INVESTIGATION OF CONCRETE BRIDGE DECK DETERIORATION

THE CAUSES OF DETERIORATION OF CONCRETE BRIDGE DECKS IN CONNECTICUT WERE STUDIED TO DETERMINE MEANS OF PREVENTING DETERIORATION AND EVALUATE ANY POSSIBLE PERMANENT DAMAGE. THE INVESTIGATION CONSISTED OF THE FOLLOWING STEPS: (1) FIELD SURVEY OF APPROXIMATELY 250 BRIDGES OF ALL AGES, TYPES AND USE, (2) STATIC ANALYSIS OF TYPICAL BRIDGES, (3) DYNAMIC ANALYSIS OF A TYPICAL BRIDGE, (4) CONTINUING SURVEILLANCE OF FOUR BRIDGES FROM SHORTLY AFTER CONSTRUCTION TO THE PRESENT, (5) LABORATORY SIMULATION OF CONCRETE BRIDGE DECK CONSTRUCTION, (6) OBSERVATION OF ACTUAL BRIDGE DECK CONSTRUCTION PROCEDURES, AND (7) ANALYSIS OF STRESSES DUE TO DIFFERENTIAL THERMAL STRAINS. IT WAS CONCLUDED THAT: (1) DETERIORATION IS DUE PRIMARILY TO RANDOM CRACKS AND POROUS CONCRETE RESULTING FROM EARLY DRYING AND POOR CURING, (2) TRANSVERSE CRACKS ARE NOT HARMFUL IF SEALED TO PREVENT CORROSION OF REINFORCING STEEL, (3) TENSILE STRESSES DUE TO DYNAMIC LOADING AND POURING SEQUENCE ARE NOT SERIOUS, (4) TENSILE STRESSES DUE TO PLACEMENT OF HOT CONCRETE CAN CAUSE TRANSVERSE CRACKS, AND (5) DEBRIS INCLUDED IN THE CONCRETE DURING CONSTRUCTION CAN CAUSE SPALLING. IT IS RECOMMENDED THAT CONCRETE SHOULD BE PLACED RAPIDLY ENOUGH TO ALLOW SCREEDING TO OCCUR WITHIN 30 MINUTES AFTER PLACEMENT AND FLOATING SHOULD BE DONE IMMEDIATELY AFTER SCREEDING. METHODS USED FOR ROUGHENING THE CONCRETE SURFACE SHOULD BE CARRIED OUT IMMEDIATELY AFTER FLOATING, SO THAT COVERING CAN BE PLACED BEFORE DRYING. THE CONCRETE SHOULD BE COOL WHEN PLACED AND BE KEPT FREE OF ALL DEBRIS. TWO STATE INSPECTORS SHOULD BE PRESENT AT ALL TIMES TO ENSURE PROPER CONSTRUCTION PROCEDURES ARE EMPLOYED.

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Filing Info

  • Accession Number: 00212529
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 17 1994 12:00AM