Technical building services

Soundproofing with innovative lightweight-concrete
resonators

The soundproofing of combined heat and power units in block-type thermal power plants is becoming increasingly important. Soundproofed steel sheet containers or concrete sound hoods are used for decentralized plants. Concrete sound hoods are preferably used in residential areas as they offer better soundproofing properties. Manufactured from conventional precast reinforced concrete elements, they achieve masses of around 60 t, which increases the effort required in terms of logistics and assembly. It has to date not been possible to integrate the plant technology at the factory.

In an interdisciplinary project (IAB Weimar gGmbH, Büscher GmbH & Co. KG, Akustikbüro Krämer & Stegmaier GmbH, Eschenröder & Osenberg GbR, AIS Kursawe Anlagenbau & Industrieservice Kemberg), a high-absorption concrete sound hood for improving the soundproofing of block-type thermal power plants was developed which allows preassembly of the concrete sound hood and plant technology.

The development is based on an acoustic concept for a sound-absorbing interior lining. The combination of porous, micro-perforated and selective, resonant absorbers on the basis of an optimized no-fines lightweight concrete results in a reduction of the interior level over a wide frequency spectrum – especially of the predominantly emitted low frequency components between 60 and 250 Hz. The wall thicknesses of the load-bearing concrete were reduced to 80 mm. Location-based requirements are taken into account in the specific design of the acoustic components.

The acoustic absorbers were developed on the basis of lightweight mineral aggregates. The experimental program used expanded-glass and expanded-clay aggregates of different par­ticle sizes, as well as varying percentages of cement paste and silica sand. The related fresh and hardened concrete properties and the acoustic properties in the impedance tube served as response variables. A suitable mix design could be derived by means of numerical opti­mization.

The frequency-based sound reduction index was determined in the IAB’s wall-testing facility. The weighted sound reduction index RW of previous wall structures could be improved by 9 dB to 53 dB, and the surface-related mass reduced by more than 35 %. The concrete sound hood suitable for preassembly has a weight of under 40 t.

Related articles:

Issue 2017-07 KLB Klimaleichtblock

Advantages of lightweight concrete for sound insulation demonstrated

Standards and national technical approvals provide a solid foundation for everyday work. This also applies to sound insulation, which is one of the most important health and safety objectives in...

more
Issue 2018-06

Precast block and installation system for construction of walls and slabs

(10) US 2018/0100302 Al (22) 06.10.2016 (43) 12.04.2018 (57) Precast blocks with a rectangular or quadrangular prism shape contain a normal weight hydraulic concrete casing, lightweight concrete or...

more
Issue 2020-02 An innovative concrete-wood composite ceiling for solid structures

Acoustic and environmental properties

The acoustic properties of wooden-beam and concrete ceilings differ systematically. More specifically, the sound reduction factor of a (cementitious) floating screed on a wooden ceiling is...

more

Schöck Isokorb: The next generation

With the thermal and impact sound insulation element Schöck Isokorb XT Schöck Bauteile GmbH (Baden-Baden/Germany) is currently launching an overall newly develop-ed generation of its successful...

more
Issue 2020-04 Submitted by: Burkhard Schuller Baustoffservice

Early-strength lightweight concrete made of volcanic rock

Lava lightweight concrete, developed by the company Burkhard Schuller Baustoffservice, is a mix of volcanic rock: e.g., of zeolite, pumice and lava. Volcanic rock can be used without additional energy...

more