Title: Amphoteric Superplasticizers for Cements Blended with a Calcined Clay

Author(s): Marlene Schmid, Nancy Beuntner, Karl-Christian Thienel, and Johann Plank

Publication: Symposium Paper

Volume: 329

Issue:

Appears on pages(s): 41-54

Keywords: superplasticizer; polycarboxylate ether, amphoteric polymer; calcined clay; blended cement; dispersing performance

DOI: 10.14359/51711202

Date: 9/24/2018

Abstract:
In this study, the interaction between a calcined clay and novel, self-synthesized amphoteric superplasticizers was investigated. For this purpose, a natural crop of mixed layer clay was calcined at 750 °C in an industrial-scale rotary kiln and its particle size, chemical and mineralogical composition and electrokinetic behavior were determined. Specific amphoteric MPEG type polycarboxylate (PCE) copolymers holding carboxylate as well as quaternary ammonium functionalities were synthesized and characterized via gel permeation chromatography and specific charge amount measurements. Successful synthesis of amphoteric polymers was proven, and attractive dispersing properties were found in ordinary Portland cement (OPC) and an OPC/calcined clay blend, but not in individual calcined clay. Furthermore, the amphoteric polymers retard hydration of the cement/calcined clay blend less than conventional anionic PCE polymers.