THE SIGNIFICANCE OF EARLY HEAT LIBERATION OF CEMENT PASTE

DIFFERENCES IN RATES OF HEAT GENERATION OF CEMENTS DURING THE FIRST 24 HOURS AFTER MIXING AND THE PROBABLE SIGNIFICANCE OF THE DIFFERENCES ARE DISCUSSED. A "CONDUCTION" CALORIMETER MEASURING INSTANTANEOUS RATES OF HEAT LIBERATION IS DESCRIBED. THE RESULTS ARE GIVEN. PLOTTED CURVES OF THE RATES OF HEAT LIBERATION OF CEMENT FOR THE FIRST 24 HOURS AFTER MIXING SHOW WIDE DIFFERENCES, SUGGESTING THAT THE EARLY HEAT CHARACTERISTICS MAY BE A SENSITIVE INDEX TO THE PERFORMANCE OF A CEMENT. THE FOLLOWING PROPERTIES OF CEMENT ARE SHOWN TO BE RELATED TO EARLY HEAT OF HYDRATION: SETTING TIMES, EARLY STRENGTH, TEMPERATURE RISE OF CONCRETE IN THIN SLABS, AND PROBABLY BLEEDING OF CONCRETE. THE EARLY HEAT CHARACTERISTICS OF CEMENTS ARE AFFECTED BY THE FOLLOWING FACTORS: FINENESS, COMPOSITION, GYPSUM CONTENT, COOLING TREATMENT OF CEMENT CLINKER, TEMPERATURE OF HYDRATION, "CONDITIONING" ON AGEING OF CEMENT, AND THE PRESENCE OF EXTRANEOUS MATERIALS. AN EXAMPLE OF THE EFFECT OF THESE VARIABLES IS THE FACT THAT A FEW PERCENT OF AN ACTIVE PUZZOLANIC MATERIAL MAY INCREASE THE MAXIMUM RATE OF HEAT LIBERATION BY A HUNDERED PERCENT OR MORE, ALTHOUGH IT MAY REDUCE THE TOTAL HEAT LIBERATION. THE PRELIMINARY STUDIES OF EARLY-HEAT CHARACTERISTICS INDICATE THAT THE CONDUCTION CALORIMETER IS A GOOD TOOL FOR RESEARCH. THE EARLY HEAT OF HYDRATION MAY PROVIDE A GUIDE TO IMPROVING THE QUALITY AND UNIFORMITY OF CEMENTS WHEN THE SIGNIFICANCE OF RESULTS IS MORE FULLY UNDERSTOOD. /AUTHOR/

• Record URL:
  https://onlinepubs.trb.org/Onlinepubs/hrbproceedings/17/17Pt1-029.pdf
• Supplemental Notes:
  • Vol 17, ParT I, PP 360 - 367, 7 FIG, 1 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.
• Authors:
  • CARLSON, R W
• Publication Date: 1938

Media Info

• Media Type: Digital/other
• Monograph Title: Proceedings of the Seventeenth Annual Meeting of the Highway Research Board Held at Washington, D.C. November 30, December 1, 2, 3, 1937. Part I
• Serial:
  • Highway Research Board Proceedings
  • Volume: 17
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Bleeding; Calorimeters; Cement; Concrete; Curves (Geometry); Heat of hydration; Pastes; Quality control; Setting (Concrete); Slabs; Standardization; Strength of materials; Temperature
• Uncontrolled Terms: Characteristics; Quality; Setting time
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00213790
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Aug 15 1971 12:00AM