Quantifying the microstructure and phase assemblage of alkali-activated fly ash/slag materials by EDS mapping analysis

Accurately quantifying the proportions and distributions of reaction products is crucial for interpreting reaction mechanisms and microstructure evolution in alkaline activated fly ash/slag pastes. However, existing techniques are limited in their ability to provide a comprehensive and visual analysis. This paper presents a versatile energy dispersive X-ray spectroscopy (EDS) mapping analysis that enables image enhancement, phase extraction, and component classification in the alkaline-activated materials (AAMs) -irrespective of the nature and quality of element mappings. The proposed methodology effectively removes the detection noise that inherently existed in EDS mappings, subsequently reinforcing the accuracy of the clustering analysis. The phase extraction procedure allows for obtaining the proportion of pores, reaction products, and unreacted solid precursors (SPs). Moreover, the component classification procedure enables further categorization of the reaction products and unreacted SPs. By analyzing the element ratios and shortest distances, the chemical compositions and spatial distributions of various reaction products could be revealed. Through the application of different analysis schemes, a consistent tendency was obtained, validating the practicability and reliability of this methodology.