Study On The Reheological Properties Of Cement Slurry In The U-type Glass Tube

At present, there are various experiments studying on the rheological properties of neat cement paste, mortar and fresh concrete, which, to some extent, can all evaluate the rheological property of cement slurry. However, along with the emergence of new building materials and admixtures, there are limitations by using the traditional experimental methods to study what influence these materials might exert on the rheological property and workability of cement pastes. For instance, as for the mortar with the same consistency or fluidity, their rheological parameter may still be different. Therefore, the workability may be different as they perform. As a consequence, much work has been carried out to research and resolve these problems.In this paper, the U-type rheometer is remoulded. By applying the developed vision measurement system to the testing process, the effects that human factors may bring to the testing result have been reduced. Furthermore, methods about how the slurry characterizes the rheological parameters in the U-type glass tube have been presented in this paper.This paper has the following main tasks:1. Research and develop the vision measurement system of U-type glass tube, a system which can measure the curves on height changing along with time of the object, drawing the collected height value of every moment on the coordinate system. The whole measurement process is a kind of visual dynamic display, with the measurement result being precise, reliable and able to be saved in the form of text, which makes it convenient to perform data analysis in the later stage.2. In order to apply this developed vision measurement system of U-type glass tube into experiment and make the curve on height changing along with time of the liquid level of the cement slurry in the U-type tube manifest itself in real time, the manufacture materials of U-type rheometer have been exchanged for common glass with a even better light-admitting quality in this paper. At the same time, the box height of the U-type rheometer has been increased, which amounts to increasing the altitude difference of both ends of the liquid level when the cement slurry begins to flow. This practice has enhanced the external force which promotes the flow of cement slurry, making the cement slurry with a higher viscosity be able to flow in the rheometer, and therefore the measurement range of the U-type rheometer has been broadened. The specific size will be displayed in Chapter 4.3. Study on the slurry in stable phase with fluid mechanics. It is put forward that the time difference between when the cement slurry passes through the scale value of 5cm and 7cm of the U-type glass tube could be used to represent the plastic viscosity of the cement slurry and that the height value of the cement slurry which becomes still after its free flow at the scale value of 6cm in the low side of the U-type glass tube could be used to represent the shear yield stress of the cement slurry.4. Find out the effects of different factors on the rheological properties of the cement slurry through experimental research, putting forward some useful engineering proposals based on the practical situations.