"You show me a man with both feet on the ground and I'll show you a man who can't get his pants on." -anonymous
The rolling stock list, except for water, is somewhat era and circumstance dependent. (The water would arrive by pipe, from the nearest stream or well.)
Looking at the photos of concrete and aggregate plant operations during the construction of the Hoover Dam, raw (unsized) aggregate was loaded into side-dump gondolas for movement to the washing/separating plant, while sized aggregate (sand and three sizes of gravel) was loaded into either drop-bottom gons or standard 2-bay hoppers. Bulk cement was delivered in box cars (!) and unloaded using the equivalent of a really big vacuum cleaner. Note that all of this (except the box cars) was confined to the rather extensive rail network operated by the Six Companies.
For a modern concrete mixing plant that won't be providing product in megaton lots, I would expect to see cement and sand arrive in covered hoppers with tight-seal unloading hatches, while the larger sizes of gravel would probably be handled in standard hopper cars. Expect to see mostly home road cars - aggregates aren't shipped any farther than necessary.
Chuck (modeling Central Japan in September, 1964)