Same here. In north Texas, our summers can be punishing. When outdoor temperatures reach the high nineties, brick walls get very hot and they expand. They not only expand horizontally, they expand in all directions. This expansion can push the last few bricks closest to the end of the wall downwardly and horzontally putting enough pressure on the corner of a concrete slab to break off a triangular shaped corner. Likewise it is not necessary to patch this separated piece of concrete slab with anything except to perhaps make it look better. Any repairs to it are merely to improve it's appearance. If you are so inclined as this home owner, be my guest. Not a bad patch, actually.