In-mixer measurements for describing mixture evolution during concrete mixing

A model of the microstructural state evolution in concrete components vs. mixing time is proposed herein. The transient mixture states are associated with different power dissipation levels (frictional, cohesive or viscous) and apparent density characteristics. It will be shown that the three sensors are also able to indicate the evolution of mixture state during mixing, thus facilitating comprehension of sensor signal variations during the mixing cycle. In addition, a method is devised to improve sensor measurement of the water-to-powder ratio by up to three times. More specifically, the precision of the measured water-to-powder mass ratio is 0.0035, 0.0042 and 0.0051 using the Viscoprobe™, Orbiter and mixing power techniques, respectively. The typical water-to-powder mass ratio values for concrete range between 0.4 and 0.6.