Experimental and theoretical considerations on sound absorption performance of waste materials including the effect of backing plates

The acoustic human comfort includes the protection from noise and it is closely related to the sound absorption concept. The paper presents an experimental study on sound absorption coefficients, including transmission, for some combined materials: waste materials (rubber particles, polypropylene, crumbled plastic, wood flour, jute and cord fabrics) with different backing plates (plasterboard, oriented strand board - OSB, polystyrene). The tests were realized following the impedance tube method (ISO 10534-1:1998 standard), except for that the end of the tube was inserted into an anechoic room. The effect of this “backing room” on the samples sound absorption performances is discussed. Also, the experimental results emphasize the influence of the combined materials placed in series on the sound absorption performances and promote the idea of environmentally friendly solutions in their improvement.