The Preparation And Quality Control Of High-Performance Self-Compacting Concrete With Low Shrinkage

As main material for concrete structure , ordinary concrete has been widely applied in civil engineering including projects related to architecture,transportation, underground, water conservancy and others with special structure. Modern civil engineering moves its way to large scale and complexity, meanwhile, people concern with the environment much more than before. Using ordinary concrete, especially using the one vibrated by strong force, appears many disadvantages, which restricts the application of concrete structure in complex structure.Non-vibratory, self-compacting concrete has good properties of fluidity,fill-in and anti-segregation, which can make moulding vibration easier. It supplies concrete a guatantee for application of new technology and makes a large scale market.The evaluation method of the performance of high-performance self-compacting concrete (HPSCC)with the properties of non-vibration has been put forward in this paper, as well as the performance index and testing method. The HPSCC mixture has been certified.In this paper, the rules that concrete gradients influence the workability and volume change of HPSCC with low shrinkage have been discussed. HPSCC with low shrinkage has been produced by cement grades: C30, C40 and C50. And its mixture ratio design and construction control have been put forward primarily. The results show that this concrete has good performance not only while preparing, but also in early age and rigidification.The main contents of this paper are as follows:1.Operating technique,evaluation method in lab and theoretical analysis at the aim of self-compacting workability.The basic mixture ratio of HPSCC with low shrinkage produced by cement with grade C30,C40 and C50 has been fixed through optimization of mixture ratio by orthogonal experiment. The evaluation methods in the lab of self-compacting concrete belonged to several countries have been compared. Then, we put forward one adapt to our country. As the results show, slump,expansion degree,upset slump barrel,equipment with type L and type U can be applied adapt to evaluation of workability of self-compacting concrete in the lab.2.Operating optimization at the aim of volume stability.Admixture and fiber have been certified as the serious factors that influence the transmutation property of concrete by analyzing concrete gradients. They have been systematically tested in long age. As the results show, new type of polycarboxylic acid-based admixture and shrinkage reducer reduce the negative influences of volume shrinkage. Flyash with a content of 30%, steel fiber and polypropylene fiber reduce the shrinkage of HPSCC. Especially, steel fiber and polypropylene fiber reduce shrinkage in early age of HPSCC as their effect overlapped.3.Durability analysisThe anti-carbonization ability of HPSCC has been investigated. The results show that it has good durability.4.Operating method of HPSCC with stable volume.Material qualification,aggregate gradation design and mixture ratio design of HPSCC with low shrinkage have been brought up.