[File:UserKTrimble-AP Taum Sauk Reservoir UnderConstruction Nov 22 2009 crop1.jpg|thumb|right|The rebuilt upper reservoir of the Taum Sauk plant, nearing completion in this photo, is the largest RCC dam in North America.]] Roller-compacted concrete (RCC) or rolled concrete is a special blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for Portland cement. RCC is a mix of cement/fly ash, water, sand, aggregate and common additives, but contains much less water. The produced mix is drier and essentially has no slump. RCC is placed in a manner similar to paving; the material is delivered by dump trucks or conveyors, spread by small bulldozers or specially modified asphalt pavers, and then compacted by vibratory rollers.