Performance of Sodium Chloride Blended with Silica Fume for Stabilizing Expansive Soils in Road Subgrade Applications

Expansive soils present considerable challenges in constructing road subgrades due to their elevated plasticity, swelling potential, and low strength. This study investigates the stabilization efficacy of Sodium Chloride (NaCl) and Silica Fume (SF) on such soils, aiming to improve performance for infrastructure applications. Initial soil characterization included Atterberg limits, compaction, and California Bearing Ratio (CBR). The research adopted a phased approach. NaCl was introduced in increments ranging from 2% to 10% at 2% intervals, resulting in a notable decrease in Plasticity Index (PI) and an increase in CBR values, with the optimal NaCl concentration identified as 6%. Subsequent experimentation explored the synergistic effects of this optimal concentration of NaCl in combination with varying amounts of SF, from 5% to 15% in 5% increments. It was found that a combination of 6% NaCl and an appropriate concentration of SF, which was determined based on the soil properties, further enhanced soil stabilization, reducing PI to a desirable level and increasing the soaked CBR value to an impressive 8%. This triphasic approach, considering the expansive soil, NaCl, and SF, illustrates the potential of combining these components to significantly improve the stability of expansive soils, thereby offering a viable, sustainable, and economical option for constructing road subgrades and presenting a promising solution to a pervasive challenge in civil engineering and construction industries.