Assessment of diffusive and mechanical properties of hardened cement pastes using a multi-coated sphere assemblage model

Bary, Benoı̂t; Béjaoui, S.

doi:10.1016/j.cemconres.2005.07.007

Cited by 71 publications

(54 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With the approximation that p ≈ 1 due to the fact that D p is much larger than D m (see e.g. [36,39]), the preceding relation simplifies into: (34) where the superscript s refers to the sound material and use has been made of the identity p = s nd − nd . The parameter remaining to be evaluated is the self-diffusivity D m of the composite matrix made up of C-S-H and initial porosity.…”

Section: Estimation Of the Diffusive Propertiesmentioning

confidence: 99%

“…Porosity of cementitious materials is commonly classified into two categories: the nanoporosity that is intrinsically incorporated in the C-S-H and then always percolates, and the capillary porosity, much bigger, with size typically greater than 0.1 m (see e.g. [36,39] and references therein). When percolating, the capillary porosity is known to govern transport.…”

Section: Estimation Of the Diffusive Propertiesmentioning

confidence: 99%

“…Note that when the microstructure evolves, some of these inclusions may dissolve or precipitate, and that in the case of leaching, the C-S-H phase is supposed to be modified in the sense of a reduction of its mechanical (and an increase of diffusive) properties. This description in terms of matrix and inclusion phases is similar to the one adopted for example in [32,33], except that in these papers two C-S-H are introduced to reproduce the experimentally observed high-density C-S-H and low-density C-S-H. Non-spherical inclusion shapes are considered in [33] and relative disposition of the phases slightly differs from the present one in [36]. The application of the MT scheme to the representation of Figure 1 is immediate, providing the knowledge of volume fractions and mechanical properties of all phases.…”

mentioning

confidence: 96%

See 2 more Smart Citations

Simplified coupled chemo‐mechanical modeling of cement pastes behavior subjected to combined leaching and external sulfate attack

Bary

2008

Num Anal Meth Geomechanics

Self Cite

View full text Add to dashboard Cite

SUMMARYIn the context of radioactive waste storage, underground concrete structures may be subjected to external sulfate attack due to penetration of sulfate combined with leaching. This paper proposes a coupled chemo-mechanical modeling relying on a simplified chemical description of the solid phase composing the cement paste to address this issue. The sulfate and calcium species diffusing through the pore solution are supposed to completely control the chemical system, in particular the precipitation of gypsum and ettringite, which may lead to significant macroscopic expansions and cracking. The crystallization pressure generated by the growing crystals is introduced in the modeling through a poroelasticity analogy. Based on a representation of the cement paste of the matrix-inclusion type, the application of the Mori-Tanaka (MT) scheme provides estimates of the mechanical and diffusive properties and of the interaction coefficient as a function of the degradation state. The obtained coupled system is applied to two-dimensional numerical simulations of laboratory tests; the confrontation between experimental and computational results shows a good agreement in terms of both hydrated product evolutions as a function of time and macroscopic cracking appearance.

show abstract

Section: Estimation Of the Diffusive Propertiesmentioning

confidence: 99%

Section: Estimation Of the Diffusive Propertiesmentioning

confidence: 99%

mentioning

confidence: 96%

See 1 more Smart Citation

Simplified coupled chemo‐mechanical modeling of cement pastes behavior subjected to combined leaching and external sulfate attack

Bary

2008

Num Anal Meth Geomechanics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Water porosities for this series of mortars (S2) are compared to (1-Vag) linear plot representing theorical case of porous medium diluted by non-porous aggregates (Figure 2b). It can be seen that experimental results are close to (1-Vag) plot and don't breached the line except for S2.60% mortar 01006-p. 4 where water porosity value is slightly above dilution line. This confirms that presence of aggregates doesn't disturb systematically the overall paste matrix porosity, which is expected since these formulations have the same water to cement ratio.…”

Section: Total Water Porositiesmentioning

confidence: 99%

Link between microstructure and tritiated water diffusivity in mortars

Larbi

Dridi

Bescop

et al. 2013

EPJ Web of Conferences

View full text Add to dashboard Cite

Abstract. Ions and radionuclide diffusivity in concrete is one of the most important factors that determine service life and safety assessment of cement based structures in nuclear power plants and radioactive-waste repositories. Apart from the influence of cement paste microstructure, the presence of aggregates may have an impact on transport properties of the material. The well-known interfacial transition zone, denoted by ITZ, is created near the aggregates and characterized by a greater porosity. The goal of this study is to investigate the competition between the more diffusing ITZ zone and the less diffusing aggregates. To this end, several series of tritiated water diffusion tests are conducted on mortars characterized by different water-to-cement ratios and sand volume fractions. In parallel, microstructure of these materials is explored by mercury and water porosimetry. It was observed that at low sand content (0% -50%), diffusion properties of mortars are dominated by aggregates dilution effect. At 60% sand, diffusion increases significantly suggesting that percolation's pores threshold has been reached. Results indicate also that sand particle size distribution has a great impact on the diffusivity of mortars.

show abstract

“…These chemical attacks are mainly linked with dissolution/precipitation processes of the solid constituents of the cement matrix (portlandite, ettringite, gypsum) [2,28].…”

mentioning

confidence: 99%

Diffusion with dissolution and precipitation in a porous medium: Mathematical analysis and numerical approximation of a simplified model

Bouillard

Eymard²,

Herbin³

et al. 2007

ESAIM: M2AN

View full text Add to dashboard Cite

Abstract.Modeling the kinetics of a precipitation dissolution reaction occurring in a porous medium where diffusion also takes place leads to a system of two parabolic equations and one ordinary differential equation coupled with a stiff reaction term. This system is discretized by a finite volume scheme which is suitable for the approximation of the discontinuous reaction term of unknown sign. Discrete solutions are shown to exist and converge towards a weak solution of the continuous problem. Uniqueness is proved under a Lipschitz condition on the equilibrium gap function. Numerical tests are shown which prove the efficiency of the scheme.Mathematics Subject Classification. 65N12, 76S05, 80A30.

show abstract

Assessment of diffusive and mechanical properties of hardened cement pastes using a multi-coated sphere assemblage model

Cited by 71 publications

References 32 publications

Simplified coupled chemo‐mechanical modeling of cement pastes behavior subjected to combined leaching and external sulfate attack

Simplified coupled chemo‐mechanical modeling of cement pastes behavior subjected to combined leaching and external sulfate attack

Link between microstructure and tritiated water diffusivity in mortars

Diffusion with dissolution and precipitation in a porous medium: Mathematical analysis and numerical approximation of a simplified model

Contact Info

Product

Resources

About