triaxial determination of shear strength of tire chips-sand-geotextile mixtures

Waste tires are widely used for geotechnical applications as backfill material that is either a substitute for natural soils or combined with them. this paper determines the shear strength parameters of tire chip-sand-geotextile mixtures using a triaxial test apparatus. for this purpose, tire chip–sand mixtures with mixing ratios of 0:100, 15:85, 25:75, 35:65, and 100:0 by volume were used as fill materials. also, for the reinforcement of these mixtures, the layer of geotextile is used. in all tests, the strain rate has been kept the same. three confining pressures have been applied in all experiments. the influences of the tire chip content, number of geotextile layers, and confining pressure at the strain levels of 3%, 6%, 9%, 12%, 15%, and 18% on the sample were studied and described. this paper focuses on the stress-strain behavior of different mixtures. the results show that the imposed strain level on the samples plays an essential role to increase the strength of the tire chip-sand mixtures compared with sand alone. it implies that the beneficial effect of tire chip content to enhance the strength of samples appears in high strain, especially for reinforced samples with geotextile, while in low strain, tire chip does not have a beneficial effect. hence, it is necessary to consider the strength of tire chip-sand mixtures compared with sand alone at the imposed strain level.