A concrete mixing control apparatus comprising: a concrete mixer with an interior surface; at least one sensor at said interior surface to monitor one of pressure and stress; a liquid supply tube attached to and in fluid communication with said concrete mixer, a valve controlling the flow of liquid through said liquid supply tube; a liquid flow meter in said liquid supply tube between said valve and said concrete mixer; a computer processing unit operably connected to said at least one sensor within said concrete mixer and said liquid flow meter, so as to control a slump of concrete mixture within said concrete mixer; and a data storage unit operably connected to said computer processing unit; wherein said computer processing unit analyzes data from said at least one sensor and said liquid flow meter, records a first interval of time that said at least one sensor is loaded as said concrete mixer rotates and said at least one sensor is submerged within the concrete mixture, records a second interval of time that said at least one sensor unloaded as said concrete mixer rotates and said at least one sensor emerges from the concrete mixture, calculates the volume of the concrete mixture within said concrete mixer by analyzing said first and second intervals, characterized in that the computer processing unit compares sensor output over several rotations of the concrete mixer until said sensor output of force on said sensor is generally consistent within a narrow predetermined range, receives data in a data storage unit of one of pressure and stress from the at least one sensor attached to said interior surface of said mixer, inputs at least the desired slump with an input device operably connected to the computer processing unit further operably connected to said data storage unit, determines the amount of liquid needed for the desired slump, and controls the addition of liquid to said mixer through a fluid supply line in fluid communication with said mixer wherein said fluid supply line has a valve operably connected to said computer processing unit and said flow meter operably connected to said data storage unit. a concrete mixer with an interior surface; at least one sensor at said interior surface to monitor one of pressure and stress; a liquid supply tube attached to and in fluid communication with said concrete mixer, a valve controlling the flow of liquid through said liquid supply tube; a liquid flow meter in said liquid supply tube between said valve and said concrete mixer; a computer processing unit operably connected to said at least one sensor within said concrete mixer and said liquid flow meter, so as to control a slump of concrete mixture within said concrete mixer; and a data storage unit operably connected to said computer processing unit; wherein said computer processing unit analyzes data from said at least one sensor and said liquid flow meter, records a first interval of time that said at least one sensor is loaded as said concrete mixer rotates and said at least one sensor is submerged within the concrete mixture, records a second interval of time that said at least one sensor unloaded as said concrete mixer rotates and said at least one sensor emerges from the concrete mixture, calculates the volume of the concrete mixture within said concrete mixer by analyzing said first and second intervals, characterized in that the computer processing unit compares sensor output over several rotations of the concrete mixer until said sensor output of force on said sensor is generally consistent within a narrow predetermined range, receives data in a data storage unit of one of pressure and stress from the at least one sensor attached to said interior surface of said mixer, inputs at least the desired slump with an input device operably connected to the computer processing unit further operably connected to said data storage unit, determines the amount of liquid needed for the desired slump, and controls the addition of liquid to said mixer through a fluid supply line in fluid communication with said mixer wherein said fluid supply line has a valve operably connected to said computer processing unit and said flow meter operably connected to said data storage unit.