Abstract: The gravel-crushed proto-machin-made sands containing stone powder (particle size being less than 75 μ m) with quantity content from 3% to 13% were used for mixing concrete of grade C30, C40 and C50. The influences of stone powder content on the workability of fresh concrete and the compressive strength, tensile strength and elastic modulus of concrete were analyzed. It can be concluded that for the proto-machine-made sands made by the gravels washed before crushed, the stone powder content can be taken over the limit specified in current standard of building sands. When the content is limited in 13%, the workability of fresh concrete is better, the compressive and tensile strength as well as the elastic modulus of concrete can satisfy the requirements of current code. The study is very important for the innovation of production techniques and the promotion of productivity.

Key words: concrete  ,  gravel-crushed proto-machine-made sands ,    stone powder content  ,  fresh concrete workability  ,  compressive strength  ,   tensile strength  ,   elastic modulus