More or less... There are Roman-era writings describing their most common method of making concrete. What made me flabbergasted is that only NOW someone say th

More or less... There are Roman-era writings describing their most common method of making concrete. What made me flabbergasted is that only NOW someone say this is news... Seriously, if the thing was written down already 2000 years ago, why noone bothered to test? Or they did, but other reasons made corporations not use it? My dad is a engineer, and he told me that some old bridges here in Brazil made with such concrete are REALLY HARD to explode for some reason... I don't know if that is the case with the bridge that Luisa Erundina tried to explode in São Paulo, but here we have a bridge that there was 4 attempts to explode by a specialized demolitions engineering company, and it barely got dented. EDIT: of course, most common for important buildings... Poor people won't use that sort of concrete, one of the ingredients is volcanic ash, and you cannot find volcanic ash everywhere, it was probably more or less expensive.