Practice on creating a common reference concrete for Round Robin Testing programmes based on the experience from COST Action TU1404

•Round robin test (RRT) performed with active participation of 34 laboratories.•All constituting materials shipped to national contact points.•Detailed protocols prepared with preconditioning, mixing and testing procedure.•Consistency, temperature, density, air content and compressive strength analysed.•With the adopted approach possible to prepare a common reference concrete for RRT.