Morphology-based indices and recommended sampling sizes for using image-based methods to quantify degradations of compacted aggregate materials

Abstract

Particle breakage and abrasion of crushed aggregate materials may cause significant changes in particle morphologies, which can adversely affect their engineering properties. Previous studies have identified the research needs of more accurately and quickly quantifying particle morphology changes and establishing specifications for controlling aggregate degradation caused by handling and compaction during constructions. In this study, a previously developed laboratory testing method by the authors, termed the Gyratory Abrasion and Image Analysis (GAIA) test, was conducted on five types of aggregate materials to evaluate their particle breakage and abrasion characteristics under simulated compaction loading conditions. Based on the laboratory testing and image analysis data, this paper proposes new indices to quantify the breakage and abrasion characteristics in terms of changes in the particle morphologies of aggregate materials and also recommends the minimum representative sample sizes for using 2D image-based analysis methods to quantify distributions of the particle size and morphology of aggregate materials. The previously developed GAIA test, the proposed morphology-based aggregate breakage and abrasion indices, and the recommended sampling sizes for 2D image analysis of aggregate materials can help both researchers and practitioners to quickly and accurately quantify the breakage and abrasion characteristics of aggregate materials under various simulated compaction loads in laboratory, which may help to develop field QC/QA specifications to control the aggregate degradation caused by handling and compaction.