FLOW OF MOISTURE IN HARDENED PORTLAND CEMENT DURING FREEZING

A MATHEMATICAL ANALYSIS, BASED UPON IDEALIZED ASSUMPTIONS, IS MADE OF THE FLOW OF MOISTURE BETWEEN THE COMPONENTS OF HYDRATED-CEMENT PASTE DURING FREEZING OR THAWING. THE COMPONENTS CONSIDERED ARE THE GEL SUBSTANCE, THE CAPILLARY PORES, AND THE AIR-ENTRAINED SPACES. IT IS SHOWN THAT A CHANGE IN TEMPERATURE FOR TEMPERATURES BELOW 0 C. GIVES RISE TO DIFFERENCES IN THERMODYNAMIC POTENTIALS BETWEEN GEL WATER; CAPILLARY WATER, OR ICE; AND ICE FROZEN IN THE AIR SPACES. THESE POTENTIALS RESULT IN PART FROM PRESSURES PRODUCED BY VOLUME CHANGES RESULTING FROM FREEZING AND, IN PART, FROM DIFFERENCES IN THE VAPOR PRESSURES OF ICE AND WATER. BASED ON THESE POTENTIAL DIFFERENCES THE ANALYSES SHOW, FOR EXAMPLE, THAT DURING FREEZING, IN WHICH THE TEMPERATURE IS BEING LOWERED CONTINUOUSLY, FLOW MAY FIRST BE FROM CAPILLARY TO GEL, THEN FROM GEL TO CAPILLARY, AND FINALLY AGAIN FROM CAPILLARY TO GEL. DURING THIS SAME TIME, FLOW MAY BE CONTINUOUSLY FROM GEL TO AIR SPACE. BY TAKING INTO ACCOUNT THE CHANGE IN VOLUME RESULTING FROM FREEZING OR THAWING OF ICE IN THE CAPILLARY SPACES AND THE CHANGES IN SHRINKING OR SWELLING TENDENCY RESULTING FROM CHANGES IN AMOUNT OF GEL WATER, VARIOUS VOLUME-TIME-TEMPERATURE RELATIONS ARE DEDUCED. IN PARTICULAR, IT IS SHOWN THAT WATER MOVEMENTS AND VOLUME CHANGES FOR A SPECIMEN DEPEND NOT ONLY ON THE PRESENT TEMPERATURE CHANGES BUT ON THE PAST TEMPERATURE HISTORY OF THE SPECIMEN. /AUTHOR/

  • Supplemental Notes:
    • Vol 32, pp 276-284, 5 FIG, 3 TAB
  • Authors:
    • Pickett, G
  • Publication Date: 1953

Media Info

  • Monograph Title: Proceedings of the Thirty-Second Annual Meeting of the Highway Research Board, Washington, D.C., January 13-16, 1953
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00213953
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 1971 12:00AM