Soil compaction is the degree to which the soil beneath a slab is packed together; well-compacted soil supports load without settling, while poorly compacted soil consolidates under weight and lets the concrete sink.
In depth
When a site is prepared, the base soil should be compacted so it can carry the slab. If that step is rushed or incomplete, the loose soil slowly consolidates under the weight of the concrete and everything on it, and the slab settles. This construction-stage shortfall is one of the most frequent causes of premature sinking.
Polyurethane injection can compensate: as the foam expands beneath the slab, it compresses and densifies the surrounding soil, effectively completing the compaction that was missing while it lifts and supports the concrete.
How Acme applies it. Acme explains that concrete built over soil that was not adequately compacted settles over time, and its injected foam raises the slab while helping compact and stabilize the subgrade.
Related terms: Subgrade, Subbase, Concrete Settlement, Under-Slab Void
Frequently asked questions
How does poor compaction cause sinking?
Loosely packed soil consolidates under the weight of the slab over time, dropping the concrete as the ground compresses beneath it.
Can polyurethane fix poorly compacted soil?
Yes. The expanding foam compresses and densifies the soil around it as it lifts, providing the firm support the original compaction lacked.