Modern noise barriers must be constructed using sustainable materials capable of reducing environmental impact throughout the entire life cycle, from production to end-of-waste recycling. This objective can be pursued by combining robust structural elements — such as engineered wood or metal joints — with advanced sound- absorbing solutions and smart, low-embodied-energy technologies. Among the most promising natural materials for this purpose are sheep wool and cork, both characterised by good sound-absorbing properties, particularly at mid-to-high frequencies, and by favourable environmental credentials in terms of renewability and recyclability. Cross-Laminated Timber (CLT) represents a further option of interest as a structural facing element, offering moderate sound insulation performance with low embodied energy and compatibility with circular economy strategies. The present work investigates the acoustic performance of three barrier configurations based on natural materials: a single-layer CLT panel, a CLT panel coupled with agglomerated cork, and a multilayer system combining CLT, cork, and sheep wool. Airborne sound insulation was measured in accordance with ISO 10140-2, and the weighted sound reduction index Rw was calculated following ISO 717-1. Sound absorption was characterised using the SonoCat instrument, with results evaluated according to ISO 11654. The reported values describe the acoustic properties of the panel assemblies at the material level, under controlled laboratory conditions, and are intended to support material selection for sustainable barrier design rather than to predict in-situ barrier insertion loss. Results show a progressive improvement in sound insulation with increasing stratification: Rw = 34 dB for CLT alone, 37 dB for CLT with cork, and 42 dB for the full multilayer system. Sound absorption measurements confirm that sheep wool and cork exhibit complementary spectral behaviours, providing broadband absorptive performance when combined. These findings demonstrate that all-natural multilayer configurations can achieve competitive acoustic performance while offering significant environmental advantages.
EXPERIMENTAL INVESTIGATION OF THE ACOUSTIC PROPERTIES OF NATURAL MATERIALS FOR SUSTAINABLE ACOUSTIC BARRIER SYSTEMS
Costantino Carlo MASTINO
;Raffaello POSSIDENTE;Andrea FRATTOLILLO;Roberto RICCIU;Roberto BACCOLI;Giovanna CONCU;
2026-01-01
Abstract
Modern noise barriers must be constructed using sustainable materials capable of reducing environmental impact throughout the entire life cycle, from production to end-of-waste recycling. This objective can be pursued by combining robust structural elements — such as engineered wood or metal joints — with advanced sound- absorbing solutions and smart, low-embodied-energy technologies. Among the most promising natural materials for this purpose are sheep wool and cork, both characterised by good sound-absorbing properties, particularly at mid-to-high frequencies, and by favourable environmental credentials in terms of renewability and recyclability. Cross-Laminated Timber (CLT) represents a further option of interest as a structural facing element, offering moderate sound insulation performance with low embodied energy and compatibility with circular economy strategies. The present work investigates the acoustic performance of three barrier configurations based on natural materials: a single-layer CLT panel, a CLT panel coupled with agglomerated cork, and a multilayer system combining CLT, cork, and sheep wool. Airborne sound insulation was measured in accordance with ISO 10140-2, and the weighted sound reduction index Rw was calculated following ISO 717-1. Sound absorption was characterised using the SonoCat instrument, with results evaluated according to ISO 11654. The reported values describe the acoustic properties of the panel assemblies at the material level, under controlled laboratory conditions, and are intended to support material selection for sustainable barrier design rather than to predict in-situ barrier insertion loss. Results show a progressive improvement in sound insulation with increasing stratification: Rw = 34 dB for CLT alone, 37 dB for CLT with cork, and 42 dB for the full multilayer system. Sound absorption measurements confirm that sheep wool and cork exhibit complementary spectral behaviours, providing broadband absorptive performance when combined. These findings demonstrate that all-natural multilayer configurations can achieve competitive acoustic performance while offering significant environmental advantages.
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