SECTION 3

ABQT Project Selection and Research Process

3.1 Project Identification and Approval

The initial idea for the ABQT stemmed from another Small Business Innovation Research (SBIR) Phase I and II award that FHWA had funded for LTI from 2005 through 2009. The SBIR awards were for developing a technology that would detect micro-cracks in concrete. When John Newman, Founder of LTI, visited the Turner-Fairbank Highway Research Center (TFHRC) in 2010 to discuss this project, Raj Dongre and Jack Youtcheff gave him a tour of the TFHRC testing lab. When they were discussing the penetration test, a test that measures the hardness of a binder sample by measuring the depth of penetration from a needle with constant force in a 5-second period, they came up with a concept for developing a test that could measure the deflection of a binder more sensitively under force using a laser.

After this meeting, Newman requested several binder samples and developed a prototype with funding through LTI. The test initially produced numeric results, but it was difficult to make sense of the findings and present them to the industry. Dongre and Youtcheff then took the output of the new device and compared it to test results from other devices, like a rheometer, to predict the PG. Because the performance grading system had been around for about 20 years at that point, the FHWA had access to a wealth of data for this prediction algorithm. This algorithm was the basis of the ANN that is included with the ABQT device now.

The development of the ANN was a good example of FHWA collaborating with a private-sector technology developer and providing sector-specific expertise and historical data that very few private-sector organizations would have. Additionally, the device was developed based on technology that was supported by FHWA for another purpose, and FHWA was able to support the advancement of the technology for additional purposes.

3.2 Timeline of Research and Dissemination Activities

Figure 3-1 provides the timeline of the development and dissemination of the ABQT device. Research associated with the concrete crack detection laser was conducted in the late 2000s. The primary development of the ABQT device took place from 2010 through 2012. Refinements continued after 2012, along with presentations of the device to state DOTs and at conferences.

LTI conducted and funded the engineering development and design of the ABQT, which were completed by the end of 2010. Through this process, LTI created the first prototype, which it sent to TFHRC. Over the next couple of years, FHWA tested the device, and minor updates were made. Initially, the device used a coaxial nozzle to produce the air jet causing the deflection in the

sample, but in 2015, the nozzle was updated to be a circular nozzle employing multiple air jets that centered on a specific point of the sample, producing the deflection.

Using the initial ABQT prototype, FHWA staff tested thousands of samples and verified the outputs from the device over the next 2 to 3 years. From 2012 through 2016, Dongre did most of his work at TFHRC to develop the ANN, which used the output from the device to predict the PG of the binder sample. In 2016, the device was introduced with the complementary ANN through presentations. Since the ANN was introduced, binder samples from multiple states have been tested to validate and enhance the ANN algorithm.

In 2014, FHWA and LTI worked together to produce a technical paper for a conference hosted by the Canadian Technical Asphalt Association. In 2016, they produced an additional report for the Eurasphalt & Eurobitume Congress on the technical details of the device, including the ANN. These reports have since been disseminated to stakeholders across the United States to provide background on the ABQT’s technical capabilities to domestic stakeholders.

Additionally, FHWA staff have given presentations at conferences hosted by trade organizations around the country, and they have loaned the device to five state DOTs and the North Central Superpave Center (NCSC) at Purdue University for testing. Testing results from state DOTs have been used to verify the ANN and improve the ABQT’s ability to predict binder PGs correctly. In 2019, TFHRC also added the ABQT to its Mobile Asphalt Testing Center (MATC). The MATC travels around the country to demonstrate asphalt testing methods and new technologies to state DOTs and industry stakeholders. Because of COVID-19, the MATC did not travel during 2020, but use of the MATC was scheduled to continue in the future. Table 3-1 provides additional details on these activities. Table 3-2 lists FHWA presentations and publications related to the ABQT. As discussed in the following sections, state DOTs that received a loaner device had a more favorable view of its potential benefits compared with those that did not have the opportunity to demo its use.

In 2018, Dongre shifted to working full time for his own company, which provides consulting and research services for the asphalt industry. In this capacity, he now provides the software for the ABQT and training on using the device. Users of the device work with Dongre to load the correct data into the ANN so that the device can properly predict the PG for the types of binders the user needs to test.

Table 3-1. ABQT outreach and collaboration activities.

Table 3-2. ABQT presentations and publications.