PROCESS OF PREPARING CONCRETE IN A MECHANICAL CONCRETE AND SYSTEM TO CONTROL THE CONCRETE PREPARATION IN A MECHANICAL CONCRETE

摘要

Concrete is mixed in a mechanical mixer which is preferably a rotating mixer drum carried on a truck, in accordance with a predetermined formulation requiring a theoretical quantity of water to achieve a predetermined workability by adding to the mixer with the solid constituents a pretedermined fraction of the theoretical quantity of water. The workability of the mix is then measured and compared with the predetermined workability to derive a measure of the additional water required to bring the workability up to the predetermined workability. There is then added to the mix a further quantity of water which does not exceed the derived measure of additional water and which preferably corresponds to the lesser of the derived measure of additional water and the balance of the theoretical value. A monitoring unit associated with the mixer monitors the workability of the mix and the speed of operation of the mixer and identifies these values through a communications link to a control apparatus which controls the loading of the solid constituents and the delivery of water to the mixer and which incorporates a memory which stores data identifying the theoretical amount of water for a given formulation and data identifying the additional amount of water required to increase the workability from one value to another, means for inhibiting loading of the solid constituents to the mixer until the speed of operation of the mixer has attained a pre-set value, means for delivering the predetermined fraction of water to the mixer, means for identifying from the measured workability of the mix and the predetermined value of workability the additional amount of water and for delivering such additional amount of water to the mix.