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

PPT Presentation

Pdf Summary

The presentation evaluates slump-flow and slump-flow velocity testing for deep-foundation tremie concrete, which must be pumpable and highly flowable while retaining stability, passing ability, and the capacity to displace support fluid without washing out or bleeding under pressure.<br /><br />Slump flow, standardized for self-compacting concrete under EN 12350-8 and ASTM C1611, is recommended in the EFFC/DFI Tremie Guide as the preferred consistency test for tremie concrete. However, its reliability for this specific application requires further study. The presentation reviews established fresh-concrete tests, including slump, flow-table spread, and slump flow, and notes that slump flow is more sensitive to changes in concrete yield stress than slump or flow-table testing.<br /><br />Laboratory trials compared several test methods using two concrete mixes, including one that did not meet relevant tremie-concrete specifications. Mixes were adjusted to a target flow-table spread, then tested by different operators. Results showed similar responses to water variation across methods, but tests without compaction had limitations at low values. The findings support combining spread measurement with flow time to provide information about both consistency and apparent viscosity.<br /><br />Plant trials on diaphragm-wall tremie concrete and round-robin testing examined operator and method variability. The presentation describes these investigations but provides limited detail on numerical precision or bias results. Overall, it argues that slump flow is promising for tremie-concrete quality control, while further validation and clearer assessment of flow velocity are needed.

Keywords

slump flow

tremie concrete

deep foundations

pumpability

flowability

support fluid displacement

EN 12350-8

ASTM C1611

yield stress

concrete quality control