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Microstructural Evolution and Strength Development of High-Water-Content Soft Soils Stabilized with
Youmin Han1,2, Yunlong Zhao1, Beiping Han1
1School of Architecture and Civil Engineering, Anhui Polytechnic University, Wuhu 241000, China.
Materials (Basel, Switzerland)
|July 15, 2026
Summary
This study reveals how cement, sulfur aluminate cement, gypsum, and lime stabilize soft soils. A composite stabilizer (ECS) enhances soil strength through ettringite (AFt) and calcium silicate hydrate (C-S-H) gel formation.
Area of Science:
- Geotechnical Engineering
- Materials Science
- Soil Science
Background:
- High-water-content soft soils present significant engineering challenges.
- Effective stabilization is crucial for coastal and riparian infrastructure.
Purpose of the Study:
- To investigate stabilization mechanisms and structure formation in high-water-content soft soils (>70%).
- To evaluate single and composite stabilizer systems for soil improvement.
Main Methods:
- Unconfined compressive strength (UCS) tests were performed.
- Microstructural analyses included Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Thermogravimetric Analysis (TG-DTG), and Fourier-Transform Infrared Spectroscopy (FTIR).
Main Results:
- Cementitious components formed calcium silicate hydrate (C-S-H) gel, increasing soil strength.
- Sulfur aluminate cement, gypsum, and lime promoted ettringite (AFt) crystal formation, enhancing early strength.
- A composite stabilizer (ECS) demonstrated significant improvements in both early and long-term strength.
Conclusions:
- Soil stabilization occurs in two stages: initial AFt network formation followed by C-S-H gel cementation.
- The findings provide mechanistic insights for stabilizing soft soils in civil engineering projects.
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