For the construction of embankments or compacted cushions, the cheapest solution is to utilize the excavated material from the site or from the vicinity. But when the backfilling material is composed of clayey expansive soil it's use may be impropriate. Expansive soils have a high activity in relation to water and are classified as material "very bad" for the construction of earthworks.

The legislation in force imposes the removal of expansive clays and their replacement with a better material. The high cost of expansive soil replacement has caused the necessity to use a stabilized soil for these constructions.