Properly stabilized subgrade soils provide a weather resistant platform, reduce swelling of expansive materials, and mitigate problems associated with frost heave.
Proper treatment of problem soil conditions and the preparation of the foundation are essential to ensuring a long-lasting pavement structure. Stabilized subgrade soils are used around the nation to strengthen pavement structures. Soils that are highly susceptible to volume and strength changes can cause severe roughness and accelerate the deterioration of the pavement structure in the form of increased cracking and decreased ride quality when combined with truck traffic. Stabilization of soils is typically performed for three reasons:
- To dry very wet soils and facilitate compaction of the upper layers (in this case, the stabilized soil is not considered as a structural layer of the pavement design process).
- To strengthen a weak soil and restrict the volume change of a highly plastic or compressible soil (in this case, the modified soil is given some structural value in the pavement design process).
- To reduce moisture susceptibility of fine grain soils.
Producing Stabilized Subgrade Soils
Mechanical and admixture stabilization methods are commonly used for pavement structure preparation. Mechanical methods blend aggregates into existing soils to strengthen the subgrade and reduce dynamic stress level. Admixture stabilization is used to control swelling and frost heave of soils, improving long-term performance. There are a variety of admixtures that can be mixed with subgrade to improve performance, the most common being:
- Lime treatment
- Lime stabilization
- Cement stabilization
- Stabilization with flyash (coal ash)
- Asphalt (bituminous) stabilization
Using stabilized subgrade soils in place with natural aggregates and additives has environmental and economic advantages – in terms of resources, production, construction, and long-term performance. Benefits of soil stabilization include reduced hauling costs, fast construction, a smaller carbon footprint, less maintenance over the life of the pavement, and the ability to repurpose recycled waste materials.
Equipment Recommendations for Stabilized Subgrade Soils
RWC Equipment Leasing recommends Rapidmix mobile pugmill plants for high volume, accurate stabilized subgrade soil production. Depending on the Rapidmix model, material can be produced at speeds up to 600 tons per hour using volumetric measurement or continuous weigh systems.
If stabilized subgrade soils are the foundation of your next pavement project, consider the benefits of leasing or renting a high-volume, Rapidmix mobile pugmill from RWC Equipment Leasing. For more information, call Bobby Carroll at (561) 400-3204.