Mesoscopic Investigation of Conventional and Weakly Bonded Cement Stabilized Macadam Based on Discrete Element...

Area of Science:

• Civil Engineering
• Materials Science
• Geotechnical Engineering

Background:

• Improving crack resistance in cement-stabilized macadam (CSM) base courses is a critical challenge for road engineers.
• Current methods may not fully address the mesoscopic mechanisms governing crack initiation and propagation in CSM.

Purpose of the Study:

• To investigate the crack resistance of normally bonded and weakly bonded CSM using realistic aggregate morphologies.
• To establish a mesoscopic theoretical foundation for the application of weakly bonded CSM in pavement base courses.

Main Methods:

• Utilizing the discrete element method (DEM) with aggregate shapes derived from X-ray computed tomography.
• Calibrating mesoscopic parameters against laboratory unconfined compressive strength (UCS) tests.
• Introducing a weakening ratio of bond strength (Wrbs) to simulate weakly bonded conditions.

Main Results:

• Unconfined compressive strength (UCS) decreases with reduced bond strength (Wrbs) and increased aggregate-related crack area (Rr_ca).
• Weakly bonded specimens exhibit more dispersed crack patterns and a gradual energy dissipation process.
• Despite strength reduction, weakly bonded CSM can meet Chinese base course material specifications with proper design.

Conclusions:

• Weakly bonded CSM demonstrates potential for enhanced crack resistance due to altered crack propagation mechanisms.
• The study provides a mesoscopic understanding crucial for the engineering application and sustainable development of weakly bonded CSM.
• This research supports the use of weakly bonded CSM as a viable and potentially more durable pavement base material.