February 13, 2017
Feature

Cracking Under Pressure is No Problem for High Strength Self-Healing Cement

With the addition of polymers, PNNL- developed "super cement" that can self-heal

Fernandez_.Cement
When geothermal wells are made using PNNL-developed self-healing cement, cracks and breaks in the well can heal automatically. T

With an average life span of 30-40 years, the cement around geothermal production wells eventually cracks over time. Because wells with cracked cement are vulnerable to leakage, reduced strength, and corrosion, it's important to repair them in a timely fashion. However, repairs can easily top $1.5 million dollars; the cost of new materials, excavation, installation, and halting power production adds up fast.

Researchers at PNNL developed cement that can heal itself when cracks occur. Using self-healing cement for geothermal wells would save geothermal plants millions of dollars and would reduce the amount of downtime necessary for repairs.

Super to the Power of Three.

PNNL chemist Carlos Fernandez and his team discovered that by adding a strong and flexible and powerful ingredient, called polymers, they could create self-healing cement. Naturally found in the human body, plant structures, and more, these large, chain-like molecules work to hold substances together. The team discovered by mixing in 5 to 20 percent of man-made polymers into typical cement before it is poured and cured, the cement can repair itself when cracks occur. PNNL’s research team has successfully proven this cement can repair itself in a few days, and they predict it has the potential to heal itself in just a matter of hours. Just as impressive, is the cement’s projected ability for continuous self-healing, meaning it can repair itself many times over and maintain the rheological and mechanical properties necessary for geothermal wells.

Acknowledgments:

Sponsor: This work is part of a collaborative project between PNNL, Brookhaven National Laboratory, and National Energy Technology Laboratory funded by DOE's Geothermal Technology Office.

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About PNNL

Pacific Northwest National Laboratory draws on its distinguishing strengths in chemistry, Earth sciences, biology and data science to advance scientific knowledge and address challenges in sustainable energy and national security. Founded in 1965, PNNL is operated by Battelle for the Department of Energy’s Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States. DOE’s Office of Science is working to address some of the most pressing challenges of our time. For more information, visit https://www.energy.gov/science/. For more information on PNNL, visit PNNL's News Center. Follow us on Twitter, Facebook, LinkedIn and Instagram.

Published: February 13, 2017

PNNL Research Team

Carlos Fernandez, Wooyong Um, Phillip K. Koech, M. Ian Childers, Kenton Rod, Vanda Glezakou, Manh T. Nguyen, Jaehun Chun, and Diana Linn