Anti-fatigue concrete sleeper and preparation method thereof

Abstract

The application belongs to the technical field of concrete, and particularly relates to an anti-fatigue concrete sleeper and a preparation method thereof. The anti-fatigue concrete sleeper provided by the application comprises a concrete sleeper and a steel bar arranged in the concrete sleeper, the concrete sleeper is formed by solidification of a concrete material, and the concrete material comprises cement, fly ash, silica ash, aggregate, an additive, fiber, a resin-based material, a curing agent and water. Through component design of the resin and the fiber, the concrete sleeper forms multiple anti-fatigue mechanisms under repeated dynamic load. The concrete sleeper is toughened by using organic silicon modified epoxy resin and acrylic modified polyurethane resin, so that rigid support of the three-dimensional network structure is retained, energy buffering is realized through flexible molecular chains, and stress concentration under repeated load of a train is reduced. Through adjustment of a curing system, the curing temperature of the resin material is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of concrete, and particularly relates to an anti-fatigue concrete sleeper and a preparation method thereof. BACKGROUND

[0002] The sleeper is an important component in the railway track structure for supporting the steel rail, maintaining the track gauge, and transmitting the train load to the track bed, and can reduce the vibration and impact during train operation and improve the comfort of train riding. Compared with the traditional wooden sleeper, the concrete sleeper has a long service life, high stability, small maintenance workload, and low damage rate and scrap rate, and has become one of the important components in modern railway construction.

[0003] The pressure applied to the steel rail when the train passes is dynamically changed, which makes the sleeper continuously subjected to complex stress states such as compression and bending. Especially on high-speed railways and heavy-load transport roads, the dynamic load borne by the sleeper is more significant due to the high train density and axle load. In order to ensure the stability and safety of the track geometry, the sleeper is required to maintain its mechanical properties without significant degradation for a long time, which puts higher requirements on the fatigue resistance of the sleeper. The current concrete sleeper has two types of ordinary reinforced concrete sleeper and prestressed reinforced concrete sleeper. The ordinary concrete sleeper has obvious deficiencies in overall bending resistance, impact resistance and fatigue resistance. Under the impact of train load, the bending resistance and fatigue resistance are poor, and the concrete structure of the end sleeper is easy to break and crack. At the same time, the end shoulder part is a plain concrete structure without steel reinforcement, which leads to poor crack resistance of the shoulder part, easy cracking and concrete spalling, and further affects the strength of the track bed structure. The brittleness of the existing prestressed concrete itself determines that it may still crack at any time when subjected to repeated load, especially when the prestress loss exceeds a certain limit, the effective prestress in the sleeper is reduced, which may cause early fatigue damage. In addition, the tensioning process of the prestressed steel requires strict quality control. If the tensioning force is not accurate, the anchoring is not firm, or the concrete pouring quality is poor with defects such as holes and honeycombs, the actual fatigue resistance of the sleeper will be affected.

[0004] The Chinese patent application file with the publication number CN113620669A discloses a kind of concrete sleeper, including P · O 42.5 Portland cement, composite admixture, fine aggregate, first coarse aggregate, second coarse aggregate, water reducing agent and mixing water, and further limit the particle size range of first coarse aggregate is 5-10mm, the particle size range of second coarse aggregate is 10-20mm, and the first coarse aggregate and second coarse aggregate are all continuous particle size coarse aggregate, the composite admixture includes fly ash, limestone ore powder and pyrite cinder, in the composite admixture, the mass percentage of fly ash, limestone ore powder and pyrite cinder is 30%-40%, 40%-50%, 10%-30% respectively.This concrete sleeper improves the compressive strength and elastic modulus of concrete by particle size grading and admixture content design, but the cement usage in its formula is relatively high, and the hydration releases a lot of heat, while the sleeper volume is small, the heat dissipation is poor, the internal and external temperature difference is easy to form, and temperature cracks are easy to cause; Composite admixture contains sulfide, free calcium oxide and other impurities in pyrite cinder, sulfide can react with water in concrete to generate acidic substances, damage the passivation film of steel bar, accelerate the corrosion of steel bar, and free calcium oxide will hydrate and expand in the later stage of cement hydration, resulting in poor volume stability of concrete. SUMMARY

[0005] To solve the technical problems of cracking, poor volume stability and poor fatigue resistance of the concrete sleeper in the prior art, the present application provides an anti-fatigue concrete sleeper and a preparation method thereof.

