Evaluation of the acoustic properties of materials made from recycled tyre granules

The paper presents the results of a wide experimental campaign on the absorbing properties of new acoustic materials made from recycled tyre granules mixed with a proper binder. The influence of the various acoustic and non acoustic parameters is investigated. The methodology used to evaluate coefficient of absorption coefficient is indicated in ISO 10534-2 standard, thanks to an impedance tube. Also the acoustic damping properties of small size samples of various thicknesses have been investigated thanks to a dynamic stiffness test rig. The results show that these new materials have satisfactory acoustic properties, comparable to the ones of commercially available materials, thus encouraging the prosecution of the research with the testing of larger size samples, both for absorption and damping properties.