Texas Tech University

Students Show Resiliency by Making Concrete Float

Concrete Boats

MacGyver would be proud.

While it doesn't rank as a life-threatening situation where an escape has to be made before something explodes, it is quite a task to do something which, on the surface, might seem impossible – getting concrete to float.

That, however, is the goal every year for engineering students from across the state who attend the annual American Society of Civil Engineers (ASCE) regional conference. As part of the conference, which features seminars and a chance for students to interact with industry leaders who could one day become their employers, the concrete canoe races are held where teams of students design, build and race canoes made from concrete.

Concrete Boats

"The concrete canoe competition, at least at the national level, has been around since 1985 because we held the first national competition here," said Audra Morse, a professor in the Department of Civil, Environmental and Construction Engineering at Texas Tech University. "We haven't always been very successful with our canoes in the past, but for the last eight to 10 years we've had a solid set of canoes that have left Texas Tech and floated off and done well."

This year's regional conference and competition was held in March in El Paso, where the team from Texas Tech – some members of which are freshmen and sophomores who hadn't even taken the basic construction materials classes prior to becoming involved in the project in the fall – finished fourth after coming in second the year before.

Concrete Boats

"I felt we had a good boat. I don't know that it was better than last year but it was up to par with it," said sophomore co-captain Elizabeth Hall. "Our presentation was good, but I felt we needed to do more. Answering questions, we struggled with that because most of us are underclassmen and we haven't taken the classes we needed to answer the harder questions. We had a few deductions from our display which messed us up, and then our races weren't as good as last year."

Building a working, floating concrete canoe is hard enough on the surface. But every year the rules change, forcing teams to alter plans and redo designs, and then that doesn't always work as far as ensuring a stable structure that can float.

Concrete Boats

But the competition also puts those who are involved a step ahead in not only advancing their academic careers but also making them more attractive to employers once their time at Texas Tech is done.

"We meet with professionals at the conference, and those are some of the people that, down the road, you're going to be working with," said sophomore Thomas Wiseman, the other co-captain of the Texas Tech team. "All the judges there come from schools that have competed in this and have been co-captains before, and they all know each other and work together."

Following the rules

The concrete canoe competition is a months-long battle for students who must build their canoes according to specifications laid out each August by the ASCE. Those rules change each year, ranging from what students are allowed to use in their concrete mix to different dimensions on the boat itself.

Concrete Boats

In the past, concrete mixes have featured items such as perlite, Styrofoam beads and glass spheres – anything lighter than rocks – as its aggregate material. For 2016, the Texas Tech team, like many others, used air bubbles and glass beads in their concrete mix instead of sand in order to make the material lighter. For the 2017 competition, however, the ASCE limited use of air bubbles and glass beads to just 25 percent of the total mixture.

That forced Texas Tech to seek other aggregate material to put in its mix. Eventually they settled on pumice, a light, porous volcanic rock.

"Adding the pumice didn't change the mix that much," Hall said. "It added some weight to it. Last year it was at 194 pounds and this year it was a little over 215. We took a bit of length and a bit of height off of it, so that made up for the higher weight."

Concrete Boats

Once a mix was settled upon, it had to be tested for its ability to fit over the mold of the boat as well as its buoyancy and strength, since teams have to actually race these canoes as part of the competition.

Students spent the fall and part of the spring testing their mixes to find what works best, and had to come up with their final mix at least 28 days prior to the drop-dead pour date in order for the concrete to cure around the mold. Texas Tech chose to use a "male mold" where the concrete is poured over the mold instead of inside the mold. Texas Tech's mold consisted of flexible strips of plywood covered with sheetrock and freezer paper.

"We spent probably 50 hours in the shop in one week just to deal with our pour that weekend," Wiseman said.

During this time, students also work on a report about the canoe that has to be submitted a month prior to the competition. They also are working on a cutaway of the canoe in order to display how it was constructed.

Concrete Boats

Teams also are required to display some sort of theme or flair with the boat. Texas Tech chose a theme related to the movie, "Pirates of the Caribbean," where their display paid tribute to the scene where the pirate attempted to steal a ship by carrying a canoe underwater. Texas Tech's display had the canoe upside down with legs sticking out from underneath.

Students then give a five-minute presentation on their canoe, what aspects they worked on that year that were new or innovative and what, if any, material they used was recyclable.

But even just getting the canoe to the competition can be tricky. The canoes are loaded into the back of a trailer and secured as best as can be, but those trips can cause cracks to form in the canoe, and students are limited to what they can use to fix them.

Concrete Boats

"There are certain rules, and you're not allowed to use an epoxy and things like that," said Russell Carter, an instructor in civil engineering and one of the team's faculty advisers. "Tape is used a lot, and that is something that is looked for in the Texas section. It's called the spirit of competition. We look for schools that help one another when something like that comes up."

But there's still one more test teams have to go through before the races – the swamp test.

In order to test the buoyancy and resiliency of the canoe and its materials, it is filled with water and intentionally sunk, then the students on the team watch for it to resurface. That tells judges the canoe is safe and ready to be raced, but often, Morse said, teams will be taping foam to the outside of the boat to get it to resurface.

"That counts against them later on, but it's still part of the spirit of the competition," Morse said.

Working together

Then it's time for the races. And even getting in the canoes can be tricky, Morse said, where often you will see teams lower competitors into the canoes rather than having them climb into it and risk poking a hole in the sidewalls. But that all goes to the aspect of teamwork that students must learn in order to complete the project.

"You are working with a bunch of different people, and that's good," Wiseman said. "It's an important part of the project because that's what we will be doing every day for the rest of our lives, working with a team. We had our ups and downs and didn't agree with everyone. But the teamwork was the most important part of the project."

Concrete Boats

Even though they didn't finish as well as last year, the Texas Tech team was still pleased with the results of their months-long efforts.

"We wanted to make our display really stand out, which we did, and it was good," Hall said. "There were a lot of good parts. The best was the compass that displayed our cross-section, and we put a lot of work into that one. The ribs for the boat were delayed about a month and that pushed us back a bit, and then we had to build the mold within a week to meet our pouring day. That was our biggest challenge, but it was worth it."

Part of the fun of the competition, the co-captains said, was going around and looking at the other canoes and how other teams approached their challenges. It also allows teams to get ideas for the competition next year.

"Our new co-captains are in charge now but we've already started talking to them about some new designs," Hall said. "We've got a few ideas that we may want to try out."

Both Wiseman and Hall said they learned a great deal from going through the competition that will not only help them after graduation but is assisting them in class right now, having learned things through the competition that they are applying to classwork this semester.

"It was a really hard year, but I'm glad we did it," Hall said.

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