Occasionaly concrete caulk should be used to fill cracks and gaps in the concrete around your home. We don't like use the word "repair" for cracks because that can be misleading. The word repair implies that it's a permanent fix. It is impossible to fix concrete once it cracks. Instead, we refer to filling cracks as "treatment".
Before applying the concrete caulk, some preparation is needed to ensure maximum adhesion. Clean the surface along the crack thoroughly to remove any dirt, debri, or previous coatings and caulk. Use a pressure rinse to clean out the crack and allow it to dry completely. Don't apply it when it's too hot or too cold. Surface temperature should be between 40 and 110 degrees. Make sure there's no rain in the immediate forecast.
Application just requires a little common sense. The instructions are printed on the tube. Obviously, wider cracks will need more caulk to fill the gap. For gaps that are 1/2 inch or wider, a foam rod backing can be inserted to significantly reduce the amount of caulk needed.
Although a crack will always be visible, especially when filled with caulk, there is an easy trick to make it less noticeable. Immediately following application, spread some dry cement on the wet caulk and sweep the excess away when it's dry.