Study On Preparation And Properties Of Self-compacting Concrete Toughened With Fiber Polymer For Bridge Expansion Joint

Bridge expansion joint is an important component which set between bridge and bridge or between bridge and abutment to coordinate deformation on both sides.However,due to poor quality of concrete construction and inadequate ability to coordinate deformation,the phenomenon of expansion joint damage is common,which increases the cost of later maintenance and economic losses caused by traffic interruption during maintenance.In order to solve the problems of expansion joint damage and beam local damage caused by insufficient ductility and workability of concrete in expansion joint area of small and medium-sized bridges,the ordinary self-compacting concrete with workability and compressive strength was prepared by mix proportion design and adjustment at first,and then polypropylene fibers and styrene-butadiene latex with different dosages were added on this basis.The influence of workability,basic mechanical properties and shrinkage properties of self-compacting concrete is systematically studied,then the fiber polymer toughened self-compacting concrete suitable for bridge expansion joints is obtained through performance comparison.Finally,the ABAQUS is used to simulate and verify the results.The following aspects are accomplished concretely:(1)Slump extensibility,J-ring extensibility and T500 were used to determine the workability of mixtures with different mixing ratios.The influence of polypropylene fiber,styrene-butadiene latex and their co-mixing on the workability of concrete was analyzed.The results showed that the workability of mixtures would be reduced by adding polypropylene fiber,while the workability would be greatly increased by adding styrene-butadiene latex.The workability of self-compacting concrete toughened by fiber polymer is similar to that of ordinary self-compacting concrete.(2)The compressive strength,flexural strength,axial compressive strength and modulus of elasticity of concrete were tested and studied.It was found that the flexural strength of concrete can be significantly improved whether it is blended with polypropylene fiber,styrene-butadiene latex or both,but the compressive strength,axial compressive strength and modulus of elasticity are similar to those of ordinary self-compacting concrete,and the mechanical properties were optimized when they are blended together.(3)The shrinkage deformations of concrete at different ages were measured by a comprehensive tester.The development trend of shrinkage deformations of concrete and the influence of fibers and polymers on shrinkage are explored.It was found that the shrinkage deformations of concrete could be reduced by mixing polypropylene fibers or both,while the shrinkage increased by mixing styrene-butadiene latex.(4)ABAQUS was used to simulate the deformation of fiber polymer toughened self-compacting concrete used in expansion joints.Compared with the deformation of ordinary concrete under the same load,it was found that the resistance load of fiber polymer toughened self-compacting concrete was stronger and the deformation in any direction was smaller than that of ordinary concrete.In this paper,a kind of high performance self-compacting concrete is formed by the co-mixing of fiber and polymer.Its workability,mechanical properties and shrinkage properties are systematically studied.The simulation analysis is carried out by ABAQUS,the results show that the concrete has good workability,flexural strength and shrinkage resistance,and can effectively resist deformation under load.Therefore it can improve the use of bridge expansion joints,and it is of great significance to reduce the service life and maintenance cost during the service life.