Undrained monotonic and cyclic behavior of sand-ground rubber mixtures

In this study the stress-strain characteristics of sand-ground rubber mixtures are investigated in the sandlike zone, at different confining pressures, using hollow cylinder specimens subjected to torsional monotonic and cyclic loading. Under monotonic loading a mixture of sand-ground rubber with 10% and 25% rubber content show more contraction behaviour than that observed in a pure sand specimen. Phase transformation point in these mixtures are located on a larger shear strain. As expected, the shear strength of specimens decreases with increase of ground rubber content. However, with increasing of effective confining pressure, the loss in shear strength of the mixture is decreased. In addition, a mixture with 25% ground rubber shows a smaller loss in shear strength compared to a mixture with 10% ground rubber mixture. Under cyclic loading mixtures with 10% and 25% ground rubber have similar liquefaction resistance, especially at confining pressures of 110 kPa and 260 kPa. Therefore, by using of the mixture with 25% ground rubber, a larger volume of scrap tires could be recycled. The addition of ground rubber to sand would affect the shear strain variation and excess pore water pressure trends, and this effect was further intensified with increasing ground rubber percentage.