Relating Fresh Concrete Viscosity Measurements from Different Rheometers

Area of Science:

• Materials Science
• Civil Engineering
• Rheology

Background:

• Accurate measurement of concrete rheological properties is crucial for workability, especially for self-consolidating concrete (SCC).
• Previous round-robin tests revealed significant discrepancies in viscosity measurements between different rheometer designs.
• Existing empirical correlations are insufficient for a scientifically sound approach to concrete rheometry.

Purpose of the Study:

• To develop a standardized method for comparing concrete rheometer data across different instrument designs.
• To establish a more scientifically rigorous basis for concrete workability assessment.
• To enable direct calibration of rheometer measurements against known viscosity standards.

Main Methods:

• A novel data interpretation was developed to address inconsistencies in concrete rheology measurements.
• The study focused on comparing various rheometer designs using a new quantitative approach.
• Relative plastic viscosity was proposed as a key metric for inter-instrument comparison.

Main Results:

• All tested rheometer instruments can be directly and quantitatively compared using relative plastic viscosity.
• This new approach moves beyond comparing individual plastic viscosity values.
• The findings provide a pathway to overcome the limitations of empirical correlations.

Conclusions:

• The proposed method using relative plastic viscosity allows for direct, quantitative comparison of different rheometers.
• This advancement is expected to place concrete rheometry and workability assessment on a more robust materials science foundation.
• Standardized measurements will improve the reliability and scientific basis of concrete rheology.