By Danny Gierhart, P.E.
Having lived my entire life in Oklahoma, I’ve been to my share of rodeos. They have a unique community atmosphere, and it’s interesting to see the different skills that the cowboys and cowgirls have developed over many years of practice. However, until recently, I had never been to a “Road-eo.”
The Texas Asphalt Pavement Association (TxAPA) staged their third annual Road-eo in December of 2019 at TxAPA headquarters in Buda, Texas, just south of Austin. The Road-eo is a unique asphalt team competition for undergraduate students at regional universities. The TxAPA Road-eo brought together a total of 12 teams of up to four students each from several universities:
• Louisiana Tech University
• Texas A&M University
• Texas State University
• University of Oklahoma
• University of Texas
• University of Texas at El Paso
• University of Texas at San Antonio
The students look forward to the Road-eo, with several of the students returning for their second year of competition. Weston Chenausky, a student from the University of Texas at El Paso, said, “For us, this competition is a learning experience. It gives us a chance to come across different problems and work on our problem-solving skills, as well as teamwork.”
The student team members, mentors and their fellow interested students are to be commended not only for driving to Buda, Texas on a Friday (some from over 8 hours away), but also for spending their Saturday at this exciting and educational asphalt competition. Their dedication is even more impressive because most of the students had finals week beginning the Monday after the competition.
TxAPA is also very enthusiastic about the Road-eo. They see benefits for the students, the universities and the asphalt industry as a whole. Emily Adams, TxAPA’s Director of Marketing observed that “students benefit from the Road-eo because it gives them a taste of how what they’re learning can apply in the real world.”
Adams added, “the Road-eo competition attracts bright young people who often don’t realize the number of opportunities that exist in our industry.” Booths were set up in the main meeting room for a small job fair, where students could talk directly with representatives from TxDOT and the asphalt industry.
Friday afternoon and evening were dedicated to letting the students tour the TxAPA laboratory facilities and providing an opportunity for the students to get to know each other and to meet industry representatives at a networking dinner.
As the students and their sponsors arrived, they were split into groups to tour TxAPA’s Hot Mix Asphalt Center (HMAC). The HMAC is where technicians who work in Texas are certified to test soils, aggregates and asphalt mixtures. HMAC staff spent a couple of hours with the students in an informal setting to show them the lab, to examine the equipment and to discuss some of the test procedures with them. The students made the most of the time with a lot of questions and comments for the HMAC staff.
Out of the chute
After a few delicious breakfast tacos on Saturday morning, the competition began in earnest. Each team brought a 20” x 20” x 2” slab of compacted asphalt mixture they had previously fabricated in their own lab using the materials provided to them by TxAPA members Austin Materials and Century Asphalt. Although aggregate and asphalt binder materials were provided, each team used differing percentages of the materials according to whichever mix design process they adopted or invented. The slabs were then tested for:
• skid resistance
• rutting resistance
• cracking resistance
Additionally, the teams were evaluated by a panel of agency and industry judges regarding the strategy and rationale they used in designing their asphalt mixture, and the research they did to come up with their particular solution.
The scoring for the competition was based on the teams’ ranking in each of the four sections (skid, rutting, cracking and presentation) of the competition. The team with the highest rating in a given section received 25 points and the team with the lowest rating received 10 points. The other teams received points as interpolated by their performance ranking.
Each slab was first tested for surface texture using a British Pendulum Tester. The device is a dynamic pendulum impact-type tester that measures the energy loss when a rubber slider edge is propelled over a test surface.
A pavement’s skid resistance is an important safety parameter, predominantly influenced by aggregate type, size, shape and texture. The asphalt mixture’s macrotexture is also an important factor.
Due to the time restraints of the competition, a method to quickly and easily assess a slab’s rutting resistance had to be devised. The team at TxAPA came up with a test using a metal plate with steel rods welded to the bottom. A truck was then parked so that a wheel rested on top of the plate for 10 minutes. Afterward, the truck static weight was removed and the resulting indentations in the slab were measured with a digital caliper.
