Expanding nozzle for component additions in a concrete truck, and method and system for use of same

A system for injecting water and chemical admixture fluid into a rotatable concrete mixer drum, the system comprising:

• a mixer drum that is rotatably mounted to permit rotation about a rotation axis inclined at an orientation of 5 to 40 degrees relative to level ground, the mixer drum having an inner circumferential wall connecting opposed first and second ends for defining a cavity within which to contain a fluid concrete, one of the two opposed ends having an opening to permit loading and unloading of fluid concrete from the mixer drum cavity, the system comprising a source of a chemical admixture and a source of water, the system further comprising a nozzle including a support member and a nozzle boot surround at least a portion of the support member, the nozzle boot having a nozzle boot inlet and a nozzle boot outlet spaced from the nozzle boot inlet and a volume between the nozzle boot inlet and the nozzle boot outlet, the nozzle boot inlet being in fluid communication with the source of water under pressure and being expandable upon the introduction of water under pressure into the volume, and collapsible upon withdrawal of water under pressure from the volume, and the support member effective for introducing chemical admixture into the concrete mixer drum.