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

Abstract 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.

[1]  E. Garboczi,et al.  Water permeability and chloride ion diffusion in portland cement mortars: Relationship to sand content and critical pore diameter , 1995 .

[2]  R. Newnham,et al.  Electrical Resistivity of Composites , 1990 .

[3]  B. Gérard,et al.  Influence of cracking on the diffusion properties of cement-based materials : Part I : Influence of continuous cracks on the steady-state regime , 2000 .

[4]  Sanford E. Thompson,et al.  THE LAWS OF PROPORTIONING CONCRETE , 1907 .

[5]  S. Kamali-Bernard,et al.  Computer modelling of tritiated water diffusion test for cement based materials , 2009 .

[6]  P. Bowen,et al.  Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment , 2011 .

[7]  Edward J. Garboczi,et al.  Multiscale Analytical/Numerical Theory of the Diffusivity of Concrete , 1998 .

[8]  Edward J. Garboczi,et al.  Percolation of phases in a three-dimensional cement paste microstructural model , 1991 .

[9]  Mingzhong Zhang,et al.  Microstructure-based modeling of permeability of cementitious materials using multiple-relaxation-time lattice Boltzmann method , 2013 .

[10]  L. Ambrosio,et al.  Journal of materials science: materials in medicine. , 2003, Journal of materials science. Materials in medicine.

[11]  Edward J. Garboczi,et al.  1. Digital Images and Computer Modeling , 1999 .

[12]  G. Remnev,et al.  Materials Research Society Symposium - Proceedings , 1995 .

[13]  R. Drew,et al.  Wettability and spreading kinetics of molten aluminum on copper-coated ceramics , 2006 .

[14]  E. Garboczi.  Three-dimensional mathematical analysis of particle shape using X-ray tomography and spherical harmonics: Application to aggregates used in concrete , 2002 .

[15]  M. Kakihana,et al.  Materials Research Society Symposium - Proceedings , 2000 .

[16]  ScienceDirect.  Advanced cement based materials , 1993 .

[17]  Richard K. Brow,et al.  Journal of the American Ceramic Society: Introduction , 2002 .

[18]  E. Garboczi,et al.  Computer simulation of the diffusivity of cement-based materials , 1992 .

[19]  S. Kamali-Bernard,et al.  Predicting the evolution of mechanical and diffusivity properties of cement pastes and mortars for various hydration degrees – A numerical simulation investigation , 2012 .

[20]  A. W. Harris,et al.  Mass transport properties of mature wasteform grouts , 2007 .

[21]  B. Oh,et al.  PREDICTION OF DIFFUSIVITY OF CONCRETE BASED ON SIMPLE ANALYTIC EQUATIONS , 2004 .

[22]  N. Buenfeld,et al.  Euclidean Distance Mapping for computing microstructural gradients at interfaces in composite materials , 2006 .

[23]  Aydin Nabovati,et al.  A general model for the permeability of fibrous porous media based on fluid flow simulations using the lattice Boltzmann method , 2009 .

[24]  E. Garboczi,et al.  Simulation Studies of the Effects of Mineral Admixtures on the Cement Paste-Aggregate Interfacial Zone (SP-105) , 1991 .

[25]  Ravindra K. Dhir,et al.  Discussion: Rapid estimation of chloride diffusion coefficient in concrete , 1991 .

[26]  P. Lugol.  Annalen der Physik , 1906 .

[27]  Cumaraswamy Vipulanandan,et al.  Cement and Concrete Research , 2009 .

[28]  Edward J. Garboczi,et al.  Multi-Scale Microstructural Modeling of Concrete Diffusivity: Identification of Significant Varibles , 1998 .

[29]  E. Garboczi,et al.  Interfacial Zone Percolation in Concrete: Effects of Interfacial Zone Thickness and Aggregate Shape , 1994 .

[30]  E. Garboczi,et al.  Percolation and pore structure in mortars and concrete , 1994 .

[31]  Richard A Williams,et al.  A packing algorithm for particles of arbitrary shapes , 2001 .

[32]  Magazine of Concrete Research , 1964, Nature.

[33]  Michel Pigeon,et al.  Influence of the interfacial zone on the chloride diffusivity of mortars , 1997 .

[34]  Nick R. Buenfeld,et al.  Assessing the influence of ITZ on the steady-state chloride diffusivity of concrete using a numerical model , 2009 .

[35]  P. McDonald,et al.  Lattice Boltzmann simulations of the permeability and capillary adsorption of cement model microstructures , 2012 .

[36]  N. Buenfeld,et al.  Characterising aggregate surface geometry in thin-sections of mortar and concrete , 2008 .

[37]  Nick R. Buenfeld,et al.  Effect of entrained air voids on the microstructure and mass transport properties of concrete , 2011 .

[38]  San-Shyan Lin,et al.  A multi-phase model for predicting the effective diffusion coefficient of chlorides in concrete , 2012 .

[39]  Jian‐Jun Zheng,et al.  A numerical method for the chloride diffusivity in concrete with aggregate shape effect , 2012 .

[40]  Edward J. Garboczi,et al.  Modelling of the microstructure and transport properties of concrete , 1996 .

[41]  K. Scrivener,et al.  The percolation of pore space in the cement paste/aggregate interfacial zone of concrete , 1996 .

[42]  Will Hansen,et al.  Volume Relationships for C-S-H Formation Based on Hydration Stoichiometries , 1986 .

[43]  M. Forde,et al.  Construction and Building Materials , 2004 .

[44]  K. Scrivener,et al.  The Interfacial Transition Zone (ITZ) Between Cement Paste and Aggregate in Concrete , 2004 .

[45]  Margaret Nichols.  Trans , 2015, De-centering queer theory.

[46]  Edward J. Garboczi,et al.  Effects of cement particle size distribution on performance properties of Portland cement-based materials , 1999 .

[47]  N. Buenfeld,et al.  Influence of the interfacial transition zone and microcracking on the diffusivity, permeability and sorptivity of cement-based materials after drying , 2009 .

[48]  Michael R Wisnom,et al.  Composites Part A: Applied Science and Manufacturing , 2012 .

[49]  Wade Babcock,et al.  Computational materials science , 2004 .

[50]  Dale P. Bentz,et al.  Influence of silica fume on diffusivity in cement-based materials: I. Experimental and computer modeling studies on cement pastes , 2000 .

[51]  D. A. G. Bruggeman.  Berechnung verschiedener physikalischer Konstanten von heterogenen Substanzen. I. Dielektrizitätskonstanten und Leitfähigkeiten der Mischkörper aus isotropen Substanzen , 1935 .

[52]  Po-zen Wong,et al.  Methods in the physics of porous media , 1999 .

[53]  Suzana Caetano da Silva Lannes,et al.  Powder Technology , 2020, Nature.