Physical properties of calcined clays differ significantly and depend to a large extent on the mineralogy of the raw clays. In this study, four common clays and one kaolinite-rich mine tailing are calcined at 800 ◦C. Their impact on flow properties of blended cement paste is measured via rotational viscometer and analyzed by (modified) Bingham and Herschel-Bulkley model, combined with the calculation of flow resistance. The demand for superplasticizers rises significantly due to the special characteristics of calcined clays, namely particle size, a high water demand and negative zeta potential. Muscovite present in raw clay is critical as it increases the water demand, yield stress and viscosity. In general, the addition of three industrial polycarboxylate-based super- plasticizers (PCEs) reveals good dispersion. Calcined kaolinite-rich clays require more PCE compared to calcined clays rich in 2:1 phyllosilicates. The studied PCEs interact well with all types of metaphyllosilicates besides metamuscovite.    «

Physical properties of calcined clays differ significantly and depend to a large extent on the mineralogy of the raw clays. In this study, four common clays and one kaolinite-rich mine tailing are calcined at 800 ◦C. Their impact on flow properties of blended cement paste is measured via rotational viscometer and analyzed by (modified) Bingham and Herschel-Bulkley model, combined with the calculation of flow resistance. The demand for superplasticizers rises significantly due to the special char...    »