[0006] To achieve the above purpose, the technical solution of the present application is as follows:

[0007] An anti-fatigue concrete sleeper, comprising a concrete sleeper and a steel bar arranged inside the concrete sleeper, the concrete sleeper is formed by solidification of a concrete material, the concrete material comprises the following components in mass fraction:

[0008] Cement 200-300 parts, fly ash 20-30 parts, silica fume 10-20 parts, aggregate 280-320 parts, additive 10-20 parts, fiber 25-40 parts, resin-based material 15-20 parts, curing agent 5-10 parts, water 70-90 parts;

[0009] The resin-based material is composed of modified epoxy resin and modified polyurethane resin in a mass ratio of 11-15:4-8, the modified epoxy resin is organosilicon modified epoxy resin, and the modified polyurethane resin is acrylic modified polyurethane resin.

[0010] The present application forms multiple anti-fatigue mechanisms of concrete sleep under repeated dynamic load through resin compounding and component design of fiber, cement and mineral admixture synergistically improve the cementing strength, improve the brittleness of concrete and reduce shrinkage cracks. The modified epoxy resin and the acrylic modified polyurethane resin are compounded, the high strength and the three-dimensional network structure of the epoxy resin are retained, and the energy buffer is realized through the flexible molecular chain of the acrylic modified polyurethane, under the repeated load of the train, the flexible chain segment can absorb impact energy through deformation, reduce the damage of stress concentration to the cement matrix. In addition, the resin-based material can fill the pores in the concrete after curing, which can reduce the porosity of the concrete and form a dense interface with the cement hydration product, the polar groups in the resin form hydrogen bonds or coordination bonds with the hydroxyl groups on the surface of the aggregate and the Ca 2+ The hydrogen bonds or coordination bonds are formed, the loose defects of the traditional interface transition zone are eliminated, the density of the concrete sleeper is significantly improved, the compressive strength and the flexural strength are improved together through the synergistic effect of the cement and the mineral admixture, and the requirements of the sleeper on the bearing capacity are met.

[0011] Further, the preparation method of the modified epoxy resin is as follows: 1-allyloxy-2,3-epoxy propane is dissolved in toluene, a catalyst and 1,1,3,3-tetraethyl disiloxane are added under the protection of inert gas, heating reaction is carried out, cooling is carried out, rotary evaporation is carried out, and a toughening agent is obtained; the toughening agent, bisphenol A type epoxy resin and toluene are mixed and uniformly stirred to obtain the modified epoxy resin.

[0012] In the present application, the toughening agent containing rigid epoxy groups and flexible chain segments in the molecule is prepared by the silicon hydrogen addition reaction of 1-allyloxy-2,3-epoxy propane and 1,1,3,3-tetraethyl disiloxane, and the bisphenol A type epoxy resin is modified. The molecular chain of the siloxane segment in the toughening agent can rotate freely, and the silicon-oxygen bond can be hydrolyzed to generate silicon hydroxyl, form a hydrogen bond with the hydroxyl on the surface of the aggregate, and the epoxy group can react with the oxide layer on the surface of the steel bar to enhance the interfacial bonding strength of the steel bar and the concrete. When the modified epoxy resin is mixed with the concrete, the flexible chain segment is uniformly dispersed in the concrete matrix to form a composite structure of rigid epoxy network + flexible siloxane. Under the repeated dynamic load of the train, the flexible chain segment in the composite structure is elastically deformed to balance the strength and toughness, and the rigid epoxy network maintains the matrix strength to avoid plastic damage caused by excessive deformation and improve the anti-fatigue performance of the concrete sleeper.

[0013] Further, the mass fraction of each component in the preparation method of the modified epoxy resin is as follows: 1-allyloxy-2,3-epoxy propane 50-60 parts, catalyst 2-5 parts, 1,1,3,3-tetraethyl disiloxane 30-40 parts, bisphenol A type epoxy resin 100-120 parts.

[0014] Further, the catalyst in the preparation method of the modified epoxy resin is a platinum gold catalyst; the temperature of the temperature rising reaction is 85-90 DEG C, and the time of the temperature rising reaction is 24-30h.

[0015] Further, the preparation method of the modified polyurethane resin is as follows: after dehydration, polyoxyethylene glycol is mixed with toluene diisocyanate, heated to 70-80 DEG C, reacted for 3-4h, hydroxyethyl acrylate is added, and the reaction is continued for 1-2h, the temperature is lowered to 45 DEG C, acrylic acid and triethylamine are added, and the stirring reaction is carried out for 0.5-1h, deionized water is added, stirred uniformly, and then potassium persulfate is added, heated to 90-100 DEG C, and reacted for 3-4h, and then distilled under reduced pressure to obtain the modified polyurethane resin.

