This data set contains two micro X-ray Computed Tomography (micro-XRCT) data sets resulting from region of interest scans (diameter 58.32 mm, height 46.06 mm) of the center region of a stone mastic asphalt (SMA) drill core. The drill core was scanned with identical scanner settings before ("reconstructed_20200429_01.tar.gz") and after ("reconstructed_20201015_01.tar.gz") a uniaxial compression test.The sample had a diameter of 75.12 mm and a height of 70.93 mm before, respectively a diameter of 78.05 mm and a height of 67.11 mm after the compression test (measured by caliper). The asphalt mixture is a stone mastic asphalt with a nominal maximum aggregate size (NMAS) of 11 mm (SMA 11 S). It contains diabase aggregates and a 50/70 bitumen binder. The material is described in detail by Hu et al. (2017).The compression test was performed by controlling the load with the following procedure: Starting the measurement at a contact load of 10 N. Increasing the load to 500 N (stress around 0.11 N/mm2) with a speed of 100 mm/min. Holding the load at 500 N (stress around 0.11 N/mm2) for 600 s. Increasing the load by another 500 N (stress around 0.11 N/mm2) with a speed of 100 mm/min and holding it for 600 s. Repeating the procedure of adding load in 500 N (stress around 0.11 N/mm2) increments, until the maximum load of 5000 N (stress around 1.13 N/mm2) is reached and held for 600 s.During the test, time (s), distance (mm), and load (N) were logged at regular intervals and can be found in "2_1_compression_test_data.csv". A visualization of the test procedure is shown in "test_procedure.pdf".NOTE: It turned out that the specimen top and bottom surfaces were not exactly plane-parallel which led to an non-uniform transmission of the load, which lead to a first full-surface contact between the load plate and top surface of the specimen when the 1500 N load increment was reached.

The research presented in this paper is focused on the three-dimensional characterisation of coarse aggregates ( $ d\geq 2 $ d & GE;2 mm) within real asphalt structures. It is based on three-dimensional images acquired by micro X-ray Computed Tomography (mu XRCT). 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.

The aim of this paper is to show the complexity of studying air void topology by giving an in-depth literature review. Factors defining air void structure are presented and relationships and correlations are highlighted. The hydraulic conductivity of asphalt is then put in context of air void analyses. A new approach to distinguish constrictions in the air void matrix is introduced. The bigger air voids represent the drainage (volumetric) capacity. The constrictions, on the other hand, have a direct influence on hydraulic conductivity, as clogging could easily diminish or eliminate them. This approach should improve the meaningfulness of studies analysing air void characteristics. With X-ray CT scans, an analysis of the middle section of two artificially soiled porous asphalt cores is then presented. As expected, approximately homogeneous behaviour of air voids as well as constrictions can be observed.

Microstructural analyses of asphalt mixtures are described in this chapter using the X-Ray computer tomography (X-Ray CT) and related digital image processing (DIP) approaches. Different parameters of single elements like aggregates or air voids as well as characteristics of the whole grain and void structure, which can be determined, are introduced. These features can be linked to different mechanical, structural and functional properties. Changes of certain parameters by load application (tensile or compressive stress) or by artificial soiling (with porous structures), e.g. in before-and-after studies, are observed and certain conclusions are drawn. Fatigue and deformation of asphalt pavements and related deterioration effects in the microstructure like cracking are presented as exemplary use cases in this chapter as well as drainage and sound absorption of porous asphalt. The virtual reconstruction of asphalt structures based on three-dimensional (3D) images of real asphalt samples is also of great relevance for computational studies, e.g. for finite element modeling, and is shown exemplarily in this chapter. Simplification approaches of the microstructure are discussed in that context briefly as well.

Different computational methods dealing with functional properties of road surfaces are presented. Drainage and skid resistance as functional properties are treated. A special focus is set on the relationship between functional properties and asphalt structures, examples of important connecting aspects are described with regard to drainage of porous pavements and relevant void structures. Furthermore, in that context, analyses of the inner structure of asphalt are performed with XRCT scanning methods in order to develop a better understanding of asphalt structures and their implications on functional properties. In addition, the deformation behavior in before/after comparisons of XRCT images after uniaxial load tests are investigated.