A THERMODYNAMIC STUDY OF THE SYSTEM HARDENED CEMENT PASTE AND WATER AND ITS DYNAMIC MECHANICAL RESPONSE AS A FUNCTION OF TEMPERATURE

THE DYNAMIC MECHANICAL RESPONSE (THE INTERNAL FRICTION AND THE DYNAMIC MODULUS) OF THE SYSTEM HARDENED CEMENT PASTE (HCP) AND WATER IS INVESTIGATED IN THE TEMPERATURE RANGE FROM -160C TO +100C. THREE TRANSITIONS ARE OBSERVED: THE SURFACE AREA TRANSITION, THE CAPILLARY TRANSITION, AND THE ADSORBATE TRANSITION. THE TEMPERATURE RANGES FOR THESE TRANSITIONS ARE GIVEN AND DISCUSSED. THE COEXISTENCE OF VARIOUS PHASES OF PHYSICALLY BOUND WATER IS INVESTIGATED FROM A THERMODYNAMIC POINT OF VIEW. THE THEROMDYNAMIC ANALYSIS IS DEVELOPED FOR A HIGH SPECIFIC SURFACE POROUS MEDIUM. THE ADSORBENT SPECIES IS SOLID, WHILE THE ADSORBATE SPECIES IS CAPABLE OF EXISTING AS A SURFACE PHASE IN ADDITION TO ITS BULK PHASES, VAPOR, LIQUID (CAPILLARY), AND SOLID. THERMODYNAMIC EQUILIBRIUM IS FORMULATED IN TERMS OF APPROPRIATE AFFINITIES AND EXTENTS OF TRANSFER. THE AFFINITIES INVOLVING TRANSFERS TO THE ADSORBED PHASE ARE WRITTEN IN TERMS OF THE ADSORBATE CONCENTRATION BY INTRODUCING A VARIABLE CALLED THE THERMODYNAMIC FACTOR. THE AFFINITIES INVOLVING TRANSFER TO THE CAPILLARY LIQUID ARE WRITTEN IN TERMS OF THE CAPILLARY CONCENTRATION BY INTRODUCING ANOTHER VARIABLE CALLED THE CAPILLARY FUNCTION. THE THERMODYNAMIC FACTOR IS INTERPRETED IN TERMS OF THE TWO- DIMENSIONAL COMPRESSIBILITY OF THE ADSORBED PHASE, WHILE THE CAPILLARY FUNCTION IS RELATED TO THE CAPILLARY PORE SIZE DISTRIBUTION FUNCTION. THE THERMODYNAMIC RESULTS ARE APPLIED TO THE EXISTING DATA FOR THE SYSTEM HCP AND WATER. IT IS DEMONSTRATED THAT VARIOUS PHASE TRANSFERS OCCUR AS A FUNCTION OF TEMPERATURE. THE INTERRELATION BETWEEN FREEZING AND ADSORPTION EXPERIMENTS IS ALSO INVESTIGATED. THE MODULUS CHANGE CORRESPONDING TO THE CAPILLARY TRANSITION IS UTILIZED TO DERIVE A CAPILLARY PORE SIZE DISTRIBUTION FUNCTION. THE MODULUS CHANGE CORRESPONDING TO THE ADSORBATE TRANSITION IS UTILIZED TO ESTIMATE THE DIFFERENTIAL AND THE MOLAR (INTEGRAL) ENTROPIES OF ADSORBED WATER. THE SURFACE AREA TRANSITION IS ASSOCIATED WITH PROCESSES INVOLVING PARTICLE GROWTH. POSSIBLE ANELASTIC EFFECTS IN THE SYSTEM HCP AND WATER ARE CONSIDERED. IT IS CONCLUDED THAT DYNAMIC MECHANICAL MEASUREMENTS IN THE SYSTEM HCP AND WATER PROVIDE VALUABLE EXPERIMENTAL INFORMATION. THERMODYNAMICS CAN BE A USEFUL TOOL FOR A STUDY OF THIS SYSTEM. THE POWERS-BROWNYARD MODEL FOR HCP IS USEFUL, AS WELL AS REASONABLE, BOTH ON A CONCEPTUAL AND AN OPERATIONAL LEVEL.

  • Supplemental Notes:
    • Tech Rpt No 90, PP 1-349, 64 FIG, 27 TAB, 47 REF
  • Corporate Authors:

    Stanford University

    Stanford, CA  United States  94305
  • Authors:
    • Radjy, F
  • Publication Date: 1968-5

Subject/Index Terms

Filing Info

  • Accession Number: 00213206
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 12 1994 12:00AM