As you search the web regarding the correction of settled or sinking concrete, you may come across claims related to the use of poly foam as a product to raise concrete.
One claim that has been made related to poly foam is that it will expand to compact existing base soils. In this video, you can see that the root cause of soil settlement can be several feet deep in the ground. Compaction of these base soils at that depth is often skipped, leading to concrete settlement failure.
While raising your concrete regardless of product may correct the settlement issue on the surface, this video will show that any claim that a concrete raising product will correct the soil settlement issue at full depth is a gross misrepresentation!