For what it's worth, the concrete used in these type of official building tend to look decent even as it ages. I've seen none of the buildings in the article a

For what it's worth, the concrete used in these type of official building tend to look decent even as it ages. I've seen none of the buildings in the article as they're mostly out of Tokyo, but for instance the national art center in Roppongi is raw concrete and it still looks very nice https://www.nact.jp https://www.nact.jp