Influence of the morphology of the cracking zone on the fracture energy of HMA materials
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Cracking is a common failure mechanism in Hot Mix Asphalt (HMA) materials. Therefore, the study and characterization of fracture processes in these mixtures is crucial to achieve more durable pavement designs. Existing fracture testing procedures typically compute the fracture energy of HMA as the ratio between the work required to generate the propagation of a crack within a specimen and the planar cross-sectional area of the fractured surface. However, the morphology of the fractured surface directly depends on the three-dimensional crack path and on the characteristics of the microstructure of the material, questioning both the accuracy of the assumed simplified two-dimensional rectangular area and the final magnitude of the fracture energy. This study presents a comprehensive experimental effort to determine the impact of the actual morphology of the crack area in the fracture behaviour of HMA. To accomplish this objective, semi-circular bending (SCB) tests were performed on 66 specimens of mixtures having three different gradations. Fracture energy values were obtained after accounting for the actual morphology of the crack zone using a scanning technology based on structured blue light. The results demonstrate that the gradation of the mixtures impact the morphology of the fracture surface of the testing specimens and, consequently, the final estimation of the fracture energy of these materials.
KeywordsHMA Fracture energy SCB test Cracking zone
This publication was partially made possible by the call for proposals ‘Research Program 2012’ from the Office of the Vice-President for Research at Universidad de los Andes (Bogota, Colombia). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the University.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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