Abstract:
The grouting in the frozen soil area and the thawing area of the shaft encountered many problems, such as long setting time of cement slurry, poor effect of reinforcement and plugging. In order to study the coagulation characteristics of cement slurry with admixtures under low temperature or negative temperature conditions, 17 kinds of cement slurry added with industrial salt, calcium formate and calcium chloride were compounded on the basis of the requirements of engineering application. The initial setting time and the final setting time at 3 ℃, 0 ℃ and -2 ℃ were studied. The influence of different temperature and different additives on the setting time of Portland cement slurry was analyzed. The results show that: the initial and final setting time of cement slurry can be effectively shortened by adding industrial salt, calcium formate or calcium chloride, the initial and final setting time of cement slurry extend with the decrease of temperature. The initial and final setting time of cement slurry is shortened with the increase of industrial salt content at 3 ℃ environmental temperature, when the content of calcium formate and calcium chloride is 4%, the initial setting time of cement slurry is the shortest, and the final setting time of cement slurry is the shortest when the content of calcium chloride is 2%. The initial and final setting time of the cement slurry is the shortest when the content of industrial salt is 5%, and the content of calcium formate or calcium chloride is 2% at 0 ℃ ambient temperature. The initial and final setting time of the cement slurry is the shortest when the content of industrial salt is 5%, and the content of calcium formate or calcium chloride is 3% at -2 ℃ ambient temperature.