Experimental Study On Mechanical Properties Of Steel Fiber Concrete And Its Application In Assembled Pavement Panels

For the temporary use of roads and temporary emergency roads for vehicles coming and going from construction sites,the use of traditional cast-in-place concrete pavement has the disadvantages of poor flexural and tensile properties,long maintenance time,maintenance obstructing traffic and dismantling after completing its function will produce a large amount of construction waste.Therefore,domestic and foreign scholars proposed assembled concrete pavement panels,but assembled concrete pavement panels failed to solve the problem of poor flexural and tensile properties,and its joints are prone to various diseases under the round-trip action of vehicles.And steel fiber concrete as a new material has better bending resistance,crack resistance,fatigue resistance and other characteristics.Therefore,the application of steel fiber concrete in assembled pavement panels is of great significance to the sustainable development of pavement engineering.In this paper,assembled steel fiber concrete pavement panels are proposed from the perspective of pavement flexural and tensile performance and energy saving and green,and the main research contents and conclusions are as follows.1.The effect of the mix design method on the mechanical properties of steel fiber concrete was investigated.It was found that all mechanical properties of steel fiber concrete formulated by both the secondary synthesis method(hereafter referred to as the synthesis method)and the equal volume replacement coarse aggregate method(hereafter referred to as the replacement method)design methods were significantly improved compared to the matrix concrete.2.The effects of two factors,steel fiber type and steel fiber volume admixture,on the mechanical properties of concrete were investigated to optimize the steel fiber concrete mixes.The test results show that the end-hook-shaped steel fibers improve the compressive,flexural and splitting tensile strengths more significantly,and the milled steel fibers are slightly inferior.The relationship between the compressive,flexural and splitting tensile strengths of steel fiber concrete and the volume admixture of steel fibers was obtained by fitting the test data.3.Through the structural optimization analysis of the assembled steel fiber concrete pavement slab,two lifting methods,four-point lifting at the side and four-point lifting at the top,were designed.The lifting hole positions of the assembled pavement slabs were simulated at3/20,1/5,1/4 and 3/10 of the slab length by using ABAQUS finite element software.The simulation results show that the tensile stresses generated by the slab are minimal when the lifting points of the two lifting methods are set at 1/4 of the slab length.4.The mechanical properties of assembled steel fiber concrete pavement panels were investigated.The effects of loading position,panel and subgrade modulus of elasticity on the load transfer performance of assembled steel fiber concrete pavement panel joints under static load were explored,and the changes of stress and displacement at the edge of assembled steel fiber concrete pavement joints under different vehicle speeds were also compared and analyzed.The simulation results show that: the most unfavorable load location in the middle edge of the longitudinal joint of the plate,with the increase of the modulus of elasticity of the road panel and the subgrade,the load transfer capacity of the road panel joints is also gradually increasing;moving load under the action of the plate in the X-direction main stress and Z-direction displacement of the maximum time point is not the same,the value of the maximum displacement difference is also different;can provide a valid and reliable basis for the assembled steel fiber concrete road panel.5.Through the actual field test process of assembled steel fiber concrete pavement panels,the whole process of field application of assembled steel fiber concrete pavement panels was established,and the construction process suitable for assembled pavement construction was developed,and the test section guided by the research results based on the thesis received a better use effect.