Engineering Reactive Clay Systems by Ground Rubber Replacement and Polyacrylamide Treatment

Area of Science:

• Geotechnical Engineering
• Materials Science
• Environmental Science

Background:

• Expansive clays exhibit poor geotechnical properties, limiting their use in construction.
• Sustainable additives are needed to improve soil performance and reduce environmental impact.

Purpose of the Study:

• To investigate the combined effects of ground rubber (GR) and polyacrylamide (PAM) on the geotechnical properties of expansive clay.
• To determine the optimal concentrations of GR and PAM for soil improvement.

Main Methods:

• Experimental investigation of PAM concentration effects on soil properties (consistency, strength, microstructure).
• Evaluation of GR content effects, with and without optimal PAM concentration.
• Analysis of soil-clay-GR interactions and volume change behavior.

Main Results:

• Optimal PAM concentration identified at 0.2 g/L; higher concentrations acted as lubricants.
• Unconfined compressive strength (UCS) increased with GR content up to 10%, beyond which rubber-clustering occurred.
• Swell-shrink capacity significantly reduced with higher GR content, further enhanced by PAM addition.

Conclusions:

• A combination of 20% GR and 0.2 g/L PAM is optimal for significantly reducing swell-shrink capacity and improving strength.
• The synergistic effect of GR and PAM offers a sustainable solution for ameliorating expansive clay properties.