The Study On Mechanical Properties Of RPC Using GBFS As Fine Aggregate

Saving resources and environmental protection are the basic national policies of china.The comprehensive utilization of industrial waste is especially critical for building a resource-saving and environment-friendly society.Granulated blast furnace slag(GBFS)which is an industrial waste slag formed by smelting and quenching the molten blast furnace slag discharged from the blast furnace When smelting pig iron.And its chemical composition is similar to ordinary Portland cement,mainly composed of glassy particles,and has potential activity.China,a large steel country,has a large amount of waste residue,and it is urgent to use these wastes.Reactive powder concrete(RPC)as a new ultrahigh performance concrete material with high strength,high durability and high toughness have been followed with sustained interests since it was first proposed by Richard and others in France in the late 1990 s.However,the quality raw materials used in traditional reactive powder concrete are expensive,therefore,finding cheap alternative materials is an urgent task.Therefore,using granulated blast furnace slag instead of quartz sand in reactive powder concrete as fine aggregate provide a reference for expanding the utilization of granulated blast furnace slag and reducing the cost of product reactive powder concrete.In this study,the mixing ratio,mechanical properties and microscopic pore structure of reactive powder concrete using granulated blast furnace slag as fine aggregate is investigated.Based on the aggregate close packing theory and minimum water requirement,the comparative mixture ratio test was carried out on reactive powder concrete using granulated blast furnace as fine aggregate and ordinary quartz sand reactive powder concrete,and 4 kinds of water binder ratio of reactive powder concrete using granulated blast furnace slag as fine aggregate better mixture ratio was obtained.And test compressive strength,flexural strength,splitting tensile strength and elastic modulus of different mixture ratio Specimens through the mechanical test,analyzes the influence of curing age,water binder ratio and sand replacement ratio on the compressive strength.Finally,the correlation between microscopic pore structure and mechanical properties of reactive powder concrete using granulated blast furnace slag as fine aggregate was studied by optical method and mercury intrusion method.The test results show that the chemical properties of granulated blast furnace slag are different from quartz sand,it has potentially hydraulic.The closely accumulation density and apparent density of granulated blast furnace slag is slightly lower than that of quartz sand,the crush index of granulated blast furnace slag is higher than that of sand,However,after reasonable mix design,it is possible to prepare reactive powder concrete using granulated blast furnace slag as fine aggregate with good working performance.In terms of mechanical properties,the compressive strength,flexural strength and splitting tensile strength of reactive powder concrete using granulated blast furnace slag as fine aggregate are slightly lower than that of ordinary reactive powder concrete,the compressive strength flexural strength and splitting tensile strength of reactive powder concrete using granulated blast furnace slag and quartz sand as fine aggregate are slightly higher than that of ordinary reactive powder concrete.And the early compressive strength growth rate of reactive powder concrete using granulated blast furnace slag as fine aggregate are higher than that of ordinary reactive powder concrete.In the relationship between microscopic pore structure and mechanical properties,it is found that the compressive strength of reactive powder concrete using granulated blast furnace slag as fine aggregate and ordinary reactive powder concrete are decrease with the increase of porosity,and both reactive powder concrete using granulated blast furnace slag as fine aggregate and ordinary reactive powder concrete can use Power,Ryshkewitch,Schiller,and Hasselman formulas to describe the relationship between compressive strength and porosity.