Old Test Sections

I may be showing my age by getting nostalgic about old test sections. One of my first pavement engineering experiences was putting down four paving fabrics and geo-composite membranes to mitigate reflection cracking on Magnolia Avenue on the northern edge of Auburn’s campus. I was a senior civil engineering student and had been working in the asphalt lab before there was such a thing as NCAT. Dr. Frazier Parker asked if I would be interested in doing a field experiment to evaluate the products aimed at slowing or stopping reflection cracking.

It was a memorable experience, especially when it started raining, and a truck hauling mix hit the brakes too hard on a little hill, and the geotextile that we had carefully placed on the heavy tack coat slipped badly and “bunched up” the fabric. By the time the supplier’s representative and I finished pulling up the fabric by hand, I was covered head to toe in asphalt and looked like Uncle Remus’s tar baby.

Ever since then, I’ve had a strong affinity for the black sticky stuff and a love for building test sections. A few years later, as a young engineer with the Florida DOT, I was fortunate to be involved in constructing and evaluating a series of test sections with ground tire rubber (GTR) in open-graded friction course mixtures on State Road 16 north of Starke, Fla., and then later with several more GTR demonstration projects across the state. Those early trial projects were instrumental in FDOT’s specifications for using GTR in both dense- and open-graded mixtures for many years.

Roughly 10 years later, while working for APAC Inc., I was back in Florida and made my way over to Starke to check out the almost forgotten GTR test sections. Not surprisingly, the test section with the highest rubber content had the least amount of cracking and was noticeably darker than the other test sections. The proof that the higher GTR content test section was superior was more meaningful to me than the experience of building the test sections. 

Throughout my career, I’ve been involved in the construction and evaluation of numerous test sections, including field experiments with glasphalt, Gilsonite, warm-mix asphalt, recycled shingles, fibers of different types, 50% RAP mixtures, 4.75 mm NMAS mixtures, and recycled plastics. Recently, while working on a literature review on longitudinal joints, we found reports from about seven states that had built longitudinal joint field experiments. Unfortunately, none of the experiments were evaluated for more than just a few years, and the reports lacked conclusive evidence about which methods were really best. 

It’s disappointing that agencies and researchers put forth a significant effort to build field test sections and then forget about them within a few years. The real value of field test sections comes when we can assess what works best over the long term. That’s the motivation behind the Long-Term Pavement Performance (LTPP) program. I think it’s time that we rekindle the LTPP spirit to help us better assess BMD tests and mixture aging procedures.

If you are in the second half of your career, encourage young people you work with to explore new technologies to make better pavements for the future. Opportunities to make a difference are often a spark to jump-start a career. 

If you’ve been involved in test sections in the past, go back to see how they are doing. If you are in the early part of your career, I encourage you to get involved in building and evaluating test sections that will provide meaningful results to help determine if something new is truly better. 

Randy C. West, Ph.D., P.E. | Director and Research Professor