Characterization of the inhomogeneity of mineralized steel slag compacts (MSSCs) and its effect on mechanical properties and damage

Abstract

In this study, the spatial and temporal evolution of mineralized steel slag compacts (MSSCs) in terms of mineral composition, microstructure, and micromechanical properties is systematically investigated to characterize and quantify their inhomogeneity. Furthermore, the impact of the inhomogeneity in MSSC on its mechanical behavior and damage mechanisms is explored to uncover the intrinsic connection between them. The results indicate that the MSSC is an inhomogeneous mass, with the extent of inhomogeneity influenced by the carbonation time. Notably, the MSSC experiences brittle damage at lower strengths and exhibits localized stress instability during loading. As the carbonation time increases from 6 to 72 h, the mineral content and carbonation degree within the MSSCs gradually shift from an inhomogeneous to a relatively homogeneous distribution; however, the micromechanical parameters remain inhomogeneously distributed. Furthermore, the proportion of tensile cracks increases from 55.2 % to 72.0 %, indicating a shift in the failure mode from mixed shear-tensile damage to predominantly tensile damage in MSCC. The outer layer of the MSSC exerts a constraining effect on the inner layer, similar to the function of steel pipe in concrete-filled steel tube, effectively inhibiting deformation and damage to the inner layer.