Study On Preparation Technology Of Ultrafine Cement With High Volume Of Cementitious Materials

The large output, high pollution and low utilization rate of industrial waste, such as low activation fly ash, slag, red mud, as well as gradually exhausted of cement resources are the background of this paper.The methods of a combination of microscopic analysis and experiment are uesd for in-depth research on how to improve the mixing volume of industrial waste in the ultrafine cement.Comprehensive performances of fly ash, red mud and slag are researched and analysised through X-ray diffraction microscopic test method, which is the theoretical basis for industrial waste used as ultrafine cement admixture.The problem of cement particles sticking to the ball and grind when prepare the ultrafine cement by the planetary ball mill has been solved through mixing iron powder. And this provides a simple and feasible way to make ultrafine cement.The influence of particle fineness on the compressive strength of concrete is explored through grinding cement and fly ash with different degree. Contrast the compressive strength of mortar specimen with different solid of mixed material to explore the effect between mixed material robustness and the compressive strength of concrete. And the related mechanism is analyzed, which provides a method and basis for increasing the amount of admixture. The results have shown that the grinding fineness of cement clinker and fly ash has a great effect on compression strength of cement mortar specimens, the smaller the particles are, the higher the compressive strength of the mortar specimen is, and the advantage of ultrafine cement is obvious. The robustness of admixture has a great influence on the compressive strength of cement mortar specimens. The strength contribution of mixed material to the mortar specimens is the results of both its activity and robustness.Compare the effect of different kinds of activator excitation through the aging, sulfate and alkali activated active provocation tests, to reach the target that high volume of admixture in ultrafine cement at low water cement ratio. The results show that the cement admixture activity is obviously improved under the sulfate excitation. The volume of mixed material has been increased to 70%, and the compressive strength of mortar specimen is almost the same as the pure cement clinker. The activity of alkali activated superfine cement admixture enhance further than that of sulphate activation. The volume of admixture can reach 90% in the situation that the compressive strength of the mortar specimens not less than pure cement clinker, which can greatly reduce the volume of cement clinker.Through X-ray diffraction and scanning electron microscopy and microscopic test method to analyze the microscopic and hydration mechanism of the optimum solution for sulfate and alkali activated ultrafine cement with high volume of cementitious materials.