We talk with leading educators in the field of asphalt technology in an effort to tune in to academia on important industry issues.
Kevin D. Hall is a Professor, Department Head and 21st Century Leadership Chair in Civil Engineering at the University of Arkansas and Executive Director of the Mack-Blackwell Rural Transportation Center.
What drew you to civil engineering, and in particular, transportation?
I love civil engineering for its relevance and immediate impact to change people’s lives for the better. My interest in transportation probably started with Tonka trucks! It solidified, however, with two summer internships with the Arkansas Highway and Transportation Department. I was drawn to the combination of design and construction offered by pavement engineering.
What existing technologies are available to improve pavement performance?
Many folks (and I am one of them) believe that a large percentage of “problems” like issues that lead to premature distress and failure, that we see on today’s roadways are not due to a lack of technology and/or understanding. Rather, they result from a failure to accomplish what we already know how to do. In our search for the next great technology, we must never brush off good, fundamental design concepts and construction practices. Thus, virtually all of our available technologies can be used to construct a very successful pavement system – if we simply ensure that every step is performed properly.
Are there new technologies or strategies to help designers with Mechanistic-Empirical Pavement Design Guide (MEPDG) implementation and use?
This is certainly a fast-moving area; it seems that every day some researcher and/or DOT announces another new nuance. In my opinion the best strategy for implementation and use is to truly THINK about the pavement you are designing. In many cases we have become a bit complacent with existing systems, regarding our ability to supply known or historic inputs to a computer program and get the design out, which requires very little thought. The tools offered by the MEPDG (particularly in characterizing new and better materials) gives us an opportunity to actually DESIGN the pavement and its constituent materials, understanding how we can tailor materials to a specific application, within a given pavement structure.
Are there new developments in asphalt pavement testing that excite you?
We live in the era of rehabilitation. While there are “new” pavements being built, the bulk of our efforts are related to rehabilitating existing roadways. Complicating this issue is the fact that many folks who designed and built a large percentage of our roadways are at-or-near retirement – taking with them tremendous experience and institutional knowledge. Thus, a crucial aspect of our job is now data. We must do a better job of collecting and analyzing design, materials, construction and performance data. The advances in automated data collection, at all stages of a given project, are very exciting. Real-time monitoring of processes and quality-related measures, coupled with near-real-time performance measures, provides us a significant opportunity to improve on creating long-life pavement systems.
Where should today’s engineering students focus their research in the asphalt field?
Three immediate areas spring to mind: (1) better performance models and transfer functions for mechanistic-empirical design – particularly related to rehabilitation; (2) furthering our understanding of the mechanisms related to “how a mixture performs” with increased use of recycled materials of all types – perhaps down to the nano level; (3) continuing the push towards true “performance-based specifications” which are suitable for routine design and construction. As a global topic, we must continue to eliminate our traditional silos that have historically separated pavement design, materials, construction, maintenance, etc. – and view the entire enterprise as an interconnected system.