Laboratory performance tests on intermediate-temperature cracking resistance: A case study

Document Type

Conference Proceeding

Publication Date

1-1-2021

Abstract

Several laboratory performance test methods are available in the pavement community for addressing the intermediate-temperature cracking resistance of asphalt mixtures. However, no general consensus has been reached on the selection for mixture design and performance evaluation. This paper presents experimental findings and comparisons on six widely used test methods, including the four-point bending beam fatigue (BF), Texas overlay (OT), simplified-viscoelastic continuum damage (S-VECD), semi-circular bend (SCB), Illinois flexibility index (I-FIT), and indirect tension (IDT) tests. The objectives were to investigate the mixture-discriminating potential of these test methods and to compare their ranking capability with reference to the field fatigue performance. A total of 16 asphalt mixtures with various material composition factors from four different sources were evaluated. Ten mixtures were contributed from the FHWA Accelerated Loading Facility (ALF) test lanes complete with the field performance data. The mixture composition factors considered the incorporation of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS), warm-mix technologies (water foaming and Evotherm), and base binder performance grade (PG). Results indicated that use of higher RAP contents generally yielded lower cracking resistance according to all the tests. The OT, SCB, and S-VECD tests reasonably ranked the two ALF mixtures in which the recycled binders had the same ratio in the total binder but different oxidation degrees. The effect of the two warm-mix technologies compared to the conventional counterparts was not conclusive, as no consistent observations were obtained. Use of soft base binder was consistently seen to improve the cracking resistance of asphalt mixtures with 40% RAP, but not so for mixtures containing 20% RAS. Investigation on the correlation of the test results with the ALF field performance was performed to evaluate the ranking capability of the test methodologies. The IDT and I-FIT tests were relatively weak, unlike all the other test. They were unable to identify the worst three performers, and also because they provided the lowest ranking correlation with the field measurements. Results reported herein are part of FHWA Transportation Pool Fund Study TPF-5(294) “Develop Mix Design and Analysis Procedures for Asphalt Mixtures Containing High-RAP Contents”.

Publication Source (Journal or Book title)

Asphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions

First Page

287

Last Page

322

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