The influence of adding rubber recyclate to laminated composites on the insulation from impact sounds

This paper examines how the manufacturing technology of composite materials influences the insulation parameters against impact sound and the capability to dampen structural vibrations. This is achieved by modifying the composite material's structure through the addition of rubber recyclate. Acoustic insulation tests were conducted on a sandwich composite made from Epidian® 6 epoxy resin, combined with Z-1 hardener, and a randomly arranged glass mat with a density of 350 g/m². Rubber recyclate, obtained from the disposal process of car tires, was used as a damping-enhancing additive. The composite materials were fabricated using the hand lamination technique and tested in three configurations, varying the number of sandwich layers containing recyclate: one, two, and three layers. Field tests were conducted under “in-situ” conditions to measure the reduction of impact sound levels. The setup compared a structure comprising a "concrete slab + composite slab + ceiling" to a reference structure of "concrete slab + ceiling." The parameter ΔL'n was determined in accordance with PN-EN ISO 16283-2 and PN-EN ISO 717-2 standards. Additionally, the reduction of impact sound levels in a ceiling fitted with the composite plate was compared to a ceiling without it, also conforming to PN-EN ISO 16283-2 and PN-EN ISO 717-2 standards. The results indicate a significant decrease in impact sound levels for the composite board with three sandwich layers compared to a composite board without rubber recyclate. This demonstrates the effectiveness of rubber recyclate additives in attenuating structural sounds. The integration of rubber recyclate, sourced from car tire disposal, not only enhances acoustic performance but also contributes to environmental protection efforts.