Mechanisms for reinforcing cement-based materials with carbonated AOD stainless steel slag rich in acicular aragonite

A slurry-phase carbonation technique was utilized, employing argon oxygen decarburization slag (AOD slag) as a source of calcium and MgCl 2 as a regulator for the crystal morphology of acicular aragonite. Subsequently, the carbonated AOD slag, enriched with acicular aragonite, was employed in fabricating composite cementitious materials, followed by an analysis of their evolution in hydration heat, hydration products, and microscopic morphology. Additionally, it delved into the mechanism through which acicular aragonite enhances the stength of composite cementitious materials. Moreover, advanced simulation software for engineering and sciences (ABAQUS) was utilized to simulate the compressive performance of composite mortar with varying dosages of acicular aragonite. The findings demonstrate that the carbonated AOD slag, containing 83.4% acicular aragonite (with an average aspect ratio of 21.31), exhibited commendable compatibility with cement. Moderate integration of carbonated AOD slag facilitated the formation of calcium sulfoaluminate hydrate (AFt) phases. The acicular aragonite within the cementitious matrix showcased remarkable filling effects. As the dosage of carbonated AOD slag increased, flexural and compressive strengths of cement mortar initially rose before declining. Upon reaching a 6% cement inclusion of carbonated AOD slag, the various constituents of the cementitious material displayed optimal synergy. The numerical simulation results confirmed the experimental findings, demonstrating a favorable increase in compressive strength and flexural strength with the addition of acicular aragonite. The acicular aragonite strengthened the matrix by serving bridging and pull-out functions.