Additive system for a concrete mixer truck

An additive admixture system for a mixer drum, comprising:

• an air inlet valve fluidly coupled with an intermediate tubular member and configured to receive compressed air from a compressed air system;
• a fluid valve;
• an air valve;
• a pump fluidly coupled with an additive tank through the intermediate tubular member, the pump fluidly coupled with the intermediate tubular member at a location downstream of a fluid coupling point of the air inlet valve, wherein an outlet of the air valve is fluidly coupled with the intermediate tubular member at a position upstream of an inlet of the pump;
• and
• a controller configured to operate the air inlet valve, the fluid valve, the air valve, and the pump of the additive admixture system to transition the additive admixture system between an additive addition mode, a drain mode, and a system clear mode, wherein the controller is configured to:
• transition the additive admixture system into the additive addition mode and operate the pump until a desired amount of an additive is added to the mixer drum;
• transition the additive admixture system into the drain mode for a first predetermined amount of time in response to the desired amount of additive being added to the mixer drum;
• and
• transition the additive admixture system into the system clear mode for a second predetermined amount of time to clear stagnant fluid or built up mixture from the additive admixture system.

A concrete mixer vehicle comprising:

• a mixer drum comprising an inner volume configured to hold a mixture for transportation and placement;
• an additive admixture system comprising a fluid valve, an air valve, an air inlet valve configured to vent to atmospheric pressure when opened, and a pump configured to receive admixture through an inlet from the fluid valve, the air valve configured to fluidly couple with an air pressurization system and to fluidly couple with the pump at a position upstream of the inlet of the pump to provide pressurized air upstream of the pump;
• and
• a controller configured to operate the fluid valve, the air valve, the air inlet valve, and the pump of the additive admixture system to transition the additive admixture system between an additive addition mode, a drain mode, and a system clear mode, wherein the controller is configured to:
• transition the additive admixture system into the additive addition mode and operate the pump to add an additive to the mixer drum;
• transition the additive admixture system into the drain mode in response to the additive being added to the mixer drum;
• and
• transition the additive admixture system into the system clear mode to clear stagnant fluid from the additive admixture system.