采用石粉（粒径小于75μm的颗粒）含量为3%～13%的卵石破碎原状机制砂配制强度等级 C30,C40 和 C50 混凝土，分析了石粉含量对混凝土拌合物工作性能及混凝土抗压强度、抗拉强度和弹性模量的影响规律。研究结果表明，对卵石冲洗后加以破碎的原状机制砂，其石粉含量可超出现行建筑用砂规范的限值，控制在13%以内时可满足混凝土拌合物的工作性能和现行规范对混凝土基本力学性能的要求。该研究对机制砂生产工艺的革新和生产效率的提高具有重要价值。

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.