Only for the record, the 100 (hopefully more) years life is expected in houses/buildings, more like 50-60 years if used in reinforced concrete structures open t

Only for the record, the 100 (hopefully more) years life is expected in houses/buildings, more like 50-60 years if used in reinforced concrete structures open to the weather (like bridges and viaducts), then some maintenance/cortical rebuilding/consolidation is usually needed. This is not only due to the kind of cement, there are a number of other factors that have an influence on the (scarce) durability of modern reinforced concrete structures. Portland cement may be cheaper than pozzolanic in some markets/countries and the contrary may be true in some other ones, but you cannot anyway make a direct comparison, as they are normally used in different kinds of structures. The "let's build things that have a set expiry date" approach could be a very good one IF we actually knew how long a construction lasts (or should last) and matters would have been organized so that this continuous demolishing/rebuilding could be planned and carried on, but this is not what AFAIK happens anywhere, exception maybe for a few (BTW wooden) temples in Japan.