Can 3D printed hemp concrete replace traditional concrete?
Petros Sideris is an assistant professor in the Zachry Department of Civil and Environmental Engineering at Texas A&M University. He became interested in building 3D printing as an alternative to traditional construction over five years ago, and his research has focused on 3D printed concrete structures and their performance under in-service conditions. and extreme events such as earthquakes. He didn’t start researching the potential of 3D printed hemp concrete.
Throughout its research in the broad field of concrete structures, Petros Sideris has conducted large-scale structural testing, computer modeling of structures, and material-level modeling.
When he first heard about construction 3D printing, he was skeptical (considering it was over five years ago). “I’m not saying I thought it wouldn’t work. I say it wasn’t as popular. Interest in this field has grown almost exponentially since then. And there’s been this idea since the 90s, it’s true. There are even works that we found online that were made in the 1930s.”
However, almost a week later, he was convinced by the idea. “I felt there was a lot of potential in terms of automation. And if you look at that in more detail, you’ll see that the construction sector is probably the least automated sector in the economy, not only in the United States but around the world. There’s a huge potential for automation there, and 3D printing was going well in that direction. And that fits very well with efforts to solve some major problems like, for example, the housing issue, the “housing crisis” as we call it in the United States, which is probably also a problem in several countries. That’s kind of how I started. saw value, then I dove into it,” Petros Sideris said. “And here we are, with several different ideas, some about concrete and now some newer ones about more sustainable materials and their applications in actual large-scale construction.”
The general idea of Petros Sideris’ research is that there is a growing need for housing in the United States and in many countries around the world. In the United States alone, the Federal Home Loan Mortgage Corporation (Freddie Mac) recently estimated that the country needs more than 3.8 million new homes. At the same time, manual labour, construction labour, is decreasing. Given this, it is highly unlikely that the current state of building practices can meet these needs.
This is where the need for automation and alternative construction techniques comes into its own. 3D printing, due to its automation, 24/7 manufacturing, requiring minimal staff, is an almost perfect solution to this problem.
However, using traditional materials in conjunction with this more contemporary technology is not ideal, as concrete, for example, is not a sustainable and environmentally friendly material.
“Concrete, as you probably know, is not a very environmentally friendly material. That comes with a lot of carbon emissions. So it’s a big problem. What our project tries to do is to marry these two ideas. One is construction 3D printing, which I would argue is a more environmentally friendly construction process for two reasons – you don’t need to place the concrete anywhere other than where you have it need, and you don’t need formwork, that you would typically only use it a few times and then throw it away. So those are two major benefits of the process itself. Now we are trying to marry this process with a durable material. This durable material is hemp concrete. Hemp itself is a very attractive material for us in construction because it has, essentially, a negative carbon footprint – it sequesters a lot of CO2. What we’re trying to do in this project is print with hempcrete. This is the big challenge.
The second challenge is for the team to design structures that are structurally up to code and also up to code in terms of energy performance. “So we are trying to rethink the way you design structures with this type of material. We will also try to end up with an entire structure that is net carbon negative over its lifetime.
The team will also look at the performance of the structures over time. If a structure itself is durable, at face value, but needs to be replaced or repaired every few years due to damage from, say, a hurricane, it is not truly durable. To prove the hypothesis, the team will have to find the harmonious balance between sustainability and resilience – and study how the two influence each other.
Regarding the process of turning the hemp plant into hempcrete, Petros Sideris noted that he is not a materials engineer, and may not be the best person to explain the process to us, “But what I can tell you is that we’re looking at different parts of the plant. We are considering using hemp fibers, and we are also looking at more innovative approaches, like hemp powder, for example. We are looking at how we can use these materials to achieve a mixed media design that would be printable and eco-friendly at the same time.
Regarding modifying hempcrete to be 3D printable – “We have a plan on how to do this. We have been thinking about different ideas and we have specific ideas on how to do this. What we have done so far, even before the official launch of this project, is that we have already started talking to producers and seeing what materials we have available and discussing what we think we need. preliminary work in these directions.We believe that our approach will meet the challenge of having a 3D printable hempcrete mix design.
As part of the research project, the team will explore the availability and accessibility of the quantities of hemp necessary for this construction technique to be viable and sustainable. For now, “what I can say is that in the United States we know there is a lot of interest in growing hemp and supporting this idea. Studies have already shown that there are plenty of benefits to growing hemp for construction applications, so we expect there won’t be a problem. The project will investigate that, however, and come up with more specific answers to those questions because, at this point, that’s an expectation we have. It looks like there are a lot of producers ready to jump on this idea, but we’ll have a more definitive answer once we do a more specific analysis,” said Petros Sideris.
When asked what Petros Sideris thinks about the potential future of hempcrete, he replied this:
“It’s very difficult to predict. I guess at this point we can only speculate in terms of the market. But if we just try to think reasonably, what we know is that current building practices are not sustainable – for example, building this massive number of houses using conventional concrete, and for that reason, it is reasonable to expect that we cannot continue them for a long time. So ultimately, to meet these huge demands, you have to find a sustainable way to do it. In that sense, our project is moving in the right direction, and you can say that a structure that addresses both sustainability and resilience is sort of the answer, or a potential answer, to the challenge we face, I say like a nation [USA]but also all over the world.
Formal research is expected to begin in September once the team has finalized details with the Department of Energy, with the first possible results to be published in two years.