CN110550885A

CN110550885A - Semi-rigid track bed material for high-speed railway ballastless track and preparation method thereof

Info

Publication number: CN110550885A
Application number: CN201810535294.6A
Authority: CN
Inventors: 肖护兵; 徐萌; 权栋; 郭兆民
Original assignee: Connaught Jiangsu Luqiao Engineering Testing Co
Current assignee: Connaught Jiangsu Luqiao Engineering Testing Co
Priority date: 2018-05-30
Filing date: 2018-05-30
Publication date: 2019-12-10

Abstract

The invention discloses a semi-rigid track bed material for a ballastless track of a high-speed railway and a preparation method thereof, belonging to the technical field of rail transit. The semi-rigid track bed material comprises a porous asphalt mixture and cement emulsified asphalt composite mortar filled in pores of the porous asphalt mixture; in particular to a preparation method thereof, which comprises the following steps: (1) a preparation method of the porous asphalt mixture; (2) a preparation method of cement emulsified asphalt composite mortar; (3) a method for preparing a semi-rigid track bed material. The semi-rigid ballast bed material has the advantages of better strength, high-temperature stability and water stability than other types of asphalt concrete, obviously better toughness, low-temperature crack resistance, fatigue resistance and chemical corrosion resistance than cement concrete, simple process, low cost, easy maintenance, shock resistance, noise reduction, strong capability of adapting to roadbed deformation, good integrity and the like.

Description

Semi-rigid track bed material for high-speed railway ballastless track and preparation method thereof

Technical Field

The invention belongs to the technical field of rail transit, relates to a semi-rigid material, and particularly relates to a semi-rigid track bed material for a ballastless track of a high-speed railway and a preparation method thereof.

Background

the track bed is an important part for ensuring the stability, smoothness and reliability of the railway line. The conventional ballast track has the problems of rapid track bed accumulation deformation, serious railway ballast pulverization, slurry pumping, compaction sinking and the like under the long-term action of high-speed train load, and the problems can increase the maintenance cost of a high-speed railway and threaten the safety of the high-speed railway. Therefore, a ballastless track capable of ensuring high stability, high flatness and high reliability of a line of a high-speed railway is required.

according to the ballastless track of China, a cement concrete material is generally adopted as a rigid foundation structure, however, a large number of practical engineering applications prove that the cement concrete has the problems of easiness in cracking, poor roadbed adaptability, high noise, complexity in construction, difficulty in maintenance and the like due to high rigidity and high brittleness, and post-cast concrete at a wide seam arranged on the cement concrete has the hidden troubles of cracking and the like, so that the long-term use performance and the maintenance function of the ballastless track of the high-speed railway are seriously restricted, and even the operation safety of the high-speed railway can be possibly damaged under the serious condition. Therefore, it is necessary to develop other materials for the foundation structure of the ballastless track of the high-speed railway.

In the 60 s of the 20 th century, engineering application research of asphalt concrete as a flexible foundation structure began at home and abroad, and various asphalt concrete materials, particularly emulsified asphalt concrete, are mainly adopted to form a stable foundation structure. The asphalt concrete is used as a flexible foundation structure, the defect of high rigidity of a cement concrete foundation structure is overcome, the elasticity close to that of the traditional gravel ballast is obtained, and the dynamic deformation of the asphalt concrete is much smaller than that of the gravel ballast. However, since the asphalt concrete directly bears the cyclic impact action of the rail and the sleeper and the change action of the external temperature, the asphalt concrete must have sufficient strength, durability, high-temperature stability and low-temperature crack resistance, otherwise the asphalt concrete can deform and locally thin, the upper sleeper is embedded, the lower part is pulled to crack and lose the waterproof function, and the like, and the concrete such as emulsified asphalt can not meet the requirement of the complaint. Therefore, at the present stage, the asphalt concrete is only suitable for waterproof sealing materials of a ballastless track non-structural layer, cushion materials on a ballastless track cement concrete base layer, surface layer materials on a ballastless track cement concrete road bed and the like, and cannot be used as a whole flexible base layer structural material of the ballastless track. Therefore, it is necessary to research a semi-rigid composite structural material as an integral track bed of a ballastless track of a high-speed railway, so that the material has the rigidity of water concrete and the flexibility of asphalt concrete.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a semi-rigid track bed material for a ballastless track of a high-speed railway and a preparation method thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

