The Effects Of Sodium-Potassium Hydroxides And Sodium Orthosilicate On The Geotechnical Properties Of A-2-7 Clayey Sand
Year: 2026
Type: article
Abstract: Non-traditional alkaline activators can provide an alternative approach for improving marginal soils for construction. This study presents a controlled comparative evaluation of sodium hydroxide (NaOH), potassium hydroxide (KOH), and sodium orthosilicate (SO) for stabilizing A-2-7 (SC) clayey sand. Soil–stabilizer blends were prepared at multiple dosages and assessed using Atterberg limits, compaction characteristics, and the California bearing ratio (CBR). NaOH and KOH reduced the plasticity index (PI) of the untreated soil (PI = 19) to 5–7 at the highest hydroxide dosage, indicating improved workability. Changes in maximum dry unit weight (γdmax) were limited for NaOH and KOH, whereas SO produced a clearer densification response (γdmax increased from 15.11 to 16.19–16.38 kN/m3). CBR increased approximately linearly with stabilizer dosage, reaching an average improvement from 77% (untreated) to ~86% at the highest evaluated dosage. Compared with earlier alkaline-stabilization studies that typically focus on a single activator, the side-by-side assessment reported here clarifies the relative effectiveness of hydroxide versus silicate-based activation for improving A-2-7 soil in pavement and foundation applications.
Authors: Omar Asad Ahmad, Shahed Sulieman Al-Mwas
Institution: Amman Arab University
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7127067740