Low-modulus low-shrinkage high-freezing-resistance supporting layer material for ballastless track of high-speed railway

Abstract

Belonging to the technical field of building materials, the invention discloses a low modulus, low shrinkage and high antifreeze supporting layer material for high speed railway ballastless tracks, which comprises the following raw materials: 100-120kg / m < 3 > of a gelling component, 1000-1150kg / m < 3 > of a coarse aggregate, 750-1000kg / m < 3 > of a fine aggregate, 200-260kg / m < 3 > of a filling material, 20-40kg / m < 3 > of an air entraining energy absorption component and 150-180kg / m < 3 > of water. Wherein the coarse aggregate and the fine aggregate are both prepared by processing low-elasticity modulus mother rock, the filling material is a low-activity powder material, and the air entraining and energy absorbing component is rubber particles. The elastic modulus of the supporting layer material is greatly reduced, low shrinkage is achieved, the anti-freezing performance of the supporting layer material is remarkably improved, and the method has important significance on improving the service performance of a ballastless track supporting layer of a high-speed rail in a severe cold area.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a low-modulus, low-shrinkage, high-freeze-resistance supporting layer material for high-speed railway ballastless tracks and an application thereof. Background Art

[0002] The supporting layer is a crucial component of CRTS II slab and bi-block ballastless track structures. Positioned between the cement emulsion asphalt mortar / track slab and the subgrade, its primary function is to transfer load downward, diffuse stress, and provide stress relief. As a key structural component and foundation of the ballastless track structure, the service life of the supporting layer comprehensively reflects the smoothness and integrity of the ballastless track, directly impacting the durability of the track structure and the safety of train operations.

[0003] The current standard for high-speed railway ballastless track supporting layer (Q / CR 8-2014) stipulates the raw materials and performance indicators of the supporting layer. Its 28d compressive strength is 15±3MPa and the 28d shrinkage rate is ≤200. 10 -6 . According to the requirements of the "General Code for Concrete Structures" (GB55008-2021), the strength of the supporting layer material is lower than the minimum strength grade of concrete. The design theory and method of the supporting layer material are significantly different from those of ordinary concrete. It is difficult to obtain supporting layer materials that meet the requirements using existing concrete design methods and preparation technologies. Engineering practice also shows that the elastic modulus of the supporting layer material prepared by existing technology is relatively high, which does not conform to the design concept of low elastic modulus supporting layer. At the same time, the existing technology does not take into account the anti-freeze performance of the supporting layer, and the supporting layer of ballastless track in cold areas has the problem of insufficient anti-freeze performance.

[0004] Therefore, providing a low modulus, low shrinkage and high frost resistance supporting layer material and its application for high-speed railway ballastless track is a problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] In order to solve the problems of high elastic modulus, large shrinkage and insufficient frost resistance of supporting layer materials prepared by traditional technology, the present invention proposes a low modulus, low shrinkage and high frost resistance supporting layer material for high-speed railway ballastless track and its application.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A low modulus, low shrinkage and high frost resistance supporting layer material for high-speed railway ballastless track, comprising the following raw materials in the following proportions: a gelling component of 100-120 kg / m 3 , coarse aggregate 900-1050kg / m 3 , fine aggregate 750-1000kg / m 3 , filling material 200-260kg / m 3, air bleed energy absorption component 20-40kg / m 3 and water 150-180kg / m 3 .

[0008] Preferably, the elastic modulus of the matrix of the coarse aggregate is 10-20 GPa; the coarse aggregate is a mixture of particles with a mass ratio of 2-3:5-6:7-8 and particle sizes of 5-10 mm, 10-20 mm and 20-3.15 mm.

[0009] Preferably, the elastic modulus of the matrix of the fine aggregate is 10-20 GPa, and the fine aggregate accounts for 45-55% of the total mass of the coarse and fine aggregates.

[0010] Preferably, the filling material is a rock-based mineral admixture with an activity index of 50-60% and a specific surface area of ​​300-400m 2 / kg.

[0011] Preferably, the air entraining energy absorbing component is one or more of natural rubber, polybutadiene rubber and styrene-butadiene rubber particles, and the particle size thereof is 0.125-2.54 mm and the elastic modulus is 6-8 MPa.

[0012] According to the above-mentioned method for preparing a low modulus, low shrinkage and high frost resistance supporting layer material for high-speed railway ballastless track, the method comprises the following specific steps:

[0013] (1) Weighing the raw materials according to the ratio;

[0014] (2) Add the gelling component, filling material and air entraining energy absorbing component into a forced mixer, stir for 30-60 seconds to fully mix them, then continue to add coarse aggregate, fine aggregate and water, and stir for 2-3 minutes to obtain the supporting layer material.

