Airlement: with 3D printing lightweight building materials from... waste

From the Federal Institute of Technology in Zurich for sustainable construction, here are the insulating elements printed in three dimensions, recyclable and cement-free

Sustainable construction thanks to 3D printing
Sustainable construction: 3D printed insulating elements arrive from ETH that are completely cement-free and recyclable (Photo: Patrick Bedarf and Hyuk Sung Kwon)

La 3d printing can make an enormous contribution to the development of asustainable building, starting with the possibility of experimenting with materials never used before and testing new construction techniques capable of reducing consumption and emissions.

A researcher from Federal Polytechnic of Zurich used this automated technology to produce new insulating elements light, completely free of cement, made from mineral foams derived from industrial waste. This mineral foam, which can be reused countless times, is processed layer by layer thanks to a 3D printer the size of a room.

The first prototype of the project Airlement it is a two-meter-tall monolithic corner column, composed of four 3D printed segments held together by simple mortar and covered in cement-free white plaster.

A more sustainable cement is ready for the construction of the future
Sustainable construction: the… mushrooms protagonists among the green materials

3D printing for sustainable construction: the study
The first Airlement prototype is a two-meter-high column made of four 3D-printed segments (Photo: Digital Building Technologies, ETH Zurich)

Sustainable construction and 3D printing: this is the research of the ETH

THEsustainable building has countless declinations: the development of smart materials and new construction methods, the use of upcycling and the reuse of resources are founding elements of a new approach to constructions dictated, first and foremost, by the need to design and inhabit spaces designed to be in harmony with nature.

More sustainable buildings are those that allow to encourage a more rational use of resources thanks to energy efficiency, but also those that they manage to combine environmental and social sustainability and which promise to be able to build without resorting to very expensive processes in terms of resources and energy.

In this context, it development of new materials and construction techniques takes on a leading role, capable of integrating the ambitions of scientists and the needs of a global market which, although extremely varied, can no longer help but deal with the needs of a planet in pain.

One of the latest innovations on the subject comes fromArch Tec Lab of research and robotics at the ETH, on the Hönggerberg campus. Here, the researcher Patrick Bedarf, who works in the group Digital Building Technologies by professor Benjamin Dillenburger, has studied a method to produce lightweight insulating construction elements of complex shape reducing materials thanks to 3D printing.

Sustainable construction starts with public toilets: the project in Sri Lanka
RESKIN: the innovative smart project for green building

New 3D printed "bricks" for sustainable construction
Thanks to the new technology, building parts can simply be printed in the factory, transported to the construction site and positioned where required (Photo: Digital Building Technologies, ETH Zurich, Hyuk Sung Kwon)

A three-dimensional printer the size of a room

La Printer 3D used by Patrick Bedarf is as large as an entire room: numerous robotic arms hang from the roof of the main room of the Arch Tec Lab, while on the ground, on work platforms and wooden crates, strange creatures similar to sand sculptures come to life.

"The robots can precisely move to any point in the room“, explains Bedarf. “We plan the route and specify where they need to travel and how fast, as well as how much material needs to flow from the printer head, at what time and where it needs to be deposited".

With this ingenious system, the ETH researcher created the first prototype of the Airlement project, a column monolithic corner piece, two meters high, composed of four 3D printed segments held together with mortar.

I four segments of the column are light, easy to lift manually to be stacked on top of each other: "Building parts can simply be printed in the factory, transported to the construction site and placed where required“, explains Bedarf.

"To make the component more robust, the hollow core can be cast with high-density mineral foam, which makes it strong enough to act as a load-bearing structure”. But it is not only the technique that is innovative in Bedarf's project.

Zero emissions and a better quality of life: “That's Smart City”
In Lucerne the first Swiss ethics committee for Smart City projects

Sustainable construction thanks to 3D printing of mineral foams
The climatic chamber created by Patrick Bedarf to keep temperature and humidity under control during printing (Photo: Digital Building Technologies, ETH Zurich)

Airlements, the "bricks" made from the ashes of blast furnaces

To create the Airlements, Patrick Bedarf used a sustainable insulation material produced by the ETH spin-off FenX: one mineral foam made from recycled industrial waste, in particular from fly ash obtained from the combustion processes of industrial blast furnaces.

"This material has already gone through the first material cycle and can simply be recycled after use”, explains Bedarf as he crumbles a piece of the new material between his fingers: once pulverized, the foam is ready to be reused.

“If the part of the building is no longer needed”, says the researcher, “it can be completely shredded and reduced to powder, ready to be transformed into new foam”. And it is completely free of cement, like the plaster used for the final treatment.

Every single prototype comes printed in less than an hour and left to dry for a week inside the production environment, at a controlled temperature between 20 and 28 degrees centigrade and with a humidity of 20-70 percent.

To check the correct adjustment of humidity and temperature, Patrick Bedarf built a special climatic chamber, a large transparent tent-shaped structure inside which the printer robot moves along the predefined path.

This production method, underlines the researcher, does not require special processing high energy intensity"This is an advance on previous work with cement-free foams, which had to be hardened with cement or subsequently cured at high temperatures in the oven".

The surprises of chemistry: so plastic waste becomes soap
Microplastic pollution: the solution comes from plants

New insulating and recyclable materials obtained thanks to 3D printing
The Airlements after a week of drying: the entire process takes place without resorting to energy-intensive processes (Photo: Digital Building Technologies, ETH Zurich)

Sustainable and economical construction thanks to automation

The new method via 3D printing allows you to use less material: for example, it does not require the use of formwork for casting, a structure that can only be partially reused and which today can be cut outright from the list of necessary resources.

The combination of 3D printing and robotics allows entire parts of custom-made buildings to be produced very economically: “Without automation”, explains the researcher, “Traditional construction methods that save on materials are very time-consuming and expensive, especially due to labor costs".

Patrick Bedarf will continue to develop the project in collaboration with FenX, which will dedicate an entire production line to Airlements: “We will thoroughly analyze the load-bearing capacity and insulation properties”, explains Bedarf, “to determine how this material acts as a wall element in a closed room".

"Infrared measurements”, concludes the researcher, “they will help us determine where thermal insulation could be further improved and how to eliminate any weak points by adjusting the print path".

Climate change: Switzerland allied with Chile, Kenya and Tunisia
Innovation Park: a future Blockchain-formatted city in the desert

The lightweight, cement-free 3D printed insulation elements for the construction of the Airlement project

3D printed lightweight cement-free insulation
The Airlement prototype, a two-meter-high column made of four segments of 3D-printed mineral foam (Photo: Digital Building Technologies, ETH Zurich)