Cracks could be a thing of the past with new self-healing concrete
Constipation doesn’t cause concrete to crack over time, but limestone-pooping bacteria might offer a solution. The term “self-healing concrete” doesn’t come from a page of the latest science fiction bestseller; it actually exists thanks to a microbiologist from the Netherlands.
All Cracked Up
Foundations, patios, driveways, streets, parking lots, and other structures made from poured concrete don’t last forever. Eventually, they develop small fissures in the surface that gradually spread and broaden until they require replacement.
Severely damaged concrete results in safety hazards and other problems. Potholes threaten to damage vehicles’ tires on streets, while foundation cracks threaten the structural integrity of a home.
Numerous factors cause concrete to crack, including settlement of the ground, shrinkage or expansion caused by temperature or humidity, stress on the structure, and corrosion of reinforcements.
Once concrete begins to crack, the steady deterioration of the surface continues until it no longer possesses sufficient stability for use. At that point, the owner must undertake the considerable expense of replacing it.
The American Road & Transportation Builders Association (ARTBA) estimates that it costs up to USD $3 million to construct a single mile of a two-lane, undivided road. On a smaller scale, the average homeowner spends USD $2,368 to build a new driveway, according to Homewyse. While repaving costs are considerably less than constructing a new surface, repair, maintenance, and repaving expenses add considerable money to the original cost of a project.
A Crack in the Case
The Engineering NewsRecord reports that Professor Henk Jonkers of Delft University of Technology now owns a patent on self-healing concrete. Casually called “limestone-pooping bacteria” by those who work with Jonkers, this product resembles traditional concrete in every sense except that it contains a bacteria that secretes calcium carbonate upon exposure to water.
The calcium carbonate fills the minute cracks in concrete, effectively sealing them against further destruction. This process requires no human intervention or supervision, which means that the bacteria act autonomously to repair small amounts of damage.
The ENR estimates that self-healing concrete could increase the lifespan of a surface by as much as 30 per cent. This reduces the long-term costs of concrete maintenance and increasing the safety of concrete surfaces. Construction companies could easily incorporate this product into their projects saving both themselves and their clients money.
Taking another Crack at It
For decades, construction companies and engineers have reinforced concrete with steel and other metals to ensure its durability and safety. When contractors build highway overpasses and other structures that must withstand a great deal of weight, reinforcements reduce the potential for structural failure.
Jonkers sees the potential cost benefits as the primary selling points of self-healing concrete. Sourceable points out that this invention would also eliminate (or at least reduce) the need for steel reinforcement. Since the bacteria in self-healing concrete readily repairs minor damage to the surface, structures built with it would automatically possess greater stability.
Opponents worry that self-healing concrete costs more to purchase and apply. While it would increase the initial costs of building a structure, it would ultimately save the owner money because of reduced maintenance and repair bills.
While self-healing concrete is not yet the norm, it presents unique possibilities. Since Jonkers’ company is currently talking with distributors, we might soon witness the viability of his product.