Purdue University is enabling Indiana to make its bridges better with a new “internally cured” high-performance concrete.
The Joint Transportation Research Program, a partnership between the Indiana Department of Transportation and Purdue, worked with 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.
“This material will reduce maintenance costs and allow bridge decks to last longer,” said Jason Weiss, a professor of civil engineering and director of Purdue’s Pankow Materials Laboratory. “Our testing indicates that internally cured high-performance concrete experiences substantially less cracking and concrete damage caused by deicing salt and, when properly designed, the service life of bridge decks can be greatly extended.”
The researchers assisted Monroe County in the specification of internally cured concrete used in a bridge built in 2010. They are studying how well it performs compared to an adjacent bridge built the same year using conventional concrete.
“The control bridge has developed three cracks, but no cracks have developed in the internally cured bridge. Tests also show the internally cured concrete is approximately 30 percent more resistant to salt ingress,” Weiss said.
The internal curing process also allows engineers to reduce the amount of cement used in the concrete by replacing a portion of it with supplementary materials, such as silica fume, fly ash and limestone. These supplements will reduce the amount of waste, lessen the need for raw materials and reduce the carbon footprint of making concrete while improving its durability, Weiss said.
Sponsors and contributors to the work include INDOT, the Joint Transportation Research Program, the Indiana Local Technical Assistance Program, the National Institute of Standards and Technology, Lafarge North America, and the Expanded Shale Clay and Slate Institute.