Study: Creating Concrete Slabs from 3D-Printed Foam
A team of researchers from public research university, ETH Zurich, have recently been reported to successfully create a pre-cast concrete slab using 3D-printed formwork elements made from recyclable mineral foam.
The research was conducted as a collaboration between ETH Zurich’s Digital Building Technologies and Swiss start-up FenX AG.
In using 70% less material than traditional concrete slabs, the team found that FoamWork, their newly developed building material, is both lighter and better insulated. The slab mold prototype used for the research was reportedly filled with 24 mineral formwork elements in 12 different shapes and sizes before concrete was cast around the material to cure.
The framework uses a 3D printer and autonomous robotic arm to print the mineral foam before being placed into a conventional timber perimeter formwork. The material itself is created by foaming cement. As a result, hollow cells are created throughout the panel.
To optimize the material’s strength and insulating materials, the team reinforced the material’s internal geometry—particularly along its stress lines—to achieve both goals, in addition to drastically reducing the amount of concrete needed to produce the slab. However, the shape and configuration of the internal cells could be customized in order to create a range of concrete building elements, such as walls or roofs.
According to reports, the foaming cement mineral material has become more popular as an insulation material in construction due to its high porosity.
To further reduce emissions associated with cement production or associated construction, the FoamWork system utilizes an alternative developed by FenX AG that creates materials using waste product from coal-fired power plants, also known as fly ash.
“Construction contributes significantly to CO2 emissions, with cement production alone responsible for 7% of emissions globally,” said Patrick Bedarf, who is an architect and researcher in the department for Digital Building Technologies (DBT) at ETH Zurich.
“With FoamWork, emissions through material consumption would be reduced in the concrete slab. The lower mass would also have secondary effects on the dimensioning of the entire load-bearing structure and would reduce efforts for shipping and handling on construction sites.”
3D Printing in Residential Construction
Earlier this month, Habitat for Humanity announced the completion of its first home entirely constructed using an Alquist 3D printer.
According to reports, the 1,200-square-foot, three-bedroom, two-bathroom concrete structure can withstand hurricanes and tornados and was constructed in just 12 hours. Following completion, the home was sold through the Habitat Homebuyer program, which works with applicants who clarify their need for safe, affordable housing from community to community around the country.
In February 2021, New York-based construction technology company SQ4D Inc. listed a 3D-printed home that was the first slated to receive a certification of occupancy in the U.S. The residential property, which was printed onsite with the company’s Autonomous Robotic Construction System, was listed on MLS for sale as new construction for $299,999, in Riverhead, New York.
The 1,400-square-foot home (plus 750-square-foot garage) offers three bedrooms, two bathrooms and features an open floor plan. The building material listed reads as insulated concrete forms and SQ4D notes that the home includes the same 50-year warranty that the company puts on all of its 3D-printed structures.
The ARCS technology reportedly built the footings and foundations as well as the interior and exterior walls and the company notes that it’s a step in its mission to help aid the affordable housing crisis.