Smart Pebbles to Monitor Aggregate Response Under Repeated Loading

This study investigates aggregate particle movements under repeated loading in a controlled laboratory environment. Smart Pebbles, 3-D printed aggregate-shaped particles instrumented with gyroscopes and accelerometers, were used to capture particle movements in a geogrid-stabilized triaxial specimen subjected to repeated load pulsing. The study aims to understand the impact of geogrid stabilization on aggregate particle movements within an unbound base layer subjected to moving wheel loads, a critical determinant of layer stability. Two Smart Pebble sensors were placed at different depths in triaxial specimens. Each test configuration was designed to monitor and comparatively assess the aggregate movement in relation to its spatial position in the specimen. The results reveal a reduction in translational and rotational acceleration of the Smart Pebble where a geogrid is present, while the sensor placed near the top of the specimen experienced a higher translational acceleration. The Smart Pebble could thus be used as a tool to quantify the zone of influence of a geogrid and could be utilized for structural health monitoring of unbound granular layers in pavements.