Quick-setting concrete for railway and preparation method thereof
By adopting components such as sulfur aluminate cement-ordinary silicate cement-anhydrous gypsum ternary composite system and alkali-free liquid quick-coagulant, combined with specific stirring and injection processes, railway quick-coagulant with excellent early strength and durability was prepared, which solved the shortcomings of railway quick-coagulant concrete in early strength, durability and construction performance.
Patent Information
- Application Number
- CN202510428190.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-27
AI Technical Summary
Rapid coagulation concrete for railways has shortcomings in early strength, durability and construction performance, especially in high temperature and strong wind environments, which are prone to surface water loss and uneven strength distribution.
The ternary composite system of sulfur aluminate cement-common silicate cement-anhydrous gypsum was adopted, and alkali-free liquid quick-coagulant, thickener, expansion agent and nanoreinforced materials were added. Through specific stirring and injection processes, railway quick-coagulant concrete with excellent early strength and durability was prepared.
It has achieved rapid development of early strength, improved durability and optimized construction performance of railway fast-coagulated concrete, adapted to complex environments such as high temperature and strong winds, and met the multiple requirements of railway projects.
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of railway building materials, and particularly to a rapid-setting concrete for railways and a preparation method thereof. Background Art
[0002] For the rapid-setting concrete used in railways, due to the short setting time and the too fast evaporation rate of surface moisture, it is easy to cause rapid water loss and shrinkage on the surface layer of the concrete. Such cracks have irregular shapes and may develop into deep cracks or through cracks, especially more likely to occur in high-temperature and strong-wind environments. Insufficient material uniformity: If the quality control of raw materials is not strict (such as poor aggregate gradation and coarse admixture particles), or the mixing time is insufficient, it is easy to cause segregation and uneven strength distribution of the rapid-setting concrete. Summary of the Invention
[0003] The main purpose of the present invention is to provide a rapid-setting concrete for railways and a preparation method thereof, which successfully solves the multiple requirements of railway engineering for the early strength, durability and construction performance of rapid-setting concrete.
[0004] A rapid-setting concrete for railways, which comprises the following raw material components in parts by weight: Sulfoaluminate cement 55 - 60 parts Ordinary Portland cement 20 - 30 parts Anhydrous gypsum 8 - 12 parts Machine-made sand 75 - 85 parts Limestone crushed stone 95 - 105 parts Accelerator 2 - 2.5 parts Thickening agent 5 - 10 parts Expansive agent 6 - 10 parts Polycarboxylate water reducer 2 - 2.5 parts Water 40 - 50 parts.
[0005] Preferably, it comprises the following raw material components in parts by weight: Sulfoaluminate cement 58 parts Ordinary Portland cement 25 parts Anhydrous gypsum 10 parts Machine-made sand 80 parts Limestone crushed stone 100 parts Accelerator 2.2 parts Thickening agent 7.5 parts Expansive agent 8 parts Polycarboxylate water reducer 2.2 parts Water 45 parts.
[0006] Preferably, the accelerator is an alkali-free liquid accelerator, which comprises the following raw material components in parts by weight: 45 - 55 parts of Al2(SO4)3・18H2O 8 - 12 parts of Na2SiF6 6 - 10 parts of EDTA 3 - 8 parts of TEA 20 - 40 parts of deionized water
[0007] Preferably, it further includes 3 - 6 parts by weight of nano - reinforcing material, and the nano - reinforcing material is composed of nano - silica fume and nano - TiO2.
[0008] Preferably, the mass ratio of the nano - silica fume to the nano - TiO2 is (2 - 4):1, the specific surface area of the nano - silica fume is 20 - 30 m² / g, and the particle size is 200 - 500 nm; the nano - TiO2 is anatase type, and the particle size is 60 - 100 nm.
[0009] Preferably, the thickening agent is hydroxypropyl methylcellulose.
[0010] Preferably, the expansive agent is UEA expansive agent.
[0011] Preferably, the fineness modulus of the manufactured sand is 2.8 - 3.2, and the stone powder content is 5 - 8%; the particle size of the limestone crushed stone is 5 - 16 mm, and the crushing index ≤ 12%.
