Effect of the Interfacial Transition Zone on the Conductivity of Portland Cement Mortars

The electrical conductivity of portland cement mortars was determined experimentally as a function of the volume fraction of sand and the degree of hydration. The results were analyzed using theoretical models that represent the mortars as three-phase, interactive composites. The three phases are the matrix paste, the aggregate, and the thin interfacial transition zone between the two. The microstructure and properties of the conductive phases (the transition zone and the matrix paste) were determined by a micrometer-scale microstructural model, and were used in conjunction with random-walk algorithms and differential-effective medium theory to determine the overall mortar conductivities. The presence of the transition zone was not found to significantly affect the global electrical conductivity of the mortar. However, there were significant differences in conductivity between the transition zone and matrix pastes when examined on a local level. These differences were found to vary with hydration and were most significant when the degree of hydration was between 0.5 and 0.8.

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

[2]  S. Diamond,et al.  Micromorphology of the Interfacial Zone Around Aggregates in Portland Cement Mortar , 1979 .

[3]  P. Monteiro,et al.  The aggregate-mortar interface , 1985 .

[4]  H. W. Whittington,et al.  The conduction of electricity through concrete , 1981 .

[5]  A. Katz,et al.  Prediction of rock electrical conductivity from mercury injection measurements , 1987 .

[6]  T. Mason,et al.  Experimental limitations in impedance spectroscopy:: Part V. Apparatus contributions and corrections , 1997 .

[7]  Edward J. Garboczi,et al.  Modeling the influence of the interfacial zone on the DC electrical conductivity of mortar , 1995 .

[8]  Thompson,et al.  Quantitative prediction of permeability in porous rock. , 1986, Physical review. B, Condensed matter.

[9]  Edward J. Garboczi,et al.  Analytical formulas for interfacial transition zone properties , 1997 .

[10]  Sidney Diamond,et al.  An Approach to Quantitative Image Analysis for Cement Pastes , 1994 .

[11]  J. Beaudoin,et al.  Modification of transition zone microstructure-silica fume coating of aggregate surfaces , 1992 .

[12]  E. Garboczi,et al.  Interfacial transport in porous media: Application to dc electrical conductivity of mortars , 1995 .

[13]  J. Beaudoin,et al.  Microstructural characterization of the transition zone in cement systems by means of A.C. impedance spectroscopy , 1993 .

[14]  David Bonen Calcium Hydroxide Deposition in the Near Interfacial Zone in Plain Concrete , 1994 .

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

[16]  Charles W. Tobias,et al.  On the Conductivity of Dispersions , 1959 .

[17]  Experimental and Computer Simulation Results for the Electrical Conductivity of Portland Cement Paste , 1991 .

[18]  H. Jennings,et al.  The influence of mixing on the microstructure of the cement paste/aggregate interfacial zone and on the strength of mortar , 1992, Journal of Materials Science.

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

[20]  Electrically Induced Microstructural Changes in Portland Cement Pastes , 1998 .

[21]  Karen L. Scrivener,et al.  Microstructural Gradients in Cement Paste Around Aggregate Particles , 1987 .

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

[23]  Sidney Mindess,et al.  Properties of paste-rock interfaces and their influence on composite behaviour , 1995 .

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

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

[26]  Alexander M. Vaysburd DURABILITY OF LIGHTWEIGHT CONCRETE BRIDGES IN SEVERE ENVIRONMENTS , 1996 .

[27]  J. Beaudoin,et al.  Flat aggregate-portland cement paste interfaces, I. Electrical conductivity models , 1991 .

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

[29]  P. Tumidajski Electrical conductivity of Portland cement mortars , 1996 .

[30]  Rachel J. Detwiler,et al.  Texture of calcium hydroxide near the cement paste-aggregate interface , 1988 .

[31]  Edward J. Garboczi,et al.  Impedance Spectroscopy of Hydrating Cement‐Based Materials: Measurement, Interpretation, and Application , 1994 .

[32]  G. Ballivy,et al.  Contribution to the formation mechanism of the transition zone between rock-cement paste , 1993 .

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

[34]  James J. Beaudoin,et al.  Effect of aggregate size on transition zone properties at the Portland cement paste interface , 1991 .

[35]  J. Ollivier,et al.  Interfacial transition zone in concrete , 1995 .

[36]  D. Winslow The validity of high pressure mercury intrusion porosimetry , 1978 .