Alexander Brand, assistant professor in the Charles E. Via, Jr. Department of Civil and Environmental Engineering, has received a $600,000 National Science Foundation Faculty Early Career Development (CAREER) award to understand the physicochemical interactions between water and the primary components of cements to clarify how concrete works.
Cement, when reacted with water, makes up the binding phase of concrete. But cement production is currently the third-largest carbon dioxide source in the world after emissions from burning fossil fuels in the energy and transportation sectors.
Brand's research clears a path for scientists and engineers to design new materials for a more sustainable and resilient concrete. With concrete being the most widely used construction material in the world, Brand's research could ultimately transform civil infrastructure.
Bringing Concrete's Carbon Footprint Closer to Zero
Every year, 4 billion tons of cement and 28 billion tons of concrete are made around the world. According to Brand, this amount of concrete far outweighs the use of other materials, including steel at 1.9 billion tons, aluminum at 0.08 billion tons, and plastics at 0.39 billion tons.
"Civil engineers have become experts at designing concrete mixes to meet specific criteria, such as strength and durability. There is surprisingly little known about the reaction pathways and kinetics that drive the reaction of cement with water," Brand said.
This award will advance that knowledge by implementing novel nanoscale characterization techniques to help explain concrete behavior and establish future directions for concrete materials.
"Concrete that is used today is not going to be the same as the concrete used in 10, 20, or 50 years," Brand said. "Concrete has a fairly large carbon footprint, and the industry is working to meet carbon neutrality, which means they will need to invest in new materials. Understanding how cements fundamentally react with water will be a large step forward in finding these new candidate materials."
Cement production currently contributes 5 percent to 8 percent of all human-generated carbon dioxide. By investing in new materials, the industry is working to move away from the traditional "cook and look" methodology, which involves mixing concrete with new alternative cementitious materials, testing the properties, and repeating that process many times. With hundreds of combinations of new materials being explored or proposed, testing can be costly and labor intensive and produce significant amounts of carbon dioxide.
"The CAREER award will not immediately solve these problems upon completion of the project," said Brand. "But it will definitely serve as the first step to launch the concept of lowering the carbon dioxide footprint of concrete through fundamental studies of cement chemistry."
Making Civil Infrastructure Hands-on for Students
This CAREER award also includes education outreach through the Center for the Enhancement of Engineering Diversity, the Hokie for a Day program, and activities at the Science Museum of Western Virginia. These activities will allow K-12 students to explore the materials used in civil infrastructure by testing high strength concrete, making drink coasters out of rapid-setting concrete, and understanding dissolution and precipitation reactions.
"I created activities that are aimed at engaging students' interest in civil engineering with an outlook on the need for and the environmental impact of one of the most used materials in the world - concrete," said Brand.
His professional interest in the nanostructure of cement-based materials and reactions came from research he conducted as a National Research Council Postdoctoral Research Associate at the National Institute of Standards and Technology. His experience largely influenced his CAREER award project.
While there is much work to be done to reduce the carbon footprint of concrete to zero, Brand's work will launch a new area of research to fundamentally understand cement reactions with water.
"My overall goal is to unlock the potential to explore new materials that produce more sustainable concretes," said Brand.