CRACKED STRUCTURAL CONCRETE REPAIR THROUGH EPOXY INJECTION AND REBAR INSERTION

The objective of this project was to develop a technique for repairing cracked structural bridge concrete. The method developed consists of sealing the crack, drilling holes at 45 deg to the deck surface and crossing the crack plane at approximately 90 deg, filling the hole and crack plane with epoxy pumped under low pressure, and placing a rebar into the drilled hole in a position to span the crack. The epoxy bonds the bar to the walls of the hole, fills the crack plane bonding the cracked concrete surfaces back together in one monolithic form, and thus reinforces the section. The epoxy injection equipment utilized was developed for hollow plane injection. Injection nozzles were built, and a large vacuum swivel was designed, developed, and built. The hollow stem carbide tipped vacuum drill bits were enlarged to 3/4 inch (14.1 mm) diameter, in lengths to 8 inch (2.44m) long. Motion detectors were designed and built which amplified motion at ratios of 16:1 for Type I, or 25:1 and 50:1 for Type II. Horizontal and vertical motions of 3/64 inch and .050 inch (19.1 & 1.27mm) were detected. A 45 degree drill stand was built for the second repair which nearly eliminated the manual labor experienced. Drilling to 7 feet (2.1m) depth was accomplished in 22 minutes on the first repair, and no significant gain was noted on the second. A total of 220 feet (67m) of #4 rebar was epoxy bonded in 55 holes to repair 18 cracks in 8 girders of two bridges. The first bridge has been repaired for nearly two years, the second 9 months without failure. This test repair cost averaged $2000 per girder compared to a girder removal and replacment cost of $38,763 in 1975. Further development of implementation has reduced the cost to $1,000 per girder. /FHWA/

  • Supplemental Notes:
    • Sponsored by Kansas Department of Transportation. Prepared in cooperation with the Department of Transportation, Federal Highway Administration.
  • Corporate Authors:

    Kansas Department of Transportation

    Division of Planning and Development, State Office Building
    Topeka, KS  United States  66612
  • Authors:
    • Stratton, F W
    • Alexander, R
    • Nolting, W
  • Publication Date: 1978-11

Media Info

  • Pagination: 56 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00188508
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-KS-RD-78-3 Final Rpt.
  • Contract Numbers: Study No. 76-2
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Mar 14 2000 12:00AM