Title: Influence of PolyOxyEthylene Di-Phosphonate on the Formation of Ettringite

Author(s): A. Guerini, C. Filiatre, C. Canevet, M. Mosquet, and A. Foissy

Publication: Symposium Paper

Volume: 217

Issue:

Appears on pages(s): 573-582

Keywords: admixture; concrete; ettringite; gluconate; hydration of cement; polyoxyethylene diphosphonate; superplasticizer

DOI: 10.14359/12938

Date: 9/1/2003

Abstract:
Concrete technology has evolved considerably lately with the use of New Generation Superplasticizers (NGS). Both laboratory and job site results show some interesting results in combining NGS and Plasticizers. One example is the combination of polycarboxylate derivatives and plasticizers-with set retardation secondary effectseveral examples have been reported where these combinations are more efficient for keeping the fluidity level as a function of time than the NGS alone. Another example of particular interest is the combination of a PolyOxyEthylene DiPhosphonate (POEDP) with a Plasticizer. Some results have shown that the Plasticizer improves somehow the reactivity of the POEDP Considering that Trisulfoaluminate forms at the early stage of the hydration of cement and that this reaction has a significant influence on the rheological properties of the paste the influence of POEPD and plasticizer combinations on the synthesis of Ettringite was analyzed. Rheological and adsorption measurements have been performed on paste of ettringite produced by mixing calcium hydroxide and aluminium sulphate (i) alone, (ii) in the presence of POEDP, and (iii) in the presence of POEDP and Gluconate.