Geotechnical properties of tire-cohesive clayey soil mixtures as a fill material

Geotechnical properties of pure fine and coarse grained tire-chips and their mixtures (10, 20, 30, 40 and 50%) with a cohesive clayey soil were investigated through a series of soil mechanical tests in order to investigate possibilities of their usage as a lightweight fill material. Grain size and Atterberg limits analysis, permeability, direct shear and compaction tests were performed on the clayey soil, tire chips (both fine and coarse) alone and their mixtures.The results indicate that the use of used tire-chips mixed with clayey soils as a fill material is possible. The mixtures up to 20% coarse grained tire-chips and 30% fine grained tire-chips can be used above ground water tables where low weight, low permeability and high strength are needed in fills such as highway embankments, bridge abutments and backfills behind retaining structures especially when they are to be built on weak foundation soils with low bearing capacity and high settlement problems. They should not be used where drainage is needed to prevent the development of pore pressures during loading of fills under saturated conditions. In these cases, they may, however, be used by mixing with high permeability material such as sand and gravel.