Soil Stabilization


Supercharging your soil to perform better.soil stabilization

“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.”

*The definition of soil stabilization as quoted from the Asphalt Recycling &Reclaiming Association

The process of chemically stabilizing soils involves the incorporation of different products such as cement powder, lime, fly ash, lime kiln dust (LKD), cement kiln dust (CKD) or a combination of these into the poor, unstable soil. A geotechnical analysis of existing materials and project intentions determines the appropriate stabilization method and agent(s) used. 
The powder is spread uniformly by a spreader truck and followed by a rotary mixer or reclaimer, which incorporates and blends the powder into the soil, sometimes with the addition of water injection to insure proper moisture content. Compaction, shaping with a motor grader and a final smooth roll completes the process. 
The finished product leaves our customers with a permanently altered, stable base. The soil is now capable of carrying increased loads and traffic volumes.

The advantages of soil stabilization:

- Cost savings of up to 50% of traditional methods
- Eliminates removal of old materials and importing new materials
- Significantly reduced construction traffic
- Improved soil characteristics (shear strength and plasticity)
- Lower material costs (reduced amount of base thickness and pavement materials will result when incorporating stabilization into pavement design)
- Convenience (Generally, stabilization does not require shutting down traffic even before paving. Stabilized surfaces support vehicle traffic)

Applications for stabilization:

- New road construction. 
- Existing road rehabilitation.
- Parking lots, construction sites, building pads, pole barns, agricultural access roads and staging areas.

Soil-Cement Basics:

Cement soil stabilization is a highly compacted mixture of soil/aggregate, cement and water. It is widely used as a low-cost pavement base for roads, residential streets, parking areas, airports, shoulders and storage areas. Its advantages of great strength and durability combined with low first cost to make it the outstanding value in its field. A thin bituminous surface is usually placed on the soil-cement to complete the pavement.

What type of soil is used?

The soil material in soil-cement can be almost any combination of sand, silt, clay gravel or crushed stone. Local granular materials such as caliche, limerock, scoria plus a wide variety of waste materials including cinders, foundry sands and screenings from gravel pits can all be utilized as soil material. Old granular-base roads, with or without bituminous surfaces can also be reclaimed to make great soil-cement.

How is soil-cement built?

Before construction begins, simple laboratory tests establish the cement content, compaction, and water requirements of the soil material to be used. During construction, tests are made to see that the requirements are being met. Testing ensures that the mixture will have strength and long-term durability. No guesswork is involved.

There are four steps in soil stabilization: spreading cement, mixing, compaction and curing. The proper quantity of cement is spread on the in-place soil material. Then the cement and soil material, and the necessary amount of water are mixed thoroughly by a reclaimer. Next, the mixture is tightly compacted to obtain maximum benefit from the cement. The mixture is cemented permanently at a high density and the hardened soil-cement will not deform or consolidate further under traffic.

Curing, the final step, prevents evaporation of water to ensure maximum strength development through cement hydration. A light coat of bituminous material is commonly used to prevent moisture loss; it also forms a part of the bituminous surface. A common type of wearing surface for light traffic is a surface treatment of bituminous material and chips .5 to .75" thick. For heavy-duty use and in severe climates a 1.5" asphalt mat is used.

Why use cement stabilization?

Failing granular-base pavements, with or without their old bituminous mats, can be salvaged, strengthened, and reclaimed as soil-cement pavements. This is an efficient, economical way of rebuilding pavements. Since approximately 90% of the material used is already in place, handling and hauling costs are cut to a minimum. Many granular and waste materials from gravel pits can also be used to make soil-cement, saving high-grade materials for other purposes.

Highway and city engineers praise cement stabilization performance. It offers low cost, long life and high strength. Soil-cement is constructed quickly and easily-a fact appreciated by owners and users alike.

How does soil-cement perform?

Soil-cement thicknesses are less than those required for granular bases carrying the same traffic over the same subgrade. This is because soil-cement is a cemented, rigid material that distributes loads over broad areas. Its slab-like characteristics and beam strength are unmatched by granular bases!  Hard, rigid soil-cement resists cyclic cold, rain and spring-thaw damage.

Old soil-cement pavements in all parts of the continent are still giving good service at low maintenance costs. Cement stabilization has been used in every state of the United States. Specimens taken from roads show that the strength of soil-cement actually increase with age; some samples were four times as strong as test specimins when the roads were first opened to traffic! This reserve strength accounts in part for the soil-cements's good long-term performance."    * Quoted from Portland Cement Association

We hope this article helps you to realize the amazing benefits associated with the use of cement soil-stabilization. It is unmatched in cost-effectiveness, longevity, and unsurpassed by traditional methods of creating a stable base for your project.