What other methods of road stabilization are there?

Road stabilization techniques are typically used in place of excavation and soil replacement when weak or changeable ground is found during the construction of a road.

What is stabilization of roads?

Road stabilization is subgrade improvement where the physical characteristics of the subgrade soil are changed by the addition of a stabilization component. Typically, lime, cement, or other chemical agents, blended and mixed in-situ, are used in this process.

In order to transfer load to the subgrade and boost bearing capacity, a stronger soil layer is typically installed over the weak soil. This procedure is known as subgrade stabilization, and it frequently includes the addition of a geosynthetic at the top of the subgrade level.

By mechanically stabilization the aggregate material with a proper geogrid, one can increase the strength of an aggregate layer and its capacity for distributing loads. In this instance, the mechanically stabilization aggregate layer boosts load carrying capacity while protecting the subgrade and leaving the subgrade soil qualities untouched after the stabilization of the road.

We'll examine each of the most popular types of road stabilization in construction in this tutorial. Learn more about the following techniques for stabilizing roads by reading on:

• Stabilization of Lime
• Stabilization of Cement
• Additional chemical soil amendments
• Geogrids

Road Stabilization on Lime

The majority of earthworks engineers across the world are familiar with this form of road stabilization. Interestingly, adding lime to a subgrade soil in the UK is referred to as "modification" rather than "stabilization," even though the phrase "lime stabilization" is still more frequently used. This is according to the UK Design Manual for Roads and Bridges, DMRB HA74/07.

Chalk and limestone, both of which are made of the mineral calcium carbonate, or CaCO2, are the most prevalent sources of lime. Quicklime (CaO) is produced when calcium carbonate is burned in lime kilns (often referred to as lime or burnt lime). The production of this technique has very significant energy and CO2 expenses. The use of quicklime improves the workability of clayey soils by lowering their moisture content and plasticity. Lime is blended and added in-situ using specialised machinery. Although the majority of the improvement is anticipated to happen within 72 hours, the strength of the mix will continue to increase for up to a year following construction.

For stabilizing roads made of non-cohesive soils or clays with high sulphate levels, lime is not an appropriate material. Many engineers view lime treatment as a band-aid remedy. To guarantee a proper site-specific solution, laboratory categorization, reactivity testing of the soil, and optimum mix design are essential. During installation, lime dust from in-situ mixing may have an adverse effect on nearby properties and neighbourhood stakeholders.

Process of stabilizing lime

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Road Stabilization Using Cement

Portland cement is blended in situ with the soil to a predetermined depth for road stabilization using cement (typically up to 300mm). To put it simply, cement binds particles together by chemically reacting with soil particles to create a stronger material.

However, doing so necessitates using water to activate the cement, which adds another step to the on-site installation process. Cohesive soils and soils with more than 2% organic content should not be used with this approach, but certain problems with these challenging soils can be solved with the aid of additional binders.

To attain the necessary qualities, water content must be carefully regulated. Similar to quicklime, the production of Portland cement requires quarrying, crushing limestone, and the use of kilns, where clinker—the main component of cement mix—must be roasted at a temperature of 1500°C. This results in significant energy and CO2 manufacturing costs for Portland cement.

Deformation can result in the soil that has been stabilized with cement cracking in both temporary and permanent road installations. Therefore, deformations must be kept to a minimum to prevent breakdowns that call for repair. Many seasoned engineers will acknowledge that this system needs upkeep for use with temporary roadways. In some nations, it is believed that soil's transitory chemical improvement will eventually fail, and the question is how quickly. Similar to lime dust, clouds of cement dust that form during in-situ mixing may be a problem for nearby properties and neighbourhood stakeholders.

Process of chemical stabilization

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Additional Chemical Soil Enhancers

Synthetic polymer or biopolymer additives are less frequently utilized in the stabilization of roads. These are frequently exclusive agents with scant independent research available to confirm performance. In general, they are better suited to granular soils with more particles. They are frequently more expensive options, even if they might in some situations provide a more environmentally friendly answer than lime or cement.

Road stabilization by means of Singhal geogrids

The aggregate particles interlock with the geogrid when it is compacted over an appropriate geogrid. The aggregate particles are contained within the geogrid apertures if the geogrid has strong integral connections, suitable in-plane stiffness at low strain, and a high rib profile. The aggregate particles in contact with the geogrid are constrained in their rotation and mobility by this particle confinement. Interlocking with the fully confined particles causes the aggregate particles immediately above and below the confined layer to become also confined. As a result, a confinement zone develops around the geogrid layer. Compared to the un stabilized aggregate, this mechanically stabilized layer is stronger and more rigid.

Please contact us if you would want detailed advise on how Singhal geogrids can be used to mechanically stabilize weak and unstable subgrade soils.

Numerous triaxial tests have been conducted to characterize the characteristics of mechanically stabilized layers for a variety of aggregate types and Singhal geogrid grades. Design specifications have been established, and full-scale load tests and trafficking tests have been used to validate them.

On incredibly fragile soils, this technology can be applied with the right installation methods. This method doesn't need specialized tools or experienced workers on the job site, unlike chemical road stabilization systems. Thinner aggregate layers can be utilized over weak soils due to the mechanically stabilized layers' enhanced strength, which lowers the cost of imported materials and associated CO2 emissions.

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adding a Singhal mechanically stabilized layer

Do you wish to learn more about Singhal's capabilities?

For more than 30 years, Singhal's ground stabilization innovations have proven to be perfect for a variety of building and subgrade development projects, such as paved and unpaved roads, parking lots, airfields, heavy-duty pavements (like container ports), and working platforms.

To learn how we can reduce time, expense, and carbon on your upcoming project, contact us right away!