Dynamic properties of recycled polyurethane-coated rubber-soil mixtures

A large quantity of end-of-life tire (ELT) rubber is being blended with thermoplastic polyurethane to provide a durable and ecologically friendly material for flexible surfaces, while a significant quantity of thermoplastic elastomeric waste (left-over and cut-outs) is also generated. These waste materials can be used efficiently for seismic isolation and vibration damping at a minimal cost, a process known as frugal innovation. In this regard, waste thermoplastic elastomeric (TPE) material, which is also known as polyurethane-coated rubber (PUcR), obtained from the tire rubber recycling industry, is explored in this study. Herein, we targeted to evaluate the stiffness and energy dissipation capabilities of waste TPE or PU-coated rubber, which, to the best of our knowledge, has never been reported before. To that end, a series of cyclic triaxial tests were carried out on PU-coated rubber-soil mixtures. In comparison to untreated rubber-soil mixtures, the shear modulus of PU-coated rubber-soil mixtures reduces by 5.5–12.7%, while the damping ratio increases by up to 12.6%.