Fiber-Grains Interaction Mechanisms in Triaxial Tests Detected with X-ray Tomography

Abstract Fiber orientation plays a key role in fiber reinforcement. Fibers must undergo tensile stress to be effective and must be oriented along the minimum principal stress direction to ensure maximum interaction with the shear band. When fibers are well oriented, during shearing, porosity and strain fields are more homogeneous in the specimen, and the shear band thickness is larger. The present study is focused on the detection of the interaction mechanism between sand grains and fibers, to link the behavior observed at the macroscale with the microscale. An investigation of the soil-fibers contact would disclose the mechanisms that take place locally and affect the global behavior of the soil assembly, providing great benefits for the reinforcement’s design and performance predictions. Fiber-reinforced sand is subjected to miniature triaxial compression test and X-ray imaging. Continuum and discrete Digital Image Correlation (DIC) analysis is performed to detect fiber-grain interaction mechanisms.