Résumé
The use of recycled aggregates in concrete mixtures is a part of waste recovery strategy. The Frenchnational project RECYBETON aims at developing scientific knowledge to facilitate the use ofrecycled aggregates into concrete. In this experimental study, two exposure conditions werecombined to analyse the behaviour of fresh and hardening concrete in standard and severe dryingconditions (8 m.s-1 wind speed). High evaporation rate promotes the development of plasticshrinkage and cracking of fresh concrete. The influence of recycled concrete aggregates proportionand initial water saturation rate were investigated. Two series of concrete mixtures were designed toreach two strength classes. The strains and weight loss of concrete samples were monitored until thestabilization of plastic shrinkage. The increase in evaporation rate accelerated the development andincreased the maximum value of plastic shrinkage but did not significantly influence the shrinkage-to-weight loss ratios. In severe conditions plastic shrinkage developed before initial setting thusreached higher magnitudes. The main mix-design parameter affecting the shrinkage-to-weight lossratio and cracking was the total water-to-binder ratio. The total water content includes the wateradded and the water used to pre-saturate the aggregates. High evaporation rate triggered the releaseof water initially absorbed by recycled concrete aggregates.