The effects of sodium-potassium hydroxides and sodium orthosilicate treatment on the properties of clayey sand soil

Author : shahed almwas

Abstract : Non-traditional soil stabilizers can offer a solution for making soils more suitable for construction purposes. The present study aims to investigate the geotechnical properties of A-2-7 soil when treated with sodium hydroxide (NaOH, SH), potassium hydroxide (KOH, KH), and sodium orthosilicate (SO) as alkaline stabilizers. Untreated A-2-7 soil exposed to various concentrations of alkaline stabilizers (5%, 10%, and 15%). The stabilized soil samples subjected to a series of tests to determine their index properties, including Atterberg limits, compaction characteristics, and the California Bearing Ratio (CBR). The results show that SH, KH, and SO significantly affected the soil’s plasticity index (PI), reducing it from 19 to 7 with 15% KH and 15% SH additions, respectively. Increasing the proportion of SH and KH had little effect on enhancing the maximum dry unit weight (γdmax), whereas an increase in SO concentration led to a noticeable improvement, from 15.11 kN/m³ to 16.19–16.38 kN/m³. The CBR increased linearly with the addition of all stabilizers, reaching a maximum of 12% at 15% stabilizer concentration. This study provides new insights into soil stabilization using alkaline stabilizers, offering a novel approach to effectively improve A-2-7 soil, making it more suitable for specific civil engineering applications

Keywords : Clay Soil Stabilization; Ground Improvement; A-2-7 Soil; Engineering Index; Alkaline Activators

Conference Name : International Conference on Soil Mineralogy and Geochemistry (ICSMG - 26)

Conference Place : Jeddah, Saudi Arabia

Conference Date : 17th Feb 2026