The role of pore structure in sound absorption performance of lime based plasters

摘要

Sound absorption performance is directly related to the pore structure of materials. The effect of materials’ pore characteristics on sound absorption performance has been examined in detail, especially for materials like mineral wool, foamed metals, porous concrete, sand and soils. However, there is scarcity of knowledge in literature on relationships between sound absorption characteristics of lime-based plasters used as finishing layer(s) in buildings and their pore structure.In this study sets of lime-based plaster samples, composed of non-hydraulic lime as the binder, various binder/aggregate ratios and aggregate size distribution, were prepared in the laboratory. Basic physical and physico-mechanical properties of plasters were defined in terms of density, open porosity and ultrasonic velocity. Sound absorption characteristics of plaster samples were measured by the impedance tube method. Pore structures of the samples were analyzed in terms of pore shape and pore size through image analyses of their cross sections. Correlations between the parameters related with the pore structure and sound absorption were evaluated to reveal major porosity characteristics contributing to different sound absorption behavior at certain frequencies.