How is your concrete lasting

[Filliam H. Muffman]

JoeH wrote:
[quote=Buck]
The Colosseum is still standing. Well, most of it, and it's made from concrete

Yes, but a totally different formulation than used today for concrete.
100+ years can be done if the builder is willing to put in enough effort and money to source reliable materials. There was business building in my mom's home town that had been built by a guy after he went to Italy where he spent three years tracking down legendary concrete mixes. 65 years later, two different demolition companies bid, started work, and then walked away from their contracts trying to take it down. A few years later, another company used explosives and eventually got the site clear.