Manufacturing process optimization of resilient materials made from recycled tyre granules

The disposal of used tyres is a significant environmental problem in developed countries. The production of acoustic materials from rubber crumbs can therefore represent a valid alternative to incineration or to the disposal of used tyres into landfill. The paper presents the first results of the collaboration between the Department of Industrial Engineering of the University of Perugia and the European Center of Nanostructured Polymers. The goal of this multidisciplinary partnership is to analyze and optimize the manufacturing process of impact sound insulating materials made of recycled tyre granules mixed with binders by studying the different stages of production. Several prototypes were manufactured by means of the developed process and tested in order to evaluate their dynamic stiffness in compliance with the European standard EN 29052-1:1993. The indexes of impact sound reduction ?L w were also estimated. Finally, the prototypes showing the best properties were produced in bigger size and tested in two overlapping reverberating rooms according to the standard ISO 140-8. Results confirm that the materials manufactured through the developed process have satisfactory acoustic properties, comparable to the ones of commercially available materials.