How much does reinforced concrete weigh per cubic yard?

Normal weight concrete -- a mixture or sand, cement, and stone gravel -- has an accepted density of 145 pounds per cubic foot. Since there are 27 cubic feet per cubic yard, a cu.yd. weighs 3915 pounds, or almost two tons. Complicating your question is the Word "reinforced." Reinforced concrete has steel bars in it, called rebar. Steel has a density of about 490 pounds per cubic foot, which is more than three times the density of concrete, so the generally accepted density of normally reinforced concrete is 150 pounds per cubic foot which results in a cubic yard weighing 4050 pounds, but this depends on the quantity and grade of the rebar used. (Ref. AISC Steel Construction Manual, 13th Ed. Page 17-24. Also older editions have this same information.) There is light weight concrete made with lighter weight substitutes such as vermiculite for the stone and sand. These can have weights from 85 pcf. Also, there are heavy weight concretes made with steel punchings or pieces of lead used to line rooms for x-ray machines or other radioactive sources. There is a Wikipedia article on rebar, if you're interested in looking it up.