Guide to Tremie Concrete For Deep Foundations, 2nd Edition-PDF

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Pdf Summary

The 2018 EFFC/DFI Guide provides practical guidance for specifying, designing, placing, and assessing tremie concrete in deep foundations, including bored piles, barrettes, and diaphragm walls. It complements—not replaces—project standards and codes.<br /><br />The guide emphasizes that successful foundations require collaboration among the client, structural designer, contractor, and concrete supplier. Concrete must balance flowability, workability retention, and stability: it must fill and pass through reinforcement under gravity without blocking, segregating, bleeding excessively, or filtering water under pressure. Mix design and reinforcement detailing should be developed together. The guide recommends at least 100 mm clear spacing between vertical bars and nominal concrete cover of at least 75 mm, with greater allowances where conditions make flow difficult.<br /><br />Fresh concrete should be characterized by more than strength, cement content, water-cement ratio, or slump alone. Recommended tests include slump flow (target range 400–550 mm), slump-flow velocity (10–50 mm/s), and a visual stability index; additional tests for segregation, bleeding, filtration, and workability retention may be required based on project risks. Suitability trials, production conformity controls, and regular acceptance testing are essential.<br /><br />For execution, the guide covers excavation preparation, tremie equipment and spacing, initial placement, pipe embedment, concrete-flow behavior, and placement records. It recommends continuous, controlled pouring, maintaining adequate tremie embedment, minimizing delays, and recording concrete levels and volumes after each load. Full-scale trials can identify risks before permanent works begin.<br /><br />The guide also describes post-construction inspection and testing, including coring, cross-hole sonic logging, and thermal integrity profiling. It distinguishes imperfections—such as inclusions, bleed channels, and “mattressing”—from defects, which require assessment of their structural and durability significance. Numerical modelling can help evaluate flow and design sensitivities, but should be interpreted alongside field evidence and trials.

Keywords

tremie concrete

deep foundations

bored piles

barrettes

diaphragm walls

slump flow

workability retention

segregation resistance

cross-hole sonic logging

thermal integrity profiling