Figure 5-21 Epoxy grouting of concrete pile.
Concrete Crack Repair by Epoxy Grout Injection
Problem: Cracks caused by weathering, deterioration, or reinforcing steel corrosion allow water to penetrate the concrete
Description of Repairs: The technique involves forcing a suitable underwater grout to fill voids in cracks and displace existing water (Figure 1). Small cracks can be filled using hand-operated grout gun applicators while large cracks would require pressure grouting. Some epoxy grouts are hand molded into balls and then hand forced into the crack. Underwater grouts will not adhere directiy to wet surfaces; the application method should strive to drive off the water at the grout-surface interface. Epoxy grouts adhere better to rough and clean surfaces.
• Thoroughly clean crack and adjacent surface by using waterblaster and mechanical tools - wire brush and scrapers, which will fit into the void. Remove loose material and marine growth. Clean any exposed reinforcing.
• Seal the full length of the surface of the crack using sealing tape or epoxy or similar grout pressed into the crack to form a dam. Use a fiberglass tape with a suitable underwater setting epoxy grout to seal the surface. Allow the seal to cure completely before proceeding.
• After the crack dam has cured, drill 1/2-inch or larger injection holes to the bottom of the crack and along the crack at 6-inch intervals. Size of hole depends injector tip.
• Insert nozzle of grout injector/dispenser into lowest drilled hole and inject flowable grout until it comes out the next higher hole. Proceed up the crack until all holes are filled.
Note: It may be necessary to add an extension tip to the nozzle to reach the end of the crack.
Materials: Manufacturers are listed in Appendix A.
• Select a flowable, low viscosity epoxy suitable for wet surfaces and underwater application for injection into hole. For temperatures below 55°F, use a polyester resin-based grout.
• For sealing grout, select a fast curing epoxy paste suitable for wet surface and underwater compatible that can be applied by hand or blade.
• Epoxy grout injection gun described in Section 2.11 cnn be used to dispense I two-part epoxy grouts.___
Section from _ pile or seawall
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