International Summit on Cement Hydration Kinetics

Jie Zhang*, George Scherer and Emily Weissinger

Department of Civil and Environmental engineering

princeton University

princeton, NJ 08544, US

A broad experimental study has been performed on characterization of early hydration and setting of cement pastes prepared with Class H oil well cement, cured at various temperatures, mixed with different chemical additives and various mixing times. Various parameters for characterizing early-age hydration have been analyzed by multiple techniques, such as chemical shrinkage measured by a newly developed chemical shrinkage measurement system, degree of the cement hydration determined by the thermogravimetric analysis (TGA), and setting times tested by Vicat method and ultrasonic measurement. To obtain a sufficient time resolution, a freeze drying procedure is used to instantaneously cease the hydration at setting time for TGA measurement. This study found that the degree of hydration at initial setting time is constant at a given water to cement ratio (w/c) regardless of the effects of ambient temperature or presence of additives. In other words, though it is shown that temperature increases expedite the rate of cement hydration, causing more rapid production of hydration products and earlier setting; conversely, additives such as retarder maltodextrin and the free-water agents hydroxythecellulose and diutan are shown to delay cement hydration, causing later setting times, the amount of hydration product formed at setting is a constant which depends only on particle packing determined by w/c.

zhang-Poster

* Presenter