19 June 2001
CR-6: COMBINATION REPAIR CAST-IN-PLACE CONCRETE AND EPOXY
Problem: Concrete footings with many cracks with some spalling, scaling, and
Description of Repairs
: Repair footings using
of restoration with
Portland cement concrete, and filling cracks and delaminated concrete by
injecting urethane resin. Tools required: air hammer, conventional hand and
power tools, and injection gun or pump for urethane.
a. Portland cement concrete.
b. Urethane resin for injection.
a. Remove all unsound concrete.
b. Wire brush or sandblast all surfaces to receive bonding agent and
c. Thoroughly clean and coat any exposed reinforcing steel with
d. Sound concrete with metal rod to determine extent of delamination
and outline the areas.
e. After restoration of concrete is completed, rout and clean racks to
be filled with injected urethane.
a. Place, cure, and finish concrete repairs to restore structure to its
original shape (CPM-3).
b. Select epoxy injection points and drill holes if required. Insert
injection tubes or valves if required. See repair CR-1.
c. Fill cracks 0.08 mm (3.1 mils) wide and larger, and delaminated
areas, by injecting the low-viscosity urethane. For jobs with large areas of
delamination and deep cracks, pressures up to 6.9 MPa (1,000 psi) may be
d. Plug the injection holes with epoxy paste.