Use a broom to sweep any dirt away from the working area. Put on your rubber gloves and gather the pH-neutral cleanser. Pour about a cup of the cleanser into an old bowl. Place the sponge in the cleanser to soak it up. Rub the sponge over the damaged areas on the concrete. Repeat until the entire damaged area is covered with the cleanser. Allow about an hour for the concrete to dry completely.
Pour a cup of epoxy into a bowl and add about 1/2 cup of concrete sand to the epoxy. Consider using a single-component type of epoxy for best results. Use a paint stick or another type of clean mixing stick to sir the concoction together. Keep stirring until you have created a lump-free spread.
Use the putty knife to spread the epoxy and sand mixture over the damaged area of the concrete. Be sure to carefully fill in any holes in the concrete that have developed. Try and cover the area evenly so it meets the level of the healthy concrete. You can easily smooth the mixture using the putty knife.
Place a coating of the aggregate used for the concrete over the damaged area on top of the epoxy. Press the aggregate down so it fits firmly into the concrete paste. You can use a shovel to make sure the aggregate is tapped down as far as it will go. Make sure the level of the aggregate is consistent with the rest of the concrete area.
Sprinkle a handful of the concrete sand over the epoxy and aggregate layers to seal any small cracks. Allow the areas to dry for a at least one day. Apply a layer of concrete sealant over the sand layer, using a roller brush to apply it. Give the sealant about two days to completely dry before use.