Concrete mixing trucks may be used for mixing or agitation. Typically, a concrete mixing truck will have two capacity ratings, as a mixer and as an agitator. The agitator rating is usually significantly larger. For example, a mixer truck may be rated for 6 cu. yd. as a mixer and for 8 cu. yd. as an agitator. This means that if the concrete is centrally mixed and then loaded into the mixer truck, a larger load can be transported to the project. Otherwise, the smaller mixer rated capacity must be used.

True agitator trucks are sometimes used on TxDOT projects. Agitator trucks can be used to deliver agitated concrete to the project, but never to mix concrete. Typically, these trucks will resemble a mixer truck, except that the mixer drum is open on the top. Instead of a drum turning, a series of paddles will rotate within the agitator drum. These paddles can be seen as they rotate above the mix. Use of agitator trucks is more common when higher slump concretes are used that may be more susceptible to segregation during delivery.