- Author
- Snyder, K. A. | Winslow, D. N. | Bentz, D. P. | Garboczi, E. J.
- Title
- Interfacial Zone Percolation in Cement-Aggregate Composites.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD Purdue Univ., West Lafayette, IN
- Book or Conf
- RILEM. Interfaces in Cementitious Composites. International Conference. Proceedings 18. October 21-23, 1992, E & FN Spon, New York, Toulouse, France, Maso, J. C., Editors, 259-268 p., 1992
- Keywords
- composite materials | percolation | hard core-soft shell | microstructure | computer models | interfacial zone | mercury intrusion | sand
- Abstract
- Interfacial zones exist between the aggregates and paste in portland cement mortars and concretes. The microstructure of these interfacial zones consists of both larger pore diameters and higher porosity than the microstructure of the bulk paste. If a sufficient number of the aggregate particles are present, the interfacial zones may overlap and link together, percolating the system. Mercury intrusion experiments performed on mortars indicate that the intrusion characteristics change dramatically at a critical sand content. A computer simulation model has been developed that can predict the volume of sand required for the percolation of the interfacial zone phase given an interfacial zone thickness and an aggregate size distribution. The model was used to simulate 1 cm³ of mortar, consisting of approximately 10000 aggregate particles. A comparison of the results of the computer simulation model with the results of the mercury intrusion experiment yields an estimate of the interfacial zone thickness which is in agreement with published values. The model is also applied to 27 cm³ systems of concrete in order to predict the critical aggregate content required for percolation.