Air entrainment, as it is called, is only one component of concrete workability and longevity but primarily in areas subject to freezing and thawing.My friend in Colorado is an engineer who was in charge of building roads and bridges in Boulder county, CO.
I asked him why they would demolish the concrete pilings. He said it was probably because they did not properly sample the concrete as it was being poured for proper air content. The result would be substandard concrete that would have to be taken down and done again. Without being there , that was his best guess.
I think what happened is Corraplata had to come in and do some new water main work thereSeveral months ago, they also screwed up pouring the curbs in Sosua from the traffic light to Pappaterra and had to take them out. They're just finally getting around to repouring them now. Hopefully, they'll get them right this time. That section of the road in Sosua looks like a real shyt hole.
Tons of mix designs. Yes they screw up concrete here to make it easier to use, shameful.I was associated with the concrete industry for many years, now retired. There are hundreds of different mix designs according to the project. Here it seems they just add water to make it easier to shovel or pour. Its the Resident Engineers responsibility ... take cubes and test for 28day strength ? However did Brunel build anything hundreds of years ago ? !!!
I'm betting on "double T" beams for the span, as they are used in industrial buildings and the overpasses in the cities.That's the pile cap. Each side will have an abutment poured over drilled piles and the beams will span between, and maybe there could be some columns in the river ?