Concrete is by far one of the most important building materials of all time. Over time, however, it cracks and peels easily, which is aesthetically unpleasing and compromises its otherwise great strength.
But recent developments in materials science may lead to concrete that can repair itself. The material will help the construction industry, but it also finds another interesting potential customer: the U.S. Armed Forces. One major area where this material is beneficial is runways. Over time
, these structures will wear down, but they are also vulnerable to damage from air strikes. If the runway can be made of this material, they can repair themselves to ensure that the surface can continue to be used for aircraft.
To that end, the Pentagon's research office, the Defense Advanced Research Projects Agency (DARPA), aims to develop a specific type of concrete for military installations. Known as BRACE, or Bio-Inspired Restoration of Old Concrete Buildings, the program aims to restore aging concrete structures by combining the principles of biology and concrete.
BRACE uses biological organisms to build a vascular system within the concrete that can repair cracks internally, preventing them from reaching the surface of the structure. This allows the concrete to undergo a healing process similar to that of an organism. Concrete deterioration can also be diagnosed using this method.
"BRACE's core hypothesis is that concrete can be infused with self-healing capabilities common in organisms, drawing inspiration from the vascular system found in humans and the vast network of filamentous fungi that can span acres of land on a scale similar to concrete buildings," DARPA said in a recent press release. "Such a system could provide a transport network for healing deep in the material to repair cracks before they reach the surface and cause failure," he added.
BRACE will last 4.5 years as it is developed by several contractors, including the University of Colorado at Boulder, Lawrence Livermore National Laboratory, and Battelle Memorial Institute.
DARPA's announcement emphasized that "safety is paramount and all research will be subject to regular review by independent laboratories and regulatory agencies to ensure that BRACE technology does not pose a threat to human or structural health," possibly because BRACE uses biological organisms and processes. When testing BRACE outside the laboratory, researchers must comply with EPA regulations and consult with experts on the "ethical, legal, and social implications" of the technology.
"Bio-concrete" or self-healing concrete is not entirely new, but military applications may have significant advantages. Old and dilapidated buildings have become a serious problem at U.S. military sites, from barracks to supply depots. Self-healing structures will reduce costs. A self-healing runway would reduce maintenance costs during a conflict, but would also make it harder for attackers to plan their attacks because they would not know when the airport would return to operations.
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