RATES AND MECHANISMS OF HYDRATION OF CLINKER MINERALS IN PASTE FORM

ALL THE USUAL METHODS OF DETERMINING THE RATE OF HYDRATION OF CLINKER MINERALS, IN WHICH THE PROGRESS OF HYDRATION IS DETERMINED IN DRIED AND PULVERIZED SAMPLES ARE, STRICTLY SPEAKING, INDIRECT METHODS. THE HYDRATION MECHANISM CAN BE ELUCIDATED ONLY BY EXAMINING THE REACTION IN THE ACTUAL PASTE CONSISTING OF THE RELEVANT MINERAL AND WATER. IN THE PRESENT INVESTIGATIONS, PURE SPECIMENS OF TRICALCIUM ALUMINATE, TETRACALCIUM ALUMINATE FERRITE, TRICALCIUM SULFATE, ALITE, AND BETA-DICALCIUM SULFATE WERE STUDIED. THE PASTE MIXED WITH WATER IS PUT INTO A SPECIMEN-HOLDER SEALED WITH PLASTIC SHEET, AND THE REDUCTION OF THE STRONGEST X-RAY REFLECTION OF THE INITIAL SUBSTANCE IS CHECKED WITH THE AID OF A GEIGER COUNTER. THE FIRST OBSERVATION CAN BE MADE 6 MINUTES AFTER THE SUBSTANCE IS BROUGHT INTO CONTACT WITH WATER. THE HYDRATION RATES OF THE SUBSTANCES EXAMINED VARY EXCEEDINGLY BUT, IN ALL OF THEM, TWO STAGES OF THE REACTION ARE CLEARLY DISTINGUISHABLE: THE SURFACE REACTION, IN WHICH THE WATER PENETRATES INTO THE INTERIOR OF THE GRAINS AT A CONSTANT RATE, AND THE DIFFUSION REACTION, IN WHICH THE DIFFUSION OF THE WATER THROUGH THE REACTION LAYER THAT HAS FORMED BECOMES THE FACTOR WHICH DETERMINES THE RATE. THE TRANSITION FROM THE SURFACE REACTION TO THE DIFFUSION REACTION OCCURS AFTER 11 MINUTES IN THE CASE OF TRICALCIUM ALUMINATE, AND AFTER 18 DAYS IN THE CASE OF BETA-DICALCIUM SULFATE. /AUTHOR/

• Supplemental Notes:
  • Vol 19, No 11, && 511-518
• Authors:
  • Tsumura, S
• Publication Date: 0

Media Info

• Serial:
  • Zement-Kalk-Gips
  • Issue Number: 0

Subject/Index Terms

• TRT Terms: Aluminates; Calcium compounds; Clinkers; Diffusion (Optics); Hydration; Pastes; Sulfates; Surfaces; X rays
• Uncontrolled Terms: Surface area
• Old TRIS Terms: Geiger counter; Reaction
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00212510
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 1 1970 12:00AM