1. Determination of water-cement ratios of hardened cement pastes based on the estimation of under-pixel porosity in backscattered electron images
- Author
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Dang Giang Hoang and Shin-ichi Igarashi
- Subjects
Materials science ,Powers and Brownyard model ,Calcium hydroxide ,Cement gel ,W/C ,Mineralogy ,Cement paste ,Grey level histogram ,Image analysis ,Mean atomic number ,capillary pores ,Forensic engineering ,Backscattered electron image ,Porosity ,Civil and Structural Engineering ,Cement ,Pixel ,business.industry ,Structural engineering ,Backscattered electron ,Microstructure ,C-S-H ,Unhydrated cement ,Grey level ,Under-pixel porosity ,Cementitious ,business - Abstract
SEM-BSE image analysis technique is one of promising approaches to determine water/cement ratios in hardened cementitious materials. In this study, a method using under-pixel information in the BSE images is proposed. It is hypothesised that a grey level of each pixel reflects the under-pixel porosity. It is also assumed that the porosity smaller than the resolution results in the shifts in position of the grey levels of specific phases. The amounts of shifting are combined with the Powers and Brownyard model so that the degree of hydration is directly estimated from the BSE images. The method was applied to hardened cement pastes with different water/cement ratios. There was a good agreement between estimated and real water/cement ratios. An estimate within an error of ±0.02 was attained except an extremely low water/cement ratio. The shift in the grey level histogram is useful information on microstructure in cement pastes. Copyright © 2013 Inderscience Enterprises Ltd.
- Published
- 2013