ABSTRACT
Micro-reinforcement using engineered fibres or particulate inclusions, such as strip fibres, has potential for improving the performance of coarse granular aggregates, such as materials for road bases or railway ballast. During loading, the aggregate particles move, and the soil skeleton is rearranged. Recent studies have shown the effectiveness of fibre reinforcement of soils and coarse granular aggregates. Usually, the fibres are mixed randomly within the soil skeleton, with consequences on packing. Fibres can be considered micro-reinforcements, as these are inclusions at the particle scale. Alternatively, other forms of micro-reinforcements can be used. Small elements of geogrids, herein designated microgrids, are alternative forms of micro-reinforcement. Their inclusion may also affect the packing of the particles of aggregate, as the presence of the reinforcement my affect the displacement and rotation of the adjacent particles. In this paper, the influence of microgrids on the packing of a coarse aggregate is analysed. For that, a container with two transparent faces was used. The aggregate and the micro-reinforcement elements were mixed at a predetermined volumetric ratio, placed in the container, and submitted to compaction. The addition of microgrids disrupted the natural grain packing, and corresponding increases in emax and emin were observed. For the microgrid with higher anchorage length, non-natural void formation was observed due to microgrid-microgrid interaction rather than microgrid-grain interlocking
