STUDIO DELL'ISOLAMENTO ACUSTICO IN LABORATORIO DI MATERIALI PROVENIENTI DA RICICLO APPLICATI ALLE STRUTTURE EDILIZIE

The acoustic insulation of elements and materials for building construction is becoming more and more important in Italy due to the recent evolutions in the Italian national regulation. This work concerns the experimental studies on sound insulation and reduction of floors and walls, principally using materials made of recycled rubber and synthetic fibrous panels. In particular, impact noise of floors was investigated, taking also into account the mechanical properties of tested materials. The tests were carried out in a new laboratory, built especially for the evaluation of acoustic properties of building elements. The laboratory has an opening, for testing the transmission loss of walls, and two floors: one is a reference concrete slab and the other is a beam and clay block floor with flanking transmission suppression. The steps of the laboratory construction and the procedure adopted for the qualication of sound fields in the rooms are described in this work. The qualication was carried out for transmission loss and impact noise measurements, with some limitations for the airborne sound insulation of floors. The impact noise of floors was studied considering different issues. The two bare floors acoustic behaviour has been analyzed, pointing out the different sound emission, that is due to the technical characteristics of the building elements. The correlation between impact noise reduction and dynamic stiffness of materials used in floating floors has been studied, in particular as regarding the influence of sample preparation and the choice of the predictive formulas. For some materials, repeated measurements have been carried out, to analyze the influence of the screed aging during impact noise reduction laboratory tests, with the aim of reducing the test waiting time. Impact noise reduction of resilient underfloor heating systems has been investigated: the products have been tested on both laboratory floors to check the influence of the base structure and the evaluation methods; different floor finishings have also been tested. Furthermore, airborne sound reduction of walls was studied to improve the knowledge of the influence of recycled materials (in particular rubber and synthetic fibrous panels) on the acoustic performance of gypsum and covered brick walls. For some of the samples, the influence of electric equipments was also studied.

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