More than 40,000 bridges in the United States are deemed structurally deficient, and as many as 221,000 deemed in need or repair, according to the American Road & Transportation Builders Association. FIU researchers have developed a system that could play a key role in restoring them.
Engineers have created a system that sprays Ultra-High Performance Concrete (UHPC) onto structures. Such concrete not only has the potential to patch walls, fix pipes and restore drainage culverts, it can make these structures stronger than they were in the first place.
UHPC is many times stronger and more water-resistant than regular concrete. Despite its inception some 30 years ago, its use in United States has been limited due mainly to high cost.
That might be about to change.
"UHPC has historically been very expensive to use, mainly because most of those available [mixes] on the market have been commercial versions. Even a very thin layer of UHPC can drastically improve the strength of a structure and protect it from water," says Atorod Azizinamini, a professor of civil engineering and director of a U.S. Department of Transportation-funded research center at FIU.
"We have developed an affordable type of UHPC, and a system that can spray it. This could become a major tool in repairing or upgrading structurally deficient bridges quickly and efficiently."
At around $500 per cubic yard, the FIU-made UHPC mix comes at a fraction of the cost of many comparable commercial versions of UHPC, Azizinamini says. And since only a thin layer of it is needed, the overall costs are manageable for many projects.
