The use of truck mixers to make concrete for pavement construction has long been a subject of debate among contractors and the people responsible for the quality of pavements. The basic objections to truck mixers are can the quality of the concrete be controlled satisfactory. It is true that the type of concrete suitable for paving construction is more difficult to control than the type required for structures the difference being for less water being used in pavement construction. One of the basic problems here is the difficulty of controlling water additions at the job site. This has come about because of human laziness rather than mechanical deficiencies in equipment because so often the foreman calls for more water that to push the concrete to the remote corners. It may be desirable to add the mixing water to the drum at the plant only and not even allow wash water to be carried by the mixer.