Author: Lorella Angelini, Angelini Consulting Services LLC
Interview with: Ted Hopwood, P.E., Engineer Associate with KY Transportation Center
The National Testing Product Evaluation Program (NTPEP) by AASHTO is dedicated to the US highway industry. In the last 10 years it has gathered a lot of consensus but it has also raised some questions. I am going to explore different perceptions of NTPEP through conversations with industry opinion leaders. The first conversation is with Ted Hopwood, Engineer Associate with Kentucky (KY) Transportation Center.
You are considered an authority in the industry with an outstanding 31 years of service at KY Transportation Center. How would you define your area of expertise?
- You can say that I am “1 mile wide and 1 inch deep”. I deal with bridge maintenance and inspection with the purpose of keeping bridges in a good state. There are so many topics related to bridge preservation that no one person can be considered an expert of them all. I am kind of a generalist, who understands the topics and locates the expertise that is needed to properly address them.
Are you active with NTPEP?
- Yes, the KY Transportation Center is part of the NTPEP team. We do tests for concrete coatings. NTPEP is a testing program focused on materials. People in the NTPEP group are primarily from highway agencies. They essentially define test programs and put together committees when they need to tackle a particular topic. Since most DOT labs are very busy, NTPEP committees tend to outsource testing, collaborating with universities or private testing firms.
Can you summarize how the NTPEP testing program works?
- Speaking from the point of view of a manufacturer wanting to test a concrete coating product, the process starts with the manufacturer signing a contract with AASHTO. The manufacturer pays AASHTO so that AASHTO can pay the contracted lab for testing the product. Tests are done according to a protocol created by experts from different state Agencies. The manufacturer, who knows what tests are performed, furnishes the lab with the coating product. The lab performs some tests at its location, some others in the field. For example, concrete coating samples go to Florida DOT for exposure testing. When tests are completed, the lab develops test data, which are uploaded in a software program developed by AASHTO. This set of data is available to highway Agency material divisions.
What are your reasons for supporting NTPEP?
- Before NTPEP, when a manufacturing company had a product for DOT applications, the company had to contact 50 states to get approval. Each DOT created its list of approved products based on its own test program and the successful use of products in other states. This put a strain on both the manufacturers and the highway material divisions due to the amount of tests they had to perform. In other words, things did not work out very efficiently for either group. The NTPEP concept stemmed from this inefficiency. It entails having one centralized group (DOT, university or private contractor) that tests the products and provides data. Each DOT looks at these data and establishes its own criteria for acceptance.
Are there other benefits of NTPEP?
- I believe the NTPEP test data mine is another major benefit of the program. Almost any question about the performance of certain types of materials can be answered through the NTPEP test data mine.
What are your suggestions for improving NTPEP?
- Looking into the future, I suggest that end users will get together under the TSP2 banner and establish uniform criteria for evaluating the test data, either regionally or nationally. My vision is for NTPEP to evolve from a testing to a certification program. Otherwise, the certification program could be a product of the TSP2 regional partnerships.
- I also think that the NTPEP program needs to expand the number of products to be evaluated for bridge preservation since a significant number of materials are not currently included in the NTPEP program. This also calls for a more structured relationship between NTPEP and TSP2.
If there were something about the program you could change, what would it be?
- I would try to create standardization for acceptance of materials nationally or, at least, at regional level. Right now each state has its own criteria for acceptance.
- I would also try to create a NTPEP test protocol for those materials that have niche properties that apply to a few states only. There are a lot of unique materials that are coming out, which are hard to characterize under the current NTPEP program.
- Lastly, I support the idea of creating a NTPEP test protocol for testing superior materials, not only the good ones. How do we go from the currently established standards to accepting better materials? How do we evaluate great performing materials, when the testing is set up to evaluate the good ones only? It is nice to have good performing materials for bridge preservation but we also like to get great performing ones.
What are you going to focus on in the next years?
- In the next couple of years I will focus my attention on test methods and procedures for the repair of concrete. I am also planning to study the diagnosis of concrete distress, an important aspect of the repair process. Too many highway repairs of reinforced concrete are not very durable. Successful applications require a combination of factors: proper damage evaluation, selection of repair material and procedure, and its correct execution in the field.