Sound absorption enhancement using solid-solid interfaces in a non-porous 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 α, the propagation constant Γ and the reflectivity R were determined for cement-based materials. At 125-500 Hz, α ranges from 0.039 to 0.160; Γ ranges from 2.6 × 10^-4/mm to 3.5 × 10^-4/mm; R > 0.9. Silica fume (∼0.1 μm) provides interfaces, thereby enhancing α and Γ by 40% and 20% respectively for cement paste (125 Hz), but it does not affect R.