This report deals with numerical modelling of early age concrete. The hydration process giving the strength and stiffness development after casting is discussed. Several factors influence the progress of hydration such as the temperature level and the moisture activity. The factors are coupled and a material model is proposed which includes some of the couplings. It is shown how more factors may be incorporated. The model is illustrated through analysis of measured creep response both at a varying load history and at a varying temperature history.