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 which is the optimum reinforcement angle,filling the hole and crack plane with epoxy pumped under low pressure,and placing the 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. A modified injection nozzle was built,and an enlarged vacuum swivel was designed,developed,and built. The hollow stem carbide tipped vacuum drill bits were enlarged to 3/4in. (14.1mm) diameter,in lengths to 8' (2.44m) long. A mechanical advantage motion detector was designed and built which worked very well and detected fractional,vertical and horizontal motions of 3/64in. (1.19mm) and recorded them as 3/4in. (19.1mm) motion. Drilling to 7' (2.1m) depth was accomplished in 22minutes. A total of fifteen 36in. (.014m) long rebars were successfully placed in four repair zones. All attempted epoxy crack injection was successfully completed in 3working days. Six months after completing the repair,no motion has been detected and the repair appears to be permanent at this time.