The Research Of Resin Composite Material Under The High-speed Railway Slab Track

China’s high-speed rail develop rapidly, it is an opportunity for the development of high-speed rail, with a lot of foreign projects being signed, so the improvement of technology is necessary. The main structure of the high speed railway is slab ballastless track. Due to the complex construction and low intensity of CA mortar,resin filler material caused higher attention. But its cost is high, inorganic fillers are adopted to decrease the cost.This paper introduces the research status of inorganic particle filling polyurethane composite materials at home and abroad. With hardness, compressive strength and thermogravimetric analysis(TG) as a standard, silica fume, carbon black and pumice from the ten kinds of inorganic filler were selected. Because the incompatibility between the inorganic filler and organic matrix, we modified the silica fume and carbon black with silane coupling agent KH-550. The effect of the modification was evaluated with infrared spectroscopy(FT-IR), scanning electron microscope(SEM), transmission electron microscopy(TEM) and TG. Meanwhile, we compared the inorganic filler added to the polyurethane before and after modification,and compared the influence to cross section morphology, thermal stability, hardness,and compressive strength. In order to reduce the cost and improve the performance,we had found the best proportion of modified silica fume, modified carbon black and pumice. Finally, to improve the performance of composites, we compared tributyl phosphate, XP3018 defoaming agent, DF8868 defoaming agent and DF176 defoaming agent and found the best type of defoaming agent. The following conclusions were found in the paper:(1) Adding inorganic filler improved the hardness, compressive strength and thermal stability of the polyurethane. Moreover adding silica fume, carbon black and pumice, the performance of the composite was better.(2) Modified the silica fume with KH-550 improved the dispersion in PU. When the dosage of modified silica fume was 40 %, composite materials presented the optimum properties.(3) Modified the carbon black with KH-550 improved the dispersion in PU.When the dosage of modified carbon black was 3 %, composite materials presented the optimum properties.(4) When the ratio of the modified silica fume, modified carbon black and pumice was 30:1:3, the polyurethane/inorganic filler composites got the best performance. Filling with different size added to the composite material, increased the compactness of the structure. And it was hard for saline medium to corrode. At the same time, the filling could prevent crack extension or change the direction of crack propagation, thus improving the performance of material. And denser network of the inorganic filler increased the coverage of organic materials and the limitation on the movement of polymer chain, thus the heat resistance also improved.(5) Because of the low surface tension, DF-8868 defoaming agent could thiner the liquid film, burst the bubble, realise tightly packed, and further improve the mechanical properties and heat resistance. Due to the reduction of defect, it was hard for the salt medium to soft and swells the matrix, so the weather resistance improved.