Dynamic Behavior of Sand/Rubber Mixtures. Part I: Effect of Rubber Content and Duration of Confinement on Small-Strain Shear Modulus and Damping Ratio

The paper examines the small-strain dynamic properties of mixtures composed of sandy soils with recycled tire rubber. For this purpose, the experimental results stemming from a torsional resonant column testing program on twenty four [24] saturated and dry specimens are analyzed. The percentages of rubber used range between 0 and 35 % by mixture weight. GO values increase whereas DTO values decrease systematically as the content of rubber decreases and the mean confining pressure increases. Based on the experimental results we propose an analytical relationship for the estimation of GO, which is expressed in terms of an equivalent void ratio that considers the volume of rubber solids as part of the total volume of voids, along with an analytical relationship for the estimation of DTO. Finally, the effect of the specimen’s size and the duration of confinement on the initial shear modulus and damping ratio of the mixtures are also discussed.