Researchers at Purdue University are studying a process of internal curing of concrete that could reduce cracking and double the life expectancy of concrete bridge decks. Cracks form in conventional concrete decks due to weathering, years of wear and tear, and “shrinkage” caused by the water used in the process of externally curing concrete. Once cracks form, deicing salts may slip through to the underlying steel, thereby weakening the structure. As a solution, internally cured concrete cures from the inside out as water is released within the mixture, reacting more of the cement and strengthening the bond of the concrete (reducing shrinkage).
Jason Weiss, Ph.D., M.ASCE, a professor of civil engineering at Purdue and the director of the Pankow Materials Laboratory, began his research on internally curing concrete in 2004, based on similar studies published in Europe. He and his team have experimented on nearly full-scale concrete deck samples in the Pankow Lab, collaborating closely with the Federal Highway Administration, National Institute of Standards and Technology, and Indiana Department of Transportation.
Together, the team subjected the samples to conditions that typically lead to rapid salt ingress, corrosion, and cracking. “The internally cured samples remain crack free and corrosion free after more than three years of testing,” Weiss said in an interview with the American Society of Civil Engineers’ Civil Engineering magazine (May 2013).
According to a recent news release from Purdue, “The Joint Transportation Research Program, a partnership between INDOT and Purdue, worked with Weiss and INDOT to create specifications for implementing the internally cured high-performance concrete. It will be used on four bridges this year, the first of which will be on State Road 933 in St. Joseph County, Indiana.”
Learn more about the process here.