Concrete Driveway Frost Heave
The concrete is too thin.
The concrete is the wrong mix.
There's no reinforcing, or insufficient reinforcing in the slabs.
There are insufficient, incorrectly constructed, and/or inadequate control joints, expansion joints, and construction joints in the slabs.
The base material isn't free-draining gravel.
The base gravel is too thin.
The base gravel wasn't compacted correctly.
The existing sub-base wasn't prepared correctly.
There may be other reasons, but the baloney about the slab "settling" into place is just that...baloney.
[This message has been edited by treebeard (edited April 09, 2003).]
Frost heave is just that,water expands when it freezes and creates a hydraulic pressure,lifting the slab, when it thaws the pressure is relived and the slab lowers.
This is a very serious problem mostly stemming from an impropper subbase. Your city/village should have codes regarding subbase prep. and they should have approved this.
DO NOT SETTLE FOR THIS SHODDY WORKMANSHOP!!!!
You will regret it later, if you have a high water table, the contractor should know this and compensated for it in the subbase(i.e open grade ca7 stone instead of ca6 gravel and fines).