Jacques Marchand, Dale Bentz, Eric Samson, and Yannick Maltais, Published in "Reactions of Calcium Hydroxide in Concrete," American Ceramic Society, Westerville, OH, 2001.

( (PDF Version of Original Paper)

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INFLUENCE OF CALCIUM HYDROXIDE DISSOLUTION ON THE TRANSPORT PROPERTIES OF HYDRATED CEMENT SYSTEMS

Jacques Marchand1,2, Dale Bentz3, Eric Samson1,2 and Yannick Maltais1,2

1CRIB - Department of Civil Engineering,
Laval University, Canada, G1K 7P4

2SIMCO Technologies Inc.,
1400 boul. du Parc Technologique, Québec, Canada, G1P 4R7

3Building and Fire Research Laboratory
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA

ABSTRACT

Calcium hydroxide is one of the main reaction products resulting from the hydration of portland cement with water. It is also one of the more soluble phases found in hydrated cement systems. The influence of calcium hydroxide dissolution and its effect on the diffusion properties of hydrated cement pastes were investigated using the NIST CEMHYD3D cement hydration and microstructure development model. The results of these simulations were implemented in another numerical model called STADIUM. This latter model can be used to predict the transport of ions in unsaturated porous systems. Numerical simulations clearly indicate that calcium hydroxide dissolution contributes to a marked increase in the porosity of the hydrated cement paste. This increase in porosity has a detrimental influence on the material transport properties. The results yielded by the numerical simulations are in good agreement with data of calcium leaching experiments performed in deionized water.

Keywords: Calcium hydroxide, dissolution, leaching, alteration, transport properties, modeling.

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