SUMMARY

Evaluation of the Asphalt Binder Quality Tester

This report presents the findings from an evaluation study conducted by TRB to assess the development process and potential economic impact of the Asphalt Binder Quality Tester (ABQT). The ABQT is a novel rapid testing device that verifies the performance grade of asphalt binder by measuring deflection and recovery in a sample of asphalt binder. This device has the potential to increase the detection of out-of-specification binder before it is used in asphalt pavement, thereby reducing road maintenance costs for asphalt roads.

The ABQT device was developed under a cooperative research and development agreement between the FHWA and Laser Technology, Inc. The ABQT project was identified and scoped jointly by FHWA and Laser Technology, Inc., while they were jointly researching related laser testing technologies. Thus, the ABQT development project was a spinoff of related research funded by FHWA and a collaborative development effort by the principals from this work. It was an opportune joint research venture that required FHWA leadership but a modest FHWA investment. Many scientific and research advances are produced in such a manner, and these spontaneous public- and private-sector collaborations reflect the opportunities and entrepreneurial nature of innovation in general.

S.1 Evaluation Approach

The evaluation team conducted 35 interviews with subject matter experts (SMEs) from organizations representing six types of stakeholder groups in the ecosystem of potential users and beneficiaries of the ABQT device. Table S-1 provides a summary of the number of interviews by stakeholder group. The interviews were used to collect information on the process by which the ABQT device was developed and promoted and the data needed to quantify the potential economic impact of the device.

A probabilistic model was used to estimate the potential impact that adoption of the ABQT device could have on maintenance and replacement costs. Reduced road maintenance and replacement costs are the core of the monetized benefits calculated in the analysis. The model calculated how using the ABQT device as a screening tool can increase the probability of identifying out-of-specification binder and, hence, reduce the probability of using a subpar binder, which leads to decreased maintenance and replacement costs.

S.2 Findings

Based on the interviews with SMEs, the most promising use case for the ABQT is as a screening tool for quick tests on binder samples that are either not tested currently or have to go through more time-consuming and labor-intensive testing. For owner agencies [primarily

Table S-1. Number of SME interviews by stakeholder group.

state departments of transportation (DOTs)], the ABQT could be used as a quick screening test on the many samples they collect from contractors. The screening test could be conducted as samples are received, which could potentially allow the identification of out-of-specification samples more quickly. The potential net benefits of using the ABQT as a screening tool could be sizable, more than $300 million over 15 years of use for 50 state DOTs; moreover, adoption by DOTs seems feasible.

Because of uncertainty of the ABQT device’s acceptance and uptake, the evaluation team modeled three adoption scenarios. Table S-2 provides a summary of the annual benefits in $2021, equivalent annual benefits, and net equivalent annual benefits for each of the three adoption scenarios. The FHWA investment to date has been approximately $400,000. If adoption of the ABQT meets the levels specified in Scenario 3, the maximum adoption scenario, the net annual benefits over the 15-year life expectancy of the ABQT device would be about $10 million. Scenario 1, adoption by state DOTs, has the largest rate of return (ROR). However, this is in part because DOTs are likely to be the first adopters, with suppliers and mix plants following their lead.

From the FHWA’s perspective, the ROR on its investment has the potential to be quite high. For the DOT adoption scenario (Scenario 1), the FHWA’s initial investment of $0.4 million has the potential to yield an annual return of $8 million. These figures are based on a high level of adoption by state DOTs. However, only two states need to adopt the ABQT for the FHWA to break even on its investment.

From an individual DOT’s perspective, the return on investment from adopting the ABQT as a screening tool depends on the number of asphalt lane-miles the state DOT is responsible for, which determines the resulting decrease in maintenance costs. Table S-3 shows how the returns vary for states with different numbers of asphalt lane-miles. For example, Michigan

Table S-2. Summary of the economic impact analysis for three ABQT adoption scenarios.

Note: Cost and benefit numbers were rounded to the nearest $1,000 due to the precision of the evaluation team’s underlying assumptions. This may result in minor discrepancies due to rounding.

Table S-3. Return to state DOTs from adopting the ABQT as a screening tool.

Note: Cost and benefit numbers were rounded to the nearest $1,000 due to the precision of the evaluation team’s underlying assumptions. This may result in minor discrepancies due to rounding.

is the median state, with about 20,000 asphalt lane-miles. For Michigan, the use of the ABQT is estimated to have a net annual benefit of about $112,000, which corresponds to a ROR of 380% and a benefit-cost ratio of 5.0. A large state like Texas has a much larger return. However, Hawaii, the state with the fewest asphalt lane-miles, has an ROR of −5% and a benefit-to-cost ratio that is a little less than 1.0.

S.3 Uncertainties

The analysis presented in this evaluation is a prospective assessment of the potential benefits of the ABQT if it is adopted as a screening tool to supplement the existing asphalt binder testing being conducted throughout the supply chain. As such, there is uncertainty around the magnitude of these potential net benefits. Throughout this evaluation report, the evaluation team has flagged several parameters that might have a high level of uncertainty. These parameters are ones that drive the probabilistic model that was used to calculate the annual benefits of using the ABQT device:

• The effectiveness of the ABQT device,
• The percentage of samples collected by state DOTs that are tested (with the remaining samples not tested),
• The percentage of tested-failed samples that do not have an adverse effect on paved roads, and
• The percentage of increased maintenance costs from using an out-of-specification binder.

To reduce the uncertainty surrounding these key parameters, after the interviews, a subset of SMEs was asked to take an online survey to review the values of the key parameters used

in the model. This semi-Delphi process shared back with state DOTs the average values for parameters obtained from the interviews. SME respondents were asked to comment on whether they thought the average/typical values identified during the interviews were representative of the industry as a whole (too high, too low, about right). In all instances, the SMEs thought the key parameter values used in the analysis were reasonable.

S.4 Significance and Promoting Adoption

If adopted by stakeholders in the binder/asphalt sector, primarily state DOTs, the ABQT has the potential to deliver measurable reductions in the cost of maintenance for asphalt roads throughout the United States. At about $38,000, the device is relatively low cost. It is simple to use and delivers results quickly (in less than 1 hour). Although current asphalt binder quality is high and binder testing is extensive, even marginal improvement in the quality of the binder being used in asphalt pavement and in testing effectiveness can have a meaningful economic benefit. The ABQT would likely be one of many testing activities in the quality assurance toolkit. However, as shown by the quantitative findings of this evaluation, the adoption of the device could have a nontrivial economic impact in terms of reduced maintenance costs.

The ABQT device would likely need additional marketing, demonstration, and promotional activities to gain meaningful adoption by DOTs, suppliers, and/or mix plants. Going forward, FHWA could consider several activities to promote and increase adoption of the device. These activities would be primarily related to technology transfer and information dissemination and would not require significant additional FHWA investment. (Only minor technical enhancements/changes for the device itself were recommended by the interviewed SMEs.) To promote and increase adoption of the ABQT, the following activities could be considered:

• Expanding access to demonstrations of the device will be the most effective approach for increasing adoption.
• Engaging in the AASHTO standard specification process would increase the ABQT’s visibility and credibility while also increasing acceptance and adoption.
• Organizing a round robin testing program would help increase visibility and credibility.
• Investigating options that would reduce the up-front cost of the device to the user would help promote uptake. Options could range from establishing leasing programs to offering rebates for early adopters to looking for ways to reduce the production cost of the device itself.