Regulation Of Admixtures On The Rheological Behavior Of Cementitious Grout

Cementitious grout is one of the widely used inorganic grouting materials in grouting engineering. Cementitious grout is of high compressive strength and from a wealth of sources. However, the segregation and poor stability of cementitious grout can’t be ignored. The viscosity’s suddenly increase of the returned paste problem caused by high temperature during construction process. And the temperature rises more than10℃in an instant. Thus, the rheological behavior and groutability of cement paste get reducted, as a result of which, the construction efficiency and quality are badly influenced. Therefore, it’s more than important to focus the rheological behavior of cement paste, especially the change rules of viscosity, in high temperature. This will also of great significance in solving the problem during grouting engineering.Water reducing agent and sucrose were selected to regulate the rheological behavior of cement paste, so as to solve" the viscosity’s suddenly increase of the returned paste" problem caused by high temperature during construction process. Firstly, the adsorption processes and dispersion effects of different water reducing agents of different chemical structures into cement particles were investigated. Meanwhile, the influence of different retarders on the setting time and hydration process were studied. And the water reducing agent of the maximum dispersion effect, the retarder:sucrose of the maximum retarding effect were selected. The effects of the dosage of water reducing agent and sucrose and the temperature and time on the rheological behavior of cement paste were investigated. The results show that, the shear stress and the apparent viscosity of cement paste increase without significantly with the delay of time, while the shear stress and the apparent viscosity of cement paste increase obviously with the increase of temperature. The shear stress and the apparent viscosity of cement paste present a sharply descend incorporating with water reducing agent and retarder, thus to obtain a better rheological behavior of cement paste.