System and method of the invention involves use of a sensor-containing body which is mounted and/or rotatably disposed along the longitudinal rotational axis of a concrete mixer drum at the close end, the sensor-containing body being connected to a conduit for introducing water, chemical admixture, gas, and/or cleansing fluid through the closed end of the drum into the mixer drum. Numerous heretofore unrealized combinations of advantages and benefits are provided within the concrete industry by the invention.