Abstract:
VOLUME CHANGE OF CONCRETE HAS BEEN SUGGESTED AS THE EXPLANATION OF SOME OF THE OBSERVED CRACKING AND SUBSEQUENT DISINTEGRATION OF MANY CONCRETE STRUCTURES; THE POSSIBILITY THAT ADDITIONS OF CALCIUM CHLORIDE MIGHT DECREASE CHANGES IN VOLUME RESULTING FROM WETTING AND DRYING APPEARED TO WARRANT INVESTIGATION. PART I DEALS WITH THE BEHAVIOR OF PORTLAND CEMENT PASTES, WITH AND WITHOUT THE ADDITION OF CALCIUM CHLORIDE, THE CEMENT PASTES BEING INCLOSED IN RUBBER BAGS AND IMMERSED IN A VOLUMETER USING WATER AS THE MEASURING LIQUID. THE LEVEL OF THE WATER WAS READ AT INTERVALS STARTING WITH TEN MINUTES FROM THE TIME CEMENT AND WATER WERE MIXED TO FORM THE PASTE, AND CONTINUING UP TO ONE YEAR. COVENTIONAL LENGTH MEASUREMENTS ON 4 BY 4 BY 30-INCH BARS, MADE FROM 1: 2: 4 (BY VOLUME) CONCRETE, WITH AND WITHOUT ADDITIONS OF CALCIUM CHLORIDE AND SUBJECTED TO DIFFERENT TYPES OF EXPOSURE WITH RESPECT TO RELATIVE HUMIDITY AND TEMPERATURE, ARE REPORTED IN PART II. THE EXPOSURES INCLUDED (SERIES I) 270 DAYS AT 70 PLUS OR MINUS 2 F AND RELATIVE HUMIDITY OF APPROXIMATELY 100 PERCENT; (SERIES 2) ONE YEAR ADDITIONAL EXPOSURE FOR THE SAME SPECIMENS WHICH HAD BEEN USED IN SERIES 1, WITH THE SAME TEMPERATURE AS IN SERIES 1 BUT WITH A RELATIVE HUMIDITY OF FROM 50 TO 65 PERCENT; (SERIES 3) ON AND ONE-HALF YEARS' EXPOSURE WITH UNCONTROLLED TEMPERATURE (50 TO 100F) AND UNCONTROLLED RELATIVE HUMIDITY (30 TO 83 PERCENT). /AUTHOR/
Supplemental Notes:
Vol 21, pp 294-304, 1 FIG, 4 TAB. 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.