[0016] In the application, polyoxyethylene glycol, toluene diisocyanate and cyanoethyl acrylate are used as main raw materials to synthesize water-based polyurethane prepolymer, and the modified polyurethane resin is prepared through chain extension, crosslinking and acrylic modification. By grafting the acrylate segment on the polyurethane resin segment, the modified polyurethane resin provides certain rigidity, and forms a rigid-flexible alternating network structure with the flexible polyurethane segment. In the concrete sleeper, the stress can be dispersed through the chain segment slip and tension, and the toughness of the concrete is improved. Meanwhile, the polar groups in the modified polyurethane resin molecule can form hydrogen bonds or coordination bonds with the cement hydration products, Ca 2+ OH and SiO4, improve the interfacial bonding strength, optimize the interfacial performance, and improve the fatigue resistance of the concrete sleeper.

[0017] Further, in the preparation method of the modified polyurethane resin, the mass fraction of each component is as follows: polyoxyethylene glycol 80-90 parts, toluene diisocyanate 35-50 parts, hydroxyethyl acrylate 10-15 parts, acrylic acid 10-15 parts, triethylamine 5-8 parts, and potassium persulfate 3-5 parts.

[0018] Further, the curing agent is composed of diethylene triamine, dibutyltin dilaurate and amino urea in a mass ratio of 8-11:5-9:2-5.

[0019] In the application, diethylene triamine, dibutyltin dilaurate and amino urea are used to form a curing system, wherein diethylene triamine has strong nucleophilicity and high reactivity with the epoxy groups of the modified epoxy resin, which can effectively reduce the curing temperature of the modified epoxy resin; dibutyltin dilaurate can activate the -NCO groups in the modified polyurethane resin through coordination, thereby reducing the reaction temperature of the curing reaction; and amino urea has high reactivity with the -NCO groups at normal temperature, and can realize the normal temperature curing reaction of the modified polyurethane resin.

[0020] Further, the aggregate is composed of coarse aggregate and fine aggregate in a mass ratio of 2-4:5-9; the coarse aggregate is continuous particle size gravel with a particle size range of 5-20mm; and the fine aggregate is continuous particle size machine-made sand with a fineness modulus of 3.0.

[0021] Further, the additive is composed of polycarboxylate high-performance water-reducing agent and defoaming agent in a mass ratio of 10-12:3-5; the polycarboxylate high-performance water-reducing agent has a water-reducing rate of 25%-30%, and the defoaming agent is polydimethylsiloxane.

[0022] In the present application, the polycarboxylate high-performance water-reducing agent is added in the concrete mixing process, which can not only realize efficient dispersion of cement particles, reduce water-cement ratio, and improve the compactness of concrete, but also prevent cement particle agglomeration through steric hindrance effect, so that a more compact interfacial transition zone is formed on the surface of the aggregate; the defoaming agent can reduce the amount of bubbles generated in the concrete mixing process, improve the homogeneity of concrete, and enhance the impermeability and durability of concrete.

[0023] Further, the fiber is one of carbon fiber, basalt fiber and glass fiber.

[0024] The present application also provides a preparation method of the anti-fatigue concrete sleeper.

[0025] The cement, fly ash, silica ash, aggregate and water are mixed, the additive is added, and after stirring for 5-10min, the resin and the material and the curing agent are continuously added, and stirring is carried out for 10-20min, then the fiber is added, and after stirring for 5-10min, the mixture is poured into a sleeper mold in which steel bars are placed, and vibration is carried out through a vibration table for 2-5min, and after curing for 1 day, demolding is carried out, steam curing is carried out at a temperature of 60-80℃, the temperature increasing rate is 10-15℃ / h, cooling is carried out, and the cooling rate is 5-10℃ / h, so that the anti-fatigue concrete sleeper is obtained.

[0026] In the preparation process of the concrete sleeper, the temperature increasing rate and the cooling rate of steam curing are strictly controlled, so that the temperature increasing rate is prevented from being too fast, internal defects of the concrete sleeper are reduced, the anti-fatigue performance is improved, the cooling rate is prevented from being too fast, residual stress is accumulated, and fatigue damage is aggravated.

[0027] Compared with the prior art, the anti-fatigue concrete sleeper and the preparation method thereof have the following technical advantages:

[0028] (1) In the present application, through the component design of resin compounding and fiber, a multiple anti-fatigue mechanism of the concrete sleeper is formed under repeated dynamic load, cement and mineral admixture are used to improve the cementing strength and improve the brittleness of concrete and reduce shrinkage cracks;

[0029] (2) The organic silicon modified epoxy resin and the acrylic modified polyurethane resin are used for toughening the concrete sleeper, rigid support of three-dimensional network structure is reserved, energy buffering is realized through flexible molecular chain, and stress concentration under repeated load of train is reduced.

