Compounding Technology For Wood-Residue Based Railway Sleeper

Railway ensures the rapid economic development of China.Railway sleeper is an important hardware of the railway system,which determines the traffic speed,traffic safety and passenger comfort.With rapid development of the railroad system in China,the traditional sleeper materials could no longer meet the requirements for quality,quantity,and technical performance.A new composite material for railway sleeper was introduced by taking wood residues as filling,Moso bamboo slice and glass fiber as reinforcement,and taking resole phenol resin as substrate.The compounding technology of the composite material was studied. The compounding factors and process conditions for the compounding technology of the composite material were identified based on material component,structure design,mechanical properties,etc.The compounding technology for the new sleeper material compatible with the railway sleeper technical performance standards was proposed.Experiments with welldistribution design and orthogonal design were used in this study.Data were analyzed using DPS data processing system.The major content of this study include:the component selection and analysis for the railway sleeper composite material,component properties and their effect on material performance,structure design principles,technological requirements,and structure design of the composite material,basic assumptions for mechanical property analysis of the composite material,mechanical analysis for the reinforcement,substrate,and material structure of the composite,optimum compounding factors of the composite,and process condition for the preparation of the railway sleeper composite material.,etc.The following conclusions were obtained:(1)Determined that the composite material could be prepared by taking wood residues as filling,glass fiber and Moso bamboo slice as reinforcement,resole phenol resin as substrate,aminoorganosilane as interface modification additives,benzene sulfonic acid as waterproof agent,and taking urea as diluent to the resole phenol resin;(2)Proposed a layer jacketed structure of the railway sleeper composite material. Which shows obvious advantages in MOR,elastic modulus,thickness swelling,internal bonding stringing under dry and wet state as well as compressive strength with static loading. It also identified that wood residues is the best filling material for the railway sleeper composite;(3)The major mechanical properties of strength,modulus,deformation and stiffness of the composite material were analyzed theoretically based on the study of tensile, compression,bending,and shearing cut of the material and their variations under varied loading were obtained;(4)Derived the interrelationship between compounding factors of pressing time(X₁),glue content(X₂),and density(X₃) and physical and mechanical properties of MOR(Y₁),elastic modulus(Y₂),thickness swelling(Y₃),internal bonding strength under dry (Y₄) and wet state(Y₅),compressive strength(Y₆) and determined that the optimum compounding factors are as follows:pressing time t=0.7min/mm;glue content m=14.30%; densityρ=0.96 g.cm-3;(5)Determined the basic processing condition of the composite material as follows:pressing temperature T=180～200℃;compound pressure:unit pressure P=3.5MPa,consistent unit pressure P₁=1.9MPa,balancing unit pressure P₂=0.3～0.5MPa; pressing time t=0.7min/mm;glue content q=14.30%;densityρ=0.96g.cm-3;(6) According to American ASTM D1037 Six-cycling Speeding Aging method,thickness swelling meets the requirement,and major physical and mechanical properties of MOR and elastic modulus also meet the requirements.