A solid foundation is critical for any type of construction. Unfortunately, not all jobsites are created equal. Whether due to natural soil compositions and/ or conditions or a preponderance of ground water that have seeped in over the years, some areas are not fully capable of supporting structures over the long term. Although they may look stable initially, over time the varying strength and durability of soils can lead to cracks and potholes developing in roadways as they erode and settle underneath them. This is why chemical soil stabilization is a crucial process for many mass grading and asphalt paving contractors.
The main purpose of the chemical soil stabilization process is to create a more stable, uniform base for whatever is being built on top of it. However, it also has the additional benefit of helping protect the environment. But what is chemical stabilization, and how is it performed? Read on to learn more about this technique.
The Process of Chemical Soil Stabilization
What is soil stabilization using chemical methods, and how does it affect conditions on a jobsite? Generally speaking, the process involves mixing specially developed chemical reagents into the soil and mixing them together. Chemical stabilization may be used in conjunction with mechanical stabilization methods or on its own, depending on the requirements. Many of the most commonly used additives for this technique include:
- Quicklime: Also known as lime or calcium oxide, quicklime works especially well in soils with high clay content. When added to soil, it raises the pH level of the earth so much that certain components become soluble. This allows for the formation of more cementitious bonds inside the chemical composition of the earth that are permanent.
- Fly ash: This is a byproduct of burning coal for electrical generation and is commonly used for soil stabilization. It works by enhancing the ground’s physical properties, adding shear and compressive strength as well as reducing soil plasticity and shrink-swell potential. Another benefit to using fly ash is how it helps prevent the absorption of moisture that causes instability.
- Cement: Mixing cement and water into the soil is another popular soil stabilization technique. This serves to bond the soil together and create a stronger subgrade than if the soil was left untreated.
- Polymers: Synthetic polymers including polyacrylamide and polyvinyl acetate may be used to enhance the load-bearing capabilities and durability of soils. These form bonds to soil particles that help them bind together and increase shear strength.
- Calcium chloride: When added to soil, calcium chloride absorbs excess moisture from the earth, after which it dissolves into a deliquescent solution that resists evaporation. This solution also has a high degree of surface tension, which lubricates the aggregate and helps each particle interlock with the others around it.
The purpose of adding these reagents is to change the chemical composition of the soil. This includes removing any excess moisture that may be contained within it and improving its structural integrity. What is left behind is something that will be a better subgrade for any construction that will be performed on it, providing a better platform for pavement or a building pad.
The Step-By-Step Chemical Stabilization Process
The process typically begins with selecting the soil stabilization method that will be most effective and appropriate based on the composition of the soil. For example, clay soils and sites that have a lot of wet soil are served especially well by adding quicklime. Highly plastic soils and jobsites in areas that experience a lot of heavy rainfall may be ideal for fly ash. In areas that feature a heavy concentration of sandy or silty soils, contractors may want to consider the use of cement to hold them together.
After selecting the chemical soil stabilization techniques that are the best fit for the site, the next step is to add the agent to the ground. These are added to the soil with the use of large-scale rotary mixing tools that cover large areas. Once these are added successfully, the resulting mixture is compacted with a vibratory compactor. The use of heavy equipment is critical for ensuring the consistency of the finished results as well as the ability to perform the work at scale with the highest degree of efficiency.
Applications of Chemical Soil Stabilization Methods
The lasting effects of the various types of chemical stabilization of soil make it an ideal method of site preparation for a wide range of construction projects. These techniques ensure strong, stable foundations for virtually any type of hard surface pavement or structural fill zone. Examples of projects that can benefit from this approach include:
- Parking lots
- Roads and sidewalks
- Building pads
- Airport runways
- Tracks and athletic fields
Benefits of Chemical Soil Stabilization
Projects that employ chemical soil stabilization receive numerous benefits through its application. First and foremost, the procedure results in greater structural integrity for the soil underneath the project. This reduces the risks of soil shifting or sinking after construction, which can lead to foundation failures and costly repairs to roadways. It also helps ensure that work can be completed faster and more efficiently, saving time and money for contractors.
Measuring Success: Quality Control and Testing
Strong quality control practices are important for making sure soil stabilization techniques are as effective as they need to be for the site. This is why contractors should perform regular checks and tests on the site to ensure the soil will be capable of providing the best overall support for the roadway or structure. Compaction tests, strength tests including California Bearing Ratio tests, and moisture checks are all important ways to validate that the soil stabilization methods employed are meeting the project requirements.
Environmental and Regulatory Considerations
Depending on where the project is, there may be additional steps that must be taken to ensure the project meets all applicable regulations. For example, the use of certain chemical additives may not be advisable if there is the potential for groundwater contamination, or else added precautions for preventing runoff may be necessary. It is always advisable to check local laws and statutes for the project site to prevent any oversights or mistakes that could lead to rework or violations.
Turn to Rock Solid for Complete Expertise
When you want to take full advantage of everything chemical soil stabilization can do for your project, Rock Solid Stabilization & Reclamation, Inc., is your ideal partner. We have the experience necessary to deliver these capabilities and more to provide you with the perfect foundation for whatever work you’re performing. Follow the links to learn more about our soil stabilization and soil modification services, or reach out to speak with one of our representatives today.