As far as my knowledge is concerned, PCC is used for 2 purposes 1. It is used as a protective layer for the RCC above so that water from the RCC is not absorbed by the earth below.2. Provides a base...
Concrete actually contains cement as well as sand and gravel. We say "cement concrete" because cement is an ingredient in concrete. And because the cement is what binds together the sand and gravel...
Limestone, shale, iron ore and sand. Grind it all together super fine and heat to about 2700 degrees F. and then grind the resulting "clinker" together with gypsum. That is basic Portland...