The team at DARPA is developing a revolutionary breakthrough in construction technology: self-healing concrete. This type of concrete is designed to repair itself after it has been damaged or cracked, eliminating the need for costly repairs and reducing maintenance costs. In this article, we take a closer look at this fascinating innovation, how it works and some of the possible applications.

What is Self-Healing Concrete?

Self-healing concrete (bioconcrete) is a revolutionary material that has the potential to not only transform the construction industry but also military applications. It is a type of concrete that has the ability to repair cracks and other damages or imperfections on its own without any human intervention.

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The Science behind Self-Healing Concrete

The science behind self-healing concrete is based on the use of specific bacteria and minerals. The bacteria used in self-healing concrete are specially selected to be resistant to the harsh alkaline environment of concrete.

These bacteria remain in a dormant state until they come into contact with water, which activates their metabolism. When the bacteria consume the nutrients provided by the minerals in the concrete, they produce limestone that fills the cracks.

It uses the natural process of biomineralisation, which is when a substance forms through the action of living organisms. The self-healing concrete contains small capsules filled with bacteria and calcium lactate that are activated by water when they come into contact with air.

When the capsule is exposed to air, the bacteria inside starts to work its magic and the calcium lactate gets converted into limestone, which is a natural building material. This process seals any cracks or weak spots in the concrete, essentially healing it.

Potential Applications Of Self-Healing Concrete

Self-healing concrete has the potential to transform many industries, from construction and infrastructure to military applications. In terms of construction, this type of concrete could be used for roads, bridges, buildings and much more. It may also allow for early diagnosis and preventive maintenance of concrete deterioration issues.

For military applications, self-healing concrete could be used to create stronger structures such as runways, bunkers or shelters that are more resistant to damage. The Defense Advanced Research Projects Agency (DARPA) of the Pentagon is researching the development of BRACE (bio-inspired restoration of old concrete edifices).

According to a DARPA press release: “The central hypothesis of BRACE is that concrete can be infused with self-repair capabilities typically found in living organisms, drawing inspiration from vascular systems found in humans and vast networks of filamentous fungi that can span acres of land similar in scale to concrete buildings.”

Is Bioconcrete Safe?

Bioconcrete is considered to be very safe. Since the bacteria used in the process are inert and inactive until they come into contact with air, there is no risk of them spreading or contaminating any other materials. The limestone that forms as a result of the biomineralisation process also does not pose any health risks.

However, DARPA stated that “safety is paramount, and all research will be subject to regular review by both an independent laboratory and regulatory agencies to ensure BRACE technologies do not pose a threat to human or structural health.”

Considering BRACE uses biological organisms and processes, when testing it outside the lab, DARPA researchers may need to adhere to EPA regulations and ensure everything is above board in terms of “ethical, legal, and societal implications” of the technology.

DARPA’s Contribution to Self-Healing Concrete

The Defense Advanced Research Projects Agency (DARPA) has made significant contributions to the development of self-healing concrete. In 2015, DARPA launched the Engineered Living Materials (ELM) program, which aimed to create building materials that can grow and repair themselves. One of the projects under this program is the development of self-healing concrete.

Whilst impressive in itself, the concept of self-healing concrete is not new as it was first introduced by Dutch microbiologist Hendrik Jonkers in 2006. His goal was to maximise the tensile strength and environmental integrity of concrete through natural means, thereby decreasing production costs and maintenance while limiting CO2 emissions.

To fulfil this mission, Jonkers created a bio-concrete with bacteria that can survive for up to 200 years embedded in concrete structures. When damage occurs, these bacteria would “wake up” and naturally form limestone to mend the concrete.

Benefits of Self-Healing Concrete

Self-healing concrete has numerous benefits that could make it a indispensable in many sectors, especially construction. Some of the advantages of bioconcrete include the following:

• Improved durability and longevity of structures
• Reduced maintenance costs
• Increased safety and reliability
• Reduced environmental impact
• Faster construction and repair times

Conclusion

Bioconcrete is a groundbreaking development in the construction industry as this innovative material can repair itself and extend the durability and lifespan of structures. The science behind self-healing concrete, which involves specific bacteria and minerals, is fascinating and holds great promise for the future.

In addition to the work done by microbiologist Hendrik Jonkers in 2006, DARPA’s significant contributions to the research and development of self-healing concrete have also accelerated its progress and opened up a wide range of potential applications and countless benefits.

It sure is an exciting time for the construction industry as self-healing concrete and we can expect to see more exciting breakthroughs in this field in the future. For more interesting updates on all things engineering, manufacturing and technology, read our weekly blog and find us on Facebook, Twitter, LinkedIn and YouTube.