[0015] According to the above-mentioned application of a low modulus, low shrinkage and high frost resistance supporting layer material in high-speed railway ballastless track.

[0016] Preferably, the supporting layer material is used between the cement emulsified asphalt mortar and the roadbed of the CRTSⅡ type slab ballastless track or between the roadbed slab and the roadbed of the double-span ballastless track.

[0017] Preferably, the support layer material is constructed by paving and rolling or slipform paving method.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention significantly reduces the elastic modulus of the supporting layer material, has lower shrinkage, and significantly improves the antifreeze performance of the supporting layer material, which is of great significance for improving the service performance of the high-speed railway ballastless track supporting layer in severely cold areas. DETAILED DESCRIPTION

[0020] The following describes embodiments of the present invention. These embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0021] Raw materials and sources

[0022] Cement: Beijing Jinyu P·O 42.5;

[0023] Fly ash: Class F, Grade I fly ash produced by Sichuan Huadian Gongxian Power Generation Co., Ltd., activity index 85%;

[0024] Coarse aggregate: parent rock elastic modulus 15.5GPa;

[0025] Fine aggregate: elastic modulus of parent rock 15.5GPa;

[0026] The filling material is limestone powder, with a 28-day activity index of 54% and a specific surface area of ​​325m2 / kg;

[0027] The air entraining energy absorbing component is polybutadiene rubber particles with a particle size of 0.125-2.54 mm and an elastic modulus of 7.5 MPa.

[0028] Examples 1-3 and Comparative Examples 1-2

[0029] The present invention provides a method for preparing a low-modulus, low-shrinkage, and high-freeze-resistant supporting layer material for high-speed railway ballastless track, which specifically comprises the following steps:

[0030] (1) Weigh the raw materials according to the proportions in Table 1;

[0031] (2) Add the cementitious component, filling material and air-entraining energy-absorbing component into a forced mixer and stir for 30-60 seconds to fully mix them. Then, add coarse aggregate, fine aggregate and water and stir for 2-3 minutes.

[0032] (3) The supporting layer material is constructed using the spreading and rolling method. The relevant performance data are shown in Table 1.

[0033] Table 1 Support layer material ratio and performance data

[0034]

[0035] As can be seen from the table, by adopting the material ratio and preparation method in the embodiment, the compressive strength grade of the supporting layer material is C15. Compared with the comparative example, the embodiment has a lower elastic modulus and drying shrinkage of the supporting layer material, and the antifreeze grade is improved to above F200, which is of great significance for ensuring the service performance of the supporting layer material in severe cold and cold regions.

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A low modulus, low shrinkage and high frost resistance supporting layer material for high-speed railway ballastless track, characterized in that: Includes the following raw materials: gelling component 100-120kg / m 3 , coarse aggregate 900-1050kg / m 3 , fine aggregate 750-1000kg / m 3 , filling material 200-260kg / m 3 , air bleed energy absorption component 20-40kg / m 3 and water 150-180kg / m 3 .

2. The low modulus, low shrinkage, and high frost resistance supporting layer material for high-speed railway ballastless track according to claim 1, characterized in that: The elastic modulus of the matrix of the coarse aggregate is 10-20 GPa, and the coarse aggregate is a mixture of particles with a mass ratio of 2-3:5-6:7-8 and particle sizes of 5-10 mm, 10-20 mm and 20-3.15 mm.

3. The low modulus, low shrinkage, and high frost resistance supporting layer material for high-speed railway ballastless track according to claim 1, characterized in that: The elastic modulus of the matrix of the fine aggregate is 10-20 GPa, and the fine aggregate accounts for 45-55% of the total mass of the coarse and fine aggregates.

4. The low modulus, low shrinkage, and high frost resistance supporting layer material for high-speed railway ballastless track according to claim 1, characterized in that: The filling material is a rock-based mineral admixture with an activity index of 50-60% and a specific surface area of ​​300-400m 2 / kg.

5. The low modulus, low shrinkage, and high frost resistance supporting layer material for high-speed railway ballastless track according to claim 1, characterized in that: The air entraining energy absorbing component is one or more of natural rubber, polybutadiene rubber and styrene-butadiene rubber particles, and the particle size thereof is 0.125-2.54 mm and the elastic modulus is 6-8 MPa.

6. The method for preparing a low modulus, low shrinkage, and high frost resistance supporting layer material for high-speed railway ballastless track according to any one of claims 1 to 5, characterized in that: The specific steps include: (1) Weighing the raw materials according to the ratio; (2) Add the gelling component, filling material and air entraining energy absorbing component into a forced mixer, stir for 30-60 seconds to fully mix them, then continue to add coarse aggregate, fine aggregate and water, and stir for 2-3 minutes to obtain the supporting layer material.

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