What is Concrete Canoe Team?
The concrete canoe team is mainly comprised of civil engineering students who build a canoe out of concrete. In the fall semester, the main focus of the team is mix design while the spring semester focuses on casting the canoe.
How did it start?
University of Illinois professor Clyde Kesler challenged his concrete design class to build a canoe in 1970. They successfully constructed “Misled”, weighing over 350 pounds.
The civil engineers over at Purdue University got wind of what happened, crafted their own concrete canoe, and challenged the Illini. The Illini ended up victorious becoming the first winners of a concrete canoe race.
Professor Kesler wore his “Concrete Canoe World Champions” t-shirt to the next American Concrete Institute which sparked a national phenomenon.
How do you compete?
Regional competitions are held every spring. Teams are judged on presentations, aesthetics, a design paper, and races.
There are 5 different races: women’s and men’s endurance, women’s, men’s and co-ed sprints. There are 2 paddlers in each race with the exception of the co-ed sprint which has 4.
The winners of each regional competition advance to the national competition.
What is Concrete?
Concrete is a material used for construction and is found in roads and structures. It has three main ingredients: cement, water, and aggregate.
Comparing concrete to a chocolate chip cookie, the cement is like the dry ingredients (flour, salt, baking powder). It binds everything together and there are many types of cementitious materials like Portland cement, VCAS, and fly ash. Water is like the wet ingredients (sugars, butter, vanilla, eggs). Besides water, we use liquid latex and other liquids that can make the concrete flexible and strong. Lastly, the aggregate is like the chocolate chips. In sidewalks, for example, the aggregate is usually gravel or stone. That’s really bulky for our canoe so we use small aggregates like microspheres.
Doesn't the Concrete Canoe Sink?
Nope! Gravity pulls down on the canoe, but the water counteracts it with a force called buoyancy.
In addition to buoyancy, all canoes must pass the “swamp test” to race. We purposely sink the canoe and make sure it stays near the surface of the water.
An object must be less dense than water to float. Our aggregates and other cementitious materials have low densities compared to what’s used in traditional concrete. Because of this, our concrete floats in water!!
How do you figure out what "recipe" to use?
We know the basic recipe of concrete, but there are variations of each ingredient. We isolate a variable and fix all the other proportions and see how the ingredient affects the strength of the concrete.
We test the strength of our mixes in compression (pushing down), tension (pulling apart), and flexure (bending).