Documents disponibles écrits par cet auteur

µic: A new platform for modelling the hydration of cements / Shashank Bishnoi in Cement and concrete research, Vol. 39 N° 4 (Avril 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 4 (Avril 2009) . - pp. 266–274 Titre : µic: A new platform for modelling the hydration of cements Type de document : texte imprimé Auteurs : Shashank Bishnoi, Auteur ; Scrivener, Karen, Auteur Année de publication : 2009 Article en page(s) : pp. 266–274 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Microstructure;  Modelling;  Platform;  Cement;  Hydration Résumé : A new modelling platform, called µic has been developed to model the microstructural evolution of hydrating cement paste. The platform uses the vector approach and can be used for modelling particulate reactions including the hydration of many different cementitious systems involving millions of particles. In this paper, the ideas behind the development of µic and its main features are presented. The complexity of cement hydration and the gaps in our current understanding of cement played an important role in its design, so the platform has the primary objective of aiding, rather than replacing experiments. The platform is highly customisable as users can define materials, particles and reactions and choose or create external plugins to define models of microstructural development. The platform can be used to test the validity of hypotheses by easily formulating them as input and comparing simulations with experimental results. This paper presents the design of µic and examples that demonstrate the important features of its performance and design. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002214 [article] µic: A new platform for modelling the hydration of cements [texte imprimé] / Shashank Bishnoi, Auteur ; Scrivener, Karen, Auteur . - 2009 . - pp. 266–274. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 4 (Avril 2009) . - pp. 266–274 Mots-clés : Microstructure;  Modelling;  Platform;  Cement;  Hydration Résumé : A new modelling platform, called µic has been developed to model the microstructural evolution of hydrating cement paste. The platform uses the vector approach and can be used for modelling particulate reactions including the hydration of many different cementitious systems involving millions of particles. In this paper, the ideas behind the development of µic and its main features are presented. The complexity of cement hydration and the gaps in our current understanding of cement played an important role in its design, so the platform has the primary objective of aiding, rather than replacing experiments. The platform is highly customisable as users can define materials, particles and reactions and choose or create external plugins to define models of microstructural development. The platform can be used to test the validity of hypotheses by easily formulating them as input and comparing simulations with experimental results. This paper presents the design of µic and examples that demonstrate the important features of its performance and design. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002214

Studying nucleation and growth kinetics of alite hydration using μic / Shashank Bishnoi in Cement and concrete research, Vol. 39 N° 10 (Octobre 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 10 (Octobre 2009) . - pp. 849–860 Titre : Studying nucleation and growth kinetics of alite hydration using μic Type de document : texte imprimé Auteurs : Shashank Bishnoi, Auteur ; Scrivener, Karen, Auteur Année de publication : 2009 Article en page(s) : pp. 849–860 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Alite;  Hydration;  Kinetics;  Modelling;  Microstructure;  Calcium–silicate–hydrate  (C–S–H) Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : This paper investigates the applicability of nucleation and growth mechanisms to the hydration of alite. Various possible mechanisms of nucleation and growth were simulated using the recently-developed microstructural modelling platform μic. Comparison with the Avrami equation and the boundary nucleation model demonstrate the limitations of these equations. Experimental measurements of the rates of hydration of alite powders with different particle size distributions were then simulated with a boundary nucleation and growth model in μic. The results show that while the nucleation and growth of C–S–H having bulk densities in the currently accepted range can explain the acceleration during the first few hours of hydration, it cannot explain the later deceleration. It was also found that the resistance to flow of ions offered by the layer of hydrates forming over the surface of the alite particles (diffusion control) cannot explain the deceleration. The deceleration could be reproduced when C–S–H was assumed to be loosely packed in the beginning with its density of packing increasing with hydration. It is proposed that during the early hours of hydration a loosely-packed C–S–H fills a large fraction of the microstructure and the further development of its microstructure occurs due to an increase in its packing. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001641 [article] Studying nucleation and growth kinetics of alite hydration using μic [texte imprimé] / Shashank Bishnoi, Auteur ; Scrivener, Karen, Auteur . - 2009 . - pp. 849–860. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 10 (Octobre 2009) . - pp. 849–860 Mots-clés : Alite;  Hydration;  Kinetics;  Modelling;  Microstructure;  Calcium–silicate–hydrate  (C–S–H) Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : This paper investigates the applicability of nucleation and growth mechanisms to the hydration of alite. Various possible mechanisms of nucleation and growth were simulated using the recently-developed microstructural modelling platform μic. Comparison with the Avrami equation and the boundary nucleation model demonstrate the limitations of these equations. Experimental measurements of the rates of hydration of alite powders with different particle size distributions were then simulated with a boundary nucleation and growth model in μic. The results show that while the nucleation and growth of C–S–H having bulk densities in the currently accepted range can explain the acceleration during the first few hours of hydration, it cannot explain the later deceleration. It was also found that the resistance to flow of ions offered by the layer of hydrates forming over the surface of the alite particles (diffusion control) cannot explain the deceleration. The deceleration could be reproduced when C–S–H was assumed to be loosely packed in the beginning with its density of packing increasing with hydration. It is proposed that during the early hours of hydration a loosely-packed C–S–H fills a large fraction of the microstructure and the further development of its microstructure occurs due to an increase in its packing. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001641