In order to prepare SCC (self-compacting concrete) which is used as the packing layer in CRTS III type track system this paper primary researched the influence of sand ratio on its performance through experiments of the design of mix proportion. Test results show that when sand ratio is too small, the fluidity of SCC will be bad and the concrete will generate segregation and weeping. If sand ratio is too great, the workability of SCC will not be good either, but segregation will not occur again. The optimum range of sand ratio is 0.56 to 0.58 in this paper, while the range proposed by China Academy of Railway Sciences is 0.50 to 0.55.
This paper primary researched the influence of limestone powder on the workability, the strength performance and the volume stability of self-compacting concrete (SCC). Results showed that the workability of self-compacting concrete was improved greatly by mixing proper limestone powder; besides, limestone powder could improve early age strength of concrete obviously, but had little influence on long age strength; the self-shrinkage of concrete increased as the admixture of limestone powder increased. The content of limestone should be capped at 10% and the optimum mix amount is about 7%.
In this paper,the functions and performances of filling layer of self-compacting concrete(SCC) in CRTS(China Railway Track System)-Ⅲ type track system were introduced. Developments of SCC including design methods and test method was described in detail. The influencing factors of workability of SCC was analysised. The trends of future development of mix proportion design methods,durability evaluation admixtures,applications were discussed.This paper also pointed that it's importance for SCC to studying the quality control methods and the application.
DLP technology is one of the 3D printing methods for ceramic materials, and its forming accuracy is affected by the preparation of ceramic slurry, debinding and sintering process. In view of three different slurry preparation methods and solid content, the flow characteristics of slurry were studied. The reasonable debinding and sintering process was formulated, and the debinding and sintering treatment were carried out. The influence of slurry preparation methods on the forming accuracy of green parts and sintered parts was found out. The results show that with the increase of solid content, the viscosity of slurry also increases and the fluidity becomes worse. Increasing milling time and rotating speed can improve the flow characteristics of the slurry with 70% zirconia solid content. The C method can not only increase the solid content of the slurry, but also reduce the shrinkage of the sintered parts and improve the dimensional accuracy of the sintered parts.
Self-compacting concrete(SCC) is the current trend of new concrete.A variety of materials have been added in it on the purpose of changing the properties of SCC[1].In this paper,three viscous materials of limestone powder, silica fume and metakaolin have been added in SCC to change self-compactability and strength.
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