Creep and crack growth govern the long-term deformability of concrete and thus its service behavior and its durability. The mechanisms involved in the couplings between these effects are not yet clearly identified. The aim of this research was to investigate experimentally and numerically at both the macro and the meso-level (heterogeneous material) the interactions between creep and crack growth in concrete and identify, the main phenomena acting on the overall viscoelastic response of concrete, at various stages of fracture, during relaxations. (c) 2005 Elsevier Ltd. All rights reserved.