Void Filling or Wash-Out
Void filling will eliminate the voids and compact the supporting soils.
The root causes of voids are often poor compaction of the fill materials, erosion, high water content (shrink and swell cycles), decaying organic materials, freeze and thaw cycles, animals, and vibration. These voids, if left unattended, will lead to the eventual breaking or settling of the concrete. Voids can lead to erosion by allowing water to travel under the slab. These voids can be very common under driveways, attached garages, and walkways.
In industry the vibrations of machinery causes the supporting base material to vibrate, which allows the finer particles to settle out and consolidate lower down, leaving a void; resulting in settled and eventually broken concrete.
Underground Municipal infrastructures are susceptible to voids especially around manholes, catch basins and utility raceways. Void filling and leak repair can be done either from the inside or from the surface eliminating the need to excavate.
Bridge aprons are known for roller-coaster dips that occur at the edge of the bridge deck. The recommendation for these are to stabilize soil before lifting and/or void filling to ensure that the root cause is attended to first.
Void filling foam is designed to flow longer before it cures. The low viscosity of the polyurethane allows it to flow and fill voids.
Settlement can destroy the integrity of concrete slabs and foundations. The root causes are often poor compaction of original fill materials, high water content, decaying organic materials, freeze thaw cycles, animals, vibration, heavy equipment, erosion caused by poor drainage, or broken underground pipes.
Edge curl is another issue that can develop with new concrete. Edge curling is a result of the way concrete cures, resulting in a hollow area at the edge. When heavy vehicles drive over these hollow areas the concrete will deflect under the weight and eventually break.
Poor compaction is the most common reason concrete settles, and when water is added to the equation, even the most compacted sub grades will settle. By tending to the root cause, the job gets done correctly and the slab is only lifted once.