Abstract: Rubber-sand mixture (RSM) has long been recognized as a light energy absorbing material with wide applications in engineering. The moisture content of RSM may vary depending on the application and external conditions. Therefore, it is important to investigate the influence of water content on dynamic shear modulus and damping ratio of RSM for its appropriate application. Shear tests using large-scale cyclic SGI simple shear test apparatus were carried out on RSM with 6 kinds of water content under 3 kinds of vertical pressures. Test results show that RSM dynamic shear modulus and damping ratio vary with water content when the cyclic shear strain amplitude ranges from 1% to 3%. Test results indicate that: The decrease of dynamic shear modulus of pure sand with increase of water content is restrained by adding rubber particles. When the rubber content reaches 30%, the dynamic shear modulus of RSM shows an increasing trend with the increase of water content, which is contrary to the case of pure sand. With the increase of the rubber content, the damping ratio of RSM shows a decreasing trend with the increase of water content. Though dispersion of results is present, the effect of water content on the dynamic characteristics of RSM is significant. Specifically, the average influence of water content on dynamic shear modulus of RSM reaches up to 20%, and the maximum average variation of damping ratio of RSM shows an absolute value 0.025 under the influence of water content. For the stability of dynamic characteristics with water content variation, a rubber mass content of 20% in RSM may be the optimum content.

Key words: rubber sand mixture, water content, dynamic shear modulus, damping ratio, cyclic simple shear tests