Early-Age Microstructure Evolution of Cement Pastes
Giri Venkiteela* and Zhihui Sun
University of Louisville
In fresh concrete, cement paste plays a major role in the development of its properties. During early age all the behaviors of cement pastes are governed by its microstructure evolution, which include cement particles dispersion, growth, percolation, agglomeration, flocculation and wide variety of other chemical and physical reactions. However, it is still unclear, during hydration how these developments in cement paste microstructure influence the concrete. In this study for better understanding of the hydration kinetics, real observations on various cement pastes microstructure evolutions were carried out by employing a new sampling system called Quantomix WETSEMTM capsuling system and a conventional scanning electron microscope (SEM). All the cement pastes (water to cement ratio 0.5, 0.6 and 0.7) micrographs were captured from 15 minutes after mixing and up to the initial setting of respective pastes at a specified time interval. The role of different phases, individual cement particles and different sized particles growth in microstructure evolution were studied quantitatively by using image analysis techniques on observed micrographs.
* Presenter