Exclusive: One startup's paper-thin stainless steel could change how bridges are built | TechCrunch

"Bridges, which are exposed to water and salt, are some of the most vulnerable. About one third of bridges in the United States need to be repaired or replaced, which could cost nearly $400 billion over the next decade. There are plenty of ways engineers cope with rust, from coating the rebar with epoxy to pouring extra concrete to buy some time before seeping water reaches the rebar."

"But Allium is proposing a compromise, of sorts, by covering regular rebar with a thin layer of stainless steel to prolong the intended life of a bridge from 30 to 100 years. 'As long as we're getting full coverage of the surface, a thin layer is enough stainless steel to where it's going to resist corrosion for hundreds or thousands of years,' said Samuel McAlpine, co-founder and CTO at Allium."

Rust-driven corrosion of steel rebar causes premature concrete failure, and bridges exposed to water and salt are particularly vulnerable. About one third of U.S. bridges need repair or replacement, with potential costs nearing $400 billion over the next decade. Common mitigation methods include epoxy coatings and additional concrete cover, but those approaches eventually fail. Full stainless-steel rebar prevents corrosion but is substantially more expensive. A thin stainless-steel cladding on ordinary rebar can significantly prolong service life, and the approach has been applied in several bridge deck replacements and a commercial boat yard.

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