EVALUATION OF METHODS OF REPLACEMENT OF DETERIORATED CONCRETE IN STRUCTURES

TECHNIQUES FOR THE REPAIR OF DETERIORATED CONCRETE BRIDGE DECKS ARE DESCRIBED. FIELD INSPECTION WAS CONDUCTED OF 238 DIFFERENT CONCRETE REPAIR PROJECTS SCATTERED THROUGHOUT 28 STATES AND THE DISTRICT OF COLUMBIA. REGARDLESS OF THE TYPE OF PATCHING MATERIAL TO FOLLOW, IT WAS DETERMINED THAT THE METICULOUS PREPARATION OF REPAIR AREAS WAS ESSENTIAL TO THE CONSISTENT SUCCESS OF THE REPAIR PROGRAM. A NUMBER OF SIMPLE AND EFFECTIVE SYSTEMS WERE DEVELOPED FOR FORMING THE BOTTOM OF DECK REPAIRS. SEVERAL REMOVABLE FORMS WERE PLACED FROM THE LOWER FLANGE OF FLOOR BEAMS, TEMPORARY LIFTS AND SUPPORTS FOR DECK SPANS WERE PROVIDED BY JACKS AND STEEL BEAM COLUMNS BASED ON PIER OR ABUTMENT FOUNDATIONS. ANOTHER EFFECTIVE SYSTEM USED A HEAVY HORIZONTAL BEAM BROKEN UP TO SPAN THE DECK SECTION AND TO LIFT AND SUPPORT IT WHILE REPAIRS WERE BEING MADE. PERHAPS THE FOREMOST AMONG THE REPAIR TECHNIQUES BEING SUCCESSFULLY EMPLOYED WAS THE USE OF PORTLAND CEMENT CONCRETE PATCHES. DENSE, WELL-COMPACTED CONCRETE MORTARS, WITH A LOW CEMENT RATIO OF 6 TO 7 BAGS PER CUBIC YARD AND AN AIR CONTENT / IN PLACE / OF 5 TO 7 PERCENT SHOWED THE BEST RESULTS. GOOD BOND WAS OBTAINED USING CEMENT GROUTS AND EPOXY RESIN COMPOUNDS. PROPER CURING WAS PROVIDED MOST CONSISTENTLY BY SPRAY-APPLIED CURING MEMBRANE COATINGS. THE USE OF WATERPROOFING MEMBRANE COURSES UNDER A SUPPLEMENTAL WEARING SURFACE SHOWED PROMISE OF EXTENDING THE SERVICE LIFE OF REPAIRED DECKS. PNEUMATICALLY APPLIED MORTAR WAS USED FOR MANY VERTICAL AND OVERHEAD REPAIRS AS WELL AS SEVERAL DECK SURFACE PATCHES. A MAJOR MAINTENANCE PROBLEM WAS THE REPAIR OF LOOSENED DECK EXPANSION DAMS. SUCCESSFUL REPAIR PROCEDURES INCLUDED' REMOVAL AND REPLACING OF THE END OF THE DECK SLAB, REFASTENING OF THE DAM BY WELDING STRAPS TO THE DAM AND TO THE ADJACENT REINFORCING STEEL, PUMPING EPOXY COMPOUNDS INTO THE VOIDS BENEATH THE DAM FACE TO REESTABLISHED BOND, AND PARTIAL REMOVAL OF ADJACENT BROKEN CONCRETE AND REPLACEMENT WITH EPOXY MORTAR. THE DEVELOPMENT OF SIGNIFICANT SPECIFIC UNIT COST DATA FROM AVAILABLE RECORDS OF REPAIR WORK WAS GENERALLY NOT POSSIBLE. HOWEVER, COST RANGES WERE PROVIDED WHICH ARE A SUGGESTED BASIS TO JUDGE ESTIMATES FOR SPECIFIC MAINTENANCE JOBS.

Media Info

  • Pagination: 56p
  • Serial:
    • NCHRP Report
    • Issue Number: 1
    • Publisher: Transportation Research Board
    • ISSN: 0077-5614
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 00217986
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Nov 7 1994 12:00AM