When compared, aluminum weighs about one-third of the weight of steel but has a higher carrying capacity. Aluminum provides bridges with higher performance at lower transportation and installation costs. Aluminum has a natural protective coating and has outstanding properties against corrosion. This leaves little or no budget for maintenance at all. Aluminum is a non-corrosive metal because it naturally produces a protective oxide that regenerates when scratched, which coats the outside. This oxide layer is highly corrosion-resistant, resulting in maintenance costs, and produces an aesthetic metal face without rust stains. Aluminum is a non-corrosive metal because it naturally produces a protective oxide that regenerates when scratched, which coats the outside. This oxide layer is highly corrosion-resistant, resulting in maintenance costs, and produces an aesthetic metal face without rust stains.