SECTION 1
Introduction
To ensure that the FHWA’s Research and Technology (R&T) Program is meeting the objectives laid out in the FHWA Research and Policy Agenda, formal evaluations of projects and programs are periodically conducted. The primary purpose of these evaluations is to quantify the socioeconomic returns of R&T Program activities and to guide future research agendas and technology transfer activities.
RTI International was engaged by TRB to evaluate the Asphalt Binder Quality Tester (ABQT), which was developed under a cooperative research and development agreement (CRADA) between FHWA and Laser Technology, Inc. (LTI).
The ABQT is a rapid testing device that measures deflection and recovery in a sample of asphalt binder (Appendix A presents a detailed description of the device and its capabilities). The ABQT uses an artificial neural network (ANN) to estimate the performance grade (PG) of the binder sample based on the test results. The device is smaller than most other existing asphalt binder testing equipment and requires less complicated calibration, making it more portable than most binder rheological testing equipment. The ABQT is also easy to use; the test requires only a 3-ounce tin of asphalt binder that must be conditioned to 25°C (77°F). The ABQT uses an air jet to produce a 20-second load on the asphalt binder sample and then allows a 70-second recovery time. A laser deflectometer in the ABQT measures the resulting deflection and recovery of the sample over this 90-second period.
FHWA also developed an ANN model as part of the ABQT. The ANN model incorporates test data from known binders meeting the Superpave PGs and uses the deflection and recovery curve measured over the 90-second test period to predict the PG of the asphalt binder sample. Furthermore, the ABQT was tested to compare the percentage recovery of the sample to the percentage recovery of the multi-stress creep-recover (MSCR) test, and the results from the two tests were very similar, indicating that the recovery results from the ABQT relate to the recovery of asphalt binders. The ABQT can predict the PG of softer binders used in recycled asphalt pavement (RAP) mixes and modified PG plus graded binders (FHWA, 2017).
At the time of this evaluation, the ABQT had limited commercial availability and was not being used as part of official testing by the private sector or road owner agencies, including state departments of transportation (DOTs). As a result, this study was a prospective evaluation of the potential costs and benefits of the ABQT as opposed to a retrospective benefit-cost study of a technology that has seen widespread adoption. Thus, in addition to quantifying the potential future benefits of the ABQT technology, this evaluation assessed the business case for and barriers to widespread adoption. The assessment of the business case and barriers to adoption considered both market factors and regulatory factors associated with existing testing processes and state requirements.
The potential benefits of the ABQT that this evaluation assessed are a combination of reduced testing costs, increased testing capacity, decreased latency time for test results, and a potential
increase in the average quality of asphalt pavement. The degree of increase in quality of asphalt pavement was hard to assess because the ABQT has not yet been used in testing labs or field operations, so its impact has not been demonstrated. However, the economic impact of improvements in asphalt pavement quality potentially represents the largest benefit category investigated, even if a sizable level of uncertainty is associated with potential quantitative economic impacts.
Based on the findings of the evaluation related to the business case, barriers to adoption, and socioeconomic benefits, RTI considered how advocates might proceed in promoting adoption of the ABQT. Options ranged from letting market forces drive adoption to the public sector embracing a more active role by working to integrate the ABQT into state DOT testing activities.
In summary, this evaluation had five core objectives:
- Evaluate the process by which ABQT research was selected and conducted.
- Evaluate the effectiveness of research, technology transfer, and collaborative activities with state owner agencies and the private sector in promoting adoption of the ABQT.
- Evaluate the business case and barriers to adoption of the ABQT for asphalt-sector stakeholders.
- Quantitatively estimate the potential benefits of ABQT use and the costs of device development and adoption.
- Assess how the ABQT program aligns with FHWA’s research strategy and identify options for changes or enhancements to the program that may improve outcomes.
RTI developed this evaluation report from research gathered through a literature review and interviews with subject matter experts (SMEs). RTI reviewed literature describing the function and development of the ABQT, as well as literature on the history of binder testing and the development of binder performance specifications. RTI also conducted interviews with Raj Dongre, an FHWA consultant; Jack Youtcheff, an FHWA employee who led the ABQT development; and over 35 industry professionals who have extensive experience with the binder supply chain or experience testing binders.
The rest of this report is organized as follows. Section 2 provides an overview of our data collection, analysis, and modeling approach. Section 3 discusses the process by which ABQT research was selected and conducted, and Section 4 assesses technology transfer and collaborative activities. Section 5 presents the business case and barriers to adoption. Section 6 and Section 7 present the quantitative modeling and the benefit-cost analysis, respectively. Section 8 provides some context around the uncertainty of the assumptions in the report. The report concludes with Section 9 discussing the core findings from the evaluation.
