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[Dr. N. Subramanian]

Self-Healing Concrete: Research Yields Cost-Effective System to Extend Life of Structures

ScienceDaily (May 25, 2010) — Efforts to extend the life of structures and reduce repair costs have led engineers to develop "smart materials" that have self-healing properties, but many of these new materials are difficult to commercialize. A new self-healing concrete developed and tested by a graduate student at the University of Rhode Island, however, may prove to be cost-effective.

Michelle Pelletier, a URI master's degree candidate from Woonsocket, embedded a microencapsulated sodium silicate healing agent directly into a concrete matrix. When tiny stress cracks begin to form in the concrete, the capsules rupture and release the healing agent into the adjacent areas.

The sodium silicate reacts with the calcium hydroxide naturally present in the concrete to form a calcium-silica-hydrate product to heal the cracks and block the pores in the concrete. The chemical reaction creates a gel-like material that hardens in about one week.

One additional advantage to the use of self-healing concrete is that it could reduce the significant CO2 emissions that result from concrete production. Because the production of concrete is very energy intensive -- when mining, transportation and concrete plants are considered -- the industry is responsible for about 10 percent of all CO2 emissions in the United States.

"If self-healing concrete can lengthen the life of the concrete and reduce maintenance and repairs, it will ultimately reduce the production of excess amounts of concrete and result in a decrease in CO2 emissions," she said.

Read more at:http://www.sciencedaily.com/releases/2010/05/100524143421.htm