My driveway goes uphill. It is 35 years old and still in pretty good shape so it was installed pretty well. 15 years ago we had a 1 1/2" topping installed. It has developed a few cracks across it. We fill these in the summer and in winter they open up again, a little wider. The number of cracks is increasing. Now the filler is as much as 2" across. The filler doesn't come out, just settles. What are my options?