World’s first ceiling made of lightweight concrete and formwork of 3D-printed sandstone – Smart Slab DFAB House
Foto eines zellularen Verbungwerkstoffs mit Poraver
Syntactic Foams with Poraver® as cellular filler
19. January 2019
Einweihung der Poraver-Straße in Schlüsselfeld
Inauguration of the Poraver road to the new production plant Schlüsselfeld
6. September 2019

A novel production process and optimized lightweight concretes with Poraver® provide 70 percent weight savings 


ETH Zurich has installed the world's first lightweight concrete slab with 3D sand printer moulds in its future-oriented research building, the DFAB House in Zurich Dübendorf. Poraver® expanded glass was used as lightweight aggregate for the special glass fiber reinforced concrete formulation for the so-called Smart Slab.

70 percent weight reduction

Concrete as a building material offers almost unlimited possibilities in the design of architectural elements. This range has been considerably extended in recent years by the invention of 3D printing. Now a research group led by Prof. Benjamin Dillenburger from ETH Zurich has proven that the possibilities of modern architecture with concrete are far from exhausted. The researchers developed a technique to produce moulds for shotcrete elements using the 3D sand printing process. The new completely digitized construction method enables the fabrication of highly optimized concrete components with complex ornamental structures and combines the excellent structural properties of concrete with the geometrical freedom of 3D printing.

All injection moulds for the complex ceiling elements of the Smart Slab were created and optimised on the computer. This enabled massive material savings. The software specially developed for production calculated the exact amount of concrete required for each point of the entire construction in order to guarantee sufficient stability. As a result, the Smart Slab, which has a total area of 78 m2, weighs only 15 tons and is only 20 mm thick at the thinnest points. Thanks to the new construction method, about 70 percent of the weight is saved compared to a concrete slab in traditional design.

Lightweight Concrete with glass fibres and expanded glass spheres

Special lightweight concretes with and without glass fibre reinforcement were used, which combine low weight with high strength. In order to achieve the required low concrete density of around 1,350 kg/m3, Poraver expanded glass was used as lightweight aggregate. The industrially produced granules of recycled glass offer consistent quality and considerably reduce the density of the concrete. The slab consists of a total of eleven concrete segments and connects the basement with the two-storey wooden building above in the NEST research and innovation building of Empa and Eawag in Dübendorf.

Realisation by Bürgin Creations Switzerland

Bürgin Creations Switzerland was responsible for the technical realisation of the Smart Slab ceiling. In 2016, Bürgin built the art installation “Incidental Space” by architecture professor Christian Kerez in the Swiss Pavilion at the Venice Biennale. Also in this case Poraver® was the perfect filler for the concrete formulation. Thanks to the polymer shotcrete with Poraver® expanded glass developed by Theo Bürgin, the wall thickness of the elements could be reduced to only 1 to 4 centimetres and with sufficient stability. The positive properties of the modern concrete formulation were tested and confirmed by fracture tests and static studies carried out by Prof. Dr Joseph Schwartz at the ETH Zurich. Thanks to the innovative concrete formulation, the total weight of the 220 elements for the “Incidental Space” was only around 8 tons.

More information about Smart Slab:

Smart Slab very thin
The Smart Slab, which is only 20 mm thick at its thinnest point, being placed piece by piece on the 12cm wide mesh mould wall. The reduced weight of the segments allows easier handling. © Digital Building Technologies (dbt), ETH Zürich / Andrei Jipa

Foto: Die Smart Slab-Decke, welche auf der «Mesh Mould» Wand aufliegt, während der Montage des darüber liegenden Holzbaus «Spatial timber assemblies».
The Smart Slab ceiling, which rests on the "Mesh Mould" wall, during the assembly of the wooden structure above. © NCCR Digital Fabrication / Michael Lyrenmann

 

3D printed formwork made of sand for the innovative lightweight concrete ceiling

Concrete as a building material offers almost unlimited possibilities in the design of architectural elements. This range has been considerably extended in recent years by the invention of 3D printing. Now a research group led by Prof. Benjamin Dillenburger from ETH Zurich has proven that the possibilities of modern architecture with concrete are far from exhausted. The researchers developed a technique to produce moulds for shotcrete elements using the 3D sand printing process. The new completely digitized construction method enables the fabrication of highly optimized concrete components with complex ornamental structures and combines the excellent structural properties of concrete with the geometrical freedom of 3D printing.

