As others have identified, very likely to be carbonation, particularly given the age of the building. The problem is only going to get worse over time as more reinforcement will get affected as the carbonated zone deepens.
Be careful about incipient anode effect with localised concrete patch...
I would further investigate the differences between your 14 day cubes vs. 28 day cubes, be it handling, curing, the exact test procedures or whatever. I have several times found differences in how cubes are prepared and tested affecting results. Testing cubes dry or soaked is a significant...
If your 28 day strengths are lower than your 14 day strengths for the same batch of grout, that suggests significant issues with sampling, curing and testing. Do any of these aspects raise red flags to you after talking with and/or watching the sampler and testing lab?
You tend to need a little more cement paste to cover the angular aggregate's increased surface area but otherwise no major problems, provided the angular aggregate is fairly regular in shape, rather than flaky. I don't know the situation in your region but crushed aggregate shape could be an issue.
The table says XAS, Exposed to sea water, Concrete surfaces in contact with sea water.
Table A.13 Limiting values of composition for unreinforced concrete in contact with sea water (exposure class XAS) might apply.
In that environment, I would choose J2 unless you have a reasonable justification to pick a less onerous steel grade (e.g. steelwork within a permanently heated building). What will you do if the heating goes off for a significant length of time?
Generally to check for fill settlement or fill loss. The concrete capping is typically considered to be supported on the fill.
On rare occasions, there might be an earthing point under a pit lid but earthing is commonly directly to the sheet piles.
In my part of the world, a duct bank is multiple ducts in the same duct run as noted by Heaviside1925 but not necessarily concrete encased. Concrete encasement (and reinforcement if concrete encased) is optional, depending on applied loading, duct strength and duct bank cover. We tend to require...
Most of those barriers/ poles look to be cast in situ while the OP refers to mounting poles to precast barriers. The difference is likely to have some effect on the design.
Don't you just need to write a project-specific material specification for this material? Micropile casing shall have minimum 80 ksi yield and weldability shall conform to etc. etc.
I very rarely use American standards, so I may be talking out of my <choose your own>
When I think of soldier piles, I usually think of small retaining walls with steel H-sections and timber planks. In my world, using tubular piles mostly defaults to king pile walls with sheet piling retaining soil between the tubular piles, generally with much larger dimensions (e.g. ports and...
The foundation's similar diameter and depth complicates selecting a non-destructive test method. Some test methods merely indicate the distance to the nearest surface, some to the furthest. Those methods measuring to the furthest surface tend to filter out 'premature responses' from nearer surfaces.
Two dead after a walkway collapse of an aging Italian housing estate.
https://www.theguardian.com/world/article/2024/jul/23/walkway-collapse-naples-le-vele-di-scampia
That design isn't just unusual, it seems to be poorly detailed relative to the design concept.
Those deck construction joints seem to be letting a lot of water through. Given those construction joints are directly above beam expansion joints, I would expect the construction joints to also try...
It is likely one of the earlier responses has nailed the actual cause but, for my own amusement, here are some alternative guesses.
Generally sulphate attack takes much longer, so unlikely.
Does the granular base contain cobbles within the well-graded aggregates. They can cause hard spots if...
