Biopolymer Stabilization/Solidification of Soils: A Rapid, Micro-Macro, Cross-Disciplinary Approach.

Area of Science:

• Geotechnical Engineering
• Materials Science
• Biotechnology

Background:

• Biopolymer stabilization of soils is crucial for earthwork applications.
• Efficient methods are needed to screen and design effective biopolymer-soil systems.
• Existing methods for evaluating biopolymer-soil interactions are time-consuming.

Purpose of the Study:

• To present a novel, high-throughput micro-macro approach for identifying and designing biopolymer-stabilized soil systems.
• To evaluate the efficacy of different biopolymers for stabilizing iron oxide-silica mine tailings.
• To demonstrate the speed and effectiveness of the proposed methodology compared to traditional methods.

Main Methods:

• Developed a "microscopic" scale Membrane Enabled Bio-Mineral Affinity Screening (MEBAS) coupled with Mineral Binding Characterization (MBC) (TGA, ATR-FTIR, ζ Potential).
• Validated "macroscopic" scale results using Geotechnical Verification (GV) via unconfined compression testing.
• Tested five biopolymers (locust bean gum, guar gum, gellan gum, xanthan gum, sodium carboxymethyl cellulose) against an Fe2O3-SiO2 mine tailings system.

Main Results:

• Locust bean gum and guar gum exhibited the highest affinity for Fe2O3, forming covalent C-O-Fe bonds.
• 1% addition of locust bean gum and guar gum to the Fe2O3-based system yielded unconfined compressive strengths of 5171 kPa and 3848 kPa, respectively.
• The MEBAS approach demonstrated an approximately 50-fold increase in assessment rate compared to GV alone.

Conclusions:

• The integrated MEBAS-MBC-GV approach provides an efficient and rapid method for designing biopolymer-stabilized soil systems.
• Locust bean gum and guar gum are effective stabilizers for Fe2O3-rich mine tailings.
• The methodology is applicable to a wide range of soil/earthwork components and additives.