An asphalt mixture’s resistance to rutting is an important safety factor. Ruts, whether caused by a poor-quality asphalt mixture or lack of underlying layer support, can hold water and increase the possibility of vehicle hydroplaning.
Another quick test had to be developed to evaluate each asphalt slab’s resistance to fatigue cracking. For this test, the slab was placed in a metal frame, fully supported at first with square metal tubing. A truck was slowly driven back and forth over the slab, which was subsequently reviewed for signs of cracking. After each set of passes, a pair of the metal tubes were removed, and the process repeated. If the slab cracked as the test progressed, the number of tubes remaining were noted.
If the slab showed no signs of cracking after all of the tubes were removed the number of subsequent passes to cracking was noted. If the slab still did not crack after 20 unsupported passes, the truck tire was positioned over the slab and the time until cracking was determined.
An asphalt pavement needs to be resistant to load-related cracking, as well as other types of cracking. Cracks tend to increase in length and width over time, allowing water and incompressible materials to infiltrate into the pavement section. This can lead to further physical deterioration and weakening of the pavement section through stripping of the asphalt binder from the aggregate particles in the asphalt mixture.
In the final portion of the competition, each team presented their asphalt mix design information to a panel of judges. This year, the judging team consisted of Michael Lee, Director of Engineering and Safety Operations at TxDOT, Robert Lee, Hot Mix Asphalt Performance Manager at CRH Americas and Chuck Fuller, Industry Relations Consultant at TxAPA.
Each team put together a presentation and talked to the judges about their experience. In the presentation, they discussed the process and rationale they used to design their asphalt mixture. The teams spent time researching different asphalt mix design methods to come up with what they wanted to use. There were no specific design parameters to follow, so the problem was open-ended. Each team understood the criteria on which their slab would be judged, so they designed the mix to address those criteria.
The research that was required of the teams is integral to TxAPA’s goals for the competition. Not only does it introduce the students to asphalt materials, design and performance, but it also gives them a hunger to continue research in the field.
Thondo Mpofu, a participant from the University of Oklahoma, explained: “It’s important to keep innovating because the world does not stop.”
In the money
By Saturday afternoon, every slab had been checked for texture, rut resistance and crack resistance and every team had its opportunity to present their work to the judges. Here’s a look at the final standings:
• Third Place – University of Texas at San Antonio, Team ITE (Rolando Moreno, Miranda Castillo)
• Second Place – University of Texas at El Paso, Blue Team (Victor Garcia, Mayra Reyna, Juan Galvan, Alberto Valverde)
• First Place – Louisiana Tech University (Garrett Anders, PJ Hasten, Chase Menendez, Gabriel Clottey)
In addition to all of the work putting the Road-eo together, TxAPA is also very generous with awards. Each of the top three teams received a nice-looking, light-up acrylic trophy for their university. Additionally, each member of the third-place team received a $75 Amazon gift card. Second place team members each received a $150 Amazon gift card. As you can see from the photo, first place team members each received a check for $1,000, which is not only a substantial reward but also quite an incentive for next year’s teams.
All-in-all, the Third Annual TxAPA Road-eo was a resounding success. It has grown from just a couple of University of Texas teams at the first Road-eo to twelve teams from seven regional universities this year.
A lot of students have gotten some great exposure to the work and opportunities that abound in the asphalt industry. Emily Adams also highlighted another benefit for the students, “they get to meet real professionals who have been working in the industry for years and are very excited and passionate about what they do.”
The folks from TxDOT, TxAPA and the asphalt industry who help run the event certainly got a shot in the arm of enthusiasm from these lively and promising participants, as did I. Next year I can finally say, “this ain’t my first Road-eo!”
Gierhart is an Asphalt Institute Senior Regional Engineer based in Oklahoma.