Numerical study on rubber compounds made of reactivated ethylene propylene diene monomer for fiber reinforced elastomeric isolators

A huge amount of rubber waste coming from tire industry or other sources (eg, weather strips producers) has attracted interest from researchers to investigate the possibility of recycling used rubber for various products, particularly in construction sector. This article presents a series of experimental and numerical investigations to evaluate the feasibility of regenerated synthetic rubber ethylene propylene diene monomer (EPDM) for production of a building seismic isolation system. Four rubber blends using two different sources of regenerated EPDM are considered in this study. The mechanical properties of the recycled rubber under study are evaluated through uniaxial tensile and relaxation tests, considering the accelerated aging effect. Based on several hyperelasticity and viscosity models of rubber available in the literature, several numerical test simulations on rubber compounds and on a prototype of fiber reinforced elastomeric isolators (FREIs) are performed. The test results reveal that the proposed regenerated EPDM compounds can be particularly suitable for the production of unbonded FREIs, especially because they are able to exhibit low/moderate tensile stresses at high-shear strain. The results also show that not all regenerated rubber blends fulfill the durability requirements of rubber for seismic isolation after accelerated aging tests. The durability of the specimens seems to be mainly affected by the choice of the regenerated rubber source.