Time-Dependent Response of a Recycled C&D Material-Geotextile Interface under Direct Shear Mode

Area of Science:

• Geotechnical Engineering
• Materials Science

Background:

• Geosynthetic-reinforced soil structures offer cost-effective and time-saving alternatives to conventional retaining structures.
• Utilizing recycled construction and demolition (C&D) wastes in backfill is advantageous.
• Understanding time-dependent shear behavior at geosynthetic-soil interfaces is crucial for long-term structural integrity.

Purpose of the Study:

• To characterize the time-dependent shear response of a high-strength geotextile-recycled C&D material interface.
• To introduce and validate an innovative multistage direct shear test procedure.

Main Methods:

• An innovative multistage direct shear test was developed.
• The test involved periods of stationary shear box to observe stress relaxation.
• Interface shear strength was measured at peak and large displacements.

Main Results:

• Multistage tests demonstrated progressive stress relaxation over time, particularly under lower normal stresses.
• The observed stress relaxation was dependent on the duration of the stationary period.
• Peak and residual shear strength parameters were comparable to conventional tests.

Conclusions:

• The proposed multistage direct shear test effectively characterizes time-dependent interface behavior.
• Despite stress relaxation, the interface maintains stable shear strength parameters.
• This research contributes to the reliable design of geosynthetic-reinforced soil structures using recycled materials.