[0030] (3) The diethylene triamine, dibutyl tin dilaurate and amino urea are used to form the curing system in the application, and the curing temperature of the resin material is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The nuclear magnetic hydrogen spectrum of the toughening agent in the modified epoxy resin prepared in Example 4;

[0032] Figure 2 The infrared spectrum of the modified polyurethane resin prepared in Example 4. DETAILED DESCRIPTION

[0033] The following will be further described in combination with specific embodiments, but the application is not limited to the following embodiments. Those skilled in the art can make various modifications according to the basic idea of the application, as long as the modifications do not deviate from the basic idea of the application, and are within the scope of the application.

[0034] The raw materials in the embodiment are commercially available without special instructions. The cement in the embodiment is P·O 52.5 Portland cement; the molecular weight of the polyoxyethylene glycol in the preparation method of the modified polyurethane resin is 1000-2000; the coarse aggregate is continuous particle size gravel, and the particle size range is 5-20 mm; and the fine aggregate is continuous particle size machine-made sand, and the fineness modulus is 3.0.

[0035] Preparation Example 1

[0036] The preparation method of the modified epoxy resin is as follows: 50 g of 1-allyloxy-2,3-epoxy propane is dissolved in 150 mL of dry toluene, stirred uniformly, 2 g of platinum gold catalyst and 40 g of 1,1,3,3-tetraethyl disiloxane are added under nitrogen protection, heated to 85 DEG C and reacted for 30 h, cooled to room temperature, heated to 80 DEG C and rotary evaporated to obtain the toughening agent; the toughening agent, 100 g of bisphenol A type epoxy resin and 50 mL of toluene are mixed and stirred uniformly to obtain the modified epoxy resin.

[0037] Preparation Example 2

[0038] The preparation method of the modified epoxy resin is as follows: 60 g of 1-allyloxy-2,3-epoxypropane is dissolved in 150 mL of dry toluene, stirred uniformly, 5 g of platinum gold catalyst and 30 g of 1,1,3,3-tetraethyldisiloxane are added under nitrogen protection, heated to 90℃ for 24 h, cooled to room temperature, heated to 80℃ for rotary evaporation, to obtain a toughening agent; the toughening agent, 120 g of bisphenol A type epoxy resin and 50 mL of toluene are mixed and stirred uniformly to obtain the modified epoxy resin.

[0039] Preparation Example 3

[0040] The preparation method of the modified epoxy resin is as follows: 58 g of 1-allyloxy-2,3-epoxypropane is dissolved in 150 mL of dry toluene, stirred uniformly, 4 g of platinum gold catalyst and 36 g of 1,1,3,3-tetraethyldisiloxane are added under nitrogen protection, heated to 88℃ for 28 h, cooled to room temperature, heated to 80℃ for rotary evaporation, to obtain a toughening agent; the toughening agent, 110 g of bisphenol A type epoxy resin and 50 mL of toluene are mixed and stirred uniformly to obtain the modified epoxy resin.

[0041] Preparation Example 4

[0042] The preparation method of the modified polyurethane resin is as follows: 80 g of polyoxyethylene glycol is added to a four-necked flask, dehydrated at 100℃ under a vacuum degree of-0.09 MPa for 2 h, cooled to 70℃, 35 g of toluene diisocyanate is added, and reacted for 3 h, 10 g of hydroxyethyl acrylate is added, and reacted for 1 h, cooled to 45℃, 10 g of acrylic acid and 5 g of triethylamine are added, stirred for 0.5 h, 55 g of deionized water is added, stirred for 10 min at a speed of 1000 rpm, 3 g of potassium persulfate is added, heated to 90℃, and reacted for 3 h, distilled under reduced pressure at 40℃ and-0.08 MPa to obtain the modified polyurethane resin.

[0043] Preparation Example 5

[0044] The preparation method of the modified polyurethane resin is as follows: 90 g of polyoxyethylene glycol is added to a four-necked flask, dehydrated at 120℃ under a vacuum degree of-0.09 MPa for 3 h, cooled to 80℃, 50 g of toluene diisocyanate is added, and reacted for 4 h, 15 g of hydroxyethyl acrylate is added, and reacted for 2 h, cooled to 45℃, 15 g of acrylic acid and 8 g of triethylamine are added, stirred for 1 h, 45 g of deionized water is added, stirred for 15 min at a speed of 1200 rpm, 5 g of potassium persulfate is added, heated to 100℃, and reacted for 4 h, distilled under reduced pressure at 50℃ and-0.08 MPa to obtain the modified polyurethane resin.

