Author: April Smith Major: Civic Engineering
My honors thesis journey has been an interesting one to say the least. Every deadline goal was missed, every step was more challenging than expected, and almost everything that could go wrong, did just that. It took time and advice from others to understand that in research, these things just happen. For example, my mentor, Dr. Kevin Hall, and I came up with a timeline where I started my lab work the summer of 2018. Unfortunately, Dr. Hall suffered from a medical emergency the week before we planned to start out at the lab. We decided it would be best to shift the timeline a few months so he could have time to recover. Therefore, I didn’t begin working in the lab until the beginning of the fall semester. Add in a few equipment malfunctions, a shortage of supplies, and the responsibilities that come with twelve other college credit hours, and you can imagine how this has been one wild ride for me. In the next few paragraphs, I’ll get into the specifics and share with you my overall conclusions of my thesis titled, ‘Determining a Structural Design Method for Pervious Concrete Pavements’.
The first thing you’ll need to know is that pervious concrete is concrete that allows water to flow through it. It generally uses less cementitious material to produce, and when paired with a stone recharge layer, has the ability to recharge groundwater supplies. Pervious concrete pavements also have major potential to become a best management practice for roadway drainage, eliminating the need for expensive pipe installations. All of these criteria and more make pervious concrete pavements a more sustainable option than conventional concrete pavements, when designed and constructed properly. However, the proper way of designing and constructing pervious concrete pavements has not been standardized thus far, and it appears that success stories develop from mass experimentation in a wide range of environmental conditions. Therefore, I wanted to try and produce a method that could make use of the existing and most popular guide to concrete pavement design, the 1993 AASHTO Design Guide for Rigid Pavement Structures. This way, engineers could design pervious concrete pavements more easily, saving time and money. I hoped that this new method would inspire an increase in the use of pervious concrete, reducing the production of high carbon-footprint Portland cement and making the Transportation sector more eco-friendly in turn.
During my time as a researcher, I have developed a few conclusions about pervious concrete. Firstly, most of its structural properties cannot be tested in the same way as traditional concrete. The openness of the specimens doesn’t allow for conventional strain gauge cages and other devices to fit on them, and the cross-section of a 4 inch diameter cylinder specimen appeared to be too small to accurately reflect how the aggregates would perform in a typical pavement slab. However, I collected data using these methods as carefully as I could, because there are no other standardized and economic ways of determining the strength properties of concrete. Retrofitting these methods to measure properties of pervious concrete was difficult and it sometimes failed. For example, a non-destructive test for axial and radial displacement turned destructive when my pervious concrete cylinder specimen crushed under what was supposed to be 40% of its available compressive strength. A few expensive pieces of equipment were damaged in the process, along with my confidence. This brings me to my next conclusion, that standardized techniques for making pervious concrete specimens as well as test methods for determining their structural properties are needed. The American Society for Testing and Materials (ASTM) should highly consider developing these standards. It would allow pervious concrete research to rapidly progress in depth and width. Lastly, further research is needed to determine a relationship between the permeability and structural capacity of different pervious concrete mixes, so that effective mix designs can be developed.
My faculty mentor, Dr. Kevin Hall, has been inspiring me since I chose to study Civil Engineering as a freshman. He is my academic advisor and my biggest cheerleader. I was able to study abroad in Italy during the summer intersession in 2017 because of his generosity, by giving me a job in his lab. He was also the tour guide of that unforgettably incredible trip. Anyone who has the pleasure of knowing him understands that he is constantly busy with both academic responsibilities and voluntary duties, yet he always comes through when you need him. I knew right away that when it was time for me to conduct my thesis I wanted him by my side. In addition to my mentor, dozens of undergraduate and graduate students, volunteers, and CTTP1 faculty members have given their time to advise, supply, and advance my research. No number of “thank-you’s” would suffice in expressing my gratitude toward these amazing people, and I will be putting all their names in the acknowledgments of my finished paper.
Although my adventure as a researcher was thrilling at times, my next step will not be in the direction of graduate school. I plan to take my learnings and apply them in an entry position of the transportation sector after I graduate in May of 2019. I know not where I will move to after graduation, as my fiance is awaiting acceptance letters to a number of graduate schools’ physics programs. Overall, my research has taught me humility and an utmost respect for those who spend their lives attempting to fill the voids of humanity’s knowledge of the universe. I just hope that the events of my life in the future don’t resemble the success of my research at the University of Arkansas.