concrete bridges are built to handle heavy loads and routine traffic for Reinforced 75 years or more. But bridges in climates like Minnesota’s are exposed to moisture and chlorides from road salts that may penetrate these structures and corrode the steel.

In a recently completed research project, funded by MnDOT and the Local Road Research Board, researchers studied a rural bridge built in 2017 near Elgin, MN, that used glass fiber–reinforced polymer (GFRP) rebar in the bridge deck. They found that GFRP performed well, proving sufficiently strong for use as an alternative to corrosion-susceptible steel rebar.

What Was the Need?
Corrosion of reinforcing steel is the primary cause of bridge deck degradation and cracking. Multiple cycles of freezing and thawing can also cause concrete to crack, further exposing reinforcement.Damage to bridge decks increases over time, requiring costly maintenance and repair, and potentially shortening the bridge deck’s service life. Crack sealing and drainage systems help manage moisture and chloride impact, but bridge owners often consider alternatives to enhance the longevity of the reinforcement. Epoxy coating of reinforcement, for example, is frequently used in Minnesota to help rebar resist corrosion.