3D Printing: The Swiss Research Group Pushing Construction Through Additive Manufacturing
3D Printing in the Construction Industry
The applications of 3D printing are vast and applicable to numerous industries. Although the technology has existed since the 1980s, recent advances and innovations within the field are showing potential for its use within the construction industry, promising significant socioeconomic and environmental benefits for the sector.
The process of 3D printing produces a fraction of the waste of traditional manufacturing and requires less energy to move parts along the production line reducing the carbon footprint of construction – A footprint that equates to 40% of all total global emissions.
Without a change in approach the environmental impact of construction is set to grow as population continues to increase. Estimated figures suggest that to meet the growing housing demand we are going to undertake 230 billion square metres of new construction.
Additive construction techniques have the potential to offer the change in approach required and create new resilient housing quickly and affordably whilst offering a sustainable reliable solution. However, the technique itself is not inherently sustainable, as some companies still rely on cement as the print source material. Cement alone is responsible for 8% of global CO2 emissions, virtually eliminating any positive impact on the environment that 3D printing can deliver.
Groups are working on applications of low CO2 alternatives to cement to address this contradiction. California-based 3D printing construction company Mighty Buildings is one of those, announcing a partnership with Fortera a materials technology company that produces an innovative cement that reduces CO2 emissions by more than 60% compared to traditional cement.
What if we can take this a step further and totally eliminate cement from the process? Is it possible to turn waste materials into a 3D printed structural form?
The Digital Building Technologies Research Group
A research team in Switzerland are tackling this challenge and exploring the potential applications of 3D-printed foams. The Digital Building Technologies (DBT) is part of ETH Zurich and explores the scope for integrating processes including computational design methods, digital fabrication and new materials into the built environment. The aim of the research is to find solutions that will challenge the traditional paradigms of construction.
The group have been looking into the applications of a 3D printed foam created from the mineral waste of coal fired power stations. The project entitled architected porosity strives to create low carbon and circular solutions from this material and is a collaboration with Innosuisse , and FenX AG – a spinoff materials company from ETH and the producer of the innovative material foam.
FenX have engineered a foam composite that transforms fly ash into a high performing sustainable insulation with remarkable properties. Fly ash is a byproduct from burning pulverized coal in electric power generating plants and the company aim to turn this readily available material which is the output from an inherently unsustainable industry into a sustainable and circular solution.
The group have developed prototypes in various scales and in combination with other conventional construction materials to explore the potential application of the mineral waste foam composite.
FoamWork - A Material Saving Prototype
The FoamWork prototype used a combination of other conventional construction materials, in an already existing manufacturing technique, to explore the environmental benefits of using additive manufacturing. Taking the innovative material and applying it to the existing formwork process to increase efficiency.
The research group designed 24 internal 3D printed elements, to be set in a wooden rectangular mould before ultra-high-performance fiber-reinforced concrete was cast around the forms and left to cure. The internal formwork created by the 3D printed elements created a geometric shape that was designed to reinforce the slab across its principal stress lines.
The embedded 3D printed foam moulds created a concrete slab with the necessary strength whilst using 70% less material. According to Patrick Bedarf a researcher for DBT “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.”
The FoamWork elements can be left in place to improve the insulation of the precast concrete slab or recycled and reprinted to create new formwork. Considering that no offcuts are created in the additive manufacturing process, this means the entire system has the potential to be zero-waste.
The prototype reduces the concrete used for the end product, through a technique that creates zero waste and contributes to the circular economy. The innovative solution demonstrates how we can better manage our limited resources.
Airlements - A Vertical Breakthrough
This year DBT unveiled its latest prototype, Airlements a 2m high monolithic structure. The structure is an assembly of four 3D printed parts and is the largest of its type conceived in this research. Each part was 3D printed in under an hour, and then hardened for 1 week inside the fabrication environment with a controlled temperature of 20 – 28°C and relative humidity of 20 – 70%.
The construction process for the foam monolith was both waste and energy efficient. No energy-intensive processes were used in the hardening process which is an advancement on previous research on cement-free mineral foams. Whilst the additive manufacturing technique utilises mouldless fabrication which is resource efficient for material, labour and costs.
A remarkable property of the material is that it has a tuneable degree of porosity. This enables the group to adjust the density of the material, creating either a low-density foam with high insulating properties or a high-density foam with increased structural strength. The structural strength has been enhanced further by the corrugated texture of the walls created by the design path used when printing.
The monolithic structure has the potential to create non load bearing walls for construction and the benefits are extensive. Due to the thermal properties of the porous material, these structures have the potential to reduce the operational energy required for heating buildings. Each of the 3D-printed parts is lightweight (weighing only 25kg), improving the ease of handling and movement of the structure. The structures are easy to recycle and can be reemployed into new foams at the end of their life, contributing to the circular economy.
Future development from the research group will focus on increasing the load-bearing capacity of resulting elements and fabrication precision of the 3D-printing system.
Learn More on Firstplanit
Click here to read about Europe’s largest 3D printed building situated in Germany’s city of science