[0012] A construction process of rapid - setting concrete for railways includes the following steps: S1. Prepare sulfoaluminate cement, ordinary Portland cement, anhydrous gypsum, manufactured sand, limestone crushed stone, rapid - setting agent, thickening agent, expansive agent, polycarboxylate water - reducing agent and water according to parts by weight; S2. First, put the manufactured sand and limestone crushed stone into a compulsory mixer for dry mixing until evenly mixed; then add sulfoaluminate cement, ordinary Portland cement and anhydrous gypsum, and continue dry mixing to ensure full mixing of each component; after mixing the thickening agent, polycarboxylate water - reducing agent and water evenly, add them into the compulsory mixer and stir to obtain a concrete mixture; finally, add the expansive agent and nano - reinforcing material, and continue stirring to make the expansive agent and nano - reinforcing material evenly dispersed in the concrete mixture; S3. Add the rapid - setting agent evenly into the concrete mixture through the rapid - setting agent adding system of the spraying machine, and adopt the wet - spraying process to spray the well - stirred concrete mixture to the construction site of the railway project through the spraying machine and the conveying pipeline; S4. After spraying, trim the surface of the concrete, and carry out spray curing within 1 - 2 h. The curing temperature is controlled at 20 ± 2 °C, the curing humidity ≥ 90%, and the curing time is not less than 7 days.
[0013] Preferably, the construction parameters of the spraying machine in S3 are: Air pressure control: 0.4 - 0.6 MPa; Spraying angle: Keep 90° with the sprayed surface; Spraying distance: 0.8 - 1.2 m; Thickness of layered spraying: Each layer ≤ 100 mm.
[0014] Advantages of the present invention: Adopt a ternary composite system of sulfoaluminate cement - ordinary Portland cement - anhydrous gypsum: The hydration of sulfoaluminate cement generates ettringite and monosulfate hydrated calcium aluminate, and a strength skeleton can be formed in 1 h. Ordinary Portland cement supplements the later strength development and improves the volume stability. Anhydrous gypsum is used as a sulfate activator to regulate the setting time and inhibit the flash setting phenomenon of sulfoaluminate cement.
[0015] In the alkali-free liquid accelerator, Al2(SO4)3・18H2O hydrolyzes to generate Al(OH)3 colloid, which quickly wraps the cement particles to form a flocculent structure. Sodium fluorosilicate releases F⁻ ions to promote the hydration of C3S to generate C-S-H gel. EDTA and TEA cooperate to complex Ca²⁺, delay the rapid reaction in the initial stage of cement hydration, control the setting speed, and ensure the adhesion of the sprayed layer. Specific embodiments
[0016] The present invention will be further described below in conjunction with embodiments.
[0017] <Example 1> A rapid-setting concrete for railways, which comprises the following components in parts by weight: 55 parts of sulfoaluminate cement 20 parts of ordinary Portland cement 8 parts of anhydrous gypsum 75 parts of manufactured sand 95 parts of limestone crushed stone 2 parts of accelerator 5 parts of thickener 6 parts of expansive agent 2 parts of polycarboxylate water reducer 40 parts of water.
[0018] The accelerator is an alkali-free liquid accelerator, which comprises the following components in parts by weight: 45 parts of Al2(SO4)3・18H2O 8 parts of Na2SiF6 6 parts of EDTA 3 parts of TEA 20 parts of deionized water.
[0019] The thickener is hydroxypropyl methylcellulose.
[0020] The expansive agent is UEA expansive agent.
[0021] The fineness modulus of the manufactured sand is 2.8, and the stone powder content is 5%; the limestone crushed stone has a particle size of 5 - 16 mm, and the crushing index is ≤ 12%.
