Production of high-performance concretes to specification

Rheology-based mixing process management

1 → Schematic overview of the approach to a rheology-based mixing process management, including development of the mix design, mixing process and fine tuning to produce high-performance concretes exactly to specification

2 → Determination of the yield value by analyzing the velocity of the rotary encoder [mrad/s] depending on the linearly increasing torque of the inner drive (PMSM). The yield value is defined as the point of intersection of the two straight lines above which irreversible deformation takes place (viscoelastic or viscous flow)

Rationale

High-performance concretes (HPCs) are becoming increasingly attractive in construction practice due to their very dense matrix that results in outstanding durability and strength parameters. HPCs contain a very high amount of fines; they are produced with only a small water ratio. For this reason, the production of the fresh concrete requires a high amount of mixing energy associated with significantly longer mixing times. Higher mixing tool speeds enable an increase in the amount of mixing energy introduced but result in greater tool wear. HPC mixes are also very sensitive to minor...