Maes, Ben; Audenaert, Amaryllis; Craeye, Bart; Buyle, Matthias

A new treatment process for Class F fly ashes is being developed, using a proprietary technology to separate the fly ash into several fractions based on their particle size, with the ultra-fine fly ashes being used to act as a substitute for silica fume in Ultra-High-Performance Concrete. In order to assess the environmental impact of this technology when it is fully developed, an LCA study was performed on the technology using an ex-ante approach. This study used the developer’s expert opinion to upscale the innovative technology and took into account changes to the electricity mix using projections found in literature. The results indicated that an environmental benefit could be gained by using the treatment process, compared to its direct use in concrete. The results where mainly influenced by the amount of cement that could be saved with the use of fly ash, as well as the amount of ultra-fine fly ash that could be gained with the treatment process. The goal of this study is to refine the previous assessment. First, by incorporating potential changes that may have occurred to the cement industry and its background system by the time the innovative technology is released. This will be done using a cornerstone scenario approach which will look at changes to clinker and cement production, as well as changes to the electricity mix and fuel market for clinker. Second, by refining the assumption made on the collection efficiency of the ultra-fine fly ash. Since the time of the previous study a new pilot model of the technology has been developed on a larger scale. This new model will be used along with the previous models to assess the collection efficiency of the ultra-fine fly ash of the technology on an industrial scale.