My concrete bay at the carwash is a little short (30 feet) and I need to make some concrete footers for the entry gate. I need to cut the asphalt then dig it up to pour the concrete footers (3 feet from the concrete bay). I am not really sure how to do this but I purchased a DeWalt XP Diamond blade (DW4701) for my grinder. My plan is to cut the asphalt with the grinder then pick axe and shovel the asphalt out?