A probabilistic assessment of the influence of age factor on the service life of concretes with limestone cement/GGBS binders

•The influence of varying GGBS content on age factor is determined.•Probabilistic models for predicted service life are developed.•Significant impact of age factor is confirmed. The use of Supplementary Cementitious Materials (SCMs) in concrete manufacture has increased significantly in recent years. Utilising SCMs in the concrete mix reduces CO2 footprint while also generally enhancing durability. Time-dependent characteristics of concrete become more significant as SCM replacement levels increase. Service life modelling requires incorporation of accurate age factors; however limited research has been published on the influence of time-dependent characteristics of SCM concretes when manufactured with limestone cement (CEM II/A-LL). In this study, mix-specific age factors were determined based on the chloride diffusivity of concretes produced using a limestone cement binder with varying replacement levels of ground granulated blast-furnace slag (GGBS). The experimentally-determined age factors were validated against field data. Application of the validated factors in service life assessment models indicated increased sensitivity of the models to increased GGBS replacement level while affirming the enhanced durability effect of GGBS when used in combination with limestone cement.