Polyurethane high-elasticity concrete for steel bridge deck and preparation method thereof

Abstract

This invention discloses a polyurethane high-elasticity concrete for steel bridge decks and its preparation method, belonging to the field of road engineering construction materials. First, under an inert atmosphere, poly(ε-caprolactone) glycol and hydroxyl-terminated polybutadiene I are mixed and dehydrated, and isophorone diisocyanate I is added dropwise to react and obtain a polyurethane prepolymer. Then, a reactive plasticizer, a UV stabilizer composition, an defoamer, and a nano-scale rheology modifier are added sequentially and mixed to obtain component A. Simultaneously, a silane coupling agent, a reactive entanglement agent, and solvent I are mixed and diluted to obtain an interface treatment liquid, which is sprayed onto the surface of a multi-graded composite aggregate. A composite latent curing agent system is added and mixed to obtain component B. Finally, components A and B are mixed and placed on a steel bridge deck, leveled, and cured. The polyurethane high-elasticity concrete for steel bridge decks provided by this invention has excellent comprehensive mechanical properties, fracture toughness, fatigue resistance, and impact resistance, as well as excellent anti-aging properties and noise reduction properties.

Description

Technical Field

[0001] This invention relates to the field of road engineering construction materials, specifically to a polyurethane high-elasticity concrete for steel bridge decks and its preparation method. Background Technology

[0002] Long-span steel bridges play a crucial role in modern transportation networks. Their bridge deck pavement, as a system directly bearing vehicle loads and environmental effects, has extremely stringent performance requirements. Traditional pavement materials, such as epoxy asphalt concrete and high-elasticity modified asphalt SMA, have revealed many limitations in practical applications: while epoxy asphalt concrete has high strength, it lacks toughness and is prone to brittle cracking under repeated deformation of the steel bridge deck, and its construction conditions are demanding (requiring high-temperature storage and specific time windows); although high-elasticity modified asphalt SMA has improved high-temperature stability and fatigue resistance, it still faces the risk of rutting at extreme temperatures, its low-temperature crack resistance is not ideal, and its bonding durability with steel plates faces challenges.

[0003] Polyurethane, with its excellent elasticity, wear resistance, and chemical corrosion resistance, is considered an ideal matrix for next-generation steel bridge deck pavement materials. However, applying polyurethane to bridge deck pavement also presents several challenges. First, existing material systems struggle to achieve an ideal distribution of rigidity and flexibility. Pursuing high elasticity often comes at the cost of sacrificing the material's compressive and tensile strength, as well as its rutting resistance, leading to permanent deformation or excessive wear under long-term vehicle impact. Conversely, materials designed for high strength often lack sufficient elasticity, making them prone to fatigue cracking under alternating stress. Second, improper gradation in concrete can result in excessively high or low porosity, negatively impacting mechanical properties and durability. Third, current technologies commonly use silane coupling agents to treat aggregate surfaces, connecting them to inorganic aggregates via single siloxane bonds. This results in limited interfacial bonding strength and insufficient toughness. Under repeated bending and tensile deformation of the steel bridge deck and the impact and shearing effects of traffic loads, stress is highly concentrated at a limited number of chemical bonding points, easily leading to early interfacial failure and pavement debonding. Poor interfacial bonding easily leads to delamination and early damage. Fourth, existing curing systems struggle to balance pot life, permeability, and final performance. Excessive curing leads to rushed construction and uneven spreading of the mixture; excessive curing delays traffic opening and slows initial strength development. Incompatible curing systems can also result in insufficient resin coating of aggregates or uneven internal reactions, affecting the uniformity and long-term performance of the finished product. Fifth, concrete is susceptible to irreversible degradation under harsh conditions involving UV radiation, water, temperature cycling, and de-icing salt, leading to embrittlement, softening, strength loss, and crack propagation, making it difficult to meet design life requirements.

[0004] Existing polyurethane concrete technologies often focus on improving only one aspect of performance, failing to address the problem synergistically from multiple dimensions such as aggregate gradation, interface modification, and curing. This limits the full realization of material performance and long service life. Based on these shortcomings, it is essential to propose a new polyurethane high-elasticity concrete for steel bridge decks and its preparation method. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a polyurethane high-elasticity concrete for steel bridge decks and its preparation method.

