It’s long been proven that adding nanoparticles to concrete improves the materials’ strength and durability, but the cost of such processes has outweighed the benefits. A Missouri S&T researcher is working on a safer, simpler and potentially more affordable method of combining nanoparticles with concrete.
Dr. Hongyan Ma, Missouri S&T assistant professor of civil, architectural and environmental engineering, compares the technique to blowing bubbles into limewater.
“Our method is to create calcium carbonate nanoparticles inside the concrete by blowing carbon dioxide into the highly diluted wet cement,” says Ma. “The nanoparticles will be formed inside this part of the suspension in the presence of siliceous ingredients, and you use that to mix the concrete.”
Previous attempts to add nanoparticles into fresh concrete were not successful because the superfine particles would always stick together – not disperse, says Ma. His method involves forming the nanoparticles inside the fresh concrete, creating an even disbursement.
A $160,000 grant from the National Science Foundation will allow Ma to test the method for creating nanoparticles in concrete through 2021. At the end of the next three years, Ma hopes to have the technology available to make this method ready for existing concrete plants to use.
Ma’s method would mitigate another potential problem of working with nanoparticles in concrete – the fact that they are harmful to humans. They have harmful side effects especially when people use dry particles, including potential lung inflammation and heart problems.
“Our method is a wet method, so the workers and the laborers at concrete plants will not be exposed to the harmful nanoparticles,” Ma says.
The potential benefits of stronger and more durable concrete to civil infrastructure, the economy and the environment could be substantial, he says.
“Concrete durability is one of the main issues in preservation of transportation infrastructure,” says Dr. Genda Chen, the Robert W. Abbett Distinguished Chair in Civil Engineering at S&T. “If you could reduce microcracking and increase durability in concrete that would certainly be a good benefit for all concrete structures.”
Missouri S&T is one of the few U.S. universities that focus on studying materials for construction and other applications through one of four signature research areas – Advanced Materials for Sustainable Infrastructure (AMSI).
Dr. Kamal Khayat, the Vernon & Maralee Jones Professor of Civil Engineering and director of Missouri S&T’s Center for Infrastructure Engineering Studies (CIES), says that such fundamental research combined with numerical studies and simulations will lead to the development of new construction materials.
“We hope to grow the AMSI signature research area to be best in class in the critical field of transportation infrastructure,” says Khayat.
“We have a nice environment to do this research,” says Ma. “I was hired through the AMSI research focus, and we have hired several new professors working in this area.”
Ma says he also hopes to work with the CIES at Missouri S&T and the Missouri Department of Transportation (MoDOT) on pilot trials and field implementations.