Fillers in cementitious materials — Experience, recent advances and future potential

The paper discusses the potential of fillers in CO2 mitigation in the cement industry. A historical overview of the use of fillers is presented as well as the limits of filler use given in cement standards. Globally, limestone filler currently represents only 7% of average worldwide cement composition. The limits of the current route to adding filler in cement by means of intergrinding are discussed. An innovative technology, that compensates binder dilution by a reduction of the water required for good rheological behavior, is presented; this allows clinker replacement rates of up to 70%. The theory that enables the design of such multimodal particle size distributions with high particle packing and low-water demand is presented, and examples of its application in concrete production are given. The efficiency in terms of CO2 mitigation is demonstrated by comparing concrete formulations designed with this innovative approach with a global benchmark of current technology. New filler minerals, as well as the effects of high-filler content on production processes and on durability are also discussed.