UFC 3-270-04
15 March 2001
5.8. Placement of Patch Materials, All sandblasting residue should be removed using oil-free
airblowing equipment just prior to placing the bonding agent. The bonding agent should be
applied with a stiff bristle and scrubbed into the patch area. It should be applied evenly and in a
thin coat (approximately 1/16 inch (2 millimeters) thick) and should not be allowed to puddle
(Figure 5.9.). The volume of material required for a partial-depth repair is usually less than
2.0 cubic feet (0.056 cubic meters). Therefore, patching material should be mixed on site in a
small mobile drum or paddle mixer. Transit mix trucks and other large equipment cannot
efficiently produce such small quantities, since maximum mixing times for a given temperature
may be exceeded, decrease the quality, and result in waste of material. The repair area should
be slightly overfilled to compensate for consolidation. Primary consolidation should be by
tamping. The patch material also may be consolidated by small spud vibrators to eliminate voids
at the interface of the patch and the existing concrete (Figure 5.10.). Vibrators greater than 1
inch (25 millimeters) in diameter are not recommended for this work. On very small repairs, hand
tools should be sufficient to work the repair and attain adequate consolidation.
5.9. Finishing. The finishing area should be finished to the cross section of the existing
pavement without leaving excess material on the adjacent pavement surface. The recommended
finishing procedure is to screed from the center of the patch area to the patch boundaries. By
moving the screed toward the patch boundaries, the material is pushed toward the interface to
increase the potential for high bond strength. After finishing, the patch should be given a burlap
drag or broom finish to approximately match the surface finish of the existing adjacent concrete
pavement, unless a grinding operation is to follow.
5.10. Saw-cut Runouts. Epoxy mortar should be used to fill any saw-cut runouts that extend
beyond the patch perimeter at patch corners. The mortar will help to prevent moisture
penetration that may undermine the bond.
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