The semi-rigid track bed material for the ballastless track of the high-speed railway comprises a porous asphalt mixture and cement-emulsified asphalt composite mortar filled in pores of the porous asphalt mixture. The porous asphalt mixture comprises the following components, by mass, 3% -6% of asphalt cement, 93% -96% of aggregate and 1% -3% of mineral powder, wherein the total mass is 100%; the cement-emulsified asphalt composite mortar comprises the following components, by mass, 10% -25% of emulsified asphalt, 20% -30% of cement, 2% -8% of an active admixture, 30% -45% of sand, 2% -10% of water, 0.2% -0.4% of a water reducing agent, 0.2% -1.5% of a defoaming agent, 1% -3% of an expanding agent and 0.2% -0.4% of an air entraining agent, and the total mass is 100%.

The porosity of the porous asphalt mixture is 15-28%, and the porosity can enable the semi-rigid track bed material after grouting to be rigid and flexible, so that proper strength, modulus, crack resistance and fatigue resistance can be achieved.

The asphalt cementing material can be road petroleum asphalt A grade, polymer modified asphalt and the like, and the performance index of the asphalt cementing material can meet the requirements of technical Specifications for road asphalt pavement construction (JTG F40-2004).

The aggregate can be selected from limestone, basalt, granite, diabase and the like, and the performance index of the aggregate should meet the requirements of technical Specification for construction of road asphalt pavements (JTG F40-2004).

The quality index of the mineral powder preferably limestone mineral powder meets the requirement of technical Specification for road asphalt pavement construction (JTG F40-2004).

The mixture of the aggregate and the mineral powder has the grading which meets the requirements of the table 1.

TABLE 1

The technical indexes of the cement-emulsified asphalt composite mortar meet the requirements of table 2, so that the strength, durability, stability and fatigue resistance of the semi-rigid track bed material can meet the operation requirements of a high-speed railway.

TABLE 2

Cation modified emulsified asphalt (BCR) is preferably selected as the emulsified asphalt, the content of evaporation residues is not less than 60 percent, and other performance indexes meet the requirements of technical Specifications for road asphalt pavement construction (JTG F40-2004).

The cement is preferably silicate cement with the strength of more than 42.5, and the performance index of the silicate cement meets the national standard requirement.

The active admixture is preferably one or more of fly ash, granulated blast furnace slag, lithium-containing tailings and silica fume, and the technical indexes of the admixture are shown in the table 3.

TABLE 3

The sand is river sand or machine-made sand, the fineness modulus is 1.4-2.2, and other performance indexes meet the TB10210-97 standard.

The water is preferably drinking water with pH being more than or equal to 7.

The water reducing agent is preferably a poly hydroxy acid water reducing agent, and the main properties of the water reducing agent meet the requirements of GB 8076.

The defoaming agent is preferably a silicone defoaming agent, and the main performance of the defoaming agent meets the requirements of GB/T26527-2011.

The aluminum powder is preferably scale-shaped aluminum powder, and the main performance of the aluminum powder meets the regulation of GB/T2085.1-2007.

The expanding agent is preferably calcium sulphoaluminate expanding agent, and the main performance of the expanding agent meets the regulation of GB 23439-2009.

the air entraining agent is preferably alkyl aromatic hydrocarbon sulfonic acid air entraining agent, and the main performance meets the regulation of GB 8076-2008.

