Samples of glass powders used by students. Image from Pranshoo Solanki
Normal, Ill. — A team of students led by Illinois State University’s Pranshoo Solanki was awarded a grant by the Environmental Protection Agency (EPA) for efforts to make construction materials more sustainable. The EPA’s competitive People, Prosperity, and the Planet (P3) grants program funds innovative technology projects at universities across the nation. The Illinois State team received $15,000 to conduct research on a project titled “Recycled Glass as a Substitute for Portland Cement and Fly Ash in Controlled Low-Strength Material.”
“Portland cement is one of the main ingredients in concrete, which is the most widely used construction material in the world,” said Solanki, an associate professor of construction management at Illinois State. “Unfortunately, making cement also emits a lot of carbon dioxide. In fact, it constitutes about eight percent of the Earth’s carbon dioxide emissions.”
Solanki’s team is exploring partial substitution of cement and fly ash with recycled glass in controlled low-strength material (CLSM), also called as flowable fill. CLSM is a cement-based construction material commonly used for backfilling trenches or other excavations, as well as soil-stabilization. It can be produced at any ready-mix concrete plant by mixing cement, fly ash, sand, and water in designed proportions.
“Fly ash is an industrial byproduct of burning coal in U.S. thermal power plants,” said Solanki, who noted that using fly ash is not economical in many parts of the country, due to distance from coal-fired power plant, the closing of coal-fired plants, and the impaired quality of fly ash. As a result, many concrete users are looking for an alternative which is sustainable and economical. The Illinois State team turned its attention to the possibility of using recycled glass powder to offset the use of cement/fly ash. Solanki noted preliminary results are promising and show that required flow and strength can be met by replacing cement/fly ash with recycled glass powder.
Graduate and undergraduate students in Illinois State’s Construction Management and Project Management programs are working to make flowable fill samples using glass in the laboratory and testing them for required flow and compressive strength value.
“Working on the project has invoked my intellect about all the waste in the world, and how sustainability can be achieved through research which directly preserves the environment,” said Mobi Singh, a graduate student from Faridabad, India. Singh, who works with Joseph Aderoju and Michael Boffa, said innovation has been key to the effort. “The project has made me think deeper about the application of innovation in diverse fields.”
The team also includes Environmental Health Program students Travis Brook and Lillian Lantz, who are working to evaluate the glass for areas such as the levels of contamination and solubility.
“This project would not be possible without collaboration between construction management and environmental health,” said Professor of Environmental Health Guang Jin, who added work with the Department of Chemistry equipment also aided the work.
The EPA grant is for phase one of the recycled glass project. Students from the Illinois State team will travel to Boston this summer to present their work to a TechConnect World Innovation Conference. The plan is to then apply for a phase two grant, which would enable students to test their product in the real-world.
“We also plan to work with our business partners to determine opportunities for using our research results to reduce costs for producing recycled glass powder,” said Solanki. “As users and producers of concrete gain experience with recycled glass, the ultimate outcome would be the broader acceptance and use of recycled glass as a cement/fly ash substitute in concrete projects.”
The Illinois State team joins universities such as Brown, Cornell, University of Central Florida, and Carnegie Mellon in earning the EPA grant.