U.S. Researchers Develop Cement That Heals Itself from Cracks

When geothermal wells are made using PNNL-developed self-healing cement, cracks and breaks in the well can heal automatically. Image courtesy of PNNL.

Chemist Carlos Fernandez and other Pacific Northwest National Laboratory (PNNL) (Richland, Washington) researchers are developing cement for geothermal production wells that can heal itself when cracks occur.

Because wells with cracked cement are vulnerable to leakage, reduced strength, and corrosion, PNNL explains that it is important to repair them in a timely fashion. However, the costs of new materials, excavation, installation, and halting power production can be significant.

Fernandez discovered that adding synthetic polymers to cement could create self-healing properties. These chain-like molecules hold substances together, and Fernandez’s team learned that by mixing in 5% to 20% of these polymers into cement before it is poured and cured, the cement could repair itself. The researchers say they have proven this cement can repair within days, and they say it has potential to heal within hours.

Just as impressive, however, is the cement’s projected ability for continuous self-healing, meaning it can repair itself repeatedly and still maintain its rheological and mechanical properties.

The work is a collaboration between PNNL, Brookhaven National Laboratory (Upton, New York), and the National Energy Technology Laboratory, funded by the U.S. Department of Energy’s Geothermal Technologies Office (Washington, DC).

For more information, visit pnnl.gov.