAL ENERGIES. THE NET CHANGE IN ENERGY IS PRESUMED TO BE NEGATIVE. THEREFORE, THE WATER IS ABSORBED SPONTANEOUSLY. WATER ABSORPTION (SWELLING) STOP WHEN NO FURTHER STRUCTURAL ADJUSTMENTS OCCUR, I.E., WHEN THE B-DIMENSION REACHES ITS FINAL VALUE. THUS, SWELLING IS RELATED TO THE CHANGE IN B-DIMENSION.

  • Supplemental Notes:
    • Proceedings, Workshops on Expansive Clays and Shales in Highway Design and Construction, Denver, Colorado, 1972. Available in 2 volumes from NTIS, PB-225842.
  • Corporate Authors:

    University of Wyoming, Laramie

    Wyoming Survey and Analysis Center, 710 Garfield
    Laramie, WY  USA  82070
  • Authors:
    • Low, P F
  • Publication Date: 1973-5

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00238181
  • Record Type: Publication
  • Report/Paper Numbers: Workshop Proceedings
  • Files: TRIS
  • Created Date: Jul 31 1974 12:00AM