One thing about concrete is that it is a very forgiving construction material where people who don't know what they are doing are able to achieve somewhat satisfactory results subject to the test of time. When there is a problem later on it is always the fault of the concrete.Clues to it anyway.
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If we adhered to correct portions and stayed away from adding water for ease of placement or at least embrace the concept of wet curing we would have much longer lasting concrete again subject to deicing chemicals and loader buckets. Another issue is we use too much cement per cubic meter for the most part again to protect against uncontrollable variables and many of the molecules take years to hydrate if ever.
I'm probably one of the few people interested in the potential of concrete and would love to show the Romans how we do it now but politicians and bureaucrats keep getting in the way. We were hopeful of 750 years of good service for the hydro dams I was part of.
Good concrete placers are hard to find and part of the reason sub standard work can take place. 7 days damp curing can help immensely.