In this study, the interaction between a calcined clay and novel, self-synthesized amphoteric superplasticizers was investigated. For this purpose, a natural occurring 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.Further investigations revealed an improved alumina and silicon ion solubility with increasing alkali content. While metakaolin exhibits a significant concentration of dissolved alumina and silicon ions after six hours, the influences of illite and muscovite are less pronounced and start at later times of hydration. The formation of C-S-H and in presence of sulfate and calcite the formation of AFm- and AFt-phases can be quantified. C-A-S-H and strätlingite are formed in alumina rich clay compositions. In conclusion the investigation shows the quantitative contribution to the pozzolanic reaction in model pore solutions of different calcined clay components.    «

In this study, the interaction between a calcined clay and novel, self-synthesized amphoteric superplasticizers was investigated. For this purpose, a natural occurring 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...    »