• Smart steel repairs bridge cracks and boosts strength 2× when heated at 392°F The method uses fiber-optic sensors and digital imaging to track structural changes. • Swiss scientists have made significant progress in improving the lifespan of aging concrete bridges after developing a smart shape-memory steel that tightens itself when heated, closing cracks and doubling structural strength. • The new strengthening system that pairs ultra-high-performance fiber-reinforced concrete (UHPFRC) with shape-memory steel, can be heat-activated to recover its original form. • It was developed by scientists at the Swiss Federal Laboratories for Materials Science and Technology (Empa). • According to the team, this high-strength concrete can be applied directly on the deck slabs and is extremely dense and resistant to water. • Conventional reinforcing steel is embedded in it to increase its load-bearing capacity.
Article Summaries:
- Swiss researchers at Empa have developed a shape‑memory steel system that can be heat‑activated at 392 °F (200 °C) to close cracks in concrete bridges and double their load‑bearing capacity. The method combines ultra‑high‑performance fiber‑reinforced concrete (UHPFRC) with iron‑based shape‑memory alloy (Fe‑SMA) bars that contract when heated, creating internal stresses that seal damage. In trials on full‑size concrete slabs and cantilevered decks, the hybrid system outperformed conventional UHPFRC‑only reinforcement, restoring cracked slabs and improving strength without complex tensioning devices. Fiber‑optic sensors monitored bar deformation, confirming the process. Although Fe‑SMA is costly, the team suggests targeting heavily damaged infrastructure for retrofit.
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