Development in Aggregate Quality Characterization Approaches for Pavement Construction

Abstract

The aggregate properties play a major role in the structural and functional performance of various pavement layers. The present chapter provides an introduction to aggregate sources, types, quality, and different size distribution requirements for pavement layers. Further, the chapter is categorized into two broad sections. The first section offers an extensive discussion on past and presently available conventional aggregate characterization practices, limiting values, and their significance. For example, the properties associated with the aggregate source (i.e., abrasion, impact, soundness, and absorption) and consensus or shape (i.e., FAA: fine aggregate angularity; coarse aggregate angularity, flatness and elongation, and sand equivalent) are discussed. The second part of the chapter talks about the application of various image-based techniques for aggregate shape characterization and its futuristic importance for the production of quality aggregates. The Digital Image Technique (DIT)-based methods like University of Illinois Aggregate Image Analyzer (UIAIA), Aggregate Image Measurement System (AIMS), Laser-based Aggregate Analysis System (LAAS), Videographer-40 (VDG-40), and CT-Scan are discussed. Moreover, a brief overview of various algorithms associated with digital image techniques is presented. The part also includes a comparative discussion on conventional and image-based shape characterization approaches. Additionally, the futuristic application of DIT in different aspects like aggregate production, quality control, and pavement forensic investigations are outlined. Overall, it is expected that the chapter will develop a broad understanding among researchers, practitioners, aggregate producers, and pavement stakeholders on the qualitative characterization of aggregates.