THE EVALUATION OF CONCRETE BY OUTDOOR EXPOSURE

ONTARIO HYDRO HAS BEEN FOLLOWING THE PERFORMANCE OF CONCRETES SUBJECTED TO OUTDOOR EXPOSURE. STUDIES, MAINLY PERFORMED ON CONCRETE BLOCKS PLACED OUTDOORS IN WATER-FILLED TUBS, INCLUDE VARIATIONS IN WATER-CEMENT RATIO, AGGREGATES OF DIFFERENT QUALITY, AND VARIATIONS IN PASTE COMPOSITION. IN MOST CASES, PARALLEL TESTS WERE CARRIED OUT IN THE LABORATORY FREEZE-THAW APPARATUS BY THE RAPID WATER-FREEZE CYCLE. THE RESULTS TO DATE INDICATE THAT WHEN ONLY ONE VARIABLE IS CHANGED THE ACCELERATED FREEZE-THAW AND THE OUTDOOR EXPOSURE TESTS PLACE SIMILAR CONCRETES IN THE SAME RELATIVE ORDER OF DURABILITY. IT IS QUESTIONABLE, HOWEVER, IT THE FREEZE-THAW TEST WILL PREDICT THE RELATIVE PERFORMANCE OF CONCRETES WHEN COMPARISON INVOLVES DIFFERENT VARIABLES. A DIFFERENCE WAS NOTED IN THE METHOD OF BREAKDOWN IN OUTDOOR EXPOSURE BETWEEN THAT CAUSED BY NONDURABLE PASTE AND THAT CAUSED BY NONDURABLE AGGREGATES. PROGRESSIVE SCALING BELOW THE WATERLINE IS ASSOCIATED WITH BREAKDOWN IN THE PASTE, WHILE PROGRESSIVE POPPING AND CRACKING IS ASSOCIATED WITH UNSOUND AGGREGATES. THERE IS EVIDENCE THAT ENTRAINED AIR WILL NOT PROTECT A NONDURABLE COARSE AGGREGATE BUT UNDER CERTAIN CONDITIONS MAY DELAY DETERIORATION. WHILE THE BENEFITS OF ENTRAINED AIR ARE EVIDENT IN BOTH TESTS, THE ACCELERATED FREEZE-THAW APPEARS TO OVEREMPHASIZE ITS PERFORMANCE COMPARED WITH NON-AIR- ENTRAINED CONCRETE. BY THE OUTDOOR EXPOSURE TESTS, THE BENEFITS OF ENTRAINED AIR ARE MOST PRONOUNCED AT HIGH WATER- CEMENT RATIOS. EVALUATION OF SPECIMENS ON THE BASIS OF VISUAL EXAMINATION HAS PROVED TO DATE THE MOST CONVENIENT AND SIGNIFICANT METHOD OF APPRAISAL, ALTHOUGH THE SONISCOPE DOES PROVIDE VALUABLE SUPPORTING DATA ON THE INTERNAL CONDITIONS OF SPECIMENS. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1969/268/268-004.pdf
• Supplemental Notes:
  • Paper sponsored by Committee on Performance of Concrete--Physical Aspects and presented at the 48th Annual Meeting. 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:
  • Sturrup, V R
  • Clendenning, T G
• Publication Date: 1969

Media Info

• Media Type: Digital/other
• Features: Figures; References;
• Pagination: pp 48-61
• Monograph Title: Portland cement concrete - sealers, durability creep, reactivity, and cement determination
• Serial:
  • Highway Research Record
  • Issue Number: 268
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Accelerated tests; Aggregates; Concrete; Crash exposure; Durability; Entrained air; Freeze thaw tests; Pastes; Water cement ratio
• Uncontrolled Terms: Exposure
• Old TRIS Terms: Soniscope; Visual classifications
• Subject Areas: Geotechnology; Highways; Materials; Safety and Human Factors;

Filing Info

• Accession Number: 00213386
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Sep 22 1994 12:00AM