Blast furnace slag cement (BFSC) has been used in reinforced concrete structures in marine and road environment in The Netherlands for nearly a century. Experience is good and long service lives can be obtained. In Norway experience with BFSC is scarce. In The Netherlands, a high resistance against chloride penetration and a high electrical resistivity, was demonstrated both in the field and in the laboratory for CEM III/B with 65-75% of slag by mass of binder. Such a cement is not readily available on the Norwegian market. The introduction of CEM III/A with c. 50% slag is anticipated. An experimental program was carried out to study the properties of five mortar mixes made with: CEM III/B (two brands); a CEM III/A (with c. 50% slag) with silica fume; and a CEM I and a CEM II/A-V (fly ash cement), both with silica fume. Rapid Chloride Migration (RCM) and electrical resistivity were tested at ages between two days and one year. RCM values showed consistent decrease and resistivity showed consistent increase between two days and one year. The program is intended to collect data up to three years age. The ultimate goal is to provide a basis for evaluating the use of slag cement in Norway for durable concrete structures. The paper reports the results and discusses the preliminary conclusions@en