Utilization of Aggregate Quarry By-Product Stabilized with Ladle Furnace Slag for Sustainable Pavement Foundation

Abstract: The search for alternative construction materials to replace conventional resources has become one of the top priorities in civil engineering, driven by a growing emphasis on sustainability. Quarry by-products (QBs), recently referred to as underutilized quarry materials, are sand-sized residual aggregates produced during aggregate processing at crushed stone quarries and have been extensively studied for pavement foundation applications. These investigations demonstrate that QBs lightly stabilized with 3% cement by weight achieve sufficient compressive strength for base and subbase layers, and provide satisfactory rutting resistance and long-term durability, underscoring their potential as viable alternative aggregates. More recently, a study has explored the use of supplementary cementitious materials (SCMs), such as metakaolin, to reduce cement content, and thus the carbon footprint, without compromising strength or durability. Ladle furnace slag (LFS), a by-product of steelmaking and refining process, has a chemical composition similar to that of Portland cement and shows great promise as a chemical stabilizer. Combining LFS with QB is expected to further enhance sustainability by reducing reliance on conventional energy-intensive binding agents such as cement. Therefore, this study examines the incorporation of LFS into QB applications to determine its suitability as an effective stabilizer and the performance adequacy of stabilized QB incorporating LFS for pavement foundation applications. Systematic laboratory experiments were conducted by stabilizing QBs with just LFS, partially replacing cement with the LFS and adding additional LFS to the known cement content that provide sufficient performance as pavement foundation. Unconfined confined compressive strength tests were conducted, followed by 7 and 28 days of curing to determine the strength and stiffness development trends. For a portion of the prepared specimens, an alternative curing approach (e.g., at elevated temperature) was applied to expedite chemical reaction and evaluate the extent of strength improvement, simulating an extended curing period. This paper will present results of this laboratory effort, which provides valuable insights into using both QBs and LFS in pavement foundation layers for promoting sustainable construction practices.