A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Etude de l'hydratation d'une pate de ciment par analyse automatique d'images en microscopie electronique a balayage
For the investigation of civil engineering concrete, the hydration of the cement paste is important to know. The parameter investigated for that is the hydration degree, alpha. Different techniques are used to study this parameter. In this work, we have chosen to determine alpha using scanning electron microscope (SEM) and automatic image analysis. On a SEM image of a cement paste, two phases can be observed: hydrated phase which appears in grey and anhydrous phase (NH) which appears in white. So, after an image processing, the surface area of the anhydrous phase can be calculated. It is equal to the volume fraction of this phase, VV(NH). For this work, two cement phases are prepared. They differ by their water/cement ratio (w/c), in weight, which are respectively 0.5 and 0.3. 50 images per specimen are acquired by SEM using back scattering electron mode. This number requires to use an automatic process. It is made of three stages: a filtering of the grey image, a segmentation of the anhydrous phase, a binary process to perform the final image. The kinetic of hydration is principally studied with the hydration degree. But it is interesting to analyse the stereological parameters, like the specific connexity (NA(NH)) and intercept (NL(NH)) numbers. They allow to calculate the specific surface area (SV(NH)), the mean free path (L3(NH)), the mean curvature (H3(NH)), and the mean surface area (A(NH)) of the anhydrous phase. To validate our results obtained by automatic image analysis, they are compared with results obtained by thermogravimetric analysis (TGA): the evolution of the hydration degree by TGA gives similar results as those obtained by automatic image analysis. The analysis of the stereological parameters shows that the specific surface area of the anhydrous phase decreases during the first days, and then takes an asymptotic value. It can be interpreted like an evolution of the surface energy: during the first days, there is a minimization of the superficial energy between phases, then this interface takes an stationary value.
Etude de l'hydratation d'une pate de ciment par analyse automatique d'images en microscopie electronique a balayage
For the investigation of civil engineering concrete, the hydration of the cement paste is important to know. The parameter investigated for that is the hydration degree, alpha. Different techniques are used to study this parameter. In this work, we have chosen to determine alpha using scanning electron microscope (SEM) and automatic image analysis. On a SEM image of a cement paste, two phases can be observed: hydrated phase which appears in grey and anhydrous phase (NH) which appears in white. So, after an image processing, the surface area of the anhydrous phase can be calculated. It is equal to the volume fraction of this phase, VV(NH). For this work, two cement phases are prepared. They differ by their water/cement ratio (w/c), in weight, which are respectively 0.5 and 0.3. 50 images per specimen are acquired by SEM using back scattering electron mode. This number requires to use an automatic process. It is made of three stages: a filtering of the grey image, a segmentation of the anhydrous phase, a binary process to perform the final image. The kinetic of hydration is principally studied with the hydration degree. But it is interesting to analyse the stereological parameters, like the specific connexity (NA(NH)) and intercept (NL(NH)) numbers. They allow to calculate the specific surface area (SV(NH)), the mean free path (L3(NH)), the mean curvature (H3(NH)), and the mean surface area (A(NH)) of the anhydrous phase. To validate our results obtained by automatic image analysis, they are compared with results obtained by thermogravimetric analysis (TGA): the evolution of the hydration degree by TGA gives similar results as those obtained by automatic image analysis. The analysis of the stereological parameters shows that the specific surface area of the anhydrous phase decreases during the first days, and then takes an asymptotic value. It can be interpreted like an evolution of the surface energy: during the first days, there is a minimization of the superficial energy between phases, then this interface takes an stationary value.
Etude de l'hydratation d'une pate de ciment par analyse automatique d'images en microscopie electronique a balayage
Untersuchung der Hydratation einer Zementmasse mit der automatischen Bildanalyse unter dem Rasterelektronenmikroskop
Study of the hydration of a cement paste by automatic image analysis using scanning electron microscopy
Dequiedt, A.S. (author) / Vigneron, E. (author) / Chermant, L. (author) / Coster, M. (author)
Revue de Metallurgie, Cahiers d'Informations Techniques ; 97 ; 179-186
2000
8 Seiten, 9 Bilder, 1 Tabelle, 16 Quellen
Article (Journal)
French
| British Library Online Contents | 2002
Etude de l'hydratation d'un liant par mesure des proprietes dielectriques de la pate
| Tema Archive | 1972