A method for assessing aggregate moisture probe accuracy in concrete manufacture, comprising: comparing currently monitored slump values ( S m) obtained during delivery from a concrete batch plant to a construction delivery site pour event of a slurried concrete mixture that is uniformly mixed in a concrete delivery truck mixer drum and prepared from aggregates dispensed from a hopper or conveyor belt, with slump values predicted for the slurried concrete mixture ( S e), based on the aggregate moisture levels as detected by a probe in the hopper or conveyor belt from which the aggregates were dispensed to make the slurried concrete mixture in the concrete delivery truck mixer drum; and initiating at least one or more of the following actions, when the difference between the slump values predicted for the mixed slurried concrete mixture and the currently monitored slump values obtained during delivery of the uniformly mixed slurried concrete mixture meets or exceeds a predetermined threshold value: (i) sending a signal or alarm, to the concrete batch plant at which the aggregates were dispensed from the hopper or conveyor belt, indicating that the predetermined threshold value was met or exceeded; (ii) sending a signal or alarm, to a construction delivery site pour event at which a concrete mixture prepared from the aggregates dispensed from the hopper or conveyor belt is scheduled to be delivered, indicating that the predetermined threshold value was met or exceeded; (iii) sending a signal or alarm, to a computer processor unit that is monitoring the slump of a concrete mixture prepared from the aggregates dispensed from the hopper or conveyor belt, indicating that the predetermined threshold value was met or exceeded; or (iv) performing a combination of any of the actions (i) through (iii). comparing currently monitored slump values ( S m) obtained during delivery from a concrete batch plant to a construction delivery site pour event of a slurried concrete mixture that is uniformly mixed in a concrete delivery truck mixer drum and prepared from aggregates dispensed from a hopper or conveyor belt, with slump values predicted for the slurried concrete mixture ( S e), based on the aggregate moisture levels as detected by a probe in the hopper or conveyor belt from which the aggregates were dispensed to make the slurried concrete mixture in the concrete delivery truck mixer drum; and initiating at least one or more of the following actions, when the difference between the slump values predicted for the mixed slurried concrete mixture and the currently monitored slump values obtained during delivery of the uniformly mixed slurried concrete mixture meets or exceeds a predetermined threshold value: (i) sending a signal or alarm, to the concrete batch plant at which the aggregates were dispensed from the hopper or conveyor belt, indicating that the predetermined threshold value was met or exceeded; (ii) sending a signal or alarm, to a construction delivery site pour event at which a concrete mixture prepared from the aggregates dispensed from the hopper or conveyor belt is scheduled to be delivered, indicating that the predetermined threshold value was met or exceeded; (iii) sending a signal or alarm, to a computer processor unit that is monitoring the slump of a concrete mixture prepared from the aggregates dispensed from the hopper or conveyor belt, indicating that the predetermined threshold value was met or exceeded; or (iv) performing a combination of any of the actions (i) through (iii). (i) sending a signal or alarm, to the concrete batch plant at which the aggregates were dispensed from the hopper or conveyor belt, indicating that the predetermined threshold value was met or exceeded; (ii) sending a signal or alarm, to a construction delivery site pour event at which a concrete mixture prepared from the aggregates dispensed from the hopper or conveyor belt is scheduled to be delivered, indicating that the predetermined threshold value was met or exceeded; (iii) sending a signal or alarm, to a computer processor unit that is monitoring the slump of a concrete mixture prepared from the aggregates dispensed from the hopper or conveyor belt, indicating that the predetermined threshold value was met or exceeded; or (iv) performing a combination of any of the actions (i) through (iii).