Lethbridge College students recognized for concrete project

By Alejandra Pulido-Guzman - LETHBRIDGE HERALD on November 11, 2021.

LETHBRIDGE HERALDapulido@lethbridgeherald.com

Even though concrete has been around since 300 BC when used in its early form by the Romans, one problem is still unsolved to this day. Cracking has been and still is one of the biggest challenges when it comes to concrete. Which is something a team of former Lethbridge College Civil Engineering Technology students were hoping to address.
Their attempt at replacing rebar with polypropylene fibers caught the attention of the Association of Science and Engineering Technology Professionals of Alberta (ASET) and Lane Roggensack, Robert Beerda and Brett Porter were nominated as one of seven finalists for the Capstone Project of the Year Award.
This year there is only seven projects that the committee decided should be considered as finalists.
“The team from Lethbridge College had a big task in that they were worried about looking at concrete and how to prevent it from cracking and how to strengthen it. They decided that nobody has experimented sufficiently before adding polypropylene fibers to concrete to determine if that could prevent the cracking and deterioration that led to the deterioration of the rebar, and also second phase to it, where the polypropylene fibers could in fact be used instead of rebar. So, it is quite an undertaking to do a study like this,” said Barry Cavanaugh, CEO of ASET.
Cavanaugh added that it is very important to him and the organization to recognize the colleges and polytechnics as well as the instructors that are taking part in these types of high quality projects.
“Once we were nominated, we were really excited. There’s a lot of heart, a lot of hard work and a lot of time put into this project so we were really happy to see ourselves be rewarded with this nomination,” said Roggensack.
Roggensack added that they had a lot of input from staff and faculty around Lethbridge College, which inspired them.
“They really motivate you there, they are genuine, they try to get the best out of you every day, so that really motivates you to apply yourself when you’re doing these sorts of things especially when you’re representing the school and in a competition like this,” said Roggensack.
Doug May, a Civil Engineering Technology instructor at Lethbridge College, says that it is very rewarding to be recognized.
“To see your students that you’ve spent two or three years with, they come into a program, and they build skills that would kind of get them to that level where they get recognized either provincially or nationally, it’s pretty rewarding to see,” said May.
May added that he always shows the students the ASET website when he begins and says, “Look, you guys have some big shoes to fill because the people that came behind you, this is where they were and now you kind of got to go a little bit further…no pressure, but this is what we’re expecting out of you.”
The department and other people are invited from around the college to look at what the students are proposing, including the department of advanced research CARIE.
“That was a creative project and we’ve got some more coming as well, so some really interesting stuff,” said May.
In construction, rebar is often added to concrete to increase tensile strength. However, it cannot add strength to the exposed edges of concrete. As a result, cracks can form along those edges, allowing water to infiltrate the concrete and corrode the rebar reinforcement.
  Lane Roggensack and his team created cylinder and beam samples to compare the compressive and tensile strength of concrete containing polypropylene fibers to concrete reinforced with rebar. The cylinders with polypropylene fibers fared better than the beams in that the cracks that formed within them were smaller and less invasive, enabling the cylinders to remain intact. The beams with fibers split in half – an outcome that wasn’t expected. The concrete beam samples with rebar ultimately proved to be significantly stronger than the concrete beam samples containing fiber.
 They also discovered that the addition of fiber made the workability of concrete lower than regular concrete. Concrete slump with fiber was 16-times lower than normal slump. A slump test measures the consistency of fresh concrete before it sets, and is used to ensure uniformity for different loads of concrete under various conditions. It can serve as an indicator of an improperly mixed batch.
 In the end, the former team determined that polypropylene fibers alone are not enough to increase the tensile strength of concrete and, therefore, are not a viable replacement for rebar.
But these findings didn’t stop them from getting the ASET nomination, which made them very happy, according to Roggensack.

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