Wedoany.com Report on Feb 25th, Swiss researchers are developing a new method that utilizes two high-tech material systems to reinforce and retrofit concrete bridges. At the Swiss Federal Laboratories for Materials Science and Technology (Empa), researchers Angela Sequeira Lemos and Christoph Czaderski are combining Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) with Shape Memory Steel (Fe-SMA) in their structural engineering laboratory.

Shape memory steel is a smart material that can "remember" its original form. When this steel reinforcement is embedded in concrete and heated, it contracts, helping to close cracks and improve the performance of deformed structural elements. The Empa team is the first to explore the synergy between memory steel and UHPFRC.

In tests at the Empa laboratory, researchers used a cracked 5-meter concrete slab to simulate a damaged cantilever bridge deck. One slab served as a control group, while others were reinforced using different combinations of UHPFRC, traditional steel reinforcement, and Fe-SMA. They monitored surface deformations with digital cameras and installed optical fibers within the slabs to collect data.

The test results showed that all reinforcement systems improved load-bearing capacity, but the combination of UHPFRC and Fe-SMA performed particularly well. It delayed permanent deformation, closed existing cracks, and enhanced the performance of slightly bent structural members. Lemos and Czaderski are currently looking for an actual bridge to trial this system. Lemos stated, "If we can reinforce a real bridge with our system, industry interest could grow rapidly. As demand increases, material costs might also decrease – and then this technology could bring about lasting change in bridge renovation."