[0045] Preparation Example 6

[0046] The preparation method of the modified polyurethane resin is as follows: 86 g of polyoxyethylene glycol is added to a four-necked flask, and dehydrated at 115 DEG C under a vacuum degree of-0.09 MPa for 2.5 h, cooled to 75 DEG C, 42 g of toluene diisocyanate is added, and reacted for 3.5 h, 13 g of hydroxyethyl acrylate is added, and reacted for 1.5 h, cooled to 45 DEG C, 13 g of acrylic acid and 7 g of triethylamine are added, and stirred for 0.8 h, 50 g of deionized water is added, and stirred for 13 min at a rotation speed of 1100 rpm, 4 g of potassium persulfate is added, heated to 95 DEG C, and reacted for 3.5 h, and distilled under reduced pressure at 45 DEG C and-0.08 MPa to obtain the modified polyurethane resin.

[0047] Example 1

[0048] An anti-fatigue concrete sleeper includes a concrete sleeper and a steel bar arranged inside the concrete sleeper, and the concrete sleeper is formed by solidification of a concrete material including components in the following mass fractions:

[0049] Cement 200 parts, fly ash 30 parts, silica fume 20 parts, aggregate 280 parts, additive 10 parts, basalt fiber 25 parts, resin-based material 15 parts, curing agent 5 parts, and water 70 parts; the resin-based material is composed of modified epoxy resin and modified polyurethane resin in a mass ratio of 11:4. The modified epoxy resin is prepared by the preparation example 1, and the modified polyurethane resin is prepared by the preparation example 4.

[0050] The curing agent is composed of diethylene triamine, dibutyltin dilaurate and amino urea in a mass ratio of 8:5:2; the aggregate is composed of coarse aggregate and fine aggregate in a mass ratio of 2:5; the additive is composed of polycarboxylic acid high-performance water reducing agent and polydimethylsiloxane in a mass ratio of 10:3; and the water reducing rate of the polycarboxylic acid high-performance water reducing agent is 25%.

[0051] The preparation method of the anti-fatigue concrete sleeper is as follows:

[0052] The cement, fly ash, silica fume, aggregate and water are mixed, the additive is added, stirred for 5 min, the resin-based material and the curing agent are continuously added, stirred for 10 min, the fiber is added, stirred for 5 min, and then poured into a sleeper mold with the steel bar placed therein, and vibrated by a vibrating table for 2 min, demolded after solidification for 1 day, steam cured at 60 DEG C, the heating rate is 10 DEG C / h, cooled, and the cooling rate is 5 DEG C / h to obtain the anti-fatigue concrete sleeper.

[0053] Example 2

[0054] An anti-fatigue concrete sleeper includes a concrete sleeper and a steel bar arranged inside the concrete sleeper, and the concrete sleeper is formed by solidification of a concrete material including components in the following mass fractions:

[0055] Cement 300 parts, fly ash 20 parts, silica fume 10 parts, aggregate 320 parts, additive 20 parts, glass fiber 40 parts, resin-based material 20 parts, curing agent 10 parts, water 90 parts; the resin-based material is composed of modified epoxy resin and modified polyurethane resin in a mass ratio of 15:8; the modified epoxy resin is prepared by Preparation Example 2, and the modified polyurethane resin is prepared by Preparation Example 5.

[0056] The curing agent is composed of diethylene triamine, dibutyl tin dilaurate and amino urea in a mass ratio of 11:9:5; the aggregate is composed of coarse aggregate and fine aggregate in a mass ratio of 4:9; the additive is composed of polycarboxylic acid high-performance water reducing agent and polydimethylsiloxane in a mass ratio of 12:5; the water reducing rate of the polycarboxylic acid high-performance water reducing agent is 30%.

[0057] The preparation method of the fatigue-resistant concrete sleeper is specifically:

[0058] The cement, fly ash, silica fume, aggregate and water are mixed, the additive is added, stirring for 10 min, then the resin and the material and the curing agent are continuously added, stirring for 20 min, the fiber is added, stirring for 10 min, then poured into the sleeper mold with the steel bars placed therein, and vibrated through the vibration table for 5 min, demolded after 1 day of curing, steam curing at 80℃, the heating rate is 15℃ / h, cooling, the cooling rate is 10℃ / h, to obtain the fatigue-resistant concrete sleeper.

[0059] Example 3

[0060] A fatigue-resistant concrete sleeper, comprising a concrete sleeper and a steel bar arranged inside the concrete sleeper, the concrete sleeper is formed by solidification of a concrete material, the concrete material comprises the following components in mass fraction:

[0061] Cement 260 parts, fly ash 27 parts, silica fume 15 parts, aggregate 300 parts, additive 17 parts, carbon fiber 32 parts, resin-based material 18 parts, curing agent 8 parts, water 85 parts; the resin-based material is composed of modified epoxy resin and modified polyurethane resin in a mass ratio of 13:6. The modified epoxy resin is prepared by Preparation Example 3, and the modified polyurethane resin is prepared by Preparation Example 6.

