INVESTIGATIONS ON THE HYDRATION PRODUCTS IN THE SYSTEM 4 CAO-3AL203-SO3-CASO4-CAO-H20

INVESTIGATIONS ON THE EARLY-AGE HYDRATION PRODUCTS OF COMPOSITIONS MADE WITH VARIED PROPORTIONS OF 4CAO. 3AL203. SO3, CASO4 AND CAO WERE UNDERTAKEN TO IDENTIFY THE NATURE AND AMOUNTS OF HYDRATES FORMED AT INTERVALS OF 6, 12, 24, 48 AND 72 HOURS. THE RELATIONSHIPS BETWEEN THE PRODUCTS OF HYDRATION AND RELATIVE VOLUME CHANGES WERE EXPLORED. THE OBJECTIVE OF THE INVESTIGATIONS WAS TO DETERMINE THE POTENTIALS OF VARIOUS ANHYDROUS COMPOSITIONS AS EXPANSIVE COMPONENTS IN EXPANDING CEMENTS. IN MOST OF THE COMPOSITIONS STUDIED THE TRISULFATE HYDRATE, 3CAO. AL203.3CASO4.31H20, WAS OBSERVED TO BE THE STABLE PHASE IN THE PASTES EXCEPT WHEN THE CAO/SO3 MOLAR RATIO EXCEEDED 4.0 AND THE AL203/SO3 MOLAR RATIO EXCEEDED 1.0. IN THESE LATTER CASES, A MONOSULFATE HYDRATE OF APPROXIMATE COMPOSITION 3CAO.AL203. CASO4.18H20 WAS DISCOVERED TO BE THE STABLE PHASE IN THE PASTES. ASSUMING A HEXAGONAL LAYER-STRUCTURE LATTICE, THE UNIT CELL DIMENSIONS AND THE D-SPACINGS FOR 3CAO.AL203.CASO4 .18H20 WERE CALCULATED. A FAIR DEGREE OF AGREEMENT HAS BEEN FOUND BETWEEN THE CALCULATED AND THE OBSERVED D- SPACINGS, BUT LACK OF COMPLETE AGREEMENT AND OCCURRENCE OF MANY DOUBLETS ON THE OBSERVED PATTERN SUGGESTS THAT THE LATTICE IS ACTUALLY PSEUDOHEXAGONAL AND THE UNIT CELL MAY BE MONOCLINIC. IT WAS OBSERVED THAT FOR THE PRODUCTION OF EXPANSIVE FORCES, THOSE VOLUME CHANGES WERE MORE USEFUL WHICH OCCURRED AFTER THE HARDENING OF THE PASTES AND WHICH WERE ACCOMPANIED BY THE FORMATION OF THE TRISULFATE HYDRATE. /AUTHOR/

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/sr/sr90/90-028.pdf
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Corporate Authors:

  Highway Research Board (HRB)

  Washington, DC   
• Authors:
  • Mehta, Povindar Kumar
  • Klein, Alexander
• Publication Date: 1966

Media Info

• Media Type: Print
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: pp 328-352
• Monograph Title: Symposium on structure of Portland cement paste and concrete
• Serial:
  • Highway Research Board Special Report
  • Issue Number: 90
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Aluminates; Calcium compounds; Concrete hardening; Expansive cement; Hardness; Hydrates; Hydration; Pastes; Sulfur compounds; Volume changes
• Old TRIS Terms: Calcium sulfoaluminate hydrates; Molar ratio; Trisulfate hydrate
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00212288
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Dec 22 1994 12:00AM