Modelos estructurales del empaquetamiento aleatorio de partículas esféricas de Tobermorita: una aproximación computacional sencilla

Abstract

RESUMENEn este trabajo y con el objetivo de conjugar el punto de vista atomístico y coloidal, presentamos un método computacional Monte Carlo que reproduce el empaquetamiento coloidal de nano-partículas esféricas cristalinas de tipo Tobermorita. Variando los parámetros computacionales de empaquetamiento diferentes estructuras tipo Low Density (LD) C-S-H y High Density (HD) C-S-H han sido creadas. Posteriormente, las estructuras resultantes de nuestros experimentos computacionales han sido analizadas en términos de sus densidades, áreas especí-ficas y propiedades mecánicas.Palabras clave: gel C-S-H, modelo coloidal, simulación computacional. SUMMARYIn this work, and in order to bring together the atomistic and colloidal viewpoints, we will present a Monte Carlo computational scheme which reproduces the colloidal packing of nano-spherical crystalline tobermorite-like particles. Different Low Density (LD) C-S-H and High Density (HD) C-S-H structures will be developed just by varying the computational packing parameters. Finally, the structures resulting from our computational experiments will be analyzed in terms of their densities, surface areas and their mechanical properties.K Ke ey yw wo or rd ds s: : C-S-H gel, colloidal model, modelling.

Espectros de rayos X y propiedades elásticas teóricas de los silicatos cálcicos hidratados cristalinos: comparación con los geles de cemento

“…Finalmente, nos gustaría remarcar el potencial de los métodos de simulación atomísticos como fuente de información para modelizar la pasta de cemento a escalas mayores [49][50][51][52], y alcanzar una descripción multiescalar del material y sus propiedades. These trends of elastic constants and densities have been compared with those of the cementitious CSH gel and synthetic CSH type I.…”

“…Finally, we would like to stress the potential that atomistic simulation methods have, as a source of information for modelling the the cement paste at larger scales [49][50][51][52], and achieve a multi-scalar description of the material and its properties.…”

A comprehensive review of the models on the nanostructure of calcium silicate hydrates

“…This simplification constitutes a significant weakness of the model. In fact, the computational study published in 2010 by González-Teresa et al [48] based on Monte Carlo simulations of the packing arrangements, suggested that the computational counterpart of the ''experimentally inaccessible HD C-S-H'' could also contribute to the specific surface area measurements. Their computational model provided significant convergence with the LD C-S-H SSA measured by SANS [71].…”

“…Manzano et al [46] 2007 Two different growth mechanisms Jennite, tobermorite Ab-initio calculations at the Hartree Fock (HF) level Dolado et al [47] 2007 Analysis of polymerisation of silicic acids in a calcium rich environment Jennite, tobermorite Molecular dynamics method by Feuston and Garofalini Pellenq et al [12] 2008 Iono-covalent forces between individual C-S-H layers or C-S-H layer stacks Nanocrystals Ab-initio, molecular dynamics and energy minimisation techniques Skinner et al [5] 2010 Analysis on synthetic C-S-H and hydrated C 3 Sshort silicate chains due to nanocrystallinity Structure close to Hamid's 1.1 nm tobermorite -evidence of nanocrystallinity Pair distribution function, Monte Carlo, Fourier transformations on XRD results González-Teresa et al [48] 2010 Inaccessibility of HD by N 2 and HD also contributes to the SSA-smaller globules…”

Changes on the nanostructure of cementitius calcium silicate hydrates (C–S–H) induced by aqueous carbonation

“…The size, shape or crystallographic nature and water content of the basic building blocks, and their arrangements forming hierarchical fractal structures, are currently the focus of research efforts, both experimentally [19][20][21] and computationally [14,22]. Tobermorite or jennite are being proposed as structural references for the basic building blocks [11,23].…”