[0062] The curing agent is composed of diethylene triamine, dibutyl tin dilaurate and amino urea in a mass ratio of 9:7:4; the aggregate is composed of coarse aggregate and fine aggregate in a mass ratio of 3:7; the additive is composed of polycarboxylic acid high-performance water reducing agent and polydimethylsiloxane in a mass ratio of 11:4; the water reducing rate of the polycarboxylic acid high-performance water reducing agent is 28%.

[0063] The preparation method of the fatigue-resistant concrete sleeper is specifically:

[0064] The cement, fly ash, silica fume, aggregate and water are mixed, the additive is added, after stirring for 8 min, the resin and the material and curing agent are continuously added, stirring for 15 min, the fiber is added, stirring for 8 min, then pouring into the sleeper mold with steel bars, vibrating for 4 min through the vibrating table, demolding after 1 day curing, steam curing at 70℃, the heating rate is 13℃ / h, cooling, the cooling rate is 8℃ / h, to obtain the fatigue-resistant concrete sleeper.

[0065] Example 4

[0066] The fatigue-resistant concrete sleeper and the preparation method thereof in the example are similar to those in example 3, and the difference between the example and example 3 is that the resin-based material in the example is composed of modified epoxy resin and modified polyurethane resin in a mass ratio of 12:7. The modified epoxy resin is prepared by preparation example 3, and the modified polyurethane resin is prepared by preparation example 6.

[0067] Comparative example 1

[0068] The concrete sleeper and the preparation method thereof in the comparative example are similar to those in example 4, and the difference between the comparative example and example 4 is that the resin-based material in the comparative example is all modified epoxy resin, and the modified epoxy resin is prepared by preparation example 3.

[0069] Comparative example 2

[0070] The concrete sleeper and the preparation method thereof in the comparative example are similar to those in example 4, and the difference between the comparative example and example 4 is that the resin-based material in the comparative example is all modified polyurethane resin, and the modified polyurethane resin is prepared by preparation example 6.

[0071] Comparative example 3

[0072] The concrete sleeper and the preparation method thereof in the comparative example are similar to those in example 4, and the difference between the comparative example and example 4 is that the same amount of bisphenol A type epoxy resin is used instead of modified epoxy resin in the comparative example.

[0073] Comparative example 4

[0074] The concrete sleeper and the preparation method thereof in the present comparative example are similar to those in Example 4, and the difference between the present comparative example and Example 4 is that: in the present comparative example, an equal amount of polyurethane resin is used instead of the modified polyurethane resin, and the preparation method of the polyurethane resin is as follows: 86 g of polyoxyethylene glycol is added to a four-necked flask, and dehydrated at 115 ℃ under a vacuum degree of-0.09 MPa for 2.5 h, cooled to 75 ℃, 42 g of toluene diisocyanate is added, and incubated for 3.5 h, 13 g of hydroxyethyl acrylate is added, and the reaction is continued for 1.5 h, the temperature is lowered to 45 ℃, 13 g of deionized water and 7 g of triethylamine are added, and the reaction is stirred for 0.8 h, 50 g of deionized water is added, and stirred at a speed of 1100 rpm for 13 min, 4 g of potassium persulfate is added, the temperature is raised to 95 ℃, and the reaction is incubated for 3.5 h, and then distilled under reduced pressure at 45 ℃ and-0.08 MPa to obtain the polyurethane resin.

[0075] Comparative Example 5

[0076] The concrete sleeper and the preparation method thereof in the present comparative example are similar to those in Example 4, and the difference between the present comparative example and Example 4 is that: in the present comparative example, the mass ratio of the modified epoxy resin and the modified polyurethane resin is 2:7.

[0077] Comparative Example 6

[0078] The concrete sleeper and the preparation method thereof in the present comparative example are similar to those in Example 4, and the difference between the present comparative example and Example 4 is that: in the present comparative example, the curing agent is composed of dilauryl dibutyl tin and amino urea according to a mass ratio of 5:1.

[0079] Test Example

[0080] Mechanical property test: the compressive strength and elastic modulus of the concrete sleepers prepared in Examples 1-4 and Comparative Examples 1-6 are tested according to GB / T 50081-2019, and the test results are shown in Table 1.

[0081] Durability test: the durability of the concrete sleepers prepared in Examples 1-4 and Comparative Examples 1-6 is tested according to GB / T 50082-2024, and the test results are shown in Table 2.

