Monthly Archives

March 2019

AAPT Annual Meeting a good forum for emerging asphalt technologies

By | Asphalt | No Comments

Surface Tech’s asphalt advisor Phil Blankenship to take the President’s role in 2020

Phil BlankenshipFor more than 90 years, the worldwide membership of the Association of Asphalt Paving Technologies has provided a centralized forum for disseminating the latest developments in asphalt paving technology. The organization’s recent annual meeting provided an excellent opportunity for Joe Dennis, Surface Tech’s chief technology officer, and Phil Blankenship, P.E., asphalt advisor to Surface Tech, to explain in depth how ACE XP Polymer Fiber differs from other non-polymer fibers.

“As we all know, no good idea sits idle, and that was largely the response we saw as many of the professionals in attendance gained a better understanding of the capabilities of ACE XP,” said Dennis. “Once the differences are clear, we saw the interest in ACE XP rise dramatically.”

A stellar line-up of presentations on a variety of research projects and material advances filled the three-day event, along with plenty of opportunities to network. Presentations included a wide range of topics, including the impacts of climate change on asphalt, 3-D paving, advances in stress testing, numerical modeling and much more.

“The AAPT Annual Meeting was well attended by a large number of highly educated professionals in our industry,” said Blankenship, who will take on the role of the organization’s president in 2020. “I expect the AAPT to continue to be a significant source of information and technological advancements well into the future.”

To view YouTube videos of the various presentations, visit https://www.youtube.com/channel/UCjWgLqZUstRB_G_zl9gLqLw

IDEAL-CT & Hamburg Wheel Tracker meet the need for crack/rut balanced performance testing in asphalt mixes

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ACE XP shows 30% to 50% improvements in both tests

 Indirect Tensile Cracking Test at Intermediate Temperature (IDEAL-CT)

Figure 1. Indirect Tensile Cracking Test at Intermediate Temperature (IDEAL-CT)

Asphalt pavements need to be stiff enough to minimize rutting, but resilient enough to bend without breaking to prevent cracking. The trend over the last 20 years has been one-sided — fixing the ruts at the expense of the cracks. Many in the industry have begun to recognize the need for a “balanced approach” to developing pavement designs that will perform well in resisting both rutting and cracking.

There are seven key existing performance or index tests for asphalt cracking (see Table 1). These tests vary in complexity and cost, and as a result, the asphalt industry has not traditionally performed cracking performance tests on every project.

Hamburg Wheel Tracker (HWT) Test

Figure 2. Hamburg Wheel Tracker (HWT) Test

For rut testing, the Hamburg Wheel Tracker (HWT) test tends to be the most widely used method. However, many agencies and specifiers, including DOTs, are moving toward adopting performance-based specifications where both mix designs and daily production will need to meet certain minimums in both cracking and rutting parameters in order to be considered.

A new and promising cracking test has recently been developed by Dr. Fujie Zhou and his colleagues at the Texas A&M Transportation Institute. The Indirect Tensile Cracking Test at Intermediate Temperature (IDEAL-CT) is a reduced cost method that provides consistent results to predict field performance in cracking. This test, along with HWT, can be used daily to ensure that asphalt mixes meet both rutting and cracking performance criteria in a balanced manner.

For example, tests utilizing the HWT and IDEAL-CT methods on ACE XP asphalt mixes can be seen in Figures 1 & 2. The results compare mixes with and without ACE XP and show clear performance advantages with ACE XP in both rutting and cracking sample results.

Bottom line: In balanced performance testing, ACE XP Polymer Fiber yields an improvement of 30% to 50% in both rutting and cracking performance. To learn more about ACE XP or how to achieve a balanced approach to testing using the IDEAL-CT method, contact us.

Asphalt crack testing

Fig. 1 - Hamburg Wheel Tracker (HWT) Test Example:

Fig. 1 – Hamburg Wheel Tracker (HWT) Test Example

 

IDEAL-CT Crack Test

Fig. 2 – IDEAL-CT Crack Test Example:

ACE XP Polymer Fiber adds strength to asphalt pavement in all directions. PROVEN IN THE FIELD. DOWNLOAD THE TEST RESULTS.