Sound absorption enhancement using solid-solid interfaces in a nonporous cement-based structural material

This work shows that solid solid interfaces in a non-porous stiff material can enhance the sound absorption and provides an analytical model for describing the effects of constituents and interfaces on the sound absorption. The sound absorption coefficient alpha, the propagation constant Gamma and the reflectivity R were determined for cement-based materials. At 125-500 Hz, alpha ranges from 0.039 to 0.160; Gamma ranges from 2.6 x 10(-4)/mm to 3.5 x 10(-4)/mm; R > 0.9. Silica fume (similar to 0.1 mu m) provides interfaces, thereby enhancing alpha and Gamma by 40% and 20% respectively for cement paste (125 Hz), but it does not affect R. (C) 2016 Elsevier Ltd. All rights reserved.