Small- to Large-Strain Shear Modulus and Damping Ratio of Sand-Tyre Crumb Mixtures

Utilizing rubber tyres in vibration mitigation can be a viable approach of resolving the chronic problems associated with disposal of waste tyres. However, the dynamic properties of sand-tyre crumb mixtures (STCM) are essential for the design of a vibration isolation system. In this study, the dynamic properties of STCM in terms of shear modulus and damping ratio are presented against the shear strain. The modulus and damping ratio of STCM for small to large shear strain were measured using Torsional resonant column tests and cyclic triaxial tests, for two composition of tyre crumbs (50% and 75%) and three different confining pressure (50, 100, and 200 kPa). The results showed that, shear modulus and the damping ratio of the mixtures are strongly influenced by the percentage of rubber inclusion. Shear modulus decreased with an increase in tyre crumb inclusion for all the confining pressure, whereas the damping ratio increases with the increase in rubber content in STCM. For any percentage of tyre crumbs inclusion, the shear modulus increases and damping ratio decrease with increasing confining pressure. These results are useful to understand the dynamic response of STCM and further used in model studies to design a low cost isolation system.