Post-batching CMA dosing into concrete

A method for dosing concrete, comprising:

• monitoring the slump, on an automated basis using a processor unit, of a concrete slurry while in a rotatable mixer drum during transit from a mix plant to a construction site to which the concrete slurry is being delivered, the concrete slurry comprising a cement binder, water, aggregate, and clay which, in the absence of a clay mitigation agent, absorbs chemical admixture, and which clay is present in the concrete slurry in an amount sufficient to diminish the dosage efficiency of a cement dispersant or other chemical admixture added into the concrete slurry;
• wherein the processor unit
• (i) measures loss of slump (dS) of the concrete slurry in the rotatable mixer drum over a period of time (t) during transit to obtain a measured dS/dt value,
• (ii) compares the measured dS/dt value with a threshold dS/dt value stored in a memory location which is accessed by the processor unit, and
• (iii) detects when the measured dS/dt value meets or exceeds the stored threshold dS/dt value;
• and
• whereupon the processor unit, once the measured dS/dt value meets or exceeds the stored dS/dt threshold value, initiates administration of a controlled dosage of clay mitigation agent (CMA) into the concrete within the rotatable mixer drum during transit, the CMA administered being effective to decrease the dS/dt value as measured by the processor unit.