Shrinkage and creep behavior of an alkali-activated slag concrete

In this paper, experimental results about the shrinkage and creep behavior of an alkali-activated slag concrete (AAS-concrete) are presented. The autogenous shrinkage of AAS-concrete is pronounced at a relatively high water to binder ratio of 0.41. The ultimate value of autogenous shrinkage is determined to be higher than that of high-strength concrete (HSC). The observed self-desiccation at a later concrete age can be one of the reasons for the autogenous shrinkage. In a drying environment of 65% relative humidity AAS-concrete exhibits a significantly higher total shrinkage compared to normal-strength concrete composed of Portland cement. In the contrary to normal and HSC carbonation shrinkage must not be neglected for AAS-concrete in the early concrete age. The sum of drying and carbonation shrinkage develops much more rapidly for AAS-concrete in the first weeks after the beginning of drying. Based on the experimental results the shrinkage behavior of AAS-concrete cannot be predicted by conventional models. The creep behavior of the AAS-concrete was investigated under sealed and unsealed conditions. The creep coefficients for both conditions are higher than those calculated when using conventional models.