The invention also provides a preparation method of the semi-rigid track bed material, which comprises the following steps:

1. Preparation method of porous asphalt mixture

Weighing aggregate and mineral powder which are heated to 180-190 ℃ according to the mass percentage, putting the aggregate and the mineral powder into an asphalt mixture mixing pot, and stirring for 10-15 s; then adding asphalt cement which is weighed according to the mass percentage and heated to 150-175 ℃ into the mixing pot, and stirring for 25-40 s; and finally, taking the mixture out of the pot, and rolling by using a wheel rolling forming machine to control the internal porosity of the porous asphalt mixture to be between 15 and 28 percent.

2. Preparation method of cement emulsified asphalt composite mortar

Sequentially weighing sand, an active admixture, cement, water, a water reducing agent, an expanding agent, an air entraining agent and a defoaming agent according to the mass percentage, putting into a mixing pot, and stirring for 1.5 min; then adding the weighed modified emulsified asphalt and stirring for 3min to prepare the cement emulsified asphalt composite mortar.

3. Preparation method of semi-rigid ballast bed material

Uniformly pouring the prepared cement-emulsified asphalt composite mortar into the surface of the porous asphalt mixture, and then vibrating the cement-emulsified asphalt composite mortar into gaps of the mixture by adopting a flat vibrator until the composite mortar stops infiltrating; and finally, cleaning the laitance on the surface of the porous asphalt mixture by using a brush to enable the surface to have a stone exposing structure, curing, and obtaining the semi-rigid ballast bed material after curing.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the semi-rigid ballast bed material is a rigid-flexible composite structure material, and effectively overcomes the defects of poor deformation resistance, easy cracking, high noise, low fatigue resistance, difficult maintenance and the like of a cement concrete material due to strong rigidity, large brittleness and low toughness; overcomes the defects of poor high-temperature stability, weak water damage resistance and the like of the asphalt concrete material due to low strength and high temperature sensitivity.

2. The semi-rigid track bed material is formed by combining two materials, namely asphalt mixture and cement-emulsified asphalt composite mortar, so that the construction can be completed by using conventional asphalt mixture and cement mortar construction equipment, the construction process is simple, the requirement on the equipment is not high, the process is easy to master, and the construction speed is high.

3. The performance of the semi-rigid track bed material determines the construction process of the semi-rigid track bed material in the track bed, a series of construction joints, expansion joints and contraction joints do not need to be arranged like a cement concrete track bed, and the integrity is good; meanwhile, the intelligent asphalt mixture paver is adopted for construction, so that the flatness of the ballast bed and the smoothness of the line type can be effectively improved, and the running is more comfortable and stable.

Drawings

Fig. 1 is a graph of a porous asphalt mixture gradation range of a semi-rigid track bed material for a ballastless track of a high-speed railway disclosed by the invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and examples, which are provided for the purpose of illustration only and are not intended to limit the scope of the present invention.

Raw materials used in the examples: the asphalt cementing material is 70# A grade road petroleum asphalt and SBS polymer modified asphalt produced by Jiangsu Tiannuo road material technology Co., Ltd, the aggregate is limestone and basalt macadam produced by Liyang Shanpei stone factory of Changzhou city, the mineral powder is limestone mineral powder produced by Liyang Shanpei stone factory of Changzhou city, the emulsified asphalt is BCR cation modified emulsified asphalt produced by Jiangsu Tiannuo road material technology Co., Ltd, the cement is 42.5 grade and 52.5 grade ordinary silicate cement of Jidong brand, S95 grade and S105 grade water quenching blast furnaces are produced by Jiangsun Hubao Long technology development Co., Ltd, the water reducing agent is polycarboxylic acid series high efficiency water reducing agent JM-PCA (I) -A produced by Jiangsu Tiantong New Material Co., Ltd, the expanding agent is calcium chlorate expanding agent produced by Beijing German Chang Wei building engineering technology Co., Ltd, and the air entraining agent is DC-3 type alkyl aromatic sulfonic acid air entraining agent produced by Henan province Dai technology Co., Ltd, the defoaming agent is powdered organosilicon defoaming agent produced by Jiangsu Scott science and technology limited, the water is supplied by Hongkong tap water company in Zhenjiang, and the sand is machine-made sand and river sand produced by Liyang Shanpei stone material factory in Hezhou city.