[0082] Fatigue resistance test: the anti-cracking properties of the concrete sleepers prepared in Examples 1-4 during the fatigue process are tested by using a fatigue testing machine, the load cycle characteristic Q=0.2, the maximum column width, the maximum column height, the residual maximum column width, and the residual maximum column height are measured when the number of fatigue cycles is 200, and the number of cracks is recorded, and the test results are shown in Table 3.

[0083] Table 1 Test results of mechanical properties

[0084]

[0085] Table 2 Durability test results

[0086]

[0087] As shown in Table 1, the elastic modulus of the concrete sleeper provided by the application is 40.3-43.2 GPa, the 3d compressive strength is 41.5-45.5 MPa, the 7d compressive strength is 65.2-69.5 MPa, and the 28d compressive strength is 84.6-90.1 MPa, which shows that the concrete sleeper provided by the application has good mechanical properties and high elasticity, and can better buffer and conduct rail vibration when applied to rail transit such as railways.

[0088] As shown in Table 2, the aluminum ion diffusion coefficient of the concrete sleeper provided by the application is 2.9-3.2, the electric flux is 568-586 C, P=84.9%-89.8% after 300 freeze-thaw cycles, and AW=0.8%-1.2%, which shows that the concrete sleeper provided by the application has good freeze-thaw resistance and good durability.

[0089] Compared with Example 4, the resin-based material in Comparative Example 1 is all modified epoxy resin, but the elastic modulus of the concrete sleeper prepared is reduced, and the durability is poor, which shows that the modified polyurethane resin can form a rigid-flexible alternating network structure through its flexible chain segment to improve the toughness of the concrete sleeper; in Comparative Example 2, the resin-based material is all modified polyurethane resin, and in Comparative Example 3, an equal amount of bisphenol A type epoxy resin is used instead of modified epoxy resin, but the elastic modulus and compressive strength of the concrete sleeper prepared are reduced to varying degrees, and the durability is poor, which shows that the modified epoxy resin can not only improve the toughness of the concrete, but also improve the mechanical properties of the concrete, and the unmodified epoxy resin can ensure the mechanical properties of the concrete sleeper, but the elastic modulus is significantly reduced; in Comparative Example 4, the polyurethane resin is not modified with acrylic acid, but the compressive strength of the concrete sleeper prepared is significantly reduced, and the durability is poor, which shows that modifying the polyurethane resin with acrylic acid can effectively improve the rigidity of the polyurethane resin, so that it forms a rigid-flexible network structure in the concrete sleeper to improve the elastic modulus and compressive strength of the concrete sleeper; in Comparative Example 5, the mass ratio of modified epoxy resin and modified polyurethane resin is changed, but the elastic modulus and compressive strength of the concrete sleeper prepared are reduced to varying degrees, and the durability is poor, which shows that the modified epoxy resin and modified polyurethane resin in the application have a synergistic effect; in Comparative Example 6, the type and amount ratio of the curing agent are changed, and the elastic modulus and compressive strength of the concrete sleeper prepared are reduced to varying degrees, and the durability is poor, which is caused by the poor curing effect of the modified epoxy resin and modified polyurethane resin due to the change of the curing agent components and amount.

[0090] Table 3 Anti-fatigue performance test results

[0091]

[0092] As shown in Table 3, the concrete sleeper provided by the application has a maximum loading column width of 0.020-0.040 mm, a maximum residual column width of 0.015-0.025 mm, a maximum loading column height of 20-28 mm, a maximum residual column height of 8-13 mm, and 0-2 cracks under the conditions of a load cycle characteristic Q=0.2, Pmax=220 kN, Pmin=44 kN, and 200 times of fatigue, which fully shows that the concrete sleeper provided by the application has good load anti-fatigue performance.

[0093] In addition, the toughening agent prepared in the preparation method of the modified epoxy resin of Example 4 is subjected to a nuclear magnetic hydrogen spectrum test, and the test result is shown in Figure 1 As shown in Figure 1 , the epoxy group is fused into the organosilicon through the silicon-hydrogen addition reaction of 1-allyloxy-2,3-epoxypropane and 1,1,3,3-tetraethyldisiloxane, which shows that the silicon-hydrogen addition reaction occurs between 1-allyloxy-2,3-epoxypropane and 1,1,3,3-tetraethyldisiloxane.

[0094] The modified polyurethane resin prepared in Example 4 is subjected to an infrared spectrum test, and the test result is shown in Figure 2 As shown in Figure 2 , there are absorption peaks of -NH and C=O at 3310 cm -1 and 1172 cm -1 , which shows that the urethane bond is generated by the reaction of -NCO with -OH groups in the reaction process, the stretching vibration peak of C-O-C appears at 1125 cm -1 , which further confirms the existence of the urethane bond, and the characteristic peak of polyacrylic acid appears at 1230 cm -1 , which shows that the preparation of the modified polyurethane resin is successful.

