Study On Structural Performance Of Steel Bridge Deck Pavement Using Steel Fiber Reinforced Polymer Concrete

Since the use conditions and requirements of large-span steel bridge deck pavement are much higher than ordinary pavement,paving has always been one of the worldrecognized problems in the construction of this bridge type.Based on the excellent mechanical properties of the previous Steel Fiber Reinforced Polymer Concrete(SFRPC)materials,this paper combined theoretical analysis,numerical simulation and experimental research to bridge the pavement structure of steel fiber reinforced polymer concrete steel.The performance was studied.The main research contents and conclusions included:1.The theory of composite mechanics,fiber spacing theory,and crack tip closure force model were used in this paper to theoretically analyze the mechanism of fiber cracking enhancement and explain the mechanism of fiber pressure strengthening from microscopic point of view.2.This paper studied the physical and mechanical properties of the main materials of polymer steel fiber reinforced concrete,including slump test,dry shrinkage test,compression and flexural test at different ages,compression elastic modulus test,etc.It showed that:(1).Polymer steel fiber reinforced concrete has good workability,and its shrinkage rate is more than 50% lower than that of ordinary concrete at different ages.(2)Its early flexural and flexural strength rise slowly.The strength of the late rise is obvious,and the compressive and flexural strength of 28 d can reach 50 MPa and 10 MPa respectively.(3)The elastic modulus of the material reaches 34.4GPa,which can be used in steel bridge deck pavement to improve the deformation of the pavement layer.3.According to the material characteristics of polymer steel fiber reinforced concrete,the paper designed two pavement structures: single-layer pavement and doublelayer pavement with wear layer,and composite trabe test for pavement structure performance.The test results showed that:(1).The bending stiffness of the composite structure formed by the polymer steel fiber reinforced concrete as the pavement layer and the steel plate was significantly higher than that of the composite structure formed by the modified asphalt SMA and the epoxy asphalt pavement layer.The stiffness,in which the former was under the bending moment,was 14.4 times and 4.7 times the stiffness of the latter two,respectively.(2).Increasing the pavement thickness in the single-layer pavement structure can obviously improve the bending stiffness of the structure under the positive bending moment and the bearing capacity of the composite structure,wherein the 80 mm pavement thickness is 2.74 times of the bending stiffness of the paving thickness of 60 mm.Times.(3)The bending stiffness of the double-layer pavement with wear layer was much higher than that of the single-layer pavement structure,and the structural stiffness of 10mm+70mm was 1.6 times that of the single layer 70 mm.(4).The bearing capacity of the structure under the negative bending moment was far less than the bearing capacity of the structure under the positive bending moment,and the increase of the thickness had little contribution to the bearing capacity.(5).Regardless of the effect of simulated positive and negative bending moments,the structure still had certain ductile failure characteristics under the action of ultimate load,which proved that polymer steel fiber reinforced concrete had good mechanical properties and was an ideal steel bridge deck pavement material.4.The bending test,shear test and drawing test were applied to the interface between polymer steel fiber reinforced concrete and steel plate.The bending test and shear test were designed for the interface layer of polymer steel fiber reinforced concrete and wear layer.Tests and test protocols were all conservative designs.The shear strength,bending strength and drawing strength of the interface formed by the homemade binder I at room temperature can reach 4.7 MPa,6.2 MPa and 3.9 MPa,respectively,which was much higher than the bonding strength of epoxy resin and epoxy asphalt;The shear strength and bending strength of the interface formed by the self-made binder II at room temperature can reach 3.5 MPa and 2.6 MPa,which was much higher than the bond strength of the cement paste.The interface binders I and II destroy the interface and adhere to more concrete,proved that the interface bond strength is stronger than its own strength.5.Numerical simulation analysis of the pavement structure.The analysis showed that:(1)The maximum inter-layer shear stress level in the longitudinal and lateral directions near the diaphragm was peaked and changed rapidly.(2).The maximum vertical displacement of the pavement layer and the maximum transverse tensile stress of the pavement layer can be significantly reduced under higher elastic modulus,but the maximum longitudinal tensile stress level of the pavement layer was also higher.(3)The interlaminar shear stress level between pavement layer and steel plate was higher,and the interface bond strength formed by contrasting self-made binders I and II was much higher than the calculation results.