We talk with leading educators and researchers to learn more about the people and topics of asphalt technology.
Dr. Andrew Braham is an Associate Professor in the Department of Civil Engineering at the University of Arkansas – Fayetteville.
What drew you to pavement engineering?
I was graduating with my bachelor’s degree in Civil Engineering and I met my now wife, Brenda, who was just completing her sophomore year at the University of Wisconsin – Madison. We decided it would be best if I stayed in school instead of going directly to work, as our schedules would be similar. I emailed my three favorite professors from my undergraduate experience asking about the potential of graduate school. Dr. Hussain Bahia, whom I now consider a good friend and colleague, and who is one of the leaders of asphalt binder research in the world, immediately responded. He offered me a position and I accepted. Like so many people in our industry, once I got in, I never got out!
Are you seeing a higher level of interest in asphalt emulsion pavement maintenance treatments?
Yes, I believe that we are. With an increasing emphasis on the environmental pillar of sustainability, specifically energy usage and emissions, the interest will only grow. There are many asphalt emulsion-based surface treatments for flexible pavements, including fog seals, chip seals, scrub seals, slurry seal and micro surfacing. These treatments, in combination with thin overlays and ultra-thin bonded wearing courses, are able to extend the life of pavements in good condition at a reduced cost, while lowering energy use and emissions. These concepts are always of interest to the undergraduate students I am fortunate enough to interact with, as they are very interested in protecting the environment while still maintaining our infrastructure. In addition, I believe that the creation of free resources like RoadResource.org, which has a wealth of information on pavement maintenance treatments, will only make learning about these topics easier.
How does pavement preservation relate to pavement maintenance treatments?
I believe that there are multiple answers to this question, so I will share my perspective on what I believe is the most accurate answer. It is my opinion that pavement preservation is a concept or an idea. My definition of pavement preservation is to keep good roads in good condition and not wait until deterioration occurs before taking care of a road. To properly preserve a pavement, you place specific pavement maintenance treatments. I believe that all of the treatments I discussed above have a place on our roadway networks, and it is critical to apply the right treatment, on the right road, at the right time (thank you FHWA!).
What types of research have you been involved with related to asphalt emulsions?
There are two core areas of research that my group has been working on over the past couple of years in relation to asphalt emulsion. First, particle size. Asphalt emulsions are tiny droplets of asphalt binder suspended in water with the aid of emulsifiers. The size of the droplets heavily influences the behavior and performance of the asphalt emulsion, so understanding what changes the size of droplets and how to manage these changes is absolutely critical. Second, Cold In-place Recycling, or CIR. CIR is a treatment where 3-6” of asphalt concrete is milled, mixed with asphalt emulsion and other additives, and immediately placed with a paver. Current standards focus on material selection and final strength. However, while CIR is being placed the asphalt emulsion flocculates, coalesces and eventually fully breaks, leaving only the asphalt emulsion residue. During these stages, my research group explored the workability, compactability and cohesion gain of CIR.
In what area should today’s students focus their asphalt research?
Everything! In all seriousness, everything. I believe that the asphalt community needs to continue to work on recognizing that pavements have the highest level of success when all stages of the life cycle are integrated. This means that as you work through the life cycle stages, from material design to structural design, production, construction, use phase and end of life, we need to be thinking about how each of these areas impact other areas. For example, if we build a true perpetual pavement, we need to be very cognizant of the materials in each layer, ensure success during production and construction and take care of the surface of the beautiful pavement structure. Before the surface begins to degrade, we should place a maintenance treatment on the surface, protecting all of the layers below. While there has certainly been movement in this direction, I believe that there is still a long way to go. Therefore, I truly believe that students should be focusing on everything.
