Sand was earlier referred to as the best backfill material because of its shear strength and permeability characteristics. In view of sustainability, being a cohesion less inert material that can also be used as a backfill due to its bulk utilization, granite dust is also the best substitute for sand
[33][16]. A backfill material should not possess any lateral displacement of facia walls and should be able to resist the settlement due to loading. Granite dust is limited in cohesion property and high density; hence, the concept of granite dust reinforcement has been explored by certain authors. Among several reinforced materials, geosynthetics are considered as the best reinforcing materials due to their workability. Rama Subbarao
[51][17] stated that geo grid reinforcement reduces the shear deformations of granular materials. Reinforced granite dust exhibits a ductile behavior and improves apparent cohesion, but is insignificant in the case of friction. The deviatory stress is the governing factor of shear strength in the case of reinforced stone dust, especially in ductile reinforcements. The EPS geofoam was introduced in granite dust as the load-reduction key. Geofoam is more noticeable for gravelly and sandy fills. The interface shear strength of geofoam–granite dust is highly influenced by normal stress applied
[52][18]. In addition, the presence of geofoam reduces the backfill weight. Reinforced granite dust could be used as a backfill material, even at a lower relative density that reduces facia displacement and vertical settlements
[53][19]. The change in the dimensions of the reinforcement and its location also greatly influence the backfill behavior. Waste plastic strips serve as a reinforcing material for improving the penetration resistance of granite dust. Granite dust is highly influenced by the increase in the density of intruded plastic strips
[54][20]. Earlier works have stated that approximately 1% of plastic strip addition with an aspect ratio of 3 increases the soil CBR. The CBR was improved by the particle interlocking in reinforced layers under the dry condition (unsoaked) and the sedimentation of fines, in which the coarser particles to the top led to a confinement in the wet condition(soaked)
[51][17].
Backfills and soil walls are some of the bulk applications in geotechnical engineering. The reinforced granite dust material is the best substitute for sand. Being a high-density material, the reinforcement helps reduce the pressure on the facia walls, which consequently leads to the reduction of the horizontal displacement and the vertical settlement due to the interlocking phenomenon (Figure 65). The concept of reinforced granite dust also helps improve the penetration resistance due to the development of a confinement among particles.