Microstructural characterisation and analysis of coarse aggregates in asphalt drill cores

Abstract

The research presented in this paper is focused on the three-dimensional characterisation of coarse aggregates ($d\ge 2$ mm) within real asphalt structures. It is based on three-dimensional images acquired by micro X-ray Computed Tomography (μXRCT). A method to segment the aggregates from the other asphalt mixture components and each other, using these images is presented in detail. Subsequently, they are converted into basic data on the aggregate size, form, structure and orientation of every individual aggregate. On this database, fundamental and generally used parameters are calculated to characterise the aggregate properties. Finally, the parameters are evaluated regarding the aggregate form, angularity, location within the drill core and alignment of its main dimension. The results show that the segmentation method delivers quite precise results about the aggregates. The analysis of those basic parameters points out that the aggregates' positioning is evenly distributed but the orientation behaviour inside the structure is dependent on their shape characteristics.

Keywords:

• Asphalt analysis
• digital image processing
• X-Ray Computed Tomography (XRCT)
• aggregate characterisation
• aggregate analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors would like to acknowledge, that the research in this paper was conducted within the research unit FOR 2089, under grant [RE 1620/4] by the Deutsche Forschungsgemeinschaft (DFG).