The following is the manufacturers recommended procedure for using this product. As with all materials used, always follow the manufacturers recommended instructions unless you have specific procedures on the use of the product.
A sound base is essential for good repairs. Remove all oil, grease, dirt, and loose, disintegrated, or unsound concrete from the areas to be patched.
Saw a cut 1/2 inch deep or more to form the perimeter of each patch. A bond breaker is required at all joints. Featheredge patching is not recommended.
Where the bond between reinforcing steel and concrete is destroyed, remove the adjacent concrete to a depth that will provide a minimum of inch of new concrete over all cleaned concrete surfaces and all exposed reinforcing steel. Remove rust from rebar by wire brushing or sandblasting. Do not use a bonding agent on the steel or on the prepared concrete surface.
Flush the area thoroughly with clean water to remove dust, and then airblast to remove all water before placing the Set-45. (Note: Set-45 bonds better to a dry surface interface.)
Have the proper measuring containers and tools on the job. Be certain the labor force is adequate to handle the rapid-setting Set-45.
Use a mortar-type mixer, as the shearing action of the blades yields optimum blending. For large jobs, the mixer should be capable for mixing up to 500 lb of material. A continuous-type mixer may be used. For smaller quantities, an electric drill with a jiffler-type mixer may also be used.
Locate the mixer as close as possible to the repair area. Allow no more than 10 minutes to mix, place, and finish Set-45 in normal temperatures of 72F (22C).
IMPORTANT: Always follow this mixing order:
After mixing, immediately place the Set-45, working from side to side. Do not place Set-45 in lifts. Work the material firmly into the bottom and sides of the patch to ensure a good bond. Do not use a bonding agent.
Level the Set-45 and screed to the elevation of the surrounding concrete. When properly screed, Set-45 will self-level and yield a skid-resistant finish. Seal the edges and all saw cuts with light hand floating. Minimal finishing is required. Do not retemper Set-45. Clean tools and the mixer frequently with water to prevent any buildup.
Special Considerations: The setting speed of Set-45 is dependent upon both the temperature of the mixture and the area to be repaired.
Heat the concrete surface until it is warm to the touch. Use warm material and warm the water to 90F (32C) to increase the hardening speed. Keep the patch warm by tenting or insulating. This will aid in obtaining a more rapid strength development in cold weather. Do not use anti-freeze or accelerators.
The Set-45 Hot Weather formula is recommended. Keep the material cool. The use of ice water for mixing is recommended to extend the working time. (Caution: Placing Set-45 on a hot concrete surface may affect the bond. When the sun has heated the surface excessively, delay placement until additional dampening of the area has lowered the slab temperature. Be certain to remove all standing water immediately prior to application of Set-45.)
Set-45 should be allowed to air dry for a proper cure. Do not use a curing compound or wet-curing process. In normal temperatures, Set-45 patches will take traffic approximately 45 minutes to 1 hour after placing. If Set-45 is not being used, the following are general procedures for masonry repairs.
Cracks that are larger than a hairline crack must be enlarged using a cold
The enlarged area must be undercut so that the top of the crack is smaller than the bottom (Figure 1). The undercut area must be to a depth of at least 1 inch.
Figure 1: Repairing Large Crack in Sidewalk
Due to the heavier traffic that driveways are subjected to, the patch will be larger and deeper than that of a sidewalk repair and will use the heavier concrete mixture of 1 part cement, 2 parts sand, and 3 parts gravel. The repair is basically as above, except larger and deeper.
Preparation and application of cement is similar to preparing a crack in a sidewalk. The more difficult task is matching the finish of the new cement patch with that of the existing wall.
This may be done by trial and error as the concrete is setting up, using combinations of different trowels and brushes to match the finish (Figure 2).
Figure 2: Repairing Crack in Concrete Wall
Steps to repairing a hole in the wall:
The broken corner should be cleaned and moistened prior to applying the mixture. The repair is made using epoxy cement. The mixture is built up ? inch at a time for small repairs. For larger repairs, a form should be built around the corner to hold the epoxy mixture until it dries (Figure 3).
Figure 3: Repairing Broken Concrete Corner