All injection moulds for the complex ceiling elements of the Smart Slab were created and optimised on the computer. This enabled massive material savings. The software specially developed for production calculated the exact amount of concrete required for each point of the entire construction in order to guarantee sufficient stability. As a result, the Smart Slab, which has a total area of 78 m2, weighs only 15 tons and is only 20 mm thick at the thinnest points. Thanks to the new construction method, about 70 percent of the weight is saved compared to a concrete slab in traditional design.

Lightweight Concrete with glass fibres and expanded glass spheres

Special lightweight concretes with and without glass fibre reinforcement were used, which combine low weight with high strength. In order to achieve the required low concrete density of around 1,350 kg/m3, Poraver expanded glass was used as lightweight aggregate. The industrially produced granules of recycled glass offer consistent quality and considerably reduce the density of the concrete. The slab consists of a total of eleven concrete segments and connects the basement with the two-storey wooden building above in the NEST research and innovation building of Empa and Eawag in Dübendorf.

Realisation by Bürgin Creations Switzerland

Bürgin Creations Switzerland was responsible for the technical realisation of the Smart Slab ceiling. In 2016, Bürgin built the art installation “Incidental Space” by architecture professor Christian Kerez in the Swiss Pavilion at the Venice Biennale. Also in this case Poraver® was the perfect filler for the concrete formulation. Thanks to the polymer shotcrete with Poraver® expanded glass developed by Theo Bürgin, the wall thickness of the elements could be reduced to only 1 to 4 centimetres and with sufficient stability. The positive properties of the modern concrete formulation were tested and confirmed by fracture tests and static studies carried out by Prof. Dr Joseph Schwartz at the ETH Zurich. Thanks to the innovative concrete formulation, the total weight of the 220 elements for the “Incidental Space” was only around 8 tons.

More information about Smart Slab:

Foto: Nachbearbeitung der 3D-gedruckten Schalungs-elemente. Lose Sandpartikel werden aus dem Druckbett entfernt.
Loose sand particles are removed from the 3D-printed formwork element. © Digital Building Technologies (dbt), ETH Zürich / Tom Mundy

 

Foto: Faserverstärkter Beton wird in mehreren Schichten in die 3D-gedruckte Schalung gespritzt.
Glass fibre reinforced lightweight concrete is sprayed in several layers onto the 3D-printed formwork. © Digital Building Technologies (dbt), ETH Zürich / Andrei Jipa

 

Lightweight Concrete with glass fibres and expanded glass spheres

Special lightweight concretes with and without glass fibre reinforcement were used, which combine low weight with high strength. In order to achieve the required low concrete density of around 1,350 kg/m3, Poraver expanded glass was used as lightweight aggregate. The industrially produced granules of recycled glass offer consistent quality and considerably reduce the density of the concrete. The slab consists of a total of eleven concrete segments and connects the basement with the two-storey wooden building above in the NEST research and innovation building of Empa and Eawag in Dübendorf.

Realisation by Bürgin Creations Switzerland

Bürgin Creations Switzerland was responsible for the technical realisation of the Smart Slab ceiling. In 2016, Bürgin built the art installation “Incidental Space” by architecture professor Christian Kerez in the Swiss Pavilion at the Venice Biennale. Also in this case Poraver® was the perfect filler for the concrete formulation. Thanks to the polymer shotcrete with Poraver® expanded glass developed by Theo Bürgin, the wall thickness of the elements could be reduced to only 1 to 4 centimetres and with sufficient stability. The positive properties of the modern concrete formulation were tested and confirmed by fracture tests and static studies carried out by Prof. Dr Joseph Schwartz at the ETH Zurich. Thanks to the innovative concrete formulation, the total weight of the 220 elements for the “Incidental Space” was only around 8 tons.

More information about Smart Slab:

Bereits für die Kunstinstallation „Incidental Space“ auf der Biennale in Venedig setzte die Firma Bürgin auf Poraver® Blähglas zur Verbesserung der speziellen Betonrezeptur.
For the art installation "Incidental Space" at the Venice Biennale, the company Bürgin also used Poraver® expanded glass to improve the special concrete formula. © Bürgin Creations Switzerland

Insgesamt 220 Einzelelemente wurden für das Kunstobjekt auf der Biennale hergestellt.
A total of 220 individual elements were produced for the art object at the Biennale. © Dennert Poraver GmbH