Researchers develop hook-and-loop fastener for building components

An interdisciplinary research team at Graz University of Technology (TU Graz) has developed a hook-and-loop fastening system for buildings in the ReCon project together with company partners. This allows different parts of a building to be resiliently connected and, if necessary, easily separated from each other.

The project’s focus was placed on the connection of components with different service lives, where irreversible connections usually make replacement difficult.

On the one hand, industrial hook-and-loop components were glued onto conventional concrete or wooden components and, on the other hand, the production of hook-and-loop components from the raw building materials concrete and wood, as well as from paper materials, were investigated.

Such hook-and-loop systems make it possible to properly separate durable load-bearing structures that are intended to last for decades from more short-lived elements such as installations, surfaces, floors or non-load-bearing interior walls.

In the ReCon project, the Institute of Architectural Technology, the Laboratory for Structural Engineering and the Institute of Bioproducts and Paper Technology (BPTI) at TU Graz worked together with the companies Axtesys and NET-Automation.

Replacement of parts instead of demolition

“The central principle of ReCon is that buildings can be dismantled using clearly defined, separable interfaces,” says Matthias Lang-Raudaschl.

“This means that in the event of renovation or new use, only those components that are worn or need to meet new requirements need to be replaced. This considerably extends the overall service life of a building, as a simple replacement of parts is sufficient instead of demolition. This prevents a lot of construction waste and consumption of materials.”

The system developed with hook-and-loop components made from raw building materials works in the same way as a conventional hook-and-loop fastener—only on a slightly larger scale. Mushroom heads or hooks are incorporated directly into the components, in which hook-and-loop elements (specially produced using 3D printing) are firmly hooked.

The fastening systems developed in the project showed good adhesive tensile strength comparable to industrial products in tests in the Laboratory for Structural Engineering at TU Graz.

The hook-and-loop fastener developed is primarily intended for interiors, for example, to replace non-load-bearing wooden or plaster walls or parts with installations. The researchers hope to further increase the adhesive tensile strength by using injection molding or stamped metal for the hook-and-loop element instead of the 3D printing used in the project.

Digitization of parts data

In addition to the hook-and-loop system, the researchers in the ReCon project developed a concept for a digital application to facilitate the re-use of components. The aim was to contribute to an improved circular economy by making component data usable in the long term. There were two approaches here.

Firstly, they integrated RFID chips into the components, which means that the data stored on them—such as composition and installation date—can be read on site.

As an alternative, they investigated the direct writing or insertion of minimum data on the component in the form of QR codes on the respective element. This makes it possible to better assess the condition and potential pollutants of the component during dismantling using an ordinary smartphone, which makes re-use much easier and increases safety. For example, a testing laboratory can evaluate many risks if the year of manufacture of a construction product is known.

Exhibits from the ReCon project are currently on display as part of the special exhibition “More Than Recycling—The Exhibition on the Circular Economy” at the Vienna Museum of Science and Technology. The special exhibition lasts until the end of 2026.