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Title: BACKSCATTERED ELECTRON IMAGING TO DETERMINE WATER-TO-CEMENT RATIO OF HARDENED CONCRETE
Accession Number: 00822768
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: A methodology has been developed for the determination of the water-to-cement (w/c) ratio in hardened concrete using backscattered electron imaging (BEI) within a scanning electron microscope. Reproducible quantitative data are obtained by using standards from polished sections as well as by controlling brightness and contrast on the instrumentation. The method is based on concrete sections that have been vacuum impregnated with epoxy and polished to a flat surface. During impregnation, epoxy fills capillary porosity as well as cracks, voids, and other defects. The w/c ratio is directly related to the capillary porosity and degree of hydration and therefore can be measured. The epoxy-impregnated porosity appears black in BEI, whereas other phases such as calcium silicate hydrate, ferrite phases, and aggregate appear as brighter phases. Signal production, brightness, contrast, sample preparation, general methodology, and resolution are discussed.
Supplemental Notes: This paper appears in Transportation Research Record No. 1775, Concrete 2001.
Language: English
Corporate Authors: Transportation Research Board 500 Fifth Street, NW Authors: Badger, S RClark, B ASahu, SThaulow, NLee, R JPagination: p. 17-20
Publication Date: 2001
Serial: ISBN: 0309072395
Features: Figures
(5)
; References
(14)
; Tables
(2)
TRT Terms: Uncontrolled Terms: Subject Areas: Highways; Materials; I32: Concrete
Files: TRIS, TRB, ATRI
Created Date: Jan 31 2002 12:00AM
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