A SYSTEMS APPROACH TO ANALYSIS OF HARDENED CONCRETE

THE PREMATURE DETERIORATION OF CONCRETE WAS A MAJOR CONCERN IN A THREE-YEAR STUDY OF BRIDGE DECKS IN PENNSYLVANIA. SINCE THE MODE OF DETERIORATION IS OFTEN DEPENDENT UPON CONDITIONS OR CHARACTERISTICS OF THE CONCRETE IN ITS EARLY LIFE, AND SINCE THERE ARE SECONDARY AND CONTRIBUTORY EFFECTS, THE FUNDAMENTAL CAUSES MAY BE DIFFICULT TO IDENTIFY AT THE TIME DETERIORATION BECOMES OBVIOUS. TO PERMIT SEPARATION AND IDENTIFICATION OF BASIC AND CONTRIBUTORY MECHANISMS, A SYSTEMS APPROACH TO THE ANALYSIS OF HARDENED CONCRETE WAS DEVELOPED. THE APPROACH DEVELOPED IN THIS STUDY COMBINES THREE COMPLEMENTARY TECHNIQUES WITH A MECHANICAL DATA ACQUSITION SYSTEM AND COMPUTER EVALUATION OF THE DATA. THE FIRST PHASE CONSISTS OF LINEAR TRAVERSE ANALYSIS OF POLISHED CONCRETE SPECIMENS. A SPECIALLY DESIGNED DATA ACQUISITION SYSTEM TABULATES DISCRETE CHORD LENGTHS FOR A STATISTICALLY DETERMINED LENGTH OF RANDOM TRAVERSES. THE PERTINENT AIR VOID PARAMETERS, INCLUDING VOID SIZE DISTRIBUTION AND PHILLEO'S PROTECTED PASTE VOLUME AS WELL AS THOSE DESCRIBED IN ASTM RECOMMENDED PRACTICE FOR MICROSCOPICAL DETERMINATION OF AIR-VOID CONTENT, SPECIFIC SURFACE, AND SPACING FACTOR OF THE AIR-VOID SYSTEM IN HARDENED CONCRETE (C 457-67 T), ARE THEN DETERMINED FROM THESE DATA ON A DIGITAL ELECTRONIC COMPUTER. THE SECOND PHASE CONSISTS OF DETERMINATION OF ORIGINAL WATER/CEMENT RATIOS AND CEMENT FACTORS BASED ON A TECHNIQUE DEVELOPED BY E.O. AXON. FINALLY, PETROGRAPHIC EXAMINATIONS ARE MADE OF THE SPECIMENS, MEGASCOPICALLY AND MICROSCOPICALLY. THE SYSTEMS APPROACH TO ANALYSIS OF CORE SPECIMENS COUPLED WITH FIELD OBSERVATIONS OF THE BRIDGE DECKS PROVIDES THE INFORMATION NEEDED TO EVALUATE CAUSES OF CONCRETE DETERIORATION. A TYPICAL CASE IS DESCRIBED IN THIS PAPER. /AUTHOR/

  • Supplemental Notes:
    • Vol 8, No 10, PP 8-16, 12 FIG, 5 TAB, 9 REF
  • Authors:
    • Larson, T D
    • Cady, P D
  • Publication Date: 1968-10

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  • Accession Number: 00213321
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 28 1994 12:00AM