Performance evaluation and stabilization mechanism of red clay treated with polyurethane

Area of Science:

• Geotechnical Engineering
• Materials Science
• Environmental Science

Background:

• Red clay soils are widespread but prone to weakening when exposed to water.
• Water-induced degradation of red clay presents significant challenges for urban infrastructure foundations, leading to settlement and landslides.
• Conventional soil stabilization methods often lack environmental sustainability.

Purpose of the Study:

• To evaluate the efficacy of a green, highly permeable, water-soluble polyurethane (PSP) as a novel curing agent for red clay.
• To investigate the mechanical properties and failure mechanisms of PSP-stabilized red clay.
• To establish empirical relationships between soil properties and PSP treatment parameters.

Main Methods:

• Acoustic emission testing to analyze failure modes of PSP-stabilized red clay.
• Scanning electron microscopy (SEM) for microscopic examination of stabilization mechanisms.
• Triaxial compression tests to determine strength, stiffness, and toughness under varying PSP content, moisture content, and confining pressure.

Main Results:

• PSP treatment significantly enhances the strength and stiffness of red clay within a 3-day curing period.
• PSP-stabilized soils exhibit ductile failure and strain hardening behavior.
• Positive correlations were found between peak energy absorption, peak stress rates, and PSP content; negative correlation with moisture content. Confining pressure had minimal impact on peak stress ratios and stiffness.

Conclusions:

• The green water-soluble polyurethane (PSP) is an effective agent for improving the mechanical properties and water resistance of red clay.
• PSP treatment enhances soil ductility, distinguishing it from hydric soils and offering a sustainable alternative for foundation engineering.
• The study provides empirical data for optimizing PSP usage in geotechnical applications.