Development of new CEM X cements based on ground granulated blast furnace slag, fly ash and clinker.

Today the manufacturing of cements with less Portland cement (OPC) clinker is one of the most important levers in order to reduce the specific CO2-emissions within the cement industry. Currently such cements are already standardised in EN 197-1 as CEM II- to CEM V-cements. But these cements consider only a certain selection of potential combinations of standardised cement constituents.
The present article illustrates impressively the potentials but also the limitations to manufacture high-performance cements with less OPC clinker, ground granulated blast furnace slag (GGBS) and fly ash. The consideration of EN 197-1 technical requirements was only one important aspect. But the performance compared to the established CEM III/A-cements was rather the focus of the investigations. This includes workability properties but also the results of preliminary concrete tests in respect to fresh and hardened concrete properties as well as durability aspects. Furthermore the specific CO2-saving potential was calculated in comparison to CEM III/A-cements.

Author: V. Feldrappe, A. Ehrenberg

Section: Waste utilization

Keywords: composite cements, blast furnace slag, fly ash