Method for producing a master mixture based on carbonaceous nanofillers and superplasticiser, and the use thereof in hardenable inorganic systems

A process for the preparation of a master batch comprising at least one superplasticizer and from 0.1% to 25% by weight of carbon-based nanofillers, expressed with respect to the total weight of the master batch, comprising:

• (i) the introduction into a kneader and then the kneading of carbon-based nanofillers and of at least one superplasticizer, optionally in the presence of a water-soluble dispersing agent, in order to form a homogeneous mixture in a solid form;
• (ii) the extrusion of said mixture in the solid form in order to obtain a master batch in the solid form;
• (iii) optionally the dispersion of said master batch in the solid form in a superplasticizer identical to or different from that of stage (i), or in a water-soluble dispersant, in order to obtain a master batch in the form of a pasty composition having a Brookfield viscosity ranging from 100 to 25,000 mPas;
• (iv) optionally the introduction of the master batch in the form of a pasty composition obtained in stage (iii), into a superplasticizer which is identical to or different from that of stage (i) or that of stage (iii), in order to obtain a master batch comprising from 0.1% to 2% by weight of carbon-based nanofillers
• wherein the carbon-based nanofillers are fillers comprising at least one component from the group comprising carbon nanotubes, carbon nanofibers, and graphenes.