When repairing a concrete curb, start by cleaning the concrete. Make sure to remove any soil, plant leaves or pieces of wood from the concrete and the surrounding area. Put on safety goggles and a protective mask to make sure that you don't get hurt by small pieces of concrete that may fly around during the repair process. Try to wear clothes that safely and securely cover the entire surface of your body.
You need to have a smooth and solid concrete surface before you repair the curb, so get rid of any pieces that are chipped or peeling away or have cracks. It is best to use a chisel and a sledgehammer for this task. Smooth out the surface using some heavy-duty steel wool. Rinse the curb with water using a garden hose, and allow it to dry for two days. This cleans the surface and ensures that the patching material attaches well.
Coat the surface that needs repairing with some bond adhesive using a brush, prepare the concrete patch mixture, and spread it over the curb surface before the adhesive dries. You can do this in several layers, but allow the mixture to dry for 30 minutes before applying the next layer. Get rid of any splatters and excess material before the patching mixture dries. Place a plastic tarp over the surface of the curb, and leave it for five days to let the mixture dry.