[0006] The first aspect of this invention is to provide a polyurethane high-elasticity concrete for steel bridge decks, comprising component A and component B; By weight, component A comprises the following raw materials: 85-95 parts of polyurethane prepolymer, 5-12 parts of reactive plasticizer, 1-3 parts of UV stabilizer composition, 0.2-0.8 parts of defoamer, and 0.5-2 parts of nano-rheology modifier; By weight, component B comprises the following raw materials: 100 parts of multi-grade composite aggregate, 4-7 parts of composite latent curing agent system, 0.5-2 parts of reactive entanglement agent, 0.3-1 parts of silane coupling agent, and 3-10 parts of solvent I; The polyurethane prepolymer is a prepolymer obtained by reacting poly(ε-caprolactone) diol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I. The reactive entanglement agent is prepared by the following steps: (1) Mix hydroxyl-terminated polybutadiene II and solvent II, add catalyst under an inert atmosphere, and then add isophorone diisocyanate II dropwise to react. After the reaction is completed, an isocyanate-terminated polybutadiene solution is obtained. (2) Under an inert atmosphere, hyperbranched polyethyleneimine was dissolved in anhydrous N,N-dimethylformamide, and 3,4-dihydroxybenzoic acid was added to react and obtain catechol-modified hyperbranched polyethyleneimine solution. (3) The isocyanate-terminated polybutadiene solution was added dropwise to the catechol-modified hyperbranched polyethyleneimine solution to obtain the reaction solution; (4) Pour the reaction solution into the mixed solvent to precipitate, collect the precipitate, and obtain the reactive entanglement agent by washing and drying.

[0007] It should be noted that this invention creatively prepares a reactive entanglement agent. Hyperbranched polyethyleneimine (PEI) is a highly branched, dendritic polymer with a surface rich in amine groups, providing abundant reaction sites for grafting functional arms. First, 3,4-dihydroxybenzoic acid (DHCA) is grafted onto some of the amine groups of PEI via an amidation reaction, with catechol groups at the ends. Then, hydroxyl-terminated polybutadiene (HTPB) is reacted with isophorone diisocyanate (IPDI) to prepare a terminal-NCO prepolymer, which is then grafted onto the functionalized PEI under low-temperature conditions, resulting in a chemical structure with PEI as the core and grafted with two functional arms.

[0008] In this invention, the polyurethane prepolymer is a prepolymer obtained by reacting IPDI with a block copolymer of poly(ε-caprolactone) diol (PCL) and HTPB. IPDI provides good weather resistance and mechanical properties, PCL provides crystallinity and strength, and HTPB introduces flexible long chains, giving the prepolymer extremely high elasticity and toughness.

[0009] In some embodiments, the reactive entanglement agent comprises the following components by weight: 100 parts of hydroxyl-terminated polybutadiene II, 190-210 parts of solvent II, 0.1-0.3 parts of catalyst, 20-24 parts of isophorone diisocyanate II, 8-12 parts of hyperbranched polyethyleneimine, 145-155 parts of anhydrous N,N-dimethylformamide, and 20-25 parts of 3,4-dihydroxybenzoic acid.

[0010] In some embodiments, solvent II is anhydrous toluene or anhydrous N,N-dimethylformamide; the catalyst is one of dibutyltin dilaurate and bismuth isooctanoate; the hydroxyl-terminated polybutadiene II has a hydroxyl value of 50-56 mg KOH / g; and the mixed solvent is a mixture of glacial ether and n-hexane in a volume ratio of 1:1.

[0011] In some embodiments, in step (1), the mixing temperature is 60-70℃, the reaction temperature is 75-80℃, and the reaction time is 3-4h; in step (2), the reaction is carried out at 140-160℃ and -0.08 to -0.1MPa for 5-8h.

[0012] In some embodiments, in step (3), the catechol-modified hyperbranched polyethyleneimine solution is placed in an ice-salt bath at 0-5°C during the dropwise addition process, and the dropwise addition temperature is controlled to be <10°C. The reaction is first carried out at 0-10°C for 1.5-2.5h, and then the temperature is raised to 22-27°C for 7-9h. In step (4), the washing is carried out with anhydrous ether 3-5 times, and the drying is carried out under vacuum at 30-40°C for 46-50h.

[0013] In some embodiments, the mass ratio of poly(ε-caprolactone) glycol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I is 48-52:13-17:18-19; the NCO mass percentage of the polyurethane prepolymer is 9-11.5%; the reactive plasticizer is tri(2-ethylhexyl) trimellitate or di(2-butoxyethyl) adipic acid; the UV stabilizer composition is a compound of benzotriazole UV absorbers and hindered amine light stabilizers in a weight ratio of 2:1; the defoamer is a modified polysiloxane-polyether copolymer defoamer; and the nanoscale rheology modifier is a product obtained by surface treatment of fumed silica with hexamethyldisilazane.

