Modeling ion and fluid transport in unsaturated cement systems in isothermal conditions

Samson, E.; Marchand, J.; Snyder, Kenneth A.; Beaudoin, J.J.

doi:10.1016/j.cemconres.2004.07.016

Cited by 115 publications

(81 citation statements)

References 31 publications

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“…(in units of C m -3 ) is defined as the excess of charge per unit pore volume at full water saturation [9,10,11]. We neglect the charge density that is associated with the interface between the wetting and the non-wetting phases, since it is small in comparison with the charge density associated with the pore water-solid interface [9].…”

Section: The Reference Statementioning

confidence: 99%

“…In a future contribution, we will use our model to assess the efficiency of electro-osmotic pumping to control the migration of NAPLs in the saturated and unsaturated zone. In addition, we plan to extend this model by incorporating diffusional effects in the constitutive equations to study diffusion of ions under unsaturated conditions (see also [11]). in this research.…”

Section: Concluding Statementsmentioning

confidence: 99%

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Electrokinetic coupling in unsaturated porous media

Revil

Linde

Cérepi

et al. 2007

Journal of Colloid and Interface Science

214

337

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Abstract. We consider a charged porous material that is saturated by two fluid phases that are immiscible and continuous at the scale of a representative elementary volume. The wetting phase for the grains is water and the non-wetting phase is assumed to be an electrically insulating viscous fluid. We use a volume averaging approach to derive the linear constitutive equations for the electrical current density as well as and the seepage velocities of the wetting and non-wetting phases at the scale of a representative elementary volume. These macroscopic constitutive equations are obtained by volume-averaging Ampère's law together with the Nernst-Planck equation and the Stokes equations. The material properties entering the macroscopic constitutive equations are explicitly described as a function of the saturation of the water phase, the electrical formation factor, and parameters that describe the capillary pressure function, the relative permeability function, and the variation of electrical conductivity with saturation. New equations are derived for the streaming potential and electro-osmosis coupling coefficients. A primary drainage and imbibition experiment is simulated numerically to demonstrate that the relative streaming potential coupling coefficient depends not only on the water saturation, but also on the material properties of the sample as well as the saturation history. We also compare the predicted streaming potential coupling coefficients with experimental data from four dolomite core samples. Measurements on these samples include electrical conductivity, capillary pressure, the streaming potential coupling coefficient at various level of saturation, and the permeability at saturation of the rock samples. We found a very good agreement between these experimental data and the model predictions.

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Section: The Reference Statementioning

confidence: 99%

Section: Concluding Statementsmentioning

confidence: 99%

Electrokinetic coupling in unsaturated porous media

Revil

Linde

Cérepi

et al. 2007

Journal of Colloid and Interface Science

214

337

View full text Add to dashboard Cite

show abstract

“…There are a number of models for simulation of the ionic transport into cementitious materials [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Ion-cement hydrate interactions govern multi-ionic transport model for cementitious materials

Elakneswaran

Iwasa

Nawa

et al. 2010

Cement and Concrete Research

104

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The main objective of this investigation is to describe the interaction between cement hydrates and electrolyte solution to understand multi-ionic transport in cementitious materials. A surface complexation model in PHREEQC including an electrostatic term is used to simulate the ionic adsorption on the calcium silicate hydrate (C-S-H) surface. The equilibrium constants for the adsorption of ions on C-S-H surfaces are obtained by fitting experimental data to the model. The adsorption of both divalent and mono-valent cations, and also anions significantly changes the surface charges of hydrated paste. Chloride is being held in a chemical binding as Friedel's salt and bound mainly by the adsorptive action of C-S-H. An integrated modelling approach employing a phaseequilibrium model, a surface complexation model, and a multi-component diffusion model has been developed in PHREEQC to simulate the multi-ionic transport through hydrated cement paste. It was found that the physical adsorption of ions on C-S-H, the size of pores, and the surface site density of C-S-H govern the rate of penetration of ionic species. Finally, the proposed model has been validated against chloride profiles measured in this study as well as with data available in the literature for hydrated cement paste.

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“…8 was proposed. In the MPNP model, an additional term denoted as, cracking suction, which accounts for the acceleration effect on diffusion and was caused by newly-formed unsaturated cracks, was added to the original PNP model (Samson et al 2005). The detailed procedures for evaluating the cracking suction effect can be found in the reference (Yu et al 2015).…”

Section: Ionic Diffusion Modulementioning

confidence: 99%

Modelling the degradation of mechanical properties of cementitious materials under leaching

Zhang¹

2015

Proceedings of the Second International Conference on Performance-Based and Life-Cycle Structural Engineering (PLSE 2015)

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The calcium leaching of hydrated cement system when in contact with external solution has long been recognised as a critical problem for cementitious materials, and it can result in degradations on mechanical properties. In this research, an integrated numerical scheme is developed to simulate the degradation of Young's modulus of cementitious materials under leaching. Firstly, a cement hydration module is proposed and employed to predict the characteristics of the hydrated cement including pore structures, contents of hydrates and concentrations of initial interstitial solution. Then the hydration data obtained are incorporated into a coupled reactive diffusion procedure to evaluate the change of hydrate contents under the prescribed boundary conditions. Finally, a micromechanical approach, Mori-Tanaka method, is employed to evaluate the degradation of Young's modulus of the cementitious material. The accelerated leaching tests in 6M (6 mol L ⁄ ) of ammonium nitrate solution, which became popular recently in view of the extremely slow degradation kinetics of leaching in deionized water, are studied numerically in this study. The developed numerical scheme is employed to model two experiments, and the good agreements between the numerical results and the experimental measurements in terms of hydration outputs, leaching profiles and Young's moduli, demonstrate the applicability and accuracy of the proposed numerical scheme.

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Modeling ion and fluid transport in unsaturated cement systems in isothermal conditions

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Cited by 115 publications

References 31 publications

Electrokinetic coupling in unsaturated porous media

Electrokinetic coupling in unsaturated porous media

Ion-cement hydrate interactions govern multi-ionic transport model for cementitious materials

Modelling the degradation of mechanical properties of cementitious materials under leaching

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