Buildings are a major source of global emissions, and finding new ways to reduce this impact is key to climate goals.
“We know that we need to change the way we design. But we also know that concrete is not going to disappear from the building industry,” says Katie Heywood, a PhD researcher at Henning Larsen.
She is currently exploring the potential – and limits – of 3D printing concrete in building projects.
“One of the suggested advantages of 3D printing is that you can reduce the amount of material used, as you can deposit the material only where it is structurally needed.”
In turn, that could be a way to reduce the carbon footprint of buildings. But 3D printing does not automatically equal more sustainable solutions, as Katie Heywood explains.
3D printing on the launch pad
There is currently a debate about when and where to use 3D printing, with researchers arguing that it can in some instances even be more carbon-intensive than traditional building methods because of the types of cement used.
“We know 3D printing isn’t the solution for everything, but if we keep testing and trying new things, then the hope is this will lead to a greater understanding of how to design and use this fabrication process. Even if we discover that it only has a positive impact in specific scenarios, that is still better than nothing,” Katie Heywood says.
“We are starting with concrete because it is already used in the industry. But the hope is we can use this gained knowledge as a launch pad once a better, more sustainable material arrives,” she adds.
“But in any case, it is probably never going to be a good idea to 3D print a whole building, because for some elements like the interior partition walls, it just does not make sense to use concrete when we already have lower impact options such as timber.”
Ranking 1,050 columns from best to worst
A 2017 McKinsey report found that construction is one of the least digitised industries, second only to agriculture in the United States. But you would not know it from talking to Julie Corneliusen.
She is a computational designer at Ramboll, and she took part in designing 3D printed, hollow concrete columns for a prototype building in Fredericia, Denmark, aiming for a carbon footprint of 5 kg CO2e/m2 per year.
“There is a lot of room for CO2 optimisation in the industry – and computational design can be an essential asset in the search for optimised solutions, because it allows us to comprehensive variance studies and make more informed decisions,” Julie Corneliusen explains as she opens a design tool on her computer that she and a colleague have coded.
The tool can rank concrete columns based on a number of inputs and identify the least carbon intensive. Julie presses play as she explains:
“This can quickly calculate 1,050 versions of the same column. In this case, the column with the lowest carbon footprint has a small cross section, low strength but a lot of steel reinforcement,” she says and points to a dot in the lower right corner of the graph that has just been generated.
“You might not think it would be more sustainable to add a lot of steel, but because we save a lot of concrete that more than makes up for it. The next best solution uses a lot less steel, is still low strength, but has a larger cross section.”
Computational design could require more resources up front, but that effort is more than made up for through greater flexibility, and the ability to update designs as parameters change.
The next big thing
Trying to predict the future of technology is tricky business. Famously, the former CEO of IBM predicted in 1943 there would be a global market for about five computers.
Katie Heywood is cautious not to make similar sweeping predictions, but she sees a big potential:
“If you look at the history of architecture and design, you get these big moments where suddenly everything changes. One of the biggest is the industrial revolution and the introduction of reinforced concrete and steel.”
She continues, “Right now, we are seeing the introduction of digital fabrication into architecture, which is creating whole new design aesthetics. This is why people are getting excited, the idea that maybe this is the next big thing, which will change the way we work, think, and design buildings and architecture.”
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