I have 5x42 walk on the back of my home that joins our drive way that joins the house on the end 24 wide both are joined like an L. the concrete was replaced several years ago but has sunk several inches allowing water to pool at the house. Can asphalt be poured over the old sunk concrete and continue up the entire drive to form one solid slap of asphalt. My worry is the rise and fall of winter. Winters are not as harsh as they once were . A lot of people are pouring slabs now for garages and seem to be happy.