Evaluation of slump flow and slump flow velocity test method for deep foundation concrete-Paper

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The paper evaluates slump-flow testing as a measure of workability for tremie concrete used in deep foundations. Conventional slump testing can be insufficiently sensitive for flowable, non-self-compacting mixes, while EN 12350-8 and ASTM C1611 primarily address slump-flow values above the range commonly recommended for tremie concrete. The EFFC/DFI guide instead recommends slump flow of approximately 350–600 mm and slump-flow velocity to assess apparent viscosity.<br /><br />The study compares three methods: EN 12350-8, EN 12350-2, and the French NF P18-469 inverted-cone procedure, which also measures flow time. Laboratory trials and a seven-operator round-robin study assessed repeatability and reproducibility, alongside comparisons with the flow-table test.<br /><br />All three slump-flow methods responded similarly to changes in mix water, but produced different numerical results. Laboratory results indicated acceptable operator consistency, although NF P18-469 sometimes gave higher spread values. The inverted-cone method was considered practical and potentially useful because one test can assess both spread and viscosity. EN 12350-8 may be less suitable at the lower end of the tremie-concrete range. The round-robin testing provides precision data for EN 12350-2 and NF P18-469.<br /><br />Overall, the findings support slump flow as a more informative measure of tremie-concrete rheology than conventional slump testing. The authors recommend further work to standardize suitable procedures and establish a reliable relationship between slump-flow velocity and inverted-cone flow time.

Keywords

tremie concrete

slump flow

workability

deep foundations

EN 12350-8

ASTM C1611

NF P18-469

inverted cone test

flow time

rheology