Self-Healing Concrete...the Future of Structures?

Bonita Bay Country Club Construction 2013
Bonita Springs, FL 

Self-healing concrete? It's closer to being possible than you think.

Concrete is a remarkable material. It can be molded into a number of forms, it sets like stone and it is extremely strong when combined with a metal such as steel.  It's no wonder it is the basic structural foundation for buildings, roadways and bridges.

Despite all these notable qualities, concrete has a major weakness--water.  Water poses a serious threat to the stability of a concrete structure, as all it takes is one small crack for water to get inside to turn a concrete structure into a pile of rubber.

Corrosion of the rebar in concrete. 

In colder climates, water can freeze and expand, compromising stability.  Water can also bring carbon
dioxides, sulfates and sulfate reducing bacteria that can cause even more damage to a structure. Perhaps the worst consequence of water in concrete is if it reaches the metal rebar. Overtime, the metal will rust, expand and slowly destroy the structure.

The key to preventing water from entering concrete is preventing the cracks from occurring. This is easier said than done. As even the most carefully prepared concrete is susceptible to cracking, especially when in a moisture prone area.

Researchers at the University of Bath in collaboration with Cardiff University and the University of Cambridge may have discovered another way to prevent concrete from cracking--a concrete mix with bacteria within microcapsules. The hope is that when water enters a crack, the bacteria will germinate and produce limestone, which will then plug the crack before water can do damage to the rebar.  The bacteria would actually use the oxygen present to repair the structure.

While this study is still in its early stages, researchers are optimistic that self-healing concrete will be able to increase the life of concrete structures vastly and would remove the need for repairs, reducing the lifetime cost of a structure by up to 50 percent. It would also reduce man-made carbon dioxide revisions.

Currently, researchers are assessing how the varying strand of bacteria survive in concrete over a period of time.