At a recent symposium sponsored by the American Society of Civil Engineers, students from 17 universities took part in a contest to see which team could come up with the best flying disc — made of concrete.
“People think of concrete as hard and heavy,” says Roger Lindgren, assistant professor of civil engineering at Oregon Institute of Technology, where the symposium took place. “We wanted to challenge students to create a mix that would be light enough to fly and durable enough to hit the ground without breaking apart into dust.”
Students refined their designs for months before the competition, varying the mix design — sand, portland cement and water — to create the perfect flier. Some used Frisbees™ for molds, others used pie plates or built their own. Many used color as well, from dry shake to integral to stains. They learned that adding a lot of water made the mix easier to work with but created concrete that was not very strong. “They had to look for the happy medium between easy-to-pour and durability,” Lindgren says.
The discs generally stood up very well, Lindgren says, with the winner flying 140 feet. “And they looked really good,” he adds.
