Direct Shear Testing of Tire Bales for Soil Reinforcement Applications

Perhaps it is time to bring recycled tires into the family of geosynthetics. In particular, recycled tire bales are being proposed for applications that are traditionally accomplished using various soil reinforcement applications (e.g. MSE walls and steep slopes). There are growing environmental interests in the utilization of recycled tire bales for civil engineering applications, triggered partly by the significant volumes of tires that could be disposed of in transportation projects. In particular, tire bales have been used to stabilize steep slopes due to a combination, of their lightweight and reinforcement mechanisms. Tire bales are manufactured by compressing approximately 100 waste auto and light truck tires into a 2 cubic yard, 1-ton bales. Each bale is fastened with galvanized or stainless steel baling wire. However, only limited quantification of the mechanical properties of tire bales has been conducted so far. Accordingly, an experimental testing program was initiated by the Texas Department of Transportation at the University of Texas at Austin to quantify the interface shear strength between tire bales stacked in a brick fashion. This paper presents preliminary results of large-scale direct shear tests, undertaken to evaluate the interface shear strength between 1-ton tire bales.