Abstract:
A NEW TECHNIQUE FOR RECOVERING SILICATE STRUCTURES AS TRIMETHYLSILYL DERIVATIVES HAS BEEN USED TO STUDY THE HYDRATION OF PORTLAND CEMENT. BY THIS METHOD ONLY THE CHANGES IN THE SILICATE PORTION OF THE STRUCTURE CAN BE DETERMINED AS A FUNCTION OF HYDRATION TIME. CEMENT PASTES RANGING IN AGE FROM ONE DAY TO 14.7 YEARS WERE ANALYZED FOR THE STUDY. THE HYDRATION REACTION IS SHOWN TO BE SIMILAR TO A CONDENSATION TYPE POLYMERIZATION. THE ORTHOSILICATE CONTENT OF CEMENT PASTE /WHICH PROBABLY REPRESENTS THE ORIGINAL CALCIUM SILICATES IN THE PORTLAND CEMENT/ GRADUALLY DECREASES AS THE PASTE AGES. CONCURRENTLY A DISILICATE STRUCTURE IS FORMED WHICH REACHES A MAXIMUM QUANTITY IN ABOUT FOUR WEEKS AND THEN IT TOO DIMINISHES AS THE PASTE AGES. MINOR QUANTITIES OF A TRISILICATE AND A CYCLIC TETRASILICATE ARE SHOWN TO BE PRESENT IN HYDRATED CEMENT PASTE. AN UNIDENTIFIED POLYSILICATE STRUCTURE IS PRODUCED BY THE HYDRATION REACTION WHICH NOT ONLY INCREASES IN QUANTITY THROUGHOUT THE AGE PERIOD STUDIED, BUT ALSO INCREASES IN MOLECULAR WEIGHT AS THE PASTE AGES. /AUTHOR/
Supplemental Notes:
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