Evaluation of Slump Flow and Slump Flow Velocity Test Method for Deep Foundation Concrete

Specifications for concrete in deep foundation have evolved toward increase in durability and strength requirements pushing to lower water / cement ratio. This evolution leads to mix design with rheological properties governed by admixture system. At the same time, concrete mix design optimized to reduce carbon footprint are following pattern. Consistency test methods are not always adapted to characterize the fluid consistency of concrete mixes that are not designed to be true self levelling concrete. EFFC/DFI Guide to tremie concrete recommends slump flow in the range of 400 to 550 mm and slump flow velocity as most suitable test method to characterize concrete workability. NF EN 12350-8 for Europe and ASTM C1611 in North America do not give precision and bias for this range of consistence. Slump flow velocity has no standard method to help in specifying on projects. Authors find that there is a standard gap in using slump flow test method in the recommended range of the EFFC/DFI guide with limitation expressed in the EN 206 concrete standard. This paper presents results of different method to evaluate slump flow with repeatability testing and a comparison between slump flow velocity and viscosity measured with invert Abrams cone as per NF P18-469 standard and gives background technical data to back up the use of the slump flow method for concrete used in deep foundation.