A large experimental program about alkali-silica reaction (ASR) was carried out on beam specimens at the Laboratoire Central des Ponts et Chausees (LCPC), with Electricite de France (EDF) as a partner. The aim was to provide data intended to validate a methodology of assessment of real structures affected by this expansive reactive mechanism. Three-dimensional deformations were measured on five 3 m-long plain or reinforced concrete beams undergoing partial drying over a period of 14 months. The paper points out the effect of a moisture gradient over the depth of the beams and the influence of reinforcement on the development of ASR-induced expansions. Tests on companion specimens (cylinders and prisms) were carried out to measure the material expansion and mechanical characteristics.