Automated Control of the Fresh State of Industrial Concrete Behaviour by Rheometer Test Adjustment

Abstract

This study aimed to develop a rheometer prototype and define a procedure for adjusting the automated control of the fresh state of concrete. Sixteen batches were produced, and their fresh behaviour was measured at different testing times by applying the Abrams cone and flow curve test (FCT) as the rheological protocol. During this test, the yield stress and plastic viscosity of the concretes were measured in relative units. The rheometer prototype was used to define a new protocol to select the most suitable rheometer impeller arrangement and optimal FCT configuration. This protocol considers the torque at the end of the breakdown period, torque reduction during the breakdown period, segregation, and negative values of the yield stress in relative units. This protocol also enabled an iterative adjustment procedure, facilitating the use of a rheometer for the automated control of the homogeneity and behaviour of fresh concrete, as well as real-time decision making.

Keywords

• fresh behaviour
• flow chart
• yield stress
• plastic viscosity
• concrete characterisation