Cooper Concrete calculates that an unloaded concrete mixing truck with a capacity of 10 cubic yards weighs approximately 26,000 pounds. A loaded truck of the same size can weigh as much as 66,000 pounds.
Wikipedia states that the patent for the first concrete mixing truck was filed in 1916 by Stephen Stepanian. The initial application was rejected because Stepanian's truck design could not safely support the concrete, which Cooper Concrete reports as weighing between 3,000 and 4,000 pounds per cubic yard, depending on its composition. Undeterred, Stepanian applied for his patent again and received final approval for the design in 1933.