In fact, materials from tire recycling already have many applications in which they show that they work very well: urban furniture, sports courts, floors for playgrounds, asphalt for roads, high-end jewelry and fashion accessories, etc.
The search for possibilities to incorporate these high-quality tire components as raw materials, as befits an essential product for the operation and safety of vehicles, continues to bear fruit.
One of the latest proposals is to incorporate recycled rubber into construction elements for the building sector. A first possible application is incorporation into plaster compounds; that is, the plates with which partitions, ceilings, etc. are made.
And this is reflected in the Guide on circular materials with recycled tires in construction, prepared by Signus. This is a first publication, of a technical nature, aimed at professionals in the building sector interested in incorporating recycled materials with high added value in their construction solutions.
The Guide includes the results of the collaboration between Signus and the Higher Technical School of Building of the Polytechnic University of Madrid, through the Signus-UPM Classroom. A relationship that “emerged from the mission that Signus has – along with that of guaranteeing the management of tires at the end of their useful life – to promote the circular economy by identifying applications with which to give a second life to materials from rubber in sectors with high consumption potential,” explains Roberto Pérez, head of Development and Innovation at Signus. Search in which they coincided, in 2023, with “a working group from the UPM School of Building, who had already been interested in using recycled materials, including tires, and had done some tests.”
A rigorous process
The R&D process has been in charge of the university group “and we were seeing together at each stage where to go, what decisions to make. They are the experts and those who have defined the process, the methodology, etc. And it has been followed according to the reference technical standards “that accredit to all parties in the sector that these compounds comply with all standards and guarantees, as well as the life cycle analysis that accredits their environmental values.”
The decision to opt for application on plaster sheets was made because “the research group already had several lines of research open with prefabricated plaster. With that knowledge that they already had, it was the most viable, the most viable, the safest and the easiest to apply in the short term,” Pérez summarizes. Because, as he explains, “currently the trend is what was previously done with brick, such as interior partitions, now everything is with prefabricated pieces of that type, made of plaster.”
The result of all the laboratory tests is that “we show that not only plaster panels can be manufactured with recycled tire rubber; But we also demonstrate that doing this improves the behavior of these sheets against the action of water and humidity, and improves thermal and acoustic insulation. It also has greater elasticity and adapts better to changes in temperature, so there are fewer fissures and cracks. And, finally, it also has better fire resistance, in cases of fire.
Lower plaster consumption and assured recyclability
Life cycle analysis has shown that the incorporation of rubber granules from tire recycling into plaster sheets also has other advantages, such as economic and environmental ones. One is “that the manufacturer will need to acquire, transport and process less gypsum. That, in itself, is already an advantage in the final balance of economic costs. The other is that environmental costs are also reduced. Because it reduces the extraction needs of an aggregate, which is a non-renewable material, and the emissions associated with its transportation. “All environmental impacts decrease when rubber is used.”
Furthermore, at the end of their useful life, these panels “will also be able to be subjected to a process to recover the rubber components, just like those made with 100% virgin raw material.”
pedagogical work
The Guide on circular materials with recycled tires in buildings exhaustively covers all these aspects, from the technical characterization of the recycled cork powder and granules, the parameters for the design of plaster compounds, the laboratory results of the formulations developed and the information on recyclability and life cycle analysis of these new materials. As said at the beginning, it is a technical tool for professionals in the sector.
With which Pérez is very aware that now it is time to do a pedagogical task so that the different professionals in the construction and building sector know the possibilities and advantages of these plaster compounds. “I think architects and designers are very receptive, because there is already a clear tendency to take sustainable materials into account and they are already integrating them a lot into their daily lives.”
Perhaps it will be more difficult for manufacturers, “who have an industrial process that works for them and is profitable, to change it.” For him, what is interesting is the work that public administrations can do, “through green public procurement, which is one of the tools to increase the use of sustainable products, in this case in areas such as construction.”
More applications
This first guide is expected to be followed by others, since the spirit of both Signus and the working groups that collaborate with the Aula Signus-UPM “is clear to expand the search for more application possibilities for tire materials.” Such as the recovery of metal filaments to incorporate them as reinforcement in construction binding materials, such as concrete. Or the recovery of textile fibers, to use them mixed with plaster or other types of mortars to increase their insulating, thermal or acoustic performance.
In short, the future of recycled tires and construction has only just begun.