An Investigation on the Shear Strength Parameters of Sand-Rubber Mixtures Under the Applied Stress Paths

Vehicle tires are one of the most bulky solid wastes which are increasingly produced along with car production. In order to reuse these materials, rubber shreds in mixture with sandy soils are widely used in geotechnical purposes due to their specific controlled compressibility characteristics and lightweight. Various laboratory studies have been carried out in order to obtain the optimized portion of sand or rubber content in mixtures. Restraining the compressibility of the mass in different structures such as backfills, road embankments, etc. is as crucial as the mass shear strength. Clearly different applied stress paths lead to changes in sand-rubber mixtures shear strength parameters. Considering the effective stress to be 100 kPa, the results of drained triaxial tests on sand alone and sand mixed with two different rubber wastes i.e. granulated rubber and rubber chips are presented in this study. Mixing ratio is chosen to be 30% of rubber in weight for both types of materials. The tests on sand alone samples yielded effective strength envelope which is approximately linear and can be defined by a friction angle of approximately 36.8 degrees. Comparing two different applied stress paths, the resulted failure envelopes for mixed materials could be approximated by a bilinear envelope. Furthermore, the friction angle of chips rubber mixture samples is greater than sand alone, and for the granulated rubber it is less than that of sand and chips rubber mixtures for both applied stress paths.