The EFFC/DFI Best Practice Guide to Tremie Concrete for Deep Foundations published in 2016 has highlighted the complexity of modern tremie concrete. Concrete additions and admixtures are increasingly used to adapt tremie concrete to the particular requirements of deep foundations. Despite these advancements, issues arising during the concreting process can occur. This paper discusses these issues and shares recent experience of static segregation of tremie concrete in bored piles. The paper outlines recent industry guidance on tremie concrete behaviour and testing in the 3rd Edition of the ICE Specification for Piles and Embedded Retaining Walls, 2017. This details fresh concrete tests that can be used for site acceptance of concrete batches, and provides guidance on more detailed concrete testing at laboratory mix design, initial batching stages and during the project. The paper also summarises the results of detailed testing carried out during a recent project in London, and compares the results with suggested test acceptance limits. The benefits of carrying out these tests are listed along with recommendations for future research to refine acceptance limits.
Subjects: tremie concrete, workability, stability, static segregation, case studies, test acceptance criteria.
Author: Aidan Thorp, Christopher Wilkes, Duncan Nicholson and Bryan Marsh
Publisher: DFI, EFFC