Study On Preparation And Application Of Reactive Powder Concrete With Steel Slag

With ultra-high strength, low brittleness and excellent durability, reactive powder concrete is an emerging new family of concretes. But too high unit cost Limits the extensive applications of reactive powder concrete. In order to decrease the unit cost of reactive powder concrete and increase the utilization of steel slag, the author, considering the raw materials in our contry and basing on the domestic and international research results, studies on preparation of reactive powder concrete using air quench steel slag replacing the quartz sand as aggregate through experiment.The characters and the stability of volume of air quench steel slag have been summarized first in this paper. The air quench steel slag has good physical and chemistrial properties, and can be used to prepare concretes as aggregate. At the same time, theoretical analyzation and experiment results also show that f-CaO content is very low, and MgO exists in the RO phase, so the volume of air quench steel slag is stabile.Secondly, preparation of reactive powder concrete with air quench steel slag and its performance are mainly studied through experiment. The results show that: (1) when binder-to-sand ratio is 1, silica fume percentage of binder is 15, and steel fiber percentage in volume is 4, reactive powder concrete prepared can get best overall performances. (2) the physical properties of steel slag, such as size and grain distribution, make a great impact on the performance of reactive powder concrete with steel slag. But the chemical properties have no remarkable influence on it (3) as the water-to-binder reduces wich is one of key factors in the perpormance of reactive powder concrete with steel slag, the fluidity decreases but the strength increases; incorporation of 4 percent steel fiber in volume can decrease fluility and increase strength; heat-curing benefits the increase of strength which can still develop in 28 day water curing after heat-curing. (4) the reactive powder concrete with steel slag which is prepared in water-to-binder ratio of 0.18 can get the flexural strength of 21.6 MPa, the compressive strength of 141 MPa, and elastic modulus of 51.1 GPa. Its dry shrinkage in 56 day reach 430X10"6, in which autogenous shrinkage is 400xlO~6. And it has excellent impermeability, but fatal brittleness. Incorporation of 4 percent steel fiber in volume can not only increase strength and elastic modulus, and also reduce dry shrinkage and autogenous shrinkage and enhance greatly ductility.Finally, the author briefly discusses the application of reactive powder concrete with steel slag in engineering and produce, and points out that it is also a new emerging family ultra-high cement-based material.