尾矿砂在大流动性混凝土中的应用研究

分别用20%、40%、60%、80%和100%比率的铁矿尾矿砂取代天然砂, 并掺入矿渣微粉和粉煤灰, 配制了C30、C40大流动性混凝土。通过与基准混凝土的对比试验, 研究了不同尾矿砂取代率下混凝土和易性、强度及坍落度经时损失等性能。结果表明, 在20%～100%取代率时, 混凝土拌合物和易性均能满足要求; C30混凝土28 d强度为37.6～39.7MPa; C40混凝土28 d强度为47.7～49.2 MPa; 经80 min坍落度经时损失试验, 60%取代率时, 砼坍落度值由200 mm降至170 mm; 100%取代率时, 砼坍落度值由185 mm降至95 mm。尾矿砂可以作为细集料, 以适当的比率取代天然砂配制混凝土。

The Experiment Study of Ore Tailings Sand in High-flow Concrete

By substituting natural sands with iron ore tailings sand in a ratio of 20%, 40%, 60%, 80% or 100%, with grinding slag powder and fly ash being added, high-flow concrete was prepared with strength of C30 and C40. After contrast experiment against normal concrete, the properties such as workability, strength and slump loss through time in concrete with different ore tailings sand substitution ratios were studied. The results indicate that with ore tailings sand substitution ratio between 20%～100%, all the concrete mixtures can meet the requirement in terms of workability. Strength of C30 concrete with 28 d is between 37.6～39.7 MPa, and strength of C40 concrete with 28 d is between 47.7～49.2 MPa. In the experiment with the slump loss through time of 80 min, the slump of concrete decreased from 200 mm to 170 mm with ore tailings sand substitution ratio being of 60%, while the slump of concrete decreased from 185 mm to 95 mm with substitution ratio being of 100%. It is concluded that ore tailings sand can be used as fine aggregate to substitute natural sands with a proper substitution ratio in the preparation of concrete.