Title:
Impact of Different PCE Architectures on Flow Performance Depending on Precipitated Ettringite
Author(s):
Y. Chen, S. Wang, P. Juilland, L. Frunz, and J. Zhu
Publication:
Symposium Paper
Volume:
329
Issue:
Appears on pages(s):
165-174
Keywords:
concrete; PCE; cement; ettringite; sulfatation; Ca-sulfate
DOI:
10.14359/51711212
Date:
9/26/2018
Abstract:
In this article we investigate the effect of precipitation of ettringite on the dispersion effect of four PCE with different structures. We first developed a simple method to qualify commercial cements with respect to early ettringite precipitation. The difference in flow between a paste prepared with the PCE in the mixing water (direct mode) and a paste prepared by adding the PCE after 3 minutes of hydration (indirect mode) can be correlated to amount of ettringite forming for a specific cement. A similar test setup was used to assess the effect of the precipitating ettringite on the flow properties of the different PCE. We found that all tested PCE were impacted by ettringite precipitation but to a very different extent. This suggests that, for concrete applications, the selection of a PCE more robust against variations in ettringite precipitation due to fluctuations in the used raw materials is feasible.