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Percolation Aspects of Cement Paste and Concrete: Properties and Durability.


pdf icon Percolation Aspects of Cement Paste and Concrete: Properties and Durability. (1234 K)
Garboczi, E. J.; Bentz, D. P.

High-Performance Concrete: Research to Practice. American Concrete Institute Spring Convention. Proceedings. ACI Special Publication 189. March 14-19, 1999, Chicago, IL, 147-164 pp, 1999.

Keywords:

cements; concretes; chlorides; diffusivity; durability; materials science; microcomputers; microstructure; percolation; permeability; simulation; transport

Abstract:

Portland cement concrete is a composite material, where the matrix consists of portland cement paste. Cement paste forms from the hydration reaction of portland cement with water. The microstructure of cement paste changes drastically over a time period of about one week, with slower changes occurring over subsequent weeks to months. The effect of this hydration process on the changing microstructure can be represented using computer simulation techniques applied to three dimensional digitial image-based models. Percolation theory can be used to understand the developing microstructure of cement paste in terms of three percolation thresholds: the set point, capillary porosity percolation, and the percolation of the C-S-H phase. The percolation of the interfacial transition zones also plays an important role in concrete microstructure, and can be dispiayed using computer simulation models. These percolation aspects help determinc the transport properties and therefore the durability and service life of concrete.