Engineering Performance of Expansive Soil Stabilized with Cement and Montmorillonite Adsorption Modifier.

Area of Science:

• Geotechnical Engineering
• Soil Science
• Materials Science

Background:

• Expansive soils pose significant challenges in civil engineering due to their volume change behavior.
• Traditional stabilization methods like cement have limitations in addressing both strength and long-term water stability.

Purpose of the Study:

• To investigate the efficacy of montmorillonite adsorption modifier (MAM) and cement, individually and as a composite, for stabilizing expansive soils.
• To evaluate the impact on compaction characteristics, swell-shrink behavior, and mechanical performance.

Main Methods:

• Laboratory testing of soil samples treated with varying percentages of MAM and cement.
• Evaluation of compaction properties (optimum water content, maximum dry density).
• Assessment of swell-shrink behavior (free swelling ratio, linear shrinkage, moisture absorption) and mechanical strength (compressive strength).

Main Results:

• MAM effectively reduced optimum water content by ~2% and increased maximum dry density by ~0.04 g/cm³ at 6% content.
• 5% MAM incorporation reduced free swelling ratio by 40% and linear shrinkage, classifying the soil as non-expansive.
• Cement significantly improved compressive strength, but showed limited water stability; the cement-MAM composite offered balanced improvements.

Conclusions:

• Montmorillonite adsorption modifier (MAM) is a highly effective additive for mitigating the swell-shrink potential of expansive soils.
• The cement-MAM composite system provides a synergistic approach, enhancing soil strength, water stability, and reducing volume changes.
• Findings offer valuable insights for the practical treatment and engineering applications of problematic expansive soils.