Abstract
ABSTRACT
The effects of ethylene glycol on the setting reactions of hydrating Portland cement and on the eventual structure of the hydrated cement paste have been studied by a combination of techniques including solvent extractions with solvents of varying polarities, scanning electron microscopy, and X-ray powder diffraction. When ethylene glycol (EG) is solidified with cement, the EG appears to occupy at least 3 different kinds of sites, characterized by differing extractability. Gross alterations of the morphology of the cement matrix do not become apparent until rather large amounts of EG (EG/cement = 0.1 by weight) have been added to the hydrating cement mixture. At that point the structure is clearly weakened, and the EG is more readily extracted. However, at concentrations below the point at which major structural changes take place, there is evidence from X-ray diffraction that EG is entering the semi-crystalline calcium silicate hydrate (C-S-H) gel phase and altering its structure. A major effect of the organic additive is to retard the cement setting reactions, so that significant changes in the matrix, including changes in its ability to bind the organic, are occurring up to at least a year of curing time.
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