MEASUREMENT OF VOLUME CHANGES OF CONCRETE IN SERVICE

A PROGRAM OF PRECISE LENGTH-CHANGE MEASUREMENTS WAS UNDERTAKEN BY THE PORTLAND CEMENT ASSOCIATION IN 1954 IN COOPERATION WITH SEVERAL STATE HIGHWAY DEPARTMENTS AND OTHER ORGANIZATIONS. THE EQUIPMENT DEVELOPED CONSISTED OF A 100- IN. INVAR STEEL TAPE, WITH MEANS FOR ATTACHING TO BRASS INSERTS IN THE CONCRETE AND FOR APPLYING A TENSION OF 30 LB. TWO DIFFERENT TAPES ARE USED AND THE CALCULATED MEASUREMENTS ARE CHECKED WITHIN A TOLERANCE OF 0.002 IN. THE INTERNAL TEMPERATURE OF THE CONCRETE IS OBTAINED AND THE MEASUREMENTS ARE CORRECTED TO 74F, THE TEMPERATURE AT WHICH THE TAPE IS CALIBRATED IN THE LABORATORY. AFTER TEN YEARS OF OBSERVATION, A FEW OF THE BRASS INSERTS WERE DESTROYED OR DAMAGED BEYOND USE, BUT MANY OF THE ORIGINAL POINTS REMAINED UNDAMAGED. THE CONCRETE IN 12 BRIDGES HAS SHOWN NO APPRECIABLE DIMENSIONAL CHANGE IN EITHER DIRECTION. DURING THE SAME PERIOD, CONCRETE THAT WAS CRACKED, AND KNOWN TO BE AFFECTED BY ALKALI-AGGREGATE REACTION, HAS SHOWN A STEADY RATE OF EXPANSION.

Media Info

  • Media Type: Print
  • Features: Figures;
  • Pagination: pp 41-43
  • Monograph Title: Observations of the performance of concrete in service
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00213694
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Aug 17 1970 12:00AM