Carbonation-Induced Strength Enhancement of Saudi Marl Soil Using Industrial Pozzolanic Waste Stabilizers

Marl soil, prevalent in arid regions, exhibits low strength and high instability due to cyclic thermal fluctuations, posing severe risks to infrastructure. This study explores the synergistic use of fly ash (FA) and cement kiln dust (CKD) under CO₂ curing to enhance the mechanical properties of Saudi marl soil while promoting sustainable waste utilization. The pozzolanic nature of FA and CKD, when subjected to accelerated carbonation, facilitates the formation of stable cementitious compounds, leading to improved soil strength, durability, and reduced long-term settlement. A series of laboratory tests evaluated the influence of FA-CKD dosage and CO₂ curing duration on compressive strength, volumetric stability, and resistance to moisture variations. Results indicate that CO₂ curing significantly accelerates pozzolanic reactions, yielding a denser microstructure with enhanced mechanical performance and environmental resilience. The findings demonstrate that FA-CKD-CO₂ treatment not only provides a rapid and cost-effective ground improvement technique but also contributes to carbon sequestration, aligning with Saudi Arabia’s Vision 2030 and global sustainability goals by reducing industrial waste and carbon emissions. This research establishes a technically viable and environmentally responsible stabilization approach for mitigating the challenges associated with weak marl soils in infrastructure applications.