Method for achieving fast response time of a polycarboxylate ether polymer in a concrete mix, comprising: providing a rotatable mixer drum for containing a hydratable concrete mix; providing a system for continuous monitoring of slump of the hydratable concrete mix contained in the rotatable mixer drum and for dispensing controlled amounts of fluidizing chemical admixture into the concrete mix within the drum based on the continuous monitoring; and providing a fluidizing chemical admixture to be dispensed by the system, the admixture comprising at least one comb-type polycarboxylate ether polymer for modifying slump of the concrete mix, the polymer having a cumulative adsorptivity coefficient (A c) of 40%-75% as determined by a depletion method whereby a sample of the polymer is charged into an aqueous cement slurry containing the cement used for making the hydratable concrete mix, and mixed together and separated after 120 seconds continuous mixing of the aqueous cement slurry to obtain supernatant pore water, in accordance with the formula A c = A − B / A × 100 wherein A represents the total amount of the polymer added to the aqueous cement slurry which was then separated to obtain the supernatant pore water, B represents the amount of the polymer remaining in the supernatant pore water obtained by separation from the aqueous cement slurry, and wherein adsorptivity is measured at 25° Celsius on the supernatant pore water separated from the aqueous cement slurry after 120 seconds continuous mixing of the aqueous cementitious slurry containing the cement, water, and the polymer, wherein water/cement ratio of the slurry is 0.4 and the amount of the polymer dosed into the aqueous cementitious slurry is between 0.03%-0.5% by dry weight based on cement and polymer dosage used is calculated by mortar test whereby dosage for the polymer is that which would provide the same fluidity as adding 14% additional water into the aqueous cementitious slurry, wherein the system is programmed to monitor on a continuous basis and to adjust slump by introducing the fluidizing chemical admixture into the concrete load, and to repeat the monitoring and adjustment steps in iterative fashion during transit and/or after arrival at the delivery/pour site, wherein the method comprises dosing the fluidizing chemical admixture into the concrete mixer drum containing the hydratable concrete mix during transit and/or after arrival at the delivery/pour site, and wherein the peak molecular weight of the polycarboxylate ether polymer, as determined by GPC, is below 40,000 AMU. providing a rotatable mixer drum for containing a hydratable concrete mix; providing a system for continuous monitoring of slump of the hydratable concrete mix contained in the rotatable mixer drum and for dispensing controlled amounts of fluidizing chemical admixture into the concrete mix within the drum based on the continuous monitoring; and providing a fluidizing chemical admixture to be dispensed by the system, the admixture comprising at least one comb-type polycarboxylate ether polymer for modifying slump of the concrete mix, the polymer having a cumulative adsorptivity coefficient (A c) of 40%-75% as determined by a depletion method whereby a sample of the polymer is charged into an aqueous cement slurry containing the cement used for making the hydratable concrete mix, and mixed together and separated after 120 seconds continuous mixing of the aqueous cement slurry to obtain supernatant pore water, in accordance with the formula A c = A − B / A × 100 wherein A represents the total amount of the polymer added to the aqueous cement slurry which was then separated to obtain the supernatant pore water, B represents the amount of the polymer remaining in the supernatant pore water obtained by separation from the aqueous cement slurry, and wherein adsorptivity is measured at 25° Celsius on the supernatant pore water separated from the aqueous cement slurry after 120 seconds continuous mixing of the aqueous cementitious slurry containing the cement, water, and the polymer, wherein water/cement ratio of the slurry is 0.4 and the amount of the polymer dosed into the aqueous cementitious slurry is between 0.03%-0.5% by dry weight based on cement and polymer dosage used is calculated by mortar test whereby dosage for the polymer is that which would provide the same fluidity as adding 14% additional water into the aqueous cementitious slurry, wherein the system is programmed to monitor on a continuous basis and to adjust slump by introducing the fluidizing chemical admixture into the concrete load, and to repeat the monitoring and adjustment steps in iterative fashion during transit and/or after arrival at the delivery/pour site, wherein the method comprises dosing the fluidizing chemical admixture into the concrete mixer drum containing the hydratable concrete mix during transit and/or after arrival at the delivery/pour site, and wherein the peak molecular weight of the polycarboxylate ether polymer, as determined by GPC, is below 40,000 AMU.