Innovation based on tradition: Blast furnace slag cement for durable concrete structures in Norway?

Blast furnace slag cement (BFSC) has been used to build reinforced concrete structures in marine and road environment in The Netherlands for nearly a century. The experience is good and structures with long service lives can be obtained, as has been shown by several field studies. This is caused by a high resistance against chloride penetration and a high electrical resistivity, demonstrated both in the field and in the laboratory. Due to the high slag content, related CO2 emission and embedded energy are lower than for Portland cement. In many countries including Norway, BFSC is a novelty and long term experience is lacking. In order to study the potential for use of BFSC in Norway, a desk study was carried out, reporting on many aspects. The resistance against chloride induced corrosion stands out positively, whereas neither carbonation nor frost are problems in practice. However, the Dutch experience is mainly based on CEM III/B with 65-75% of slag by mass of binder. Such a cement is not available on the Norwegian market. The introduction of CEM III/A with c. 48% slag in Norway is anticipated. Consequently, an experimental program was drawn up to study the properties of concrete made with CEM III/B and CEM III/A (with 48% slag), with and without addition of silica fume. The ultimate goal is to provide a basis for evaluation of use of slag cement in Norway for durable coastal and marine structures. This paper describes the history and performance of slag in concrete in The Netherlands, the outline of the experimental program and expected results from the study.