[0022] A construction process for quick-setting concrete for railways includes the following steps: S1. Prepare sulfoaluminate cement, ordinary Portland cement, anhydrous gypsum, manufactured sand, limestone crushed stone, quick-setting agent, thickening agent, expansive agent, polycarboxylate water reducer, and water according to weight parts; S2. First, put the manufactured sand and limestone crushed stone into a forced mixer for dry mixing until evenly mixed; then add sulfoaluminate cement, ordinary Portland cement, and anhydrous gypsum, and continue dry mixing to ensure that all components are fully mixed; after mixing the thickening agent, polycarboxylate water reducer, and water evenly, add them to the forced mixer and stir to obtain a concrete mixture; finally, add the expansive agent and nano-enhancing material, and continue stirring to make the expansive agent and nano-enhancing material evenly dispersed in the concrete mixture; S3. Evenly add the quick-setting agent to the concrete mixture through the quick-setting agent adding system of the spraying machine, and adopt the wet spraying process to spray the well-stirred concrete mixture to the construction site of the railway project through the spraying machine and the conveying pipeline; S4. After spraying, trim the surface of the concrete, and carry out spray curing within 1 h. The curing temperature is controlled at 18°C, the curing humidity is ≥ 90%, and the curing time is not less than 7 days.
[0023] The construction parameters of the spraying machine in S3 are: air pressure control: 0.4 MPa; spraying angle: keep 90° with the sprayed surface; spraying distance: 0.8 m; layered spraying thickness: 100 mm per layer.
[0024] <Example 2> A quick-setting concrete for railways, which comprises the following raw material components in weight parts: 60 parts of sulfoaluminate cement 30 parts of ordinary Portland cement 12 parts of anhydrous gypsum 85 parts of manufactured sand 105 parts of limestone crushed stone 2.5 parts of quick-setting agent 10 parts of thickening agent 10 parts of expansive agent 2.5 parts of polycarboxylate water reducer 50 parts of water It also includes 3 parts by weight of nano-enhancing materials, which are composed of nano-silica fume and nano-TiO₂. The mass ratio of the nano-silica fume to the nano-TiO₂ is 2:1. The specific surface area of the nano-silica fume is 20 m² / g, and the particle size is 200 - 300 nm; the nano-TiO₂ is anatase type, and the particle size is 60 - 80 nm.
[0025] The accelerating agent is an alkali-free liquid accelerating agent, which includes the following raw material components in parts by weight: Al2(SO4)3・18H2O 55 parts Na2SiF6 12 parts EDTA 10 parts TEA 8 parts Deionized water 40 parts.
[0026] The thickening agent is hydroxypropyl methylcellulose.
[0027] The expansive agent is UEA expansive agent.
[0028] The fineness modulus of the manufactured sand is 3.2, and the stone powder content is 8%; the particle size of the limestone crushed stone is 5 - 16 mm, and the crushing index ≤ 12%.
[0029] A construction process for quick-setting concrete for railways includes the following steps: S1. Prepare sulfoaluminate cement, ordinary Portland cement, anhydrous gypsum, manufactured sand, limestone crushed stone, accelerating agent, thickening agent, expansive agent, polycarboxylate water reducer and water according to parts by weight; S2. First, put the manufactured sand and limestone crushed stone into a compulsory mixer for dry mixing until evenly mixed; then add sulfoaluminate cement, ordinary Portland cement and anhydrous gypsum, and continue dry mixing to ensure that all components are fully mixed; after mixing the thickening agent, polycarboxylate water reducer and water evenly, add them into the compulsory mixer and stir to obtain a concrete mixture; finally, add the expansive agent and nano-enhancing materials, and continue stirring to make the expansive agent and nano-enhancing materials evenly dispersed in the concrete mixture; S3. Add the accelerating agent evenly into the concrete mixture through the accelerating agent adding system of the spraying machine, and adopt the wet spraying process to spray the stirred concrete mixture onto the construction site of the railway project through the spraying machine and the conveying pipeline; S4. After spraying, trim the concrete surface, and carry out spray curing within 2 h. The curing temperature is controlled at 22 °C, the curing humidity ≥ 90%, and the curing time is not less than 7 days.
[0030] The construction parameters of the spraying machine in S3 are: air pressure control: 0.6 MPa; spraying angle: keep 90° with the sprayed surface; spraying distance: 1.2 m; layered spraying thickness: 90 mm per layer.
