University of Colorado Denver engineering students tossed concrete Frisbees aloft — one disc sailed more than 100 feet — in a contest to see who could best design loft, lightness and durability from an improbable material for flight.

The concrete Frisbee toss is an extra-credit project for students in the Introduction to Structural Materials class taught by Stephan Durham, PhD, assistant professor in the College of Engineering and Applied Science.

Twenty-seven students in Durham’s class participated in the event, held Nov. 17 on the soccer field next to the North Classroom. After each toss along a tape measure that extended into the soccer field, Durham and one of his students ran to the landing spot to mark the distance traveled. Discs were penalized for rolling off laterally or backward after landing.

The students’ discs were judged in three categories: aesthetics, distance of flight and weight. The Frisbee made by Elijah Rust, a senior in civil engineering, was a standout in at least two categories — weight (34 grams) and distance of flight (143 feet).

Engineering students’ concrete Frisbee toss

Rust said he noticed other students were making discs that looked like traditional Frisbees. His disc ended up resembling a compact disc, with a larger hole in the middle.

“I decided to go for the lightest design,” he said. “I basically made the smallest, lightest Frisbee I could. It’s turned out that it’s going far and it’s holding together.”

Rachel Leigh, a junior civil engineering major, said Durham told the students that mixing and proportioning concrete is like an art form. Students were encouraged to be creative in components in their mix — such as using glass beads or fiber reinforcements for lightness and durability, respectively.

“We had to try to make a concrete mixture that’s either light or might go far (through the air), so that’s kind of a challenge,” Leigh said.

Durham said he’s seen some “very creative Frisbees” in each of the 12 semesters since he joined the CU Denver faculty in 2005.

“What many of (the students) have done is gone online and researched lightweight aggregate,” Durham said. “Really, it’s for them to get creative, learn a little bit more beyond class, and just, more than anything, create enthusiasm about the subject.”

With 27 students participating in the concrete Frisbee project — out of 28 in the class — Durham has done just that.

PHOTO: Rachel Leigh, a junior civil engineering major, tosses her concrete Frisbee as part of an extra-credit program for students in Assistant Professor Stephan Durham’s Introduction to Structural Materials class.

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