US engineers use smart alloys to make concrete rail ties self-repairing

Engineers at the University of Illinois Urbana-Champaign, led by Professor Bassem Andrawes, have developed concrete rail ties reinforced with shape memory alloys (SMAs) that can self-repair cracks caused by heavy train traffic. SMAs are smart metals that "remember" their original shape and return to it when heated. By embedding SMAs into concrete ties and using induction heating to activate them, the ties can realign and repair themselves after deformation, potentially enhancing railway safety and reliability. The research, conducted in partnership with Rocla Concrete Tie, Inc., involved casting SMAs into standard ties, testing various SMA lengths under stress, and performing full-scale load tests simulating train traffic. The SMA-reinforced ties met and exceeded the American Railway Engineering and Maintenance-of-Way Association (AREMA) standards, marking a significant advancement toward practical application. The team plans to commercialize the technology and conduct real-world testing at the Federal Railroad Administration Transportation Technology Center, aiming to reduce maintenance costs, improve