THE FLOW OF HELIUM INTO THE INTERLAYER SPACES OF HYDRATED PORTLAND CEMENT PASTE

A NEW MODEL FOR HARDENED PORTLAND CEMENT PASTE, DISCUSSED PREVIOUSLY IN HIGHWAY RESEARCH RECORD 328, RECOGNIZES THAT THE HYDRATED CALCIUM SILICATES IN PORTLAND CEMENT ARE LAYER-STRUCTURED AND THAT MANY OF THE PROPERTIES OF HYDRATED PORTLAND CEMENT CAN BE ASCRIBED TO THIS. PREVIOUS PHYSICAL MEASUREMENTS SUCH AS DENSITY AND WATER SORPTION DETERMINATIONS DID NOT TAKE INTO ACCOUNT THE FACT THAT THE D-DRIED HYDRATES CAN REHYDRATE WHEN REEXPOSED TO WATER VAPOR; THUS MANY ACCEPTED PROPERTIES AND PARAMETERS HAD TO BE REASSESSED OR REVISED. IN ADDITION, IT IS NOW CONSIDERED THAT THE PROPERTIES THAT LED TO THE NOTION OF "GEL-PORES" ARE IN FACT DUE TO INTERLAYER SPACES. HOWEVER, AN EXPERIMENTAL TECHNIQUE NEEDED TO BE DEVELOPED TO FOLLOW THE CHANGES TO THE SOLID THAT RESULT FROM THE REMOVAL OR REPLACEMENT OF THE INTERLAYER WATER IN ORDER TO CONFIRM ITS EXISTENCE. A HELIUM FLOW TECHNIQUE IS REPORTED WHEREBY THE CHANGES OCCURRING TO HYDRATED PORTLANT CEMENT AS A RESULT OF THE REMOVAL OF INTERLAYER WATER CAN BE MEASURED. RESULTS WERE OBTAINED AT WATER--CEMENT RATIOS OF 0.4, 0.6, 0.8, AND 1.0. "SOLID VOLUME" MEASUREMENTS WERE ALSO MADE. IT WAS CONCLUDED THAT THE SPACES INTO WHICH HELIUM FLOWED WERE INTERLAYER SPACES AND NOT FIXED-DIMENSION, NARROW- NECKED PORES. THIS WORK SUPPORTED THE MECHANISM DISCUSSED IN THE NEW MODEL OF HYDRATED PORTLAND CEMENT ON THE SEQUENCE OF WATER REMOVAL FROM THE INTERLAYER SPACES AND SUBSEQUENT COLLAPSE OF THE SPACES. AN ESTIMATE OF THE DENSITY OF THE FIRST 5.25% OF THE WATER REMOVED FROM THE 11% RELATIVE HUMIDITY CONDITION WAS MADE: THIS WAS 1.27 PLUS OR MINUS 0.08 GM/CC. /CCR/

  • Availability:
  • Supplemental Notes:
    • Vol 1, No 3, PP 285-300, 7 FIG, 11 REF, 1 APP
  • Authors:
    • Feldman, R F
  • Publication Date: 1971-5

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00214029
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 3 1971 12:00AM