Research On Improving Clue Capability Of Rolled Compacted Concrete

The whole surface and delamination construction of rolled compacted concrete (RCC) dam will make inferior cementation between the layers, so the shearing strength of layer slot exist weakness potentially. Some years, the problem of shearing strength of layer slot is an important question, which the dometic and international expert and scholar concern closely and causes discussion broadly and deep research. Therefore the technical key of design and Construction of RCC and the technical nut that we must conquer as soon as possible is how to take effective measure to improve the shearing strength of layer slot so that the problem of combination between the layers can be resolved. This paper aims at improving the cementation between the layers of RCC, analyses the coagulate capability of RCC and all kinds of factors effecting on cementation between the layers, bring up a way which can be used to judge the cementation between the layers of RCC fast. It also analysed that the different treatment of layer and construction method impact on the cementation between the layers and the anti-seepage characteristic.The result which of the research on characteristics of cementation of the cement mud and sand mud of RCC being used in different engineering indicate that the resistance of the cement mud and sand mud to the outside dint has obvious turning point. Acording to the variation of construction in the coagulate procedure of cemend mud and gum condense material and lots of experiment result, We can think that the time of turning point is the initial setting time.Study finds that coagulate characteristic of the mix blend thing of RCC is same with it of gum condense material mud and sand mud, there is a obviousesturning point on the curve of resistance and time. The time opposes to this turning point is the initial setting time.Through researching, we find main factor, which affect on the initial setting time of RCC is the temperature of environment, the relation between it and initial setting time is logarithms. The opposite degree of humidity and wind velocity also is the factors that affect on initial setting time. The relation between them and initial setting time is approximate straight line .The effect which all kinds of factors of environment have on initial setting time of different concrete mix blend thing is same essensially. In same environment term, the difference of initial setting time of different match ratio concrete mainly coursed by match ratio oneself.Acording to analyzing environmental factors, we can get following relation:Making use of this relation, we can judge condense function of RCC. Making use of this calculative formula being applicable to initial setting time of RCC, we can anticipate the RCC initial setting time in different environmental condition . If, in temporal environmental condition, the calculating initial setting time is bigger than the interval time between layers, the concrete in layer is not initial setting ;on the contrary, if the interval time between layers is bigger than the calculating initial setting time, the concrete in layer is initial setting.In order to improve RCC cementation quality and shearing strength, we have brong up some handle measure between the layers, such as brushing cement mud in the layers; spreading cement sand mud in the layers and so on .We also put in construction method such as concave-convex layer and oblique layer.Experiment indicates that taking brushing cement mud in the layers and spreading cement sand mud in the layers can both guarantee cementation quality between the layers to reach the design request. Taking construction methodof concave-convex layer to strengthen anti-glide stability, not only can resolve the technical problem of seepage using RCC itself and of fleetness construction in the whole section RCC, but also can ensure safty and stability of dam, simplifying engineering construction and decreasing the price of project.Even push construction method of oblique layer is of many prominent advantages, enable to exert advantage of RCC mover overall and fully, and improve quality of RCC, its function not only to construction, but also can have positive signicance and far-reaching effect on layout and design of RCC. As a excellent scientific and reasonable construction craft , it can be generalized and used widely in dam engineering.