Study On Preparation And Properties Of The C80 Manufactured Sand Concrete

It is comparatively obvious that the characteristic of fine aggregate influences the performance of concrete , especially for high strength high-performance concrete, the nature , modulus of fineness and kind of the material ,etc. have greater influence of the workability, mechanical property of concrete. The manufactured sand of substituting the river sand for mixing high-performance concrete, have many characteristic, such as relatively bad grade, simply big modulus, many less than 0.075mm stone powder, and the surface is coarseness, the shape is sharp. Synthesize above characteristic, it is necessary to research to the mix ratio of the C80 concrete with machine-made sand, research the stone powder impact on performance of concrete.Based on the preparation and performance test of C80 manufactured sand concrete, the text confirmed the basic parameter of C80 manufactured sand concrete. Studied the characteristic of machine-made sand to the workability and strength of concrete, the stone powder to the workability, mechanical property, shrinkage property, anti-permeate and rheological performance, and discussed the feasibility of stone powder substituting fraction of mineral admixture.The result shows: (1) the C80 manufactured sand concrete can prepared using poly carboxylic acid water reducing agent as good performance as river sand concrete; (2) Compared with river sand concrete, the manufactured sand concrete has high strength, elastic modulus, low of diffusion coefficient of Cl~-, dry shrinkage is less higher than sand concrete; (3) certain amount of Stone powder didn't has bad influence to concrete, as MB<1.4, content of stone powder can broaden 7%; (4) Under the situation of enough cementitious material, the stone powder can replace fly ash as mineral admixtures; (5) The stone powder of a certain amount is favorable for concrete to increase the rheology performance of manufactured sand concrete , the plastic viscidity at this moment and stress of surrendering are relatively small; compare with the fresh concrete test, rheology test can be better reflect the workability of concrete.