Soil stabilization

Soil stabilization is a general term for any physical, chemical, mechanical, biological, or combined method of changing a natural soil to meet an engineering purpose.[1] Improvements include increasing the weight-bearing capabilities, tensile strength, and overall performance of unstable subsoils, sands, and waste materials in order to strengthen road pavements.

Some renewable technologies are enzymes, surfactants, biopolymers, synthetic polymers, co-polymer-based products, cross-linking styrene acrylic polymers, tree resins, ionic stabilizers, fiber reinforcement, calcium chloride, calcite, sodium chloride, magnesium chloride, and more. Some of these new stabilizing techniques create hydrophobic surfaces and mass that prevent road failure from water penetration or heavy frosts by inhibiting the ingress of water into the treated layer.

However, recent technology has increased the number of traditional additives used for soil stabilization purposes. Such non-traditional stabilizers include polymer-based products (e.g. cross-linking water-based styrene acrylic polymers that significantly improve the load-bearing capacity and tensile strength of treated soils), Copolymer Based Products, fiber reinforcement, calcium chloride, and Sodium Chloride.

Soil can also be stabilized mechanically with stabilization geosynthetics, for example, geogrids or geocells, a 3D mechanical soil stabilization technique. Stabilization is achieved via the confinement of particle movement to improve the strength of the entire layer. Confinement in geogrids is by means of interlock between the aggregate and grid (and tensioned membrane), and in geocells, by cell wall confinement (hoop) stress on the aggregate.[2]

Traditionally and widely accepted types of soil stabilization techniques use products such as bitumen emulsions which can be used as binding agents for producing a road base. However, bitumen is not an environmentally friendly product and becomes brittle when it dries out. Portland cement has been used as an alternative to soil stabilization. However, this can often be an expensive component and not an Environmentally friendly alternative. Cement fly ash, lime fly ash (separately, or with cement or lime), bitumen, tar, cement kiln dust (CKD), tree resin, and ionic stabilizers are all commonly used stabilizing agents. Other stabilization techniques include using on-site materials including subsoils, sands, mining waste, natural stone industry waste,[3] and crushed construction waste to provide stable, dust-free local roads for complete dust control and soil stabilization.

Many environmentally friendly alternatives have essentially the same formula as soap powders, merely lubricating and realigning the soil with no effective binding property. Many of the new approaches rely on large amounts of clay with its inherent binding properties. Bitumen, tar emulsions, asphalt, cement, and lime can be used as binding agents for producing a road base.

The National Society of Professional Engineers (NSPE) has explored newer types of soil stabilization technology, looking for effective and non-harmful alternatives. One alternative utilizes new soil stabilization technology, a process based on cross-linking styrene acrylic polymer. Another alternative uses long crystals to create a closed cell formation that is impermeable to water, frost, acid, and salt.

Utilizing new soil stabilization technology, a process of cross-linking within the polymeric formulation can replace traditional road/house construction methods in an environmentally friendly and effective way.

Another soil stabilization method called the Deep Mixing Method is non-destructive and effective at improving load bearing capacity of weak or loose soil strata. This method uses a small, penny-sized injection probe and minimizes debris and is ideal for re-compaction and consolidation of weak soil strata, increasing and improving load-bearing capacity under structures, and the remediation of shallow and deep sinkhole problems. This is particularly efficient when there is a need to support deficient public and private infrastructure.

  1. ^ Winterkorn, Hans F. and Sibel Pamukcu. "Soil stabilization and Grouting", Foundation Engineering Handbook. Fang, Hsai, ed. 2.nd ed. New York, NY: VanNostrand Reinhold, 1991. 317. Print.
  2. ^ Vega, E., van Gurp, C., Kwast, E. (2018). Geokunststoffen als Funderingswapening in Ongebonden Funderingslagen (Geosynthetics for Reinforcement of Unbound Base and Subbase Pavement Layers), SBRCURnet (CROW), Netherlands.
  3. ^ Gutiérrez, Erick; Riquelme, Adrián; Cano, Miguel; Tomás, Roberto; Pastor, José Luis (January 2019). "Evaluation of the Improvement Effect of Limestone Powder Waste in the Stabilization of Swelling Clayey Soil". Sustainability. 11 (3): 679. doi:10.3390/su11030679. hdl:10045/87249.