During his State of the Union address on January 30, President Trump announced a $1.5 trillion proposal to fix “crumbling infrastructure.”
His comments came just two days before the American Road & Transportation Builders Association (ARTBA) reported that 54,259 of the nation’s bridges are “structurally deficient.”
It’s clear that something needs to be done.
A Big Threat To Driver Safety
The collapse of the I-35W Mississippi River Bridge back in 2007 got the entire country talking about deficient U.S. infrastructure. 13 people died in that disaster, and 145 were injured.
In addition to the threat that decaying bridges and roads pose to drivers’ safety, there’s also a big economic cost.
Traffic bottlenecks cost the trucking industry $60 billion per year. And the cost to ordinary commuters stuck in traffic is $1.9 billion of wasted fuel over a combined total of 4.8 billion hours.
The ARTBA said it will take 37 years to bring all bridges up to standard at the current pace of repairs.
Thankfully, academia is stepping in to help. Researchers at Binghamton University have announced a formula for self-healing concrete.
The new technology uses a fungi to permanently repair cracks in aging concrete. “Without proper treatment, cracks tend to progress further and eventually require costly repair,” said Congrui Jin, assistant professor of mechanical engineering.
The secrete to self-healing concrete is a fungi called Trichoderma reesei. According to Jin, “The fungal spores, together with nutrients, will be placed into the concrete matrix during the mixing process. When cracking occurs, water and oxygen will find their way in. With enough water and oxygen, the dormant fungal spores will germinate, grow and precipitate calcium carbonate to heal the cracks.”
The technology isn’t only a potential solution for permanently repairing bridges. It has applications for other concrete structures, like the radiation shielding on nuclear power plants.
Other Players In The Field
Back in 2016, engineers at the University of Victoria in British Columbia, Canada announced their own process for creating self-healing concrete. Rather than fungi, their technology involved testing substances such as fly ash and wood cellulose to see if the proper combination would effectively seal concrete cracks.
Their experimental mixture was much stronger than standard concrete, and could withstand earthquake conditions as powerful as 9.1 on the Richter scale.
Engineers at Cardiff University in Wales have also tested self-healing concrete mixtures. Their team tested three technologies: memory-shape polymers, organic and inorganic “healing” materials, and bacteria.
A Long Way To Go
Until these experimental technologies become available on the commercial market, there isn’t much America’s civil engineers can do except monitor and repair the damage the old-fashioned way.
But even when it comes to monitoring damaged bridges, organizations are using new cutting-edge technologies. The Minnesota Department of Transportation has been using drones to assess the condition of the state’s 20,000 bridges. AT&T is also testing a sensor system that can monitor changes in the size and angle of bridge cracks.
So there is hope for our crumbling bridges. But the next step will be getting them all fixed sooner than the ARTBA’s depressing estimate of 37 years.
Sources: Construction Dive (1), Construction Dive (2), Construction Dive (3), Brookings, Science Daily