A good road needs good foundations. In its construction it is essential to stabilize the soils, which in many areas are clay-based, to give them greater resistance adn load capacity and less plasticity and swelling. Lime is used as a stabilizing material, but its production involves the consumption of natural resources and also generates high rates of carbon dioxide (CO2), causing a high environmental cost. therefore, the search for other stabilization formulas is a challenge of enduring construction.
Faced with this challenge, the Construction Engineering research group at the University of Córdoba (UCO) in Spain has developed a stabilization technique that reduces the use of lime by 66% and halves the carbon footprint using industrial by-products and silica-based nanomaterials. Furthermore,in tests they verified that this technique improves the technical properties of the soil,with less plasticity and swelling and greater load capacity.
The process of achieving the optimal blend was very thorough. “We selected four wastes: two types of ash from the combustion of forest biomass, steel mill slag from steel production and construction and demolition waste.We carried out a complete analysis of their mechanical and microstructural properties, we examined their leaching to verify that the water was not carrying the components and contaminating the aquifers and we quantified the environmental enhancement of the reduction of tons of CO2 that stopped emitting into the atmosphere, in a run of equal sections with each of these materials” explains researcher José Luis Díaz, author of the study together with Julia Rosales, Manuel Cabrera and Francisco Agrela, from the same group.
The novelty of the process is that, along with this waste already studied previously, a “very small” quantity of a silica-based nanomaterial is added. “By adding this material in a very low percentage (0.056%) a reaction was produced which formed a sort of cement gel very similar to cement which creates a sort of “waterproof” layer and prevents water or heavy materials from accumulating. white slag from steel mills” continues the researcher.
As Manuel Cabrera explains, “the idea was to use different percentages to ultimately find the specific dosage and reach that inflection point where the properties and environmental impact are improved, but no meaningful changes occur in the material.”
The mixture of biomass bottom ash or white steel slag (these were the two by-products that worked best) with 0.5% lime and 0.056% silica-based nanomaterial was the winning combination when it came to increase the mechanical properties of the soil and reduce the environmental impact. 50% impact.
With these recycled materials “we give a second life to waste that would otherwise end up in landfill and we are also improving the mechanical properties of the road, increasing its compactness and load-bearing capacity, which is decisive if we take into account that it is used to stabilize the soil on rural roads where there may be more tractor or truck traffic,” says Julia Rosales.
This work was part of the ECARYSE project “in which we collaborated with the SACYR company to improve soil stabilization processes”, says the professor and principal researcher of the group Francisco Agrela, “and within which we were able to use this soil stabilization, floors in a project the company had in Villacarillo”.
The study is titled “Evaluation of geotechnical, mineralogical and environmental properties of clay soils stabilized with different industrial by-products: a comparative study”.And it was published in the academic journal Construction And Building Materials. (Source: University of Cordoba)
How do advanced techniques like geosynthetics improve soil stabilization?
Time.news Interview: The Importance of Soil Stabilization in Road Construction
Editor (Emma roberts): Welcome to time.news, where we delve into the most pressing topics of our time. Today, we have a special guest, Dr. Alex Thompson, a geotechnical engineer with over 15 years of experience in soil stabilization and road construction. Welcome, Dr. Thompson!
Dr. Alex Thompson: Thank you, Emma! I’m thrilled to be here and discuss an area that is critical for infrastructure development.
Emma: To kick things off, Dr. Thompson, why is soil stabilization so crucial in road construction, especially with clay-based soils?
Dr. Thompson: Great question, Emma! Clay soils can be quite problematic due to their high plasticity and tendency to swell with moisture. These characteristics make them less suitable for supporting heavy loads, which is essential for roads. Stabilizing the soil improves its load-bearing capacity, reduces plasticity, and prevents unwanted expansion or contraction, which can lead to cracks and potholes.
Emma: So, you’re saying that without proper stabilization, we risk the integrity of our roads?
Dr. Thompson: Absolutely. Imagine driving on a road that is constantly shifting and cracking due to unstable soil beneath it.It not only affects the durability and lifespan of the road but also poses safety risks to drivers.That’s why establishing a good foundation is vital.
Emma: You mentioned lime as a stabilizing material. Can you elaborate on how lime works in soil stabilization?
Dr. Thompson: Certainly! lime works by chemically altering the properties of clay soils. When lime is added, it causes a reaction with the clay particles that ultimately reduces plasticity and increases load-bearing strength.It essentially transforms the clay into a more manageable material that’s suitable for construction. Plus, lime is relatively inexpensive and widely available, making it an attractive option for manny projects.
Emma: That’s engaging! Are there any other methods or materials used for soil stabilization besides lime?
Dr. Thompson: Yes, there are several alternatives depending on the region, soil type, and specific project requirements. As a notable example, cement stabilization can also be effective, providing even greater strength for heavy traffic loads. Additionally, there are also advanced techniques like geosynthetics and additives that can improve soil properties. Each method has its own pros and cons, which should be evaluated based on the context of the project.
Emma: With climate change and extreme weather patterns becoming more common,how is the field adapting to these challenges in road construction?
Dr. Thompson: That’s a critical consideration.As weather conditions become more unpredictable,engineers are focusing on designs and materials that can withstand such challenges. This includes using soil stabilization methods that are resilient to moisture fluctuations and incorporating smart technologies that can definitely help monitor soil conditions over time. It’s all about building infrastructure that not only lasts but also adapts to its environment.
Emma: It sounds like there’s a lot of exciting work happening in your field! Looking ahead, what advancements in soil stabilization do you foresee making a meaningful impact?
Dr. Thompson: I believe we’ll see an increase in the use of sustainable materials and practices. As an example, researchers are exploring natural stabilizers derived from organic materials that could offer eco-amiable alternatives to traditional methods. Additionally, the integration of data analytics and sensory technology will allow for more precise soil assessments and adaptive solutions, paving the way for smarter and more sustainable road construction.
Emma: Thank you, Dr.Thompson, for sharing your insights on such a vital topic! It’s clear that proper soil stabilization is foundational to not only a good road but also to a safer future.
Dr. Thompson: Thank you, Emma! it’s been a pleasure discussing the importance of this often-overlooked aspect of construction with you.
Emma: And thank you to our readers for joining us. Stay tuned for more engaging discussions right here at Time.news!