Example 1

1. Preparation method of porous asphalt mixture

Heating limestone aggregate accounting for 93 percent of the mass percent of the porous asphalt mixture and limestone mineral powder accounting for 3 percent of the mass percent of the porous asphalt mixture to 180 ℃, putting into an asphalt mixture stirring pot, and stirring for 10 s; then adding 70# A grade road petroleum asphalt which is heated to 150 ℃ and accounts for 4 percent of the porous asphalt mixture by mass into the mixing pot, and stirring for 40 s; and finally taking the mixture out of the pot, and rolling for 20 times by using a wheel rolling forming machine to obtain the porous asphalt mixture with the internal porosity of 15%.

2. Preparation method of cement emulsified asphalt composite mortar

Weighing 45% of river sand, 8% of S95-grade water-quenched blast furnace slag, 25% of 42.5-grade cement, 2% of water, 0.4% of water reducing agent, 1% of expanding agent, 0.4% of air entraining agent and 0.2% of defoaming agent in sequence by mass percent, putting into a mixing pot, and stirring for 1.5 min; then adding BCR modified emulsified asphalt accounting for 18 percent of the mass percent of the cement emulsified asphalt composite mortar, and stirring for 3min to prepare the cement emulsified asphalt composite mortar.

3. Preparation method of semi-rigid ballast bed material

The detection is carried out according to road engineering asphalt and asphalt mixture test procedures (JTG E20-2011) and related test detection methods:

(1) Test results for porous asphalt mixes: the void ratio is 15%, and the dynamic stability of the rut test is 1905 times/mm.

(2) The test results of the cement-emulsified asphalt composite mortar are shown in Table 4.

TABLE 4

(3) The test results after 7 days of curing of the semi-rigid track bed material are shown in table 5.

TABLE 5

Example 2

1. Preparation method of porous asphalt mixture

Heating basalt aggregate accounting for 96 percent of the mass percent of the porous asphalt mixture and 1 percent of limestone mineral powder to 190 ℃, putting into an asphalt mixture mixing pot, and stirring for 13 s; then adding polymer modified asphalt which is heated to 175 ℃ and accounts for 3 percent of the mass of the porous asphalt mixture into the mixing pot, and stirring for 30 s; and finally taking the mixture out of the pot, and rolling for 18 times by using a wheel rolling forming machine to obtain the porous asphalt mixture with the internal porosity of 28%.

2. preparation method of cement emulsified asphalt composite mortar

Weighing 30% of machine-made sand, 6% of S105-grade water-quenched blast furnace slag, 30% of 52.5-grade cement, 8% of water, 0.2% of water reducing agent, 3% of expanding agent, 0.2% of air entraining agent and 1.5% of defoaming agent in sequence by mass percent, putting into a mixing pot, and stirring for 1.5 min; then adding BCR modified emulsified asphalt which accounts for 21.1 percent of the mass percent of the cement emulsified asphalt composite mortar, and stirring for 3min to prepare the cement emulsified asphalt composite mortar.

3. Preparation method of semi-rigid ballast bed material

(1) Test results for porous asphalt mixes: the void ratio is 28%, and the dynamic stability of the rut test is 2609 times/mm.

(2) The test results of the cement-emulsified asphalt composite mortar are shown in Table 6.

TABLE 6

(3) The results of the test after 7 days of curing of the semi-rigid track bed material are shown in Table 7.

TABLE 7

Example 3

1. preparation method of porous asphalt mixture

Heating basalt aggregate accounting for 94 percent of the mass percent of the porous asphalt mixture and 1.5 percent of limestone mineral powder to 185 ℃, putting into an asphalt mixture mixing pot, and stirring for 15 s; then adding polymer modified asphalt which is heated to 170 ℃ and accounts for 4.5 percent of the mass of the porous asphalt mixture into the mixing pot, and stirring for 35 s; and finally taking the mixture out of the pot, and rolling for 23 times by using a wheel rolling forming machine to obtain the porous asphalt mixture with the internal porosity of 20%.

