| Reactive powder concrete（RPC）,due to its own super-high performance,has been widely used in the field of construction in China.However,its high preparation cost still has many limitations in practical engineering.Steel slag powder is a kind of environmental protection material obtained by secondary grinding of traditional industrial waste steel slag,and the composite material mixed with cement has a better improvement in mechanical properties.This paper uses different proportions of steel slag powder（30%,45%and 60%）to replace cement and different amounts of steel fiber（0%,1%,2%and 3%）to make 40mm×40mm×160mm non-prefabricated and prefabricated opening specimens.And consider the influence of curing temperature（70℃,80℃,and 90℃）.Analyze the influence of the above three factors on its strength,deformation,and bending（fracture）toughness.The main work content and related achievements include the following aspects.（1）Conduct bending tests on specimens with non-prefabricated openings,observe the failure of the specimens,and analyze the influence of different factors on characteristic values（strength,deformation）.The results indicate that the initial crack load Pf,r,initial crack deflection δf,r,peak load Pult,r and peak deflection δult,r achieved the best effects at 30%replacement of steel slag powder and 2%fiber rate,respectively.Calculate the toughness index T2（n-1）（n）based on energy consumption capacity,and study the influence of steel slag powder and steel fiber on it.Based on the calculation results of the post peak energy consumption ratio,it analyzes the ability of steel slag powder RPC to absorb energy and deform after reaching its peak load.（2）Conduct fracture tests on specimens with prefabricated openings,analyze the influence of different factors on characteristic values,and study the influence of each factor on double K parameters,fracture energy,and toughness indicators.The results indicate that the initiation toughness KIcini of the specimen increase nonlinearly with the increase of fiber ratio.Compared with plain steel slag powder RPC,they increase by 9.6%,14.6%,and 16.1%at the fiber ratio of 1%,2%,and 3%,respectively.The instability toughness KIcun of the specimen increase by 28.1%,44.5%,and 45.3%at the fiber ratio of 1%,2%,and 3%,respectively.When the replacement amount of steel slag powder is 30%and the fiber ratio is 2%,the fracture energy Gr of the specimen reaches its peak.The variation pattern of toughness index PT2（n-1）（n）are basically consistent with the double K fracture parameter,which can reflect the influence of parameter variables on fracture performance.（3）Conduct fracture tests on specimens with prefabricated openings at different curing temperatures.The results indicate that with the curing temperature increase,the load P-displacement δ of the specimen curve gradually steepens and Gr gradually increase.The variation pattern of the load P-opening displacement CMOD curve of each group is the same.When the curing temperature is 70℃,Pf,r and Pult,r are lower than those of ordinary RPC.The KIcini and KIcun of the specimens increase with the increase of curing temperature and the regularity is more obvious.（4）Based on the double K fracture criterion and relying on the residual strength evaluation method,the boundary toughness parameter KIclim is proposed.It decreases with the increases of replacement amount of steel slag powder,increases with the increase of fiber ratio especially ranges from 1%to 2%.When the fiber ratio ranges from 2%to 3%,the increase gradually slows down. |
