Soil stabilization in road construction involves the mixing of two or more different soils or the mixing of soil with a polymeric material that can amend its geotechnical properties as per project requirements. Soil stabilization is a very common process for different types of road projects ranging from dirt roads, gravel roads, sealed roads and highways, haul roads and industrial roads. The major reasons for soil stabilization include:
- Enhancement of the strength and hence bearing capacity, as well as some of the other engineering properties of soils.
- Dust control for workplace safety and health including communities within the vicinity of dirt roads and gravel roads.
- Waterproofing for conservation of roads as assets
- To promote the use of waste geomaterials in construction through finding fit for purpose use of the materials.
In this article we focus on soil stabilization for (1) dirt roads, (2) gravel roads, (3) sealed roads and highways, (4) haul roads and industrial roads.
Soil stabilization for dirt roads
Dirt roads are generally formed by dumping loads of the material and grading an even surface, then compacting it by driving over it or sometimes with a compactor. These roads are common as farm access roads, roads in developing countries, roads with less investment or present where there is a less available budget. Dirt roads are convenient, but not very durable as there are highly susceptible to weather an, they turn to mud during rainy season and break down if they are exposed to too much traffic.
The temptation is always to use sub-base material to create dirt roads. It is readily available at your local quarry, and it drains easily and there is a procedure to compact it to maximum density using standard tests for humidity and rate of compaction. Good dirt roads are made from mechanical stabilization with a mix of gravel and clay. The problems arise from using too much clay which results in potholes and wash boarding in the dirt road which comes from an insufficient amount of clay. Dirt roads develop ruts due to channelized traffic; the wheel ruts collect water in puddles exacerbating softening and making the road impassable.
GRT recommends the following products for dirt road soil stabilization:
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GRT 7000 (S) – a specially formulated surface stabilization liquid polymer that acts as a clear polymer sealant as well as a high performing stabilization agent. It works by physically and chemically bonding soil or dirt road particles leading to improved compressive strengths, high tensile resilience and water impermeability.
GRT 9000 – an advanced polymer soil stabilization product that is effective for shallow stabilization. Available as a clear or opaque polymer, it physically and chemically binds soil or dirt road particles and is designed to treat natural dirt road materials.
Soil stabilization for gravel roads
Gravel roads are just a notch up dirt roads. They boast good investment, high quality materials but face issues with dust. Gravel roads provide good drainage preventing the surface from mixing with water and becoming soft. Also crushed rock tends to be angular and interlocks better than rounded materials which creates a more stable and strong gravel road surface. Gravel roads can be dust, so treatment is required to reduce dust. These treatments also serve in preventing displacement of larger particles. A well-built gravel road can be shaped and graded to shed water. Gravel roads require post laying maintenance and since there are not all-weather roads this can be very difficult during the rainy season.
GRT recommends the following products for gravel road stabilization:
GRT 7000 (S): is a highly effective polymer soil stabilization agent. It can be used on its own or in conjunction with traditional soil stabilization agents it achieves extremely high UCS results with relatively low dosage rates.
GRT Wet-Loc: is is environmentally friendly, clear, and highly refined synthetic fluid designed to handle heavy and damaging traffic movements for at least 6 months at a time, making it perfect for gravel roads in packing and loading yards, container yards and ports, livestock yards, pens, stables, racetracks, horse arenas, underground mining, heavy machinery yards, and access roads.
Soil stabilization for sealed roads and highways
Our attention turns to the base course which is the layer of material immediately beneath the surface of binder course and it provides additional load distribution and contributes to the sub-surface drainage. It may be composed of crushed stone, crushed slag, and other untreated or stabilized materials. In addition, the sub-base course is the layer of material beneath the base course and the primary functions are to provide structural support, improve drainage, and reduce the intrusion of fines from the sub-grade in the pavement structure. If the base course is open graded, then the sub-base course with more fines can serve as a filler between sub-grade and the base course. Sub-bases consists of a lower quality material, sometimes crusher-run product, or the finer fraction of crushed stone production. It can also be clean, low plasticity fill material. All these layers described fall in the categories of granular layers which must be stabilized to perform their functions.
GRT offers the following products for the stabilization of sealed roads and highways:
GRT PCM – this is a high-quality polymer cement modifier used in combination with traditional cementitious stabilizing agents for cracking-sealing of cemented gravels in road construction. The goal is to overcome the shortcomings and improve properties of using cementitious materials alone. PCM, not only reduces shrinkage cracking but can also provide increased compressive strength and reduced water demand.
GRT 9000 – compared to conventional roads, GRT9000 polymer stabilization drastically reduces material and haulage costs, construction time and your carbon footprint – especially in remote areas. This makes GRT9000 roads greener, cheaper and longer lasting.
Soil stabilization for haul roads and industrial roads
Haul roads are designed based on the haul equipment that you are using. That applies to the grade, radius of turns, width, and height of any guarding berms that keep you on the haul road. Same applies to industrial roads, dust generation is more and is much likely to affect the communities within the vicinity of mining operations. Communities and workers should not bear the brunt of haul and industrial road dust.
Soil stabilization can be achieved through these GRT products:
GRT Haul-Loc – ultra-concentrate that uses GRT’s long-chain polymer technologies to improve the efficiency and effectiveness of water cart operations by up to 500%. Save water, eliminate dust, and improve safety on your haul roads.
GRT Wet Loc – features cutting edge penetrating and aggregating technology that allows it to permeate deep into the finest of dust particles, weighing them down securely like water, but without the threat of evaporation or freezing. In fact, GRT Wet-Loc’s unique formula creates a long-term, re-workable solution capable of withstanding extreme weather conditions.
GRT offers solutions for soil stabilization on a variety of road applications. Each product is unique to site specifications and using a consultative approach GRT offers expert soil stabilization solutions. This ensures that all the regulations and standards of the client are met, whilst ensuring potential health, safety, and environmental risks are realized, managed and mitigated.
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REFERENCES
Karol, R.H. 2003. Chemical Grouting and Soil Stabilization. 3rd Edition. Marcel Dekker, Inc.
Peters, F. 2019. How to use soil stabilization in road construction. K31 Road Engineering.
