Driveway bumps form when the driveway settles in front of the garage slab creating a lip. Solutions include mud-jacking, or making a slight ramp with concrete, cement or asphalt.
Vinyl concrete patch, with it’s own built-in bonder that will adhere to old cement.
Sand mix cement applied over a latex bonder.
Asphalt cold patch.
Layers of plywood cut at 10-inch, eight-inch and six-inch widths layered up against the ledge work well for a temporary solution.
The best cure is to have the sinking slab mud-jacked even with the garage entrance. Mud-jacking is a process where mud slurry is pumped through carefully placed holes in a slab of concrete. The hydraulic force of the mud will raise the concrete level with the garage floor. Most mud-jackets, also known as concrete raising, offer a one-year or more guarantees. Check their credentials so you will be covered if the slabs settle. One condition to mud jacking is the condition of the cement. If the slabs are broken or cracked, most mud-jackers will not take the job.
If mud-jacking the slab is not in your plans, you can build a ramp to allow vehicles smoother access.
The first thing you must know when working with a masonry product is you cannot patch over a seam or a crack. Living in Michigan, coming in and out of the winter all our sidewalk and driveway slabs move with the frost. When the frost moves the driveway as little as 1/8th-inch, the masonry patch will crumble and break.
If you install an expansion strip against one side of a patch, you could use a masonry product for the ramp. For smaller cracks, make cardboard expansion joints in all the cracks in the cement. The bigger the crack, the bigger the expansion joint should be. An expansion joint is about 1/2-inch thick to allow for movement, so use several layers of cardboard when making homemade ones.
Cut the expansion joint material to the height of the top of the cement. It will serve as a guide when you are pouring the cement ramp.
If the height and length of the ledge requires several bags to taper the ramp, sand-mix cement and a concrete bonder would become more economical. The bonder is a latex ‘glue’ applied to the cement just prior to pouring the ramp.
Now if you have too many cracks in your slab asphalt patch could be your best product. Wait for a nice warm day so it is more flexible to work with. Pour the patch against the ledge and smooth with a metal tamper. It is not pretty, the asphalt is black, but it is fast and flexible.