2. Preparation method of cement emulsified asphalt composite mortar

Weighing 36% of machine-made sand, 8% of S105-grade water-quenched blast furnace slag, 24% of 42.5-grade cement, 6% of water, 0.3% of water reducing agent, 2% of expanding agent, 0.3% of air entraining agent and 1.0% of defoaming agent in sequence by mass percent, putting into a mixing pot, and stirring for 1.5 min; then adding BCR modified emulsified asphalt accounting for 22.4 percent of the mass percent of the cement emulsified asphalt composite mortar, and stirring for 3min to prepare the cement emulsified asphalt composite mortar.

3. Preparation method of semi-rigid ballast bed material

(1) Test results for porous asphalt mixes: the porosity is 20 percent, and the dynamic stability of the rut test is 3357 times/mm.

(2) The test results of the cement-emulsified asphalt composite mortar are shown in Table 8.

TABLE 8

(3) The results of the test after 7 days of curing of the semi-rigid track bed material are shown in Table 9.

TABLE 9

Detecting the index	Unit of	The result of the detection	Technical requirements
				Compressive strength	Mpa	17.2	≥15
Marshall stability	kN	24.9	≥20
				Dynamic stability (70 ℃ C.)	Sub/mm	25881	≥20000
Low temperature bending failure strain (-10 ℃ C.)	με	2300	≥1800
				Ratio of residual stability	%	94.4	≥85
Freeze-thaw split strength ratio	%	90.5	≥80

The above examples of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations will be apparent to persons skilled in the art upon consideration of the foregoing description. All embodiments need not be exhaustive, and the upper and lower limits and intervals of the raw materials can be used to practice the present invention.

Claims

1. The semi-rigid track bed material for the high-speed railway ballastless track is characterized by comprising a porous asphalt mixture and cement-emulsified asphalt composite mortar filled in pores of the porous asphalt mixture.

2. The porous asphalt mixture according to claim 1, wherein the internal porosity of the mixture is 15% to 28%; the porous asphalt mixture comprises the following components, by mass, 3% -6% of asphalt cement, 93% -96% of aggregate and 1% -3% of mineral powder, and the total mass is 100%.

3. The cement-emulsified asphalt composite mortar as claimed in claim 1, wherein the composite mortar comprises, by mass, 10% to 25% of emulsified asphalt, 20% to 30% of cement, 2% to 8% of an active admixture, 30% to 45% of sand, 2% to 10% of water, 0.2% to 0.4% of a water reducing agent, 0.2% to 1.5% of an antifoaming agent, 1% to 3% of an expanding agent, and 0.2% to 0.4% of an air entraining agent, the total mass being 100%.

4. The preparation method of the semi-rigid track bed material for the ballastless track of the high-speed railway according to claim 1, characterized by comprising the following steps:

(1) Preparation method of porous asphalt mixture

Weighing aggregate and mineral powder which are heated to 180-190 ℃ according to the mass percentage, putting the aggregate and the mineral powder into an asphalt mixture mixing pot, and stirring for 10-15 s; then adding asphalt cement which is weighed according to the mass percentage and heated to 150-175 ℃ into the mixing pot, and stirring for 25-40 s; finally, taking the mixture out of the pot, and rolling by using a wheel rolling forming machine to control the internal porosity of the porous asphalt mixture to be between 15 and 28 percent;

(2) Preparation method of cement emulsified asphalt composite mortar

Sequentially weighing sand, an active admixture, cement, water, a water reducing agent, an expanding agent, an air entraining agent and a defoaming agent according to the mass percentage, putting into a mixing pot, and stirring for 1.5 min; then adding the weighed modified emulsified asphalt and stirring for 3min to prepare the cement emulsified asphalt composite mortar;

(3) preparation method of semi-rigid ballast bed material