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Concrete Countdown: It's Sink or Swim Time! (Part 3)

Concrete Countdown: It's Sink or Swim Time! (Part 3)

by AARON GRUDOWSKI, Student, Illinois Tech | Third in a series |April 14, 2016

Showtime: Great Lakes Student Conference finals are here!

Showtime: Great Lakes Student Conference finals are here!

Twenty-four hours…  24 hours... until our fate is determined... 

Will our canoe, which we spent countless hours on over the past several months, sink, or will it stay afloat? Images of the cracks in our canoe race through my mind, and I cannot help but picture the captains going down with our ship.

When I started my education at Illinois Tech, I had never even heard of a concrete canoe. I was on the same page as most people, with the mindset that, “Concrete can’t float! That’s impossible!” Yet, there I was a year later, newly appointed Illinois Tech Concrete Canoe Team Co-Captain, with the task of making concrete that can... you guessed it... float!  

So I was excited and nervous all at the same time. My co-captain, Rafal, and I had never really worked with concrete before. We had gained some knowledge as members of last year’s canoe team, but would it be enough to make a successful boat? As we began work on the canoe, the odds seemed to just keep stacking against us. First, we didn’t even have a shop to work in until November. Then, the materials did not come in... the concrete wouldn’t harden properly... and, well, lots more.  

Host committee: This is the first year IIT has hosted the event, so even the canoe stands have to be just right.

Host committee: This is the first year IIT has hosted the event, so even the canoe stands have to be just right.

Our year also started off with the big decision to completely re-design the canoe. What a great idea for a couple of kids with no experience, right? Using Solidworks design software, we created our new design and began planning construction.

But before construction could occur, we first needed a mix.  But wait… how do you even make concrete Rafal?”  Cue Chris Ochoa, former concrete canoe captain and our own concrete expert.  After a few tutorials and a lot of learning, we at least had a solid idea on how to mix concrete. And so it began... 

In a matter of three days, we made 10 mixtures, consisting of fly ash, white cement, concrete pigment, reinforcement fibers, 3M glass bubbles, and super plasticizer. But there was just one minuscule little problem. When we put the test cylinders in water after they had hardened, they sank… like a rock! 

Seal it, sister! Brianna applies coating. 

Seal it, sister! Brianna applies coating. 

Through a little more experimentation and the realization that we had been using too much super plasticizer — a component that, when used correctly, decreases the density by reducing the amount of water necessary — we found a mixture that would serve our purposes.

After that, it was on to construction of the mold. “Wouldn’t it be great if we could create a mold that we could re-use in the coming years, Aaron?"  "Yeah, that would be perfect, and it would save us so much time!” 

Using a CNC cutter, we cut out cross sections, and thin, 1/8-in plywood strips that we nailed to them with a nail gun. We then covered the mold in plaster and applied a release agent to ensure that the canoe would come off the mold. Then, it was time for casting.

“All right, we need all the help we can get Saturday for casting.  It’s a lot of work, and the concrete hardens fast… and yes, I will provide the pizza!”

Move ahead to last Saturday evening, around 8:30pm, and everything seemed on track. “Hey this is going great everyone!  Wait, is that the last of the 3M glass bubbles?”

Well, if you read the first article in the series, you know the rest. Casting turned out all right. I mean, we had a canoe. Now we just had to take it out of the mold. That would be easy... Oh wait, you read about that experience in the first article too, huh? We ended up needing chainsaws! Who knew, right?  

Style points: Who says engineering isn't art? Here, team member Talia paints a section of the canoe stand.

Style points: Who says engineering isn't art? Here, team member Talia paints a section of the canoe stand.

Now, here we are, one day before competition... After many setbacks, we still managed to make a canoe that, although it had cracks, was still in one piece. Still, a million thoughts are running through my head as I prepare for tomorrow. “We are the host school — our canoe had better not sink!” “My parents, grandparents, brothers, and friends are all going to be there. We can’t fail!” 

I do not want to let any of them down, and most importantly, I do not want to let the rest of the team down. Everyone has been working so hard to make our canoe, and if it fails, they will be so disappointed. However, if there is one thing I learned from being co-captain this year, it is to stay positive. Because if the captains lose hope, so does everyone else.

Ta-da! Behold, our finished product! But one nagging question remains...

Ta-da! Behold, our finished product! But one nagging question remains...

Fans of the old Late Night with David Letterman show on CBS may remember this silly, recurring segment.

Fans of the old Late Night with David Letterman show on CBS may remember this silly, recurring segment.

Well, it’s time to put the last touches on what has become our life this past semester. It seems like only yesterday we were designing it virtually on Solidworks, and now our baby — er, I mean canoe  is ready to row. If you’re looking for something fun to do, or you still don’t believe that concrete can float, then come on out to Washington Park near Chicago's Museum of Science & Industry tomorrow!  We'll be the ones out on the lake... or maybe in it! 

Now swimming through his third year at Illinois Tech, the author is a civil engineering major.

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