| The early damage of concrete bridge deck pavement is very serious due to the high-density traffic and overload operation in modern transportation industry.Not only does it affect the comfort in the process of driving,but also the serious cracking of the bridge deck pavement will make the rain and other harmful substances erode the bridge face plate and cause the corrosion of steel reinforcement,leading to the reduction of bridge safety.In addition,due to the low tensile strength and easy cracking of cement concrete,cracks and other diseases are more likely to occur under the comprehensive action of load and concrete shrinkage stress,and once the disease is formed,the difficulty of repair is also relatively high,the cost of maintenance is also high,which seriously affects the durability of bridge deck pavement.In this paper,the mechanical properties,impermeability and microstructure of fiber-reinforced UHPC are studied by using test methods,and the bridge deck pavement is simulated by using ABAQUS software.The main research contents are as follows:1.In the natural curing and standard curing two kinds of maintenance mode,the steel fiber,basalt fiber and polypropylene fiber is divided into four different sets of content,and then separately mixed,and the single doped fiber UHPC mechanics performance test,the results showed that: best steel fiber volume content is 1.65%,under the condition of natural curing 28 d compressive strength and tensile strength of 118.21 MPa and 20.80 MPa respectively,under the standard curing strength123.63 MPa and 21.73 MPa respectively.The optimum volume content of basalt fiber is 0.15%.The compressive and tensile strengths under natural curing condition for28 d are 100.61 MPa and 13.37 MPa respectively,and the strength under standard curing is 103.29 MPa and 13.6MPa respectively.The optimum volume content ofpolypropylene fiber is 0.15%.The compressive and tensile strength under natural curing for 28 d is 96.62 MPa and 12.56 MPa respectively,and the strength under standard curing is 98.36 MPa and 13.1MPa respectively.2.Based on single best doped fiber content,the content of three kinds of fiber according to the different can be divided into six groups of experiments,and mechanical properties test,under the conditions of mixed doped fiber is obtained,the optimal combination,and elastic modulus experiment was carried out and mixed with fiber UHPC permeability resistance test,the results showed that: when the steel fiber content is 1.65%,basalt fiber content is 0.05%,polypropylene fiber combination optimal when the dosage was 0.15%,the compressive and tensile strength were 125.52 MPa and 24.71 MPa.In addition,mixed fiber UHPC has higher internal compactness and better impermeability under the combined action of multiple factors.3.The microscopic images of single-doped fiber UHPC were obtained with the help of SEM,and various factors affecting the macro strength were analyzed,including the pores inside the material,hydration products,fiber morphology and other factors.The results show that only at the optimal mixing amount of the three kinds of fibers can the fiber not form into a group in the matrix,and there are few pores on the surface,and there are more products left after the surface hydration of the fiber.4.With the aid of the finite element analysis software ABAQUS,simulation analysis was carried out on the bridge deck pavement,establishing simulation model of precast hollow slab through to set up four kinds of different depth and the hinge joints in hinged placed seam and deck surfacing layer fiber reinforced UHPC and C30 concrete to simulate the condition of two kinds of materials,the results showthat the fiber reinforced UHPC materials and pavement of the hinge joints in hinged under stress than C30 concrete material with larger capacity,can better protect the surfacing layer are not destroyed. |
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