Determination of rheological properties of fresh concrete and similar materials in a vibration rheometer

Abstract

A vibration rheometer has been developed for the purpose of determining the viscosity coefficient and the yield value of fresh concrete under vibration. The main parts of the apparatus, a test specimen and a vibration source form a unitary oscillatory system whose parameters can be measured with sufficient precision. Two types of fine grained reference material have been prepared and examined; one with a high coefficient of viscosity and the other with a high yield value. The rheological properties of reference materials have been determined in a capillary tube viscometer. Since there is no analytical solution to the flow in the vibration rheometer, the constants of the vibration rheometer have been determined by experiment, for each position of the apparatus piston within the measuring range. The parameters of the flow depend on the maximum acceleration of the vibration source. An increase in acceleration causes an increase in the yield value as well as a reduction in the plastic viscosity coefficient of the material specimen. A testing of fresh mortar has been carried out as well. The obtained results have been compared with the impact on reference materials, which makes the results of our research applicable to fresh vibrated concrete.

The extension of thixotropy of cement paste under vibration: a shear-vibration equivalent theory

“…On the other hand, many researches have showed that the rheological properties of concrete change under vibration [9][10][11][12]. Tattersall used a vertical tube method to study fresh concrete under vibration.…”

“…However, there is still something to modify in the calculation. First, the memory modules Γ and coagulation rate H are calculated by the total shear rate, which are shown in formula (11) and (12):…”