Research On Flexural Performance Of GFRP-ECC Composite Beam

Fiber Reinforced Polymer(FRP)have many excellent characteristics such as light weight,high strength,fatigue resistance and corrosion resistance,and have broad application prospects in civil engineering,water conservancy,transportation and other fields.The use of FRP bars in concrete structures is one of the effective means to solve the problem of steel bar corrosion.However,the FRP-reinforced concrete structure is deformed and the width of the crack is large when it is bent.In order to meet the actual engineering needs,the Engineered Cementitious Composites(ECC)with toughening and crack resistance properties is used to replace the concrete in the tensile zone to form the FRP-ECC composite.The beam structure,while improving the bearing capacity of the structure,limits the development of cracks and deformations and improves its ductility.In order to study the flexural performance of GFRP-ECC composite beams,10GFRP-ECC composite beams were subjected to a static bending test,focusing on the analysis of ECC replacement height,GFRP reinforcement ratio and concrete strength in compression zone on the mechanical performance of members As a result,the theoretical analysis of the internal force changes at each stage from loading to failure of the test piece was carried out to establish a calculation method for the bending capacity of the GFRP-ECC composite beam.research shows:1.The mid-span load-deflection curve of the GFRP-ECC composite beam is trilinear,and the turning part of the load-deflection curve before and after cracking is smoother than the GFRP reinforced concrete beam.Under the same conditions,increasing the ECC replacement rate and the reinforcement rate can reduce the mid-span deflection of the specimen,limit the speed of crack development,and reduce the crack width.2.The increase of ECC replacement height,GFRP reinforcement ratio and concrete strength can increase the ultimate bearing capacity of the member.The effect of ECC replacement height of 200 mm on the ultimate bearing capacity is more obvious,but the ECC replacement height and concrete strength The effect of the initial crack load is weak.3.ECC significantly improves the performance of the specimen under the normal service limit state.The use load of the GFRP-ECC composite beam is higher than that of the GFRP reinforced concrete beam.With the increase of the ECC replacement height,the use load continues to increase and the ductility Improved.4.Combined with the existing FRP reinforced concrete beam ultimate bearing capacity calculation formula,theoretically analyze the bending process of GFRP-ECC composite beam,deduce the GFRP-ECC composite beam ultimate bearing capacity calculation formula,and compare with the test results to verify the formula Sex.