Influence of the Microstructure in the Acoustical Performance of Consolidated Lightweight Granular Materials

Abstract

This paper reports an investigation of the acoustical performance of consolidated lightweight granular materials, made of perlite, arlite and vermiculite mixed with polyurethane resin. These materials could help combat the noise control and replace some products that lack the sufficient structural strength and require expensive protection when exposed to the elements. The advantages of using these composites in acoustic applications, like noise barriers, compared with commercial materials, are their very light mass combined with a relatively high structural strength, high physical–chemical stability and low cost. Besides, these materials could be considered more acceptable, from the health point of view, and better suited to operate in an aggressive environment. Acoustical properties were assessed according to ISO 10534–2: 1998. The microstructure, through non-acoustical properties (porosity, tortuosity and flow resistivity), and the acoustical performance (sound absorption spectrum and normalized acoustic impedance) were studied, showing the influence of the non-acoustical properties in the acoustical performance.