Demolition of old structures at the end of their service life results in large amounts of waste and carbon emissions, not to mention the labor involved and the cost of producing new materials. According to official statistics, construction and demolition waste accounts for more than one third of all waste generated in Europe.
A team from Austria's Graz University of Technology (TU Graz) questioned if there might be a better, more sustainable approach to dealing with old brick buildings. What if instead of being demolished, they could be carefully deconstructed, so that the bricks could be reused in future construction projects?
This concept is similar to taking apart a Lego structure and rebuilding it elsewhere with the same parts. Obviously, using conventional mortar is not going to work in such a case. Instead of binding bricks together permanently, the researchers developed prefabricated brick wall elements connected through so-called reversible joints.
As of now, there is unfortunately not much information disclosed about the design or any technical details of the reversible joints. We've reached out to the researchers, but are still waiting to hear back.
The bricks used in the project are 44 cm (17.3 in) thick and contain insulating wool for improved thermal performance. These wall elements are pre-plastered at the factory, which reduces the amount of work required on the construction site.
One of the main goals behind the project was to reduce emissions from construction materials, and, according to project manager Hans Hafellner from the Institute of Building Physics, Services and Construction at TU Graz, the results look very promising.
“The results of our research to date show that a significant proportion of total emissions can be avoided during the second phase of use through reuse by developing an innovative jointing solution," he says. "Considering three life cycles, CO₂ emissions can be reduced by around 60% compared to conventional construction methods.”
Permanent mortar is what typically provides structural stability to a whole building, and since it could not be used, the engineers at TU Graz had to develop alternative methods to ensure the same safety standards.
This became one of the main challenges for the research team, and they came up with two solutions: stability can be achieved either through a roof that is heavy enough to stabilize the entire structure, or through vertically pre-stressed threaded rods that run through the bricks. Both methods reportedly provide the necessary structural strength, meet all safety regulations, and still allow the walls to be dismantled when required and reused for new buildings.
The idea was tested using a demonstrator building. After being dismantled and reconstructed at a different location, the new structure was fully functional and met all the requirements.
The concept of a circular economy is at the core of this project, which means that resources can be reused multiple times instead of just creating more waste. If adopted on a global scale, this solution will not only have a positive impact on the environment but also benefit the economy by increasing the residual value of buildings at the end of their service life.
Source: TU Graz
