| The durability of reinforced concrete structures is caused by corrosion of steel bars,which leads to the shortened service life of the structures and serious economic losses.And fiber-reinforced polymer(FRP)bars,as a new type of FRP bars materials with light weight,high strength,corrosion resistance,fatigue resistance and other advantages.It can effectively solve the durability problem caused by corrosion of steel reinforcement,and is considered as an ideal material to replace steel reinforcement in special environment,which has a wide application prospect in civil engineering structures.On the other hand,with the further acceleration of China’s economic construction,a large number of construction waste caused by the reduction of arable land,environmental pollution and many other problems.Therefore,scholars at home and abroad pay special attention to the development and utilization of recycled concrete.Will waste concrete after crushing,washing and screening form recycled aggregates,again will these recycled aggregate instead of natural aggregate that some or all of the recycled concrete,which can realize the construction waste recycling,not only can save natural resources,also can protect the ecological environment,and reduce the construction waste in the urbanization process,is an important part of sustainable development strategy.In recent years,scholars at home and abroad have carried out more studies on the flexural performance of reinforced regenerated concrete beams,and a lot of research achievements have been made.However,there are relatively few researches on the performance of FRP bars regenerated concrete beams(FRP-RAC),which greatly hinders the application prospect of FRP-RAC structures in practical projects.Based on this,this paper designed 9 GFRP-RAC beams,3 BFRP and 3 steel-RAC beams reinforced beam(contrast beams)of the recycled concrete beam bending performance test,analyses the replace rate of recycled aggregates(R=0,50%and 100%)and reinforcement ratio(ρ_f=0.38%,0.60%and1.17%)on GFRP-RAC beam failure mode,the cracking load,ultimate load,load-deflection curve,the load and strain curve and the effect of load crack width curve,and compared with BFRP-RAC beams and steel recycled concrete beams are compared.In addition,the cracking load,ultimate load,crack width and deflection of GFRP-RAC beams were calculated theoretically and compared with the test results by using the calculation formulas of ACI 440.1R-15,CSA S806-12,ISIS-M03-07 and GB 50608-2010.The main research results are as follows:(1)The cracking load decreases with the increase of the replacement rate of reclaimed aggregate,while the type and ratio of longitudinal reinforcement have no significant influence on the cracking load of the test beam.The average cracking load decreased by 5.1%and 14.8%as the recycled aggregate replacement ratio increases from 0 to 50%and 100%.(2)The ultimate load of GFRP-RAC beam increases significantly with the increase of reinforcement ratio,and decreases slightly with the increase of replacement ratio of recycled aggregate.In addition,by comparing the test beams with different longitudinal reinforcement types,it is found that the bearing capacity of GFRP-RAC beam is slightly higher than that of BFRP-RAC beam under the same conditions,and the bearing capacity of reinforced regenerated concrete beam is the lowest,about 1/2 of that of FRP-RAC beams.(3)The crack width and deflection of GFRP-RAC beam decreased significantly with the increase of reinforcement ratio,and increased slightly with the increase of replacement ratio of recycled aggregate.Under the same load,the deflection of THE BFRP-RAC beam is greater than that of the GFRP-RAC beam.When the rebar regenerated coagulation reaches the yield load,its deflection is 6.5mm,about 1/2 of that of the FRP-RAC beam.(4)Based on the test data,the cracking load of GFRP-RAC beam was analyzed by linear regression and the cracking load correction coefficient was obtained.The calculated results were in good agreement with the test results. |
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