Abstract:
A method for controlling at least one workability parameter of a concrete contained in the container of a mixer with a non vertical rotational axis, includes making the container turn at least at least two different rotational speeds; determining, for each of the rotational speeds, a rotary drive torque C of the container, a value of shear stress r of the concrete and a speed gradient γ of the concrete according to the following relationships: τ=T(ω)·C and γ=G(ω). ω where T and G are predetermined functions; determining a relationship of variation of shear stress τ according to the speed gradient γ by extrapolation and/or approximation from the determined values; and providing an indication of the workability parameter of the concrete based on the relationship variation.
Abstract:
A hydraulic binder includes, as percentage by mass: from 17 to 55% of a Portland cement, the particles of which have a D50 of from 2 μm to 11 μm; at least 5% of silica fume; from 36 to 70% of a mineral addition A1, the particles of which have a D50 of from 15 to 150 μm; the sum of these percentages being from 80 to 100%; the sum of the percentages of cement and of silica fume being greater than 28%; the mineral addition A1 being selected from slags, pozzolanic additions or siliceous additions such as quartz, silico-calcareous mineral additions, calcareous additions such as calcium carbonate or mixtures thereof.