The paper presents a case study and discusses the effect of carbonation on the expected service life of an existing reinforced concrete structure. The structure was built 10 years ago. The concrete was made with blast furnace slag cement. The design life of the structure was 100 years and DuraCrete was used as a guideline along with European Codes.A series of tests and measurements have been carried out to determine the quality of concrete and the condition of reinforcement. The measurements indicate that carbonation proceeds fast and that corrosion of reinforcement is anticipated earlier than expected. An analysis of the causes for the accelerated damage is presented. Based on the results the service life of the structure is evaluated. The paper analyzes also the code requirements and the tests and requirements followed by DuraCrete. A critical assessment of the limitations of the design model and the parameters of DuraCrete are discussed.Keywords: corrosion reinforcing steel slag cement DuraCrete carbonation.