A method for concrete monitoring calibration using a processor-controlled system and a delivery mixer truck mixer drum, comprising: monitoring concrete provided in the mixer drum by measuring, while the concrete is in a state of equilibrium, the energy ("E1") associated with rotating the concrete at a first constant speed ("V1") and energy ("E2") associated with rotating the concrete at a second constant speed ("V2") after a speed jump of plus or minus at least 2.5 RPM; calculating a slump value ("S") for the provided concrete based on E1, V1, E2, and V2, characterized by comparing E1, V1, E2, V2, and S as calculated from step with at least two data curves stored in processor-accessible memory, the stored data curves defining an E/V/S relationship for purposes of calculating slump across drum speed ranges of 0.5 RPM - 6 RPM and 6 RPM - 20 RPM, the at least two stored data curves comprising data obtained from previous deliveries of concrete when the previous concrete was in a state of equilibrium and comprising energy values measured before and after at least 2.5 RPM jumps in constant drum speed and slump values as calculated from the previously stored E and V data, whereby the process-controlled system determines whether any of the at least two stored data curves match the E1, V1, E2, V2, and S values of the provided concrete; and monitoring the slump of the provided concrete in the mixer drum by calculating slump through measurement of the energy associated with rotating the concrete (i) within 0.5 RPM - 6 RPM and within 6 RPM - 20 RPM drum speed ranges, based on one of the at least two stored data curves which is determined to constitute a match in step, and providing a visual indication that slump is being calculated by the system for drum speeds higher than 6 RPM; or (ii) within the 0.5 RPM - 6 RPM range only, if none of the stored curve data is determined to constitute a match in Step, and initiating an alert to a system operator or the truck driver, or dispatch center, that the system is active only for monitoring at drum speeds below 6 RPM. monitoring concrete provided in the mixer drum by measuring, while the concrete is in a state of equilibrium, the energy ("E1") associated with rotating the concrete at a first constant speed ("V1") and energy ("E2") associated with rotating the concrete at a second constant speed ("V2") after a speed jump of plus or minus at least 2.5 RPM; calculating a slump value ("S") for the provided concrete based on E1, V1, E2, and V2, characterized by comparing E1, V1, E2, V2, and S as calculated from step with at least two data curves stored in processor-accessible memory, the stored data curves defining an E/V/S relationship for purposes of calculating slump across drum speed ranges of 0.5 RPM - 6 RPM and 6 RPM - 20 RPM, the at least two stored data curves comprising data obtained from previous deliveries of concrete when the previous concrete was in a state of equilibrium and comprising energy values measured before and after at least 2.5 RPM jumps in constant drum speed and slump values as calculated from the previously stored E and V data, whereby the process-controlled system determines whether any of the at least two stored data curves match the E1, V1, E2, V2, and S values of the provided concrete; and monitoring the slump of the provided concrete in the mixer drum by calculating slump through measurement of the energy associated with rotating the concrete (i) within 0.5 RPM - 6 RPM and within 6 RPM - 20 RPM drum speed ranges, based on one of the at least two stored data curves which is determined to constitute a match in step, and providing a visual indication that slump is being calculated by the system for drum speeds higher than 6 RPM; or (ii) within the 0.5 RPM - 6 RPM range only, if none of the stored curve data is determined to constitute a match in Step, and initiating an alert to a system operator or the truck driver, or dispatch center, that the system is active only for monitoring at drum speeds below 6 RPM. (i) within 0.5 RPM - 6 RPM and within 6 RPM - 20 RPM drum speed ranges, based on one of the at least two stored data curves which is determined to constitute a match in step, and providing a visual indication that slump is being calculated by the system for drum speeds higher than 6 RPM; or (ii) within the 0.5 RPM - 6 RPM range only, if none of the stored curve data is determined to constitute a match in Step, and initiating an alert to a system operator or the truck driver, or dispatch center, that the system is active only for monitoring at drum speeds below 6 RPM.