Cracked Structural Concrete Repair through Epoxy Injection and Rebar Insertion.

摘要

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 45degrees to the deck surface and crossing the crack plane at approximately 90degrees,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. Drilling to 7'(2.1m) depth was accomplished in 22minutes on the first repair,and no significant gain was noted on the second. A total of 220'(67m) of number 4 rebar was epoxy bonded in 55holes to repair 18cracks in 8girders of two bridges. The first bridge has been repaired for nearly two years,the second 9months without failure. This test repair cost averaged $2000per girder compared to a girder removal and replacement cost of $38,763in 1975. Further development of implementation has reduced the cost to $1,000per girder.