Soil stabilization is the permanent physical and chemical alteration of soils to enhance their physical properties. Stabilization can increase the shear strength of a soil and/or control the shrink-swell properties of a soil, thus improving the load bearing capacity of a sub-grade to support pavements and foundations.
Stabilization can be used to treat a wide range of sub-grade materials from expansive clays to granular materials. Stabilization can be achieved with a variety of chemical additives including lime, fly-ash, and Portland cement, as well as by-products such as lime-kiln dust (LKD) and cement-kiln dust (CKD).
Benefits of the stabilization process can include:
- Higher resistance (R) values
- Reduction in plasticity
- Lower permeability
- Reduction of pavement thickness
- Elimination of excavation, material hauling and handling, and base importation
- Aids compaction
- Provides “all-weather” access onto and within project sites.
Another form of soil treatment closely related to soil stabilization is soil modification, sometimes referred to as “mud-drying” or soil conditioning. Although some stabilization inherently occurs in soil modification, the distinction is that soil modification is merely a means to reduce the moisture content of a soil to expedite construction, whereas stabilization can substantially increase the shear strength of a material such that it can be incorporated into the project’s structural design.
Equipment for the stabilization and modification processes include:
- chemical additive spreaders
- soil mixers (reclaimers)
- portable pneumatic storage containers
- water trucks
- deep lift compactors
- motor graders
Over the years, contractors that have owned pulverizing equipment for FDR have developed another area of business for their machines. Soil Stabilization and its “sister” Mud-Drying employ the same groups of equipment that FDR demands. Hence, agency owners and building contractors can now take advantage of an economical way to quickly dry up and stabilize their construction sites and road bases. In the photographs below, one can see how the underlying base of a roadway gets structurally improved by the addition of soil stabilizing agents.
It is not uncommon for a construction site such as a Wal-Mart or Home Depot to have impassable site conditions for ready mix concrete trucks on a Monday, followed by a stabilized site that trucks can move on the next day.