The Study And Application Of The Steady Cement Paste

It is very important to choose grouting materials in dam-grouting construct project, because the materials directly influence the physical and mechanical properties of grouting-structures, construction technology, construction period, etc. Usually, we choose the cement-grouting as the materials, and this is an unsteady paste with a high rate of bleeding water, without blocking up a narrow crack completely, and leaving the penetrate pores which are occupied by bleeding water, or leaving mane-like holes. And the problems can be solved by the steady paste, with a low rate of bleeding water.The author, from the construction need of Guan-Di hydropower station and the properties of the two pastes, thinks that the use of steady paste, mostly used in GIN, in grouting project can get a better effect than the ordinary one. In the stratums that are unsuitable to use GIN, the way to use ordinary grouting method to grout steady-paste is possible. So, the author deployed a steady-paste, according to the engineering need, which can be used in the ordinary grouting method, and got a good effect. The research results are as follows:(1) The author analyzed the rheological mechanism and movement law of the cement-paste, and determined the viscosity which restricts the speed of steady cement paste and the cohesive force which restricts the diffused radius of the steady cement paste. All of this can provide some theory basement for steady-paste.(2) The author presents a formula about the proliferation of radius under the conditions of Guan-Di geological conditions after study the steady paste. And it provides a evidence for the possibility of grouting the steady cement paste.(3) The author selects bentonite as a best stabilizer for the steady cement paste by researching the performance of bentonite. It comes to a conclusion that the factors affecting the stability of cement paste are the water-cement ratio, the stirring speed, the tackifier, the super-plasticizer and so on by researching the performance of the steady cement paste which is commixed with a different ratio of water, cement, bentonite and the other materials. The author deployed a steady-paste with a better performance, which can be used in the ordinary grouting method.(4) The author applied the steady-paste to the Guan-Di hydropower station, and it was showed, by detecting data, that the integrity of the cement stone, impermeability, durability and mechanical strength meet the design requirements, and as a result of relatively simple construction technique, thereby shorten the construction period and reduce the project cost, at the same time.