Three-dimensional examination of fly ash-PVCA composite reinforced by expanded polystyrene beads using X-ray micro-tomography

In this study, we performed a multi-scale three-dimensional (3D) analysis of a new type of lightweight composite material made with coal fly ash and expanded polystyrene wastes. For this, a methodology for identifying and quantifying the microstructure property of the lightweight composite material was developed using X-ray micro-tomography. The material studied mainly contained polystyrene beads, which have approximately the same density as the air voids; they share the same grayscale, and it is not easy to distinguish them, which makes it challenging to characterize the porous 3D structure of this material. The 3D visualization software 'Avizo' enabled the 3D reconstruction of the composite and its microstructural characterization. Several microstructure parameters were explored and characterized quantitatively, including porosity distribution, pore surface area, representative elementary volume (REV), sphericity, pore equivalent diameter, and pore network model. The results demonstrated that X-ray micro-tomography is a valuable instrument for non-destructive and complete detection of the microstructural properties of polystyrene reinforced composite.