Concrete Mix Proportion Design And Performance Of Prestressed Rubberized Concrete Sleeper

With the rapid development of railway infrastructure,the demand for sand and gravel resources is increasing.The railway track structure has presented degrees of disease during the service period,which not only greatly shortens the service life,but also bring some security risks.At the same time,used tires are piled up in large quantities with the development of social modernization,which puts a lot of pressure on the global environment.Therefore,this research aims to combine the reuse of rubber tires with the performance requirements of railway sleepers,and the applicability of rubber particles to concrete railway sleepers is explored.While consuming waste tires,the mining of concrete fine aggregates is reduced to a certain extent,which verifies the popular direction for improving railway sleeper performance and reducing track diseases.The basic mechanical properties and durability of the rubber concrete test specimens were experimentally studied to explore the feasibility of its application in sleeper production.The optimal mix ratio was selected to make concrete railway sleepers,and its mechanical properties and vibration damping properties were evaluated.This research mainly has three points as follows:(1)Optimization and adjustment of the base mix proportion,rubber particle size and modification method of rubberized concrete.Two kinds of rubber particles of 60 mesh and 1-3 mm were used to prepare rubberized concrete test specimens to study their strength and workability.Tests show that: unmodified 60 mesh rubber particles reduced the strength and workability of concrete;The 60-mesh rubberized concrete modified with Na OH solution or coupling agent Si69 had no obvious improvement in strength compared with unmodified 60 mesh rubber concrete;The unmodified 1-3mm rubber particles showed serious floating phenomenon during the process of preparing rubberized concrete.The 1-3mm rubberized concrete modified by the pre-coated cement shell limited its use due to the increase in labor costs and the fragility of the cement shell.Therefore,this study selected unmodified 60-mesh and 30-mesh rubber particles for subsequent tests on the basis of the optimized reference mix ratio.(2)Explore the optimal rubber particle content and particle size of rubberized concrete through basic mechanical properties and durability experiments.60 mesh and 30 mesh rubber particles were mixed into rubberized concrete test specimens with 0,5%,10%,15%,and 20% content to test their apparent density,working property,compressive strength,flexural strength,adhesion to steel bar,abrasion resistance,chloride penetrate resistance.The results showed that: In addition to improving the chloride penetration resistance,the incorporation of rubber particles reduced the basic indicators of concrete mechanical properties and durability.Considering to increase the utilization rate of rubber particles as much as possible on the basis of meeting the concrete performance,the rubber concrete test specimens prepared with the content of 30 mesh rubber particles at 15% was selected for the subsequent preparation and testing of rubberized concrete railway sleepers.(3)The rubberized concrete railway sleepers were fabricated and the sleeper fracture and analysis of fracture mechanical properties and vibration attenuation were performed.The rubberized concrete railway sleepers made of 30 mesh 15% rubber particles were used for static load test and digital image related technology test,in order to analyze its crack resistance and crack development.The finite element model was established to analyze the dynamic performance of the ballasted track with ordinary concrete and rubberized concrete railway sleepers.The results showed that: The static load test results met the specification requirements.The test results of digital image related technology showed that the cracks of rubberized concrete railway sleepers were generated at a higher load level than ordinary concrete,while the crack propagation rate was greater.The results of the finite element simulation showed that the use of rubberized concrete railway sleepers could reduce the vibration acceleration of the ballasted track.