[0095] The above examples are only examples of the application, but not limit the application. The skilled in the art cannot modify the above examples without departing from the spirit and scope of the application. All equivalent modifications or changes made by those skilled in the art without departing from the technical idea of the application still fall within the protection scope of the application.

Claims

1. A fatigue-resistant concrete railway sleeper, characterized in that, It includes concrete sleepers and reinforcing steel bars disposed inside the concrete sleepers. The concrete sleepers are formed by the solidification of concrete material, which comprises the following components in parts by weight: 200-300 parts cement, 20-30 parts fly ash, 10-20 parts silica fume, 280-320 parts aggregate, 10-20 parts admixture, 25-40 parts fiber, 15-20 parts resin-based material, 5-10 parts curing agent, and 70-90 parts water; The resin-based material is composed of modified epoxy resin and modified polyurethane resin in a mass ratio of 11-15:4-8, wherein the modified epoxy resin is an organosilicon-modified epoxy resin and the modified polyurethane resin is an acrylic-modified polyurethane resin. The modified epoxy resin is prepared by dissolving 1-allyloxy-2,3-epoxypropane in toluene, adding a catalyst and 1,1,3,3-tetraethyldisiloxane under inert gas protection, heating and reacting, cooling, and rotary evaporating to obtain a toughening agent; mixing the toughening agent, bisphenol A type epoxy resin and toluene, stirring evenly to obtain the modified epoxy resin. The modified polyurethane resin is prepared by mixing dehydrated polyoxyethylene glycol with toluene diisocyanate, heating to 70-80℃, reacting for 3-4 hours, adding hydroxyethyl acrylate, continuing the reaction for 1-2 hours, cooling to 45℃, adding acrylic acid and triethylamine, stirring and reacting for 0.5-1 hours, adding deionized water, stirring evenly, adding potassium persulfate, heating to 90-100℃, maintaining the temperature for 3-4 hours, and distilling under reduced pressure to obtain the modified polyurethane resin. The curing agent is composed of diethylenetriamine, dibutyltin dilaurate, and aminourea in a mass ratio of 8-11:5-9:2-5.

2. The fatigue-resistant concrete sleeper according to claim 1, characterized in that, The mass fractions of each component in the preparation method of modified epoxy resin are as follows: 50-60 parts of 1-allyloxy-2,3-epoxypropane, 2-5 parts of catalyst, 30-40 parts of 1,1,3,3-tetraethyldisiloxane, and 100-120 parts of bisphenol A type epoxy resin.

3. The fatigue-resistant concrete sleeper according to claim 1, characterized in that, The catalyst is a platinum catalyst; the temperature of the heating reaction is 85-90℃, and the heating reaction time is 24-30h.

4. The fatigue-resistant concrete sleeper according to claim 1, characterized in that, The mass fractions of each component in the preparation method of modified polyurethane resin are as follows: 80-90 parts of polyoxyethylene glycol, 35-50 parts of toluene diisocyanate, 10-15 parts of hydroxyethyl acrylate, 10-15 parts of acrylic acid, 5-8 parts of triethylamine, and 3-5 parts of potassium persulfate.

5. The fatigue-resistant concrete sleeper according to claim 1, characterized in that, The aggregate consists of coarse aggregate and fine aggregate in a mass ratio of 2-4:5-9; the coarse aggregate is continuously graded crushed stone with a particle size range of 5-20 mm; the fine aggregate is continuously graded manufactured sand with a fineness modulus of 3.

0.

6. The fatigue-resistant concrete sleeper according to claim 1, characterized in that, The additive is composed of polycarboxylate high-performance water-reducing agent and defoamer in a mass ratio of 10-12:3-5; the water reduction rate of the polycarboxylate high-performance water-reducing agent is 25%-30%, and the defoamer is polydimethylsiloxane; the fiber is one of carbon fiber, basalt fiber, and glass fiber.

7. The method for preparing fatigue-resistant concrete sleepers according to any one of claims 1-6, characterized in that, Specifically: Cement, fly ash, silica fume, aggregate, and water are mixed, admixtures are added, and the mixture is stirred for 5-10 minutes. Then, resin, materials, and curing agent are added and stirred for 10-20 minutes. Fiber is added and the mixture is stirred for another 5-10 minutes. The mixture is then poured into a sleeper mold containing reinforcing bars and vibrated on a vibrating table for 2-5 minutes. After curing for one day, the mixture is demolded and steam-cured at 60-80℃ at a rate of 10-15℃ / h. It is then cooled at a rate of 5-10℃ / h to obtain fatigue-resistant concrete sleepers.

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