On Sat, 08 Aug 2015 02:10:37 -0400, micky
wrote:

In 1970 when I was at the Panama Canal, which was built before 1910,
they told me the locks were still curing and still getting harder, but
they was already hard enough that when ships hit it, the ship got
dented. They were kept wet up to the water level.

Seems I recall it would have taken ~700 years for the (Boulder) Hoover
Dam to cure. They used pipes to circulate water through that reduced
the curing time.