Phase-Glue: An interpretable and efficient backscattered electron-energy dispersive X-ray spectroscopy (BSE-EDS) mapping analysis approach to dissect the phase assemblage of cementitious material systems

Abstract

Backscattered electron and energy dispersive X-ray spectroscopy (BSE-EDS) mapping analysis has merged as a potent spatial-resolved technique in the research of cementitious materials, offering unprecedented opportunities in depicting complex phase assemblage and microstructure changes. Here, a data-driven and knowledge-informed BSE-EDS mapping analysis approach Phase-Glue is proposed, a visualized and versatile method designed to characterize phase assemblage, phase evolution, phase interaction in cementitious material systems. Phase-Glue ingeniously integrates BSE and EDS data, utilizing machine learning algorithms for automatic phase identification. It enables the correction of the identification results using expert knowledge and clarifies the correlations between the phases in embedding space, element features, and their actual spatial distributions through multi-view linked and shared analysis. The advantages of Phase-Glue are demonstrated through in-depth analysis of three cementitious systems (OPC, LC³, AAFS). Phase-Glue delineates the hydration of C₂S/C₃S, quantifies AFt/AFm and Hc/Mc, uncovers the component heterogeneity of fly ash, and distinguishes the different reaction products formed in AAFS system. Phase-Glue can characterize the multiple-modal features of phases in cementitious systems, providing insights into how phase alterations may underline the microstructure and properties changes of systems.