Microscopic view of clay soil stabilized with biomass silica.

Can Biomass Silica Strengthen Clay Soil? The Eco-Friendly Solution You Need to Know

Lena Voss in Climate & Environment December 2025 • 4 min read.

"Discover how turning agricultural waste into a powerful soil stabilizer can help build stronger, more sustainable foundations for our future."

Soft soil, particularly clay, presents significant challenges in construction due to its low strength and high compressibility. Traditional methods of soil stabilization, like cement mixing, can be costly and environmentally damaging. As urban development expands, finding sustainable and effective solutions for reinforcing soft soils becomes increasingly critical.

Enter biomass silica (BS), an innovative material derived from agricultural waste. By repurposing materials like rice husk ash, biomass silica offers an eco-friendly alternative to conventional soil stabilizers. This approach not only enhances soil strength but also reduces environmental impact, aligning with the growing demand for sustainable construction practices.

Recent research investigates the potential of biomass silica to improve the unconfined compressive strength (UCS) and microstructure of clay soil. This study explores how BS, specifically in the form of SH-85, can transform weak clay into a robust foundation material, paving the way for safer and more sustainable infrastructure.

How Does Biomass Silica Change Clay Soil?

Microscopic view of clay soil stabilized with biomass silica.

The study focused on understanding how biomass silica (BS) interacts with clay soil at a microscopic level to improve its strength and stability. Researchers prepared multiple clay soil samples mixed with varying percentages of BS (5%, 7%, and 9%) and subjected them to different curing periods (0, 7, 14, and 28 days). The unconfined compressive strength (UCS) test was then used to measure the soil's resistance to pressure, and scanning electron microscopy (SEM) was employed to analyze its microstructure.

The results indicated that BS significantly enhances the strength of clay soil. Specifically, the sample treated with 9% BS and cured for 7 days achieved a UCS of 710 kPa—approximately six times greater than that of untreated soil. The highest strength recorded was 1216 kPa after 28 days of curing with 9% BS.

Increased Strength: BS significantly boosts the soil's ability to withstand pressure.
Microstructure Improvement: SEM images showed that BS fills the voids in the clay, creating a denser soil structure.
Sustainable Solution: Using agricultural waste reduces environmental impact.

SEM images revealed a critical insight: the voids within the clay soil were filled by new components resulting from the reaction between the BS stabilizer and the natural clay. This process leads to a continuous soil fabric, enhancing both the strength and density of the soil. This transformation at the micro-level explains the substantial improvement in UCS values.

Building a Stronger, Greener Future

Biomass silica presents a promising solution for soil stabilization, offering a sustainable and effective method to enhance the strength and stability of clay soil. By repurposing agricultural waste, this innovative approach not only improves construction outcomes but also contributes to a more environmentally friendly future. The study's findings support the continued exploration and application of BS in construction, paving the way for broader adoption of sustainable practices.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.11113/jt.v77.6382, Alternate LINK

Title: Unconfined Compressive Strength And Microstructure Of Clay Soil Stabilised With Biomass Silica

Subject: General Engineering

Journal: Jurnal Teknologi

Publisher: Penerbit UTM Press

Authors: Fauziah Kasim, Aminaton Marto, Nur Amalina Abdul Rahman, Choy Soon Tan

Published: 2015-11-23

Everything You Need To Know

What is biomass silica (BS), and why is it considered an eco-friendly solution for soil stabilization?

Biomass silica (BS) is an innovative material derived from agricultural waste, such as rice husk ash. It's considered eco-friendly because it repurposes waste materials, reducing environmental impact compared to traditional soil stabilizers like cement. By using BS, construction can become more sustainable, aligning with the growing demand for environmentally conscious practices. The specific type mentioned is SH-85.

How does biomass silica (SH-85) enhance the strength and stability of clay soil?

Biomass silica (SH-85) enhances clay soil by interacting with it at a microscopic level. When mixed with clay, it fills the voids within the soil, creating a denser and more continuous soil fabric. This process significantly increases the soil's unconfined compressive strength (UCS), making it more resistant to pressure and more stable for construction purposes. The SH-85 reacts with the clay, strengthening it.

What were the key findings regarding the use of biomass silica (SH-85) in improving the unconfined compressive strength (UCS) of clay soil?

The key findings indicated that biomass silica (SH-85) significantly improves the unconfined compressive strength (UCS) of clay soil. For example, a clay sample treated with 9% BS and cured for 7 days achieved a UCS of 710 kPa, which is six times greater than that of untreated soil. The highest strength recorded was 1216 kPa after 28 days of curing with 9% BS, demonstrating the material's potential for enhancing soil strength over time. This shows that SH-85 increases load-bearing capacity.

How does scanning electron microscopy (SEM) help in understanding the effects of biomass silica (SH-85) on clay soil?

Scanning electron microscopy (SEM) provides detailed images of the microstructure of clay soil treated with biomass silica (SH-85). These images reveal that the BS fills the voids within the clay, leading to a denser soil structure. This visual evidence confirms the transformation at the micro-level, explaining the substantial improvement in unconfined compressive strength (UCS) values. Without SEM, seeing the interaction of SH-85 and clay would be impossible.

What are the broader implications of using biomass silica (SH-85) in construction, and how does it contribute to a more sustainable future?

The use of biomass silica (SH-85) in construction has significant implications for sustainability. By repurposing agricultural waste, it reduces the environmental impact associated with traditional soil stabilization methods. This approach supports a circular economy, where waste materials are transformed into valuable resources. The adoption of BS contributes to a more environmentally friendly future by promoting sustainable construction practices and reducing reliance on costly and damaging conventional methods. The utilization of SH-85 directly reduces the carbon footprint of the construction.