Better sound insulation has traditionally been a question of increasing the mass/weight of the construction. With the SL-deck it is possible to make a very sound insulating stucture with a deck thickness of just 22 cm and a weight of 375 kg/m2.
The SL-Decks high level of sound insulation is due to two primary factors:
Reasons for SL-deck’s improved sound properties
Effects of internal arches
Arches are stiffer than a flat plate, thus creating higher eigenfrequencies, which is beneficial as the most difficult eigenfreqencies to reduce lie in the low end of the spectrum. In the SL-Deck, the self-compacting concrete is constructed as a series of arches over the lightweight blocks and thus contribute to the high level of sound insulation.
Combination of materials
Ordinary self-compacting concrete and lightweight concrete have different eigenfrequencies. When sound is transmitted, the two types of concrete in the SL-Deck thus vibrate differently. This means that a part of the sound waves are converted to heat instead of passing through the deck.
The SL-deck’s sound insulation properties have been tested by accredited test institute DELTA according EN ISO 717-2:2013 with the following results:
Impact sound transmission: L’n,w (CI) = 79 (-13) dB