CEMENT HYDRATION IN HEAT TREATMENT PART 2

THE EFFECT OF HEAT TREATMENT UPON PHASE COMPOSITION OF A PORTLAND CEMENT AND OF AN IRON PORTLAND CEMENT (PORTLAND BLASTFURNACE CEMENT) WAS INVESTIGATED WITH THE AID OF X-RAY DIFFRACTOGRAPGY, DIFFERENTIAL THERMAL ANALYSIS AND THERMOGRAVIMETRY. IT WAS FOUND THAT IN THE CEMENT PHASES WHICH HAD BEEN HEAT-TREATED, AS CONTRASTED WITH THOSE WHICH HAD UNDERGONE HYDRATION AT NORMAL TEMPERATURE, THERE IS INCREASED FORMATION OF A NEW PHASE WHICH IS CHARACTERISED BY ITS DECOMPOSITION AT ABOUT 450 C (ENDOTHERMIC EFFECT IN DIFFERENTIAL THERMAL ANALYSIS, LOSS OF MASS IN THERMOGRAVIMETRY). IT IS ASSUMED THAT THIS IS ALPHA DICALCIUM SILICATE HYDRATE. THE HEAT OF HYDRATION ENVOLVED AT 20 C AND 80 C WAS INVESTIGATED FOR TWO PORTLAND CEMENTS AND ONE IRON PORTLAND CEMENT. IN COMPARISON WITH THE SPECIMENS HYDRATED AT 20 C, THE HEAT OF HYDRATION IN THE HEAT-TREATED SPECIMENS AT FIRST PROCEEDED MORE INTENSIVELY, BUT LATER AT A MORE MODERATE RATE. THE TOTAL AMOUNT OF HEAT OF HYDRATION EVOLVED IN 28 DAYS BY THE HEAT-TREATED SPECIMENS WAS SOMEWHAT LOWER THAN THAT EVOLVED BY THE SPECIMENS HYDRATED AT 20 C IN THE CASE OF THE PORTLAND CEMENTS, BUT WAS SUBSTANTIALLY HIGHER IN THE CASE OF THE IRON PORTLAND CEMENT. THE AMOUNT OF HYDRATION HEAT EVOLVED IN 28 DAYS BY SPECIMENS WHICH HAD FIRST UNDERGONE HYDRATION AT 80 C FOR 6 HOURS AND, THEREAFTER, AT 20 C WAS SIGNIFICANTLY LOWER THAN THAT EVOLVED BY SPECIMENS WHICH HAD UNDERGONE HYDRATION EITHER AT 20 C OR AT 80 C THROUGHOUT. ON COMPARING THE HEAT OF HYDRATION EVOLVED WITH THE DEGREE OF HYDRATION ATTAINED, IT WAS ESTABLISHED THAT THE QUOTIENT OF HEAT OF HYDRATION (CAL/G) TO DEGREE OF HYDRATION (% OF COMBINED WATER) FOR THE HEAT-TREATED SPECIMENS AND FOR THOSE HYDRATED AT 20 C RESPECTIVELY SHOWS SIGNIFICANTLY DIFFERING VALUES. THIS ALSO INDICATES QUALITATIVE DIFFERENCES IN THE STRUCTURE OF THE SPECIMENS HYDRATED AT 20 C AND 80 C RESPECTIVELY. /AUTHOR/

  • Supplemental Notes:
    • Vol 19, No 7, PP 303-308
  • Authors:
    • Gebauer, J
    • Odler, I
  • Publication Date: 1966-7

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00212500
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 1 1970 12:00AM