Bridges

The use of self-compacting concrete (SCC) in identified concrete bridge elements has now been incorporated in NSW Roads and Maritime Services QA Specifications B80 as Annexure B80/G. The use of SCC in precast elements is generally allowed while a project-specific approval is required for cast-in-place application. Cast-in-place application may include deep foundations, as an alternative to concrete used by the tremie placement method, elements with congested reinforcement or where access for mechanical compaction is difficult. As part of the project verification at the Hume Highway Alliances for Tarcutta and Woomargama bypasses, three trial full-scale bored piles were cast-in-place with SCC using three common placement scenarios, namely: tremie placement on dry hole, tremie placement on wet hole, and free-fall placement on dry hole. This paper discusses (a) the acceptance testing regime implemented for production and trial piles at Hume Highway Woomargama Alliance, (b) comparison of hardened properties between mould samples and core samples including non-destructive evaluation for each placement scenario, and (c) comparison of in-place hardened properties between placement scenarios.