Macro and microscale Engineering Response of Rigid-Soft Gravel-Rubber Inclusions: Insights from Detailed Laboratory and DEM Numerical Investigations

This paper summarizes the main results of a broader research activity aimed at facilitating the use of gravel-rubber mixtures (GRMs) in geotechnical engineering applications. Precisely, the results of direct shear tests carried out on three GRMs having different aspect ratios (AR = 0.28, 0.57, and 0.66) and prepared at different volumetric rubber contents (VRC = 0, 10, 25, 40, and 100%) are reported and discussed. Additionally, an original 3D hybrid DEM numerical model (named DEM4GRM model) for rigid-soft particle mixtures is presented, and its performance is evaluated. Lastly, using newly proposed micromechanical equations, factors such as fabric and force anisotropy, and strong-force chains are systematically examined throughout the shearing process to gain insight on the particle-level behavior of mixtures with varying VRC.