Just had a replacement driveway installed, supposedly 6 bag mix 6 inches thick, driveway 21ft by 45ft, there is already a diagonal hair line crack about 2 ft long, is this normal. The installer says things like this can't be controlled. I notice that the crack is where the driveway meets the basement wall, and there was no expansion material between the new concrete and the concrete basement wall. Could this have caused the crack. Thanks for any info.