Granular Lightweight Fill Composed of Sand and Tire Scrap

A granular geomaterial, known as sand-tire lightweight fill, was proposed by blending sand with disposed tire scrap in proportions. The geomaterial can be used as alternative backfill in many infrastructure works, where less overburdens and lateral loads are expected. The reuse of tire scraps may not only address growing environmental and economic concerns, but also help solve geotechnical problems associated with low soil shear strength. In this study, an experimental testing program was undertaken with the goal of evaluating the compression and shear behavior of the materials. Three tests were implemented, i.e., 1-D compression tests, direct shear tests and consolidated drained triaxial compression tests. A compression strain-load model was proposed to describe its compression behavior. Rebound-reload tests revealed that materials' plastic deformation was associated with the mixing ratios. The tire scrap content was found to influence the stress-strain and volumetric strain behavior of the mixtures. Mixtures underwent shear contraction during shearing processes, which is different from the shear dilation of compact sands. Effects of mixing ratios and stress conditions on shear deformation behaviors were also discussed.