Dynamic behaviour of shredded rubber soil mixtures

Residential buildings in high population density areas are seismically vulnerable to the action of major seismic events. The high cost and technical difficulties related to the use of advanced seismic isolations systems precludes its installation to low-to-medium rise buildings in the developing world. The environmental issues attributed to the stockpiling of scrap tires and its use as tire derived fuel has led research to explore viable recycling solutions in civil engineering projects. Several authors have proposed a novel seismic isolation system by mixing recycled rubber tires with sand particles. However, research to date has been mainly focused on the dynamic properties of this mixture in the low-to-medium strain range at a specific loading cycle. This paper has studied the dynamic properties in the medium-to-large shear strain amplitude (0.05%-1%) of shredded rubber-soil mixtures (ShRm). The influence of the rubber percentage, size ratio, shear strain amplitude and number of cycles have been evaluated. The shear modulus decreases at larger rubber percentages and strain amplitudes. The damping ratio has been found to increase by adding 10% rubber but it decays at greater rubber percentages. The results show that the dynamic properties of ShRm are affected by the number of cycles at the strain amplitude assessed in this paper. However, the addition of up to 30% of shredded rubber particles increase significantly the resilience of sand particles against cyclic loading leading to a reduction in the stiffness and damping degradation.