Influence of Carbonation on the Microstructure and Hydraulic Properties of a Basic Oxygen Furnace Slag

This study investigates the impact of carbonation on the microstructure and hydraulic properties of basic oxygen furnace (BOF) slag, a potential alternative construction material derived from steel production. The objective was to accurately quantify the risk of pollutant release associated with BOF slag and to characterize its hydraulic properties by conducting water infiltration experiments and inverse numerical modeling at plot scale. Results revealed that the BOF slag crusted at the surface due to weathering, leading to significant differences in water retention and hydraulic conductivity functions compared to unaltered slag. While a general trend indicated a decrease in saturated hydraulic conductivity with crusting, the specific outcomes were dependent on the infiltration devices employed. Parallel scanning electron microscope (SEM) microanalysis and lysimeter measurements highlighted a reduction in porosity due to clogging, prompting the formulation of two conceptual models to predict hydraulic properties based on differing pore clogging hypotheses. The findings underscore that the development of transport properties is notably influenced by the formation and coating of precipitated phases on the slag grains, enhancing understanding of the hydraulic behavior of BOF slag in the context of carbonation.