I doubt that it was used under the turf fields because the gradation allows for too much material that is greater that 1/2" in size. It does not make as uniform of a surface as opposed to a grade that has more fines. I specified a grade of limestone called 0 to 1/4 for Teurlings and Clark Field and it worked fine. It made a good uniform surface that could be graded to fairly tight tolerances.
The 0 to 1/4 stone worked very well under the track that we put at Teurlings because a track needs to be graded to really fine lines. The Teurlings track can be certified for NCAA caliber events. It is a very nice track.