Lattice Boltzmann simulations of the permeability and capillary adsorption of cement model microstructures

Zalzale, Mohamad; McDonald, P.J.

doi:10.1016/j.cemconres.2012.09.003

Cited by 44 publications

(36 citation statements)

References 56 publications

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“…It should be mentioned that the simulated intrinsic water permeability of saturated specimens seems to be 2 or 3 times higher than experimental data from literature shown in [18,22,37]. This can be attributed to the fact that (i) the saturation conditions of specimens in simulations and experiments are generally not the same.…”

Section: D Equilibrium Distribution Of Water and Gas Phasescontrasting

confidence: 39%

“…The water-gas system whose density ratio is approximately 1000/1.29 = 775 is beyond the capacity of this model. In recent years, Zalzale and McDonald [18], Zalzale et al [19] and Li et al [20] studied the liquid water permeability and gas permeability of partially saturated cement paste using LB method and discrete element method, respectively, and found that the relative permeability values of cement paste were not only dependent on degree of saturation but also on three-dimensional (3D) microstructure of cement paste. However, it should be mentioned that the 3D microstructures used in [19,20] were virtual microstructures generated by computer-based models, which might not be able to well represent the real microstructures of cement paste and need further validation.…”

Section: Introductionmentioning

confidence: 99%

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Pore-scale modelling of relative permeability of cementitious materials using X-ray computed microtomography images

Zhang

2017

Cement and Concrete Research

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Permeability of cementitious materials is an important durability indicator. In practice, concrete is rarely saturated. Therefore, it is essential to study permeability of unsaturated cementitious materials. This paper presents an integrated modelling approach for estimating permeability of cementitious materials over the full range of saturation. An in-house code based on multiphase and single-phase lattice Boltzmann models is developed and used to simulate the moisture distribution and fluid flow in unsaturated cement paste with various curing ages, the 3D microstructures of which are obtained from X-ray micro-CT. The water permeability and gas permeability of partially saturated cement paste are then estimated. The results indicate with decreasing water saturation water permeability decreases while gas permeability increases. Additionally, the moisture distribution and permeability of unsaturated cement paste are strongly dependent on its microstructure. Moreover, there exists a unique relationship between permeability and effective porosity. The simulation results show good agreement with experimental data.

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Section: D Equilibrium Distribution Of Water and Gas Phasescontrasting

confidence: 39%

Section: Introductionmentioning

confidence: 99%

Pore-scale modelling of relative permeability of cementitious materials using X-ray computed microtomography images

Zhang

2017

Cement and Concrete Research

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“…of spherical and non-spherical aggregate particles. We note that this approach of projecting the microstructure into a regular lattice has already been applied at the pore-scale [12][13][14]. For example, Nabovati et al [14] used this approach, coupled with the lattice Boltzmann method, to investigate the effect of curvature and aspect ratio of fibres on the permeability of fibrous porous media.…”

Section: Non-spherical Aggregate Particlesmentioning

confidence: 99%

Modelling the diffusivity of mortar and concrete using a three-dimensional mesostructure with several aggregate shapes

Abyaneh

Wong

Buenfeld

2013

Computational Materials Science

165

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This paper presents a numerical investigation into the effect of ITZ and aggregate shape on the diffusivity of mortar and concrete using a three-dimensional model. Concrete is treated as a three-phase composite consisting of aggregate particles, bulk cement paste and aggregate-paste interface, i.e. the 'interfacial transition zone' (ITZ). The model is set up in two stages. First, a three-dimensional representative volume element of the concrete mesostructure is generated. Then, a finite difference method is used to simulate molecular diffusion through the mesostructure. The transport properties of the conductive phases (bulk cement paste and ITZ) are determined based on the water/cement ratio, degree of hydration and porosity gradients away from aggregate particles. The model is validated against available experimental data and compared with analytical relationships for ideal cases. The model is then used to study the effect of aggregate shape on diffusivity, which has not been attempted before in three-dimensions. The model is also applied to assess the effects of water/cement ratio, degree of hydration, aggregate size, volume fraction, shape and orientation, ITZ width and percolation on diffusivity. Some of these effects are impractical to quantify from laboratory experimentation alone. It was found that the shape and orientation of aggregate particles have a significant effect on diffusivity. Diffusivity decreased when spherical aggregate particles are replaced with ellipsoidal particles due to the consequent increase in tortuosity of the cement paste.Keywords: Concrete; Mortar; Cement-based materials; Modelling; Diffusivity; Aggregate shape Highlights:• Diffusivity of cementitious materials is modelled using a three-dimensional model.• The required characteristics of Representative Elementary Volume were investigated.• The simulations were verified by comparing with experimental and analytical results.• The effects of different variables influencing diffusivity were investigated.• The diffusivity decreased with the increase of aspect ratio of aggregate particles.

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“…Because of the inherent limitations of analytical models, many researchers have employed numerical homogenization schemes such as finite element, finite difference, random walk and Lattice Boltzmann for investigating transport behaviour in cement-based materials [Garboczi & Bentz, 2001;Kamali-Bernard, 2009;Abyaneh et al, 2013aAbyaneh et al, , 2013bAbyaneh et al, ,, 2014Zalzale & McDonald, 2012;Zhang et al, 2013;Du et al, 2014;Liu et al, 2015;Feng et al, 2016]. These methods are all very well-known approaches used in many fields to solve differential equations that govern physical behaviours, but application to study the effect of microcracks is limited.…”

Section: Introductionmentioning

confidence: 99%

Simulating the effect of microcracks on the diffusivity and permeability of concrete using a three-dimensional model

Abyaneh

Wong

Buenfeld

2016

Computational Materials Science

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Concrete inevitably contains microcracks, but their significance on transport properties and long-term durability is not well established. This is because of difficulties in isolating and evaluating the effect of microcracks whether by laboratory experiments or computer simulations, owing to their complex heterogeneous nature. In this paper, a three-dimensional numerical approach to simulate mass transport properties of concrete containing microcracks is presented. The approach is based on finite-element method and adopts aligned meshing to improve computational efficiency. The mesostructure of concrete is represented by aggregate particles that are surface meshed by triangulation and porous cement paste matrix that are discretised with tetrahedral elements. Microcracks are incorporated as interface elements at the aggregate-paste interface or at the cement paste matrix spanning neighbouring aggregate particles. The main advantage of this approach is that the smallest microcracks can be simulated independent of the discretisation size. The model was first validated by comparing the simulations to available analytical solutions. Then, the diffusivity and permeability of a range of concretes containing different amounts of microcracking with increasing complexities were simulated. The results are analysed and discussed in terms of the effect of microcrack type (bond, matrix), volume fraction, width, specific surface area and degree of percolation on transport properties.

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Lattice Boltzmann simulations of the permeability and capillary adsorption of cement model microstructures

Cited by 44 publications

References 56 publications

Pore-scale modelling of relative permeability of cementitious materials using X-ray computed microtomography images

Pore-scale modelling of relative permeability of cementitious materials using X-ray computed microtomography images

Modelling the diffusivity of mortar and concrete using a three-dimensional mesostructure with several aggregate shapes

Simulating the effect of microcracks on the diffusivity and permeability of concrete using a three-dimensional model

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