Title: Percolation Aspects of Cement Paste and Concrete—Properties and Durability
Author(s): E. J. Garboczi and D. P. Bentz
Publication: Symposium Paper
Appears on pages(s): 147-164
Keywords: cement; chlorides; diffusivity; durability; materials science; microcomputers; microstructure; percolation; permeability; simulation; transport
Portland cement concrete is a composite material, where the matrix consist of porland cement paste. Cement paste forms from the hydration reaction of portland cement with water. The microstructure of cement paste changes drastically over 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 digital 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 displayed using computer simulation models. These percolation aspects help determine the transport properties and therefore the durability and service life of concrete.