Coarse and fine aggregates form the skeleton of any type of pavement and influence the performance of the pavement structure. Characterization of the physical characteristics (shape, angularity, and texture) of coarse and fine aggregates is the first step towards the development of valid specifications for these characteristics. Current test methods used in practice have several limitations in quantifying the shape and texture properties. An imaging based test method ??Aggregate Imaging System (AIMS)?? has been recently developed and shown to be capable of directly measuring the characteristics of coarse and fine aggregates. In this thesis, the quality of AIMS measurements is evaluated through the analysis of repeatability, reproducibility, and sensitivity. The analysis results are also compared to the results from other available test methods. AIMS provides the distribution of shape characteristics in an aggregate sample. Statistical analysis is conducted in order to determine the distribution function that best describes the distribution of shape characteristics. The parameters of the distribution function can be related to the performance of pavement layers. A new method based on the ??Categorical Units?? isdeveloped to test differences between aggregate samples in terms of shape characteristics. It is demonstrated that this method is capable of quantifying the differences between aggregates and can be used to capture the influence of change in aggregate source or production techniques on aggregate characteristics.