Concrete probably isn’t the first material you’d chose to build a canoe, but it’s mandatory for canoe races involving Iowa State University students. Jessica Slavik is co-chair of the group of I-S-U engineering students who participated in this year’s concrete canoe race in Platteville, Wisconsin. Slavik says the key to floating a concrete canoe is using the right materials when mixing the concrete.The aggregates they use to mix up the concrete are lightweight glass bubbles, and not the heavy rocks used in the concrete in roadway construction. The students competed in five different races this past weekend, but the racing is only part of the event. The students are required to write a technical paper and also have a display explaining their canoe. Slavik says the whole process is a learning experience for the future engineers.While the planning took months, the actual pouring of the canoe takes just a day.This year’s canoe, christened “Fever,” weighs about 120 pounds. This is the 29th year I-S-U engineering students participated in the concrete canoe race.