Expansive clay soils present serious challenges due to their shrink-swell behavior, causing damage to infrastructure worldwide. Over 40 years of research consistently supports potassium-based chemical stabilizers—especially potassium chloride (KCl)—as an effective and lasting solution.
Key Findings Across Studies:
- Texas A&M Study (1981) – Department of Civil Engineering: Demonstrated that potassium ions (K⁺) reduce swell potential by replacing expansive sodium ions (Na⁺) in the clay’s interlayer, leading to decreased repulsion and plasticity.
- Addison & Petry (1999): Optimizing Multiagent, Multi-Injected Swell Modifier: Optimized a potassium-rich injection solution that reduced swell from 7.2% to 0.84%. Confirmed potassium’s role in collapsing the clay’s diffuse double layer and stabilizing structure through cation exchange.
- Katz et al. (2001): Mechanisms of Soil Stabilization with Liquid Ionic Stabilizer: Found that ionic stabilizers, structurally similar to potassium agents, permanently altered montmorillonite clay lattice, as shown via XRD and SEM analysis.
- Zhao, Ge, Petry, and Sun (2014): Effects of Chemical Stabilizers on an Expansive Clay: Field-replicated injections of potassium compounds in Texas clay reduced swelling by up to 75%, with evidence of moisture barrier formation and no harmful mineralogical changes.
- Stabilization of Expansive Clay Soils Using Potassium Chloride (2015 & 2018): Lab tests confirmed significant improvements in strength and reduced swelling/plasticity through chemical bonding, flocculation, and long-term cation exchange.
- S. Army Engineer Study – Fort Sam Houston (1993): Field application of a proprietary potassium-based stabilizer reduced swell potential from 6–10% to less than 1%, outperforming lime treatment. This method was deemed to permanently alter the clay, confirmed by changes in Atterberg limits and water content.
Conclusion
Potassium treatments—especially potassium chloride-based—offer a durable, chemically stable method to permanently reduce swell in expansive soils. By collapsing the diffuse double layer, exchanging cations, and stabilizing interlayer moisture, potassium provides a cost-effective alternative to lime or cement in high-risk clay regions like Texas.
