This past Friday was a really exciting time for the American Society of Civil Engineers because we poured our concrete canoe! Pour day is a lot of work because we spend a whole day measuring, mixing, and placing concrete.
In order to prepare for pour day, we had to make sure our mold was all ready to go. The mold we use is made of multiple foam blocks glued together. The curvature of the canoe is cut out of the foam so that when concrete is placed on the mold it will form a canoe! The mold also has to be sanded and covered with drywall and contact paper so that the surface is smooth and so the concrete won’t stick to the mold.
We also had to make sure we knew what concrete mix we were going to use for our canoe. All last semester different mixes were tried out by changing the amount of different aggregates in the mix. We changed the ratio of cement to the amount of aggregates to get a mix that was less dense than water but still strong.
During pour day we had three different teams all working together: one team measured out all the material and aggregates for the concrete mixes, one team mixed all the materials together so it became concrete, and one team placed the concrete by spreading it onto the mold. I spent the whole day placing concrete which was really cool because I got to watch the canoe start to come to life.
Besides using concrete, we also put reinforcements into the canoe to help strengthen it and prevent potential breaking and cracking. Overall the canoe has three layers of concrete and two layers of reinforcement, each layer alternating between the two. The first and third layer of concrete are about 1/8 in and the second layer is 1/4 in, resulting in a canoe that is about 1/2 in thick!
We also had to place bulkheads into the ends of the canoe. The bulkheads are made of foam and are cut to fit the curve of the canoe’s point. The bulkheads are then covered with concrete, and are designed to help keep the canoe afloat.
Overall, pour day lasted about 8 hours! Although it was a long and physically demanding day, it was really rewarding to know we designed and constructed a massive concrete canoe! Now that the canoe has been poured, it has to cure for 28 days. We placed a humidifier in the canoe to help prevent cracking and will leave the canoe alone for the time being.
After 28 days, we can take the canoe out of the mold to begin sanding and patch work, as well as start painting on the graphics! I can’t wait to see how the canoe turns out!