Using the Fracture Energy Index Concept to Characterize the HMA Cracking Resistance Potential under Monotonic Crack Testing

In this study, the concept of the Fracture Energy (FE) Index was explored as a fracture parameter to characterize and quantify the cracking resistance potential of hot-mix asphalt (HMA) mixes subjected to monotonic loading in the laboratory. Mathematically, the FE Index was defined as a parametric ratio of the total FE to the HMA tensile strength and tensile strain at peak failure load per unit crack length. The concept was put into practice by testing commonly used Texas HMA mixes, with cracking resistance potential ranging from poor to good, under the Overlay Tester -monotonic loading setup (OTM) along with two other more commonly used monotonic loading tests, namely: the Indirect Tensile Test (IDT) and the Semi-Circular Bending Test (SCB). Corresponding results indicated that the FE Index has promising potential to be used as a fracture parameter to discriminate and rank the cracking resistance potential of HMA mixes in the laboratory. As expected of monotonic loading crack tests, variability was within acceptable tolerances, except for the SCB that exhibited high variability, particularly at higher asphalt-binder contents. The FE Index also exhibited sensitivity to HMA mix -design variables such as the asphalt-binder content, particularly for the OTM and IDT tests. Overall, the OTM and the IDT tests exhibited superiority over the SCB test and would readily serve as surrogate crack tests for routine HMA mix-design and screening in the laboratory. For room temperature testing at 25°C, the SCB test appeared to be better suited for low asphalt -binder content mixes.


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  • Accession Number: 01518710
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 27 2014 3:05PM