Analysis and Comparison of the Microstructural Characteristics of Field Asphaltic Cores and Laboratory Asphaltic Samples in Different Compaction Energies

In most mix design methods, hot mixture asphalt (HMA) is considered to be a single object and only its macroscopic parameters are determined. This is because the microstructure of HMA is very complicated. Asphalt mixture is heterogeneous in nature; therefore, macroscopic parameters alone cannot describe the mechanical behavior of the mixture. In this paper, the analysis and evaluation of microstructure parameters of aggregates in field asphaltic samples are compared to laboratory samples in different compaction energies. Image processing and quantification of the internal structure parameters of the mixtures were performed using two-dimensional images from the cut-off of samples and iPAS2 software. The results of the comparison between the parameters of micro and field samples showed that the number of contact points in the cores was close to the number of contact points of Marshall Samples, which were made with moderate compaction energy. It was also determined that by examining mixtures of asphalt mixtures, new and useful information can be obtained that confirms the necessity of using micro parameters in the mixing design of asphalt mixtures.