Performance Study of Alkali-Activated Coal Gangue Powder-Based Geopolymer Flowable Solidified Soil.

Area of Science:

• Geotechnical Engineering
• Materials Science
• Environmental Science

Background:

• Industrial solid waste, such as coal gangue powder (CGP), presents disposal challenges.
• There is a growing need for sustainable and low-carbon materials in geotechnical construction.
• Improving the performance of problematic soils like loess is crucial for infrastructure development.

Purpose of the Study:

• To investigate the efficacy of alkali-activated CGP as a stabilizer for loess.
• To evaluate the impact of CGP binder dosage on key soil performance indicators.
• To understand the microstructural mechanisms behind CGP stabilization of loess.

Main Methods:

• Systematic evaluation of flowability, unconfined compressive strength (UCS), and water stability with varying CGP dosages.
• Microstructural analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Main Results:

• Increased CGP dosage reduced flowability but maintained practical applicability (>160 mm).
• UCS increased with curing age and binder content, reaching 2.06 MPa at 28 days.
• Significant enhancement in water stability, with no disintegration after 24h immersion; improved soil compactness and reduced capillary water absorption observed.

Conclusions:

• Alkali-activated CGP is a viable sustainable stabilizer for loess.
• The stabilization mechanism involves the formation of calcium silicate hydrate (C-S-H) gel, creating a robust particle network.
• Applications include road subgrades, foundation improvement, and embankments, offering both environmental and performance benefits.