Quality of Underwater Concrete
Quality of Underwater Concrete
(OP)
I am working on a project that involves a mass placement (100 CY, about 5 feet thick) of underwater concrete. The purpose of the concrete is scour remediation. My question is: What are some options for verifying the quality of the concrete? The concrete is not load bearing, but we want to make sure the contractor places it properly. The water is 15 feet deep and very murky.
Is the only way to take cores? The budget is limited, and I am getting complaints from the project manager that cores are overkill for this application. Its my decision, but just for due diligence - are there other options?
Is the only way to take cores? The budget is limited, and I am getting complaints from the project manager that cores are overkill for this application. Its my decision, but just for due diligence - are there other options?





RE: Quality of Underwater Concrete
RE: Quality of Underwater Concrete
Should I be concerned that the contractor will not tremie properly - i.e., not keeping the pipe embedded in fresh concrete or moving it around horizontally through the concrete? We will have divers inspecting the work. Will such deficiencies be obvious to them visually or via tactile inspection?
RE: Quality of Underwater Concrete
You have a 100 CY at 5' thick so that gives a plan area of around 24' x 24' (I'm more used to SI units so about 7m x 7m)Assuming I'm correct then I would place four tremies evenly spaced, it is then easy to calculate the depth of penetration of the tremie into the concrete during casting.
If it's as easy as this I think no need for cores. But if my assumptions are wrong and no formwork or more complicated casting shape then could be more difficult to ensure the quality.
RE: Quality of Underwater Concrete
If some of the formwork is removable then divers may be able feel for bad concrete after stripping. If it is murky then they will not see a thing.
Another check is to always ensure that the concrete in the tremie hopper is visible. ie. do not let the level drop completely down the tube. If kept in the hopper it means that there is always back pressure and the bottom of the tube is always inside the fresh concrete.
Stephen Argles
Land & Marine
www.landandmarine.com
RE: Quality of Underwater Concrete
RE: Quality of Underwater Concrete