Geotechnical properties of tire-cohesive clayey soil mixtures as a fill material: Fid-Bau Portal

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

Cetin, H. / Fener, M. / Gunaydin, O.

The volume of used rubber auto tires in the world is increasing every year and their disposal has, therefore, become a major environmental problem worldwide. Every year, millions of scrap tires are either discarded in huge piles across the landscape or dumped in landfills in large volumes. These tire piles not only cause environmental pollution but also pose fire and health hazards. Generally, weighing between 10 and 50 kg, tires are very bulky, and difficult to manage. They are less dense than other waste items, so they occupy large volumes in landfills. Rainwater tends to collect in stockpiled tires, which then become a breeding ground for mosquitoes that carry dangerous diseases such as encephalitis. Producing toxic smoke and oils, stockpiled tires are also a fire hazard. 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.