Almost everything we build (houses, buildings, bridges) depends on a material that we use without thinking too much, cement, true? It is so common that it seems inevitable, but its impact is enormous, just its production generates around 8 % of the world’s CO₂ every year. Eight percent!! But, there is a new material that is stealing the show… cardboard and paper, the same ones that end up in the trash everyday. We pollute by producing cement while wasting materials that could be used to build. But, wait, Laura, how can we use paper and cardboard in construction?
Okey, let’s explain it, regarding this scenario, a group of researchers from RMIT University in Australia decided to wonder a question that sounds almost naive and, at the same time, revolutionary, is there any possibility that can we build without cement and use resources that we already have lying around, forgotten? Wow, what a question! The answer led them to look downward (to the ground) and to the trash, to cardboard. From that unusual mix arose two new construction materials that not only eliminate cement, but are more resistant, cheaper and much less polluting. Like when you were a child and you use papier mache, do you remember it?
Both come from the same base, rammed earth, meaning soil compacted with a bit of water. A technique as old as the world, but recovered with modern eyes. The difference between one option and the other is in what wraps that earth, recycled cardboard tubes.
Carbon fiber tubes
In both cases, what matters is that there is no cement. Building with rammed earth is not a new idea. For centuries it was the norm, and it had an advantage that today sounds magical, it keeps stable temperatures. Houses that cool themselves in summer and keep heat in winter, without spending a fortune on energy. But cement arrived, it imposed itself as a standard and it was relegated to the category of primitive technique.
Now, with climate change breathing down our necks, the question is back on the table, of course, wouldn’t it be better to recover something that was cheap, abundant and efficient?
The problem with that technique was that it can crack if it supports too much weight. And here comes the clever part of the invention, to put it inside a tube that acts as “armor” and prevents it from expanding. This way, the rammed earth does not break and it is not necessary to resort to cement to reinforce it.
Recycled cardboard tubes
The first proposal is designed for small constructions, such as one-story houses. That material combines compacted earth with recycled cardboard tubes, which work at the same time as mold and structure. The result is surprising, it is resistant, stable and competes in performance with mixes that use cement.
And the number many want to see, it reduces the carbon footprint by 80 % compared to traditional concrete.
The more resistant version
The second version puts the earth inside carbon fiber tubes, an ultralight and very strong material, typical of airplanes or high-end cars. The result is a column that behaves almost like the best concrete, but with less weight and much less environmental impact.
It is not cheap, that is true. But its use makes sense in areas where lightness is critical, such as zones with seismic risk. Sometimes, spending more means avoiding catastrophes.
A possible future, but still being tested
Even the initial results look very good, the researchers say that is still necessary to study how these materials behave over the years. Durability, weather, wear… all of that is yet to be measured. But what is already clear is that there are viable alternatives to build more responsibly, without assuming that cement is the only option.
And perhaps the most powerful idea this project leaves is very simple, building does not have to pollute!