Dynamic testing of large concrete specimens with large modified Hopkinson bar apparatuses

Material models for concrete require data derived from experiments performed on large size specimens with realistic aggregate sizes. Such experiments, based on Hopkinson bar techniques, have been performed and described in the paper. They comprise several concrete types and grades with aggregate and specimen dimensions of up to 64mm and 400mm, respectively. Appropriate testing apparatuses and techniques have been developed which have proved very efficient. Full stress-strain curves have been obtained and strain-rates up to 20s-1 have been reached. The results help to assess the influence of the specimen and aggregate size in the dynamic regime. Confirming data from smaller specimens, they show overall an increase of material strength and fracture energy with increasing strain-rates, which appears to be more pronounced in tension than in compression.JRC.E.4-Safety and Security of Building