[0031] <Example 3> A quick-setting concrete for railways, which comprises the following raw materials in parts by weight: Sulphoaluminate cement: 58 parts Ordinary Portland cement: 25 parts Anhydrous gypsum: 10 parts Machine-made sand: 80 parts Limestone crushed stone: 100 parts Quick-setting agent: 2.2 parts Thickening agent: 7.5 parts Expansion agent: 8 parts Polycarboxylate water reducer: 2.2 parts Water: 45 parts It also includes 6 parts by weight of nano-enhancing materials, which are composed of nano-silica fume and nano-TiO₂. The mass ratio of nano-silica fume to nano-TiO₂ is 4:1. The specific surface area of nano-silica fume is 30 m² / g, and the particle size is 300 - 500 nm; nano-TiO₂ is anatase type, and the particle size is 80 - 100 nm.
[0032] The quick-setting agent is an alkali-free liquid quick-setting agent, which comprises the following raw materials in parts by weight: Al₂(SO₄)₃・18H₂O: 50 parts Na₂SiF₆: 10 parts EDTA: 8 parts TEA: 5 parts Deionized water: 30 parts.
[0033] The thickening agent is hydroxypropyl methylcellulose.
[0034] The expansion agent is UEA expansion agent.
[0035] The fineness modulus of the machine-made sand is 3.0, and the stone powder content is 6%; the particle size of the limestone crushed stone is 5 - 16 mm, and the crushing index ≤ 12%.
[0036] A construction process of the quick-setting concrete for railways includes the following steps: S1. Prepare sulphoaluminate cement, ordinary Portland cement, anhydrous gypsum, machine-made sand, limestone crushed stone, quick-setting agent, thickening agent, expansion agent, polycarboxylate water reducer and water according to parts by weight; S2. First, put the machine-made sand and limestone crushed stone into a compulsory mixer for dry mixing until evenly mixed; then add sulphoaluminate cement, ordinary Portland cement and anhydrous gypsum, and continue dry mixing to ensure that each component is fully mixed; after mixing the thickening agent, polycarboxylate water reducer and water evenly, add them into the compulsory mixer to stir to obtain a concrete mixture; finally, add the expansion agent and nano-enhancing materials, and continue stirring to make the expansion agent and nano-enhancing materials evenly dispersed in the concrete mixture; S3. Uniformly add the accelerating agent into the concrete mixture through the accelerating agent adding system of the shotcreting machine. Adopt the wet shotcreting process to spray the well-mixed concrete mixture onto the construction site of the railway project through the shotcreting machine and the conveying pipeline. S4. After spraying, trim the concrete surface and perform spray curing within 1.5 h. Control the curing temperature at 20°C, the curing humidity ≥ 90%, and the curing time shall not be less than 7 days.
[0037] The construction parameters of the shotcreting machine in S3 are as follows: air pressure control: 0.5 MPa; spraying angle: keep 90° with the sprayed surface; spraying distance: 1.0 m; thickness of layered spraying: 80 mm per layer.
[0038] <Testing and Experimentation> Conduct performance tests on the fresh properties, mechanical properties, durability, and special indicators of the accelerating concrete in Example 3. The test results of the fresh properties are shown in Table 1.
[0039] Table 1
[0040] The test results of the mechanical properties are shown in Table 2.
[0041] Table 2
[0042] The test results of the durability are shown in Table 3.
[0043] Table 3
[0044] The test results of the special indicators are shown in Table 4.
[0045] Table 4
[0046] The fresh properties of the accelerating concrete for railways of the present invention: the workability and setting time meet the requirements of rapid construction, and the air content and slump loss are well controlled. Mechanical properties: The early strength develops rapidly, the 28-day strength exceeds the design value, and the flexural strength meets the requirements of components such as track slabs. Durability: The frost resistance, impermeability, and chloride ion diffusion coefficient are all better than the standard limits, and it is suitable for complex environments such as alpine and humid areas. The alkali content and chloride ion content are safely controllable.
