SoundTrap is an open cellular low density cementitious non-structural material. It absorbs, instead of reflects noise, and is ideal for projects like noise abatement on freeways, and general transport applications. Hollow Core first produced the product in 1998, for the Melbourne City Link project. Due to its concrete like properties, SoundTrap is a mouldable product. Pigments, paints and special coatings can also be applied to SoundTrap. A water proofing coating is commonly applied, preventing the cells from being closed by rain to provide an al weather acoustic barrier.  | Technical Information | Noise Reduction Coefficient | 0.95 | | Sound Transmission Class | 51 | | Density | 512 - 800 kg/m3 | | Compressive Strength | 2 - 5 Mpa | The reason for the high sound absorbency is that the structure is open cellular. Under magnification, it looks like this: 
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