Concrete steps are durable, but the corners of the steps are vulnerable to chipping and breakage. The first step in mending a chipped corner to scrub the damaged area clean of all loose bits of gravel, sand, and cement with a wire brush.
Next, create an L-shaped mold, or form, by screwing together two short pieces of 1X6 (top). Hold the wood form against the chipped corner and flush with the top of the step; secure it with long strips of duct tape.
Coat the inside of the form with cooking-oil spray so it won't stick to the new cement patch. Then brush a liberal coat of latex bonding liquid onto the chipped surface. In a plastic bucket, mix a small batch of quick-setting cement, such as Quikrete's FastSet Cement. Scoop up some of the cement with a pointed trowel and tightly press it into the form (above). Slightly overfill the corner, then smooth the cement flush with the top of the step. Allow the repair to dry overnight before carefully peeling off the tape and removing the form.