Study On The Friction Reclaimed Materials Of Waste Brake-shoe On Wear Resistance And Durability Of Concrete

The waste brake shoe in the train system consists of friction material and steel back.both of them,the friction material contained steel fiber,iron powder,rubber,graphite,resin,meerschaum and other composite materials and the consumption for that is huge every year.The dispose of waste brakes is the landfill basically which could cause serious pollution to the environment and also would take up a lot of land resources.Besides,this is contrary to the sustainable development strategies.Basing on this,the waste shoe friction recovery material was added into the concrete firstly in this paper.This is in order to analyze the effect of waste shoe friction recovery material on the strength,wear resistance,carbonation resistance and chloride ion erosion resistance.The steel fiber,iron powder,rubber contained in the waste brake shoe friction material as a single component firstly and as a parallel study to make an in-depth analysis of the mechanism of waste brake shoe friction material on the basic properties of concrete.The results showed that:(1)wear resistance and compressive of concrete strength were relatively high when 20 mesh above and the content of waste shoe friction recovery material was 10%.At the same time,the diffusion coefficient of chloride ions in the concrete was effectively reducedby 61.9% compared with the benchmark concrete;the concrete had the best carbon resistance when the content of waste shoe friction recovery material was 15% and carbonation resistance was reduced compared with the reference concrete;as the circumstance of 20 mesh or less and the content of waste shoe friction recovery material was 10%,wear resistance and compressive strength of the concrete were relatively well;When the content was 15%,concrete carbonation performance was relatively well,but it was still poor compared with the reference concrete;The diffusion coefficient of chloride ions was the smallest when the content was 5%,compared with the benchmark concrete,the diffusion coefficient of chloride ion was decreased by 40.3%;(2)taking the steel fiber into concrete can effectively improve the wear resistance,compressive strength,carbonation resistance and chloride ion erosion resistance of concrete.When the steel fiber volume rate is 2.5%,the wear resistance,strength and chloride diffusion coefficient of concrete increased by 31.9%,17% and 74.6%,respectively;(3)it can effectively improve the performance of concrete in the case of appropriate content of iron powder and when the mass ratio of 100 mesh iron powder to cement in concrete is 1.4,the concrete wear resistance and compressive strength awere higher,the wear resistance than the reference concrete increasing by 31.5%;When the mass ratio of 100 mesh iron powder to cement in concrete was 0.8,the concrete chloride ion resistance can be improved and the diffusion coefficient of chloride ion was decreased by 52.9% than the reference concrete;(4)th the wear mechanism of concrete can be changed by rubber.When the adhesive wear occurs,the concrete wear was reduced,but the compressive strength of concrete was decreased by rubber.When the equal volume replacement rate of rubber particles with sand is 10%,the wear resistance of concrete was increased by 16.3% than the reference concrete,but the strength and resistance of chloride ion erosion did not to be improved.The influence mechanism of waste shoe friction recovery material on the basic properties of concrete were studied by SEM and MIP.The result of SEM shown that the wear of concrete was caused by abrasive wear,fatigue wear and adhesive wear.Fatigue wear could cause microcracks and aggravates the wear of concrete.The result of MIP shown that the pore structure of concrete could be changed due to the different content of the admixture and the content,which would affect the anti-carbonization and anti-chloride corrosion resistance of the concrete.