Polyurethane caulking material for expansion joints of ballastless track of high speed railway

Abstract

A polyurethane caulking material for expansion joints of a ballastless track of a high speed railway is disclosed. The caulking material is prepared from two parts A and B. the part A is composed of the following raw materials, by weight, 100 parts of isocyanate and its prepolymer, 10-150 parts of a plasticizer, 5-150 parts of a solid filler, 1-20 parts of a diluents, 1-5 parts of an adhesion promoter, 0-10 parts of a thixotropic agent and 1-3 parts of a water-removal agent. The part B is composed of the following raw materials, by weight, 10-20 parts of modified polyhydric alcohol, 1-5 parts of a diluent, 2-30 parts of a plasticizer, 5-30 parts of a solid filler, 0-5 parts of a thixotropic agent, 0.5-2 parts of an antifoaming agent, 0.1-1 part of an anti-aging agent and 0-0.01 part of a catalyst. The mass ratio of the part A to the part B is 4:1-10:1. The polyurethane caulking material has advantages of good low-temperature curing performance, high displacement capability, low tensile modulus, good bond property and excellent endurance quality and fatigue resistance, and is suitable for expansion joints of a ballastless track of a high speed railway as well as expansion joints of roads and airfield runways.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a polyurethane caulking material used for expansion joints of high-speed railway ballastless tracks. Background technique [0002] In the ballastless track structure of high-speed railway, the base slab and track bed slab are long-line continuous pouring structures. In order to adapt to the deformation of the concrete structure at different temperatures, it is often necessary to set expansion joints at a certain distance. There are a large number of joints, all of which require the use of caulking materials that can withstand changes in joint displacement to prevent moisture, debris, etc. from entering the joint. [0003] The displacement of expansion joints set on the base plate and ballast bed plate of the long continuous pouring structure is very large. Taking the base plate of CRTS III slab ballastless track as an example, the displacement of expansion joints mai...

AI Technical Summary

Problems solved by technology

However, the current market lacks polyurethane caulking materials designed according to the actual needs of high-speed railway ballastless track, and the existing products used in high-speed railway ballastless track expansion joints still have the following problems: (1) the joint between high-speed railway ballastless track structure The deformation characteristics do not match, the displacement capacity is low, and the tensile modulus is high, which cannot meet the requirements of 50LM sealant, and it is easy to have problems of separation and cracking during use

(2) The durability and fatigue resistance are poor, and it is easy to be damaged under the action of temperature force and train dynamic load, and it is prone to problems such as peeling, pulverization and cracking under the sun for a long time, and loses the waterproof and sealing function.

(3) It is highly sensitive to temperature and humidity. It is easy to foam when the air humidity is high, and it is difficult to cure when it is below 5°C.

(4) When stored at low temperature, solid chain-extending cross-linking agents such as MOCA are easy to precipitate

Moreover, using tap water as a chain extender, when the colloid perfusion thickness is deep, it is easy to foam and difficult to control

At the same time, the cost of aliphatic isocyanate and hydroxyl silicone oil is high, especially aliphatic isocyanate, its price is generally more than twice that of commonly used aromatic isocyanate

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