[0047] Comprehensive conclusion: All indicators of the accelerating concrete meet the requirements of railway engineering and can be used in scenarios such as tunnel support, bridge emergency repair, and track slab prefabrication.
[0048] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A quick-setting concrete for railway, characterized in that: It includes the following raw materials by weight: Sulphoaluminate cement 55-60 parts 20-30 parts of ordinary Portland cement 8-12 parts anhydrous gypsum 75-85 parts of machine-made sand Limestone crushed stone 95-105 parts 2-2.5 parts of accelerating agent Thickener 5-10 parts 6-10 parts of expansion agent Polycarboxylate water reducer 2-2.5 parts 40-50 parts of water.
2. The quick-setting concrete for railway according to claim 1, characterized in that: It includes the following raw materials by weight: Sulphoaluminate cement 58 parts 25 parts of ordinary Portland cement 10 parts anhydrous gypsum 80 parts of machine-made sand Limestone Crushed Stone 100 pieces 2.2 parts of accelerating agent Thickener 7.5 parts 8 parts of expansion agent 2.2 parts of polycarboxylate water reducer 45 parts of water.
3. The quick-setting concrete for railway according to claim 1, characterized in that: The accelerator is an alkali-free liquid accelerator, which comprises the following components in parts by weight: Al2(SO4)3・18H2O 45-55 parts Na2SiF6 8-12 parts EDTA 6-10 parts 3-8 servings of TEA 20-40 parts of deionized water.
4. The quick-setting concrete for railway according to claim 1, characterized in that: The invention also comprises 3-6 parts by weight of a nano-reinforced material, wherein the nano-reinforced material is composed of nano-silica ash and nano-TiO2.
5. The quick-setting concrete for railway according to claim 1, characterized in that: The mass ratio of the nano-silica ash to the nano-TiO2 is (2-4):1, the specific surface area of the nano-silica ash is 20-30m² / g, and the particle size is 200-500nm; the nano-TiO2 is anatase type, and the particle size is 60-100nm.
6. The quick-setting concrete for railway according to claim 1, characterized in that: The thickener is hydroxypropyl methylcellulose.
7. The quick-setting concrete for railway according to claim 1, characterized in that: The expansion agent is a UEA expansion agent.
8. The quick-setting concrete for railway according to claim 1, characterized in that: The fineness modulus of the machine-made sand is 2.8-3.2, the stone powder content is 5-8%; the particle size of the limestone gravel is 5-16mm, and the crushing index is ≤12%.
9. The construction process of a railway quick-setting concrete according to claim 4, characterized in that: The following steps are involved: S1. Prepare sulphoaluminate cement, ordinary Portland cement, anhydrous gypsum, machine-made sand, limestone gravel, accelerator, thickener, expansion agent, polycarboxylate water reducer and water according to weight parts; S2, first put the machine-made sand and limestone gravel into a forced mixer and dry mix them evenly; then add sulphoaluminate cement, ordinary Portland cement and anhydrous gypsum, and continue dry mixing to ensure that all components are fully mixed; after the thickener, polycarboxylate water reducer and water are mixed evenly, add them into the forced mixer and stir to obtain a concrete mixture; finally, add the expansion agent and nano-reinforcement material, and continue stirring to make the expansion agent and nano-reinforcement material evenly dispersed in the concrete mixture; S3, adding the accelerating setting agent evenly to the concrete mixture through the accelerating setting agent adding system of the spraying machine, and using the wet spraying process, spraying the stirred concrete mixture to the construction site of the railway project through the spraying machine and the conveying pipeline; S4. After the spraying is completed, the concrete surface shall be trimmed and spray-cured within 1-2 hours. The curing temperature shall be controlled at 20±2℃, the curing humidity shall be ≥90%, and the curing time shall be no less than 7 days.
10. The construction process of a railway quick-setting concrete according to claim 9, characterized in that: The construction parameters of the jetting machine in S3 are: Wind pressure control: 0.4-0.6MPa; Spray angle: maintain 90° with the sprayed surface; Spray distance: 0.8-1.2m; Layered spraying thickness: each layer ≤100mm.