Study on Properties of Polyurethane Grouting Foam Material for High-Speed Railway Track Lifting

In this paper, a novel polyurethane grouting foam materials (PGFM) were optimized with the polyether polyol species, molecular weight, functional degree, isocyanate index, chain extender contents, catalyst species and contents into the desired formula. Such optimized formulation design disclosed that the PGFM had the best comprehensive performance when the isocyanate index was of 1.2, polyether molecular weight of 500–800, functional degree of 3–4, and chain extender at 3% and the catalyst dosage C1 0.4% and C2 0.2%. Intensive investigation in the molding density of PGFM influence on mechanical properties, water absorption, frost/acid/alkali resistant, aging performance, environmental properties and safety tested by experiment was found that PGFM had the low water absorption rate, excellent mechanical properties, dimensional stability frost/acid/alkali resistance and safe and environmentally friendly. Lastly, after injecting polymer grouting material into the lift track, the durability and dispersion of PGFM were also tested to confirm its engineering application feasibility for high-speed railway lifting track structure. It revealed that the PGFM evenly distributed under the concrete base plate and the surface of the track subgrade. The grouting filler can not only distribute evenly on the surface of the subgrade, but also enter into the interior of the subgrade along with the graded gravel pores, which further played an important role in strengthening the subgrade.