Measurement of aggregate interfacial porosity in complex, multi-phase aggregate concrete: Binary mask production using backscattered electron, and energy dispersive X-ray images

• Published in: Cement and concrete research Vol. 36; no. 2; pp. 337 - 345
• Main Authors: Head, Martin K., Buenfeld, Nick R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Ltd 01.02.2006; Elsevier Science
• Subjects: Aggregate mineralogy; Aggregates and other concrete constituents; Applied sciences; Buildings. Public works; Cement concrete constituents; Concretes. Mortars. Grouts; Energy dispersive X-rays; Exact sciences and technology; General (composition, classification, performance, standards, patents, etc.); Image analysis; Materials; Natural aggregates; Scanning electron microscope; Energy dispersive X-rays; Image analysis; Aggregate mineralogy; Scanning electron microscope; Scanning electron microscopy; Image processing; Dispersive spectrometry; Coarse aggregate; Concrete; Natural aggregate; Measurement method; Porosity; Method study
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2005.09.007

This paper presents for the first time a method for the accurate segmentation of complex (multi-phase) natural aggregate particles, from greyscale backscattered electron images (BEI) of hardened concrete, so that interfacial porosity may be measured. Energy dispersive X-ray (EDX) spectra are collected from phases present in aggregate particles to identify the most abundant and therefore useful elements to be captured during later mapping. Appropriately captured energy dispersive X-ray dot maps are used to progressively construct a multi-phase composite aggregate binary mask, for aggregate particles composed of more than one mineral. The mask image is then re-processed in combination with the backscattered image, to produce an accurate hardened cement paste (HCP) porosity mask, which is used to measure the distribution of interfacial porosity around aggregate particles.