Evaluating the Suitability of Quarry Byproducts for Sustainable Pavement Applications

Abstract: Quarry byproducts (QBs) are generated during the crushing and screening of stone, consisting of fines that do not meet the size specifications for primary products. These byproducts include screenings, settling pond fines, and baghouse fines. Current uses of QBs include applications in asphalt, such as seal coats and mineral fillers, as well as in agriculture, where they are used as agricultural lime and fertilizer. However, these uses are not widespread due to a lack of broad applications. The limited adoption of quarry byproducts is primarily due to variations in quality and composition, which can make them less reliable for certain applications. Factors such as particle size, mineral content, and moisture levels can vary significantly depending on the source and processing method, making standardization difficult. Additionally, concerns about performance, durability, and long-term effects further restrict their use.
A comprehensive industry survey was conducted to collect information on the general characteristics of QB products in Georgia. Laboratory testing was conducted to determine the physical and engineering properties of the collected QBs. The testing program included evaluating particle shape properties, such as texture and angularity, using the Aggregate Image Measurement System (AIMS); determining mineralogical composition, including underlying crystal structure and clay components, using X-ray diffraction (XRD); and assessing the amount of harmful clay using the Methylene blue test. These findings offer valuable insights into the suitability of quarry byproducts for pavement applications, potentially enabling more sustainable practices by reducing reliance on virgin materials. A better understanding of QB properties could lead to cost-effective and environmentally friendly solutions in pavement construction.