Austin River Sand Gravel Safety Data Sheet Austin River Sand Gravel (Concrete Aggregates, Blend, Concrete Sand, Fill Sand, Masonry Sand) MANUFACTURERS NAME ADDRESS Capitol Aggregates Inc. 2330 North Loop 1604 West. San Antonio, Texas 78248 PRODUCT NAME Austin River Sand Gravel EMERGENCY TELEPHONE NUMBER (210) 871-6111 River Gravel Concrete Sand Build. Sand and Gravel in Concrete Shelly Company. 2014-1-30 If you want to get a little more technical, some concrete experts recommend going for 26 percent sand, 41 percent gravel, 11 percent cement and 16 percent water. The lacking 6 percent volume is air entrainment.