Acoustic and mechanical properties of expanded clay granulates consolidated by epoxy resin

Porous materials were prepared by agglomerating the expanded clay with an epoxy resin with the aim to produce sound absorbers which combine good noise damping performances, excellent mechanical strength and low costs. The use of a polymeric binder, instead of the concrete typically employed in present commercial products, allows obtaining light sound-absorbing panels. In our research the acoustic and mechanical properties of samples of consolidated expanded clay with different thicknesses were experimentally tested. Particularly, the sound absorption properties were measured in a vertical Kundt tube by applying the standing wave ratio method. SEM (scanning electron microscope) observations and porosity measurements were also performed. Experimental results showed a good behaviour with respect to the flexure and compression tests, together with selective sound-absorbing performances and suggest further research opportunities and possible applications of these porous materials as sound absorbers.