Research Of The Testing Measure And The Mechanism Of Cement Paste Agglomeration

The cement is the essential basic construction material in the nation economy development. Since the day it was invented 170 years ago, it has made great contribution to the social and economical development. After the Opening up and Reform, along with the rapid development of our national economy construction, the cement industry also experiences a persistent developing process after completing the "the seventh five year plan" "the eighth five year plan" "the ninth five year plan" and "the tenth five year plan", which has never appeared before. The cement industry' development helped the nation economy become more rapid, healthy and durative. As the rapid increase of the cement producing and consuming, the quality of the cement is been paid more and more attention. The cement paste agglomeration phenomenon appearing in the cement hydration has existed for long. However, the problem hasn't been paid enough attention, also there aren't enough research in explaining the forming mechanism. Therefore, not any effective method has been proposed to solve the cement paste agglomeration phenomenon. Further, the consumers and the producers also suffer. To be more important, the cement paste agglomeration has bad effect on the usage while every index in the national inspection is up to grade. Therefore, the research in the forming mechanism of the paste agglomeration is theoretically valuable and practical to the consummation of our national inspection standard.According to the enlightenment of the current coagulation time measure method, the author proposes a set of new cement paste agglomeration measure method- the cement needling method. Referring to the current cement paste agglomeration theory, the author analyses the cement needling method by experiment. The result shows that: this inspection method is reliable, and the result is with perfect stability and recurrence;Meanwhile, according to the changes under different conditions, this method can reflect the changing rules, and be respondent with current theory. It turns out to be an effective method of paste agglomeration research.Comparing the two current research methods: the cement needling and water sieve method together, the author makes a S-fitting with the nonlinear system byusing the data analysis and plot software -Origin7.5pro of American Microcalcompany. The results show that: the water sieve method is applicable with measuring the cement that paste agglomeration is small. The cement needling method is moreaccurate when measuring the cement that paste agglomeration is serious.Aiming to the characteristics of paste agglomeration, this article analyzes the cement with paste agglomeration from lithofacies, temperature, humidity, gypsum addition, heat of hydration and mineral components. The result of lithofacies shows that impertinency of cement to calcine and condensation has certain effect on the paste agglomeration. The temperature, humidity and gypsum addition have obvious regular relationship with the paste agglomeration degree. Through this regular rule, the degree of paste agglomeration can be effectively consummated.By the cement needling , XRD SEM methods in the research of hydration outcome , this article proposes the forming mechanism of paste agglomeration , which is as following:In the process of the paste agglomeration, 3~5min, is the period of cement enwrap. During this period, the wrapping forms rapidly and the wrap is dense. After this period, agglomeration begins the process of adsorbing the other cement by the center of wrap while the agglomeration is increasing. After 20mins,the liquor filters incessantly into the agglomeration and makes the outside of the agglomeration looser;Meanwhile, for the reason of water penetrating pressure, some wrap's velum breaks and the agglomeration is diminishing. After 50mins, all the cements outside the wrap are almost cankered by the liquor. The most of the cement velum breaks, the liquor penetrates into cement the inner wrap which is non- agglomeration and form new agglomeration. However, because of the amount of cement participating is very small (only the inner wrap part), just a relatively small peak value of the agglomeration would appear. As time goes by, under the corrade of the liquor, the agglomeration begins to diminish. Along with the time is longer, the water finally penetrates into the outside of the cement wrap, inters into the inner of the agglomeration and reacts with the cement which has no agglomeration. At last, the inner of the whole system will have the same characteristics with the normal cement hydration.