[0014] In some embodiments, the multi-graded composite aggregate comprises the following components in parts by weight: 15-25 parts of 3-5mm high-strength ceramsite, 20-30 parts of 1.18-3mm modified basalt fragments, 15-25 parts of 0.6-1.18mm sintered bauxite particles, 10-20 parts of 0.3-0.6mm quartz manufactured sand, 5-15 parts of 0.075-0.3mm graded rubber powder, and 3-8 parts of <0.075mm silica fume.

[0015] In some embodiments, the composite latent curing agent system is obtained by compounding a modified amine-epoxy adduct and 4,4'-methylenebis(2-ethyl-6-methylaniline) in a weight ratio of 1-1.5:1; the silane coupling agent is a mixture of 3-glycidyl etheroxypropyltriethoxysilane and 3-aminopropyltriethoxysilane in a weight ratio of 1:1; and solvent I is selected from at least one of anhydrous ethanol and anhydrous isopropanol.

[0016] This invention employs a composite latent curing agent system, which is a combination of a modified amine-epoxy adduct and 4,4'-methylenebis(2-ethyl-6-methylaniline). The former is a low-viscosity, multifunctional amine-epoxy adduct that provides moderate reactivity (adjustable gel time of 30-80 hours) and a controllable pot life, and can form a network with high chemical crosslinking density with polyurethane through urea bonds and epoxy chain-opening reactions. The latter is a sterically hindered aromatic amine with a relatively slow curing speed, which can significantly improve the heat distortion temperature and mechanical strength of the cured product.

[0017] A second aspect of this invention provides a method for preparing polyurethane high-elasticity concrete for steel bridge decks, comprising the following steps: S1.1: Under an inert atmosphere, poly(ε-caprolactone) diol and hydroxyl-terminated polybutadiene I are mixed and dehydrated, and isophorone diisocyanate I is added dropwise. After the addition is complete, the reaction is carried out to obtain a polyurethane prepolymer. S1.2: Add reactive plasticizer, UV stabilizer composition, defoamer and nanoscale rheology modifier to polyurethane prepolymer in sequence, and mix to obtain component A; S2.1: Mix and dilute the silane coupling agent, reactive entanglement agent and solvent I to obtain the interface treatment solution; S2.2: Spray the interface treatment liquid onto the surface of the multi-grade composite aggregate, add it to the composite latent curing agent system and mix to obtain component B; S3: Mix component A and component B at a weight ratio of 1:4-6 to obtain a mixture. Place the mixture on the steel bridge deck, level and cure it to obtain polyurethane high-elasticity concrete for steel bridge deck.

[0018] In some embodiments, in S1.1, the dehydration is carried out at 105-115°C and under a vacuum of -0.09 to -0.1 MPa for 2-3 hours. When isophorone diisocyanate I is added dropwise, poly(ε-caprolactone) diol and hydroxyl-terminated polybutadiene I are cooled to 70-80°C, and the temperature during the dropwise addition is <85°C. The reaction is carried out at 78-82°C for 3-4 hours. In S1.2, the mixing is carried out at 55-65°C and under a vacuum of -0.085 to -0.095 MPa for 1.5-2.5 hours. In S3, the mixing is carried out at 45-55°C and under a pressure of 15-20 MPa for 8-15 seconds.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects: 1. This invention uses IPDI-PCL-HTPB block copolymer prepolymer and combines it with a composite latent curing agent system, enabling the material to maintain high elasticity (elastic recovery rate ≥98%) within a temperature range of -30 to 80℃, while achieving a tensile strength of over 15MPa, thus achieving a perfect combination of high elasticity and high strength. Furthermore, the composite latent curing agent system used in this invention provides a good working life, facilitating large-area construction. The UV stabilizer composition and the inherent weather resistance of IPDI ensure excellent UV aging resistance of the paving layer. The excellent hydrolysis resistance and dense cross-linked network structure of PCL segments jointly guarantee the long-term stability of the material in humid and hot environments. In addition, the process of this invention employs high-temperature and high-pressure (45-55℃, 15-20MPa) impact mixing, ensuring that the more viscous component A can quickly and uniformly coat each aggregate particle in component B.

[0020] 2. The aggregates in this invention employ a six-grade mix design, forming a continuous gradation system from coarse skeleton to fine filler. High-strength ceramsite and modified basalt provide the main skeleton, while sintered bauxite and quartz sand fill the voids. Rubber powder not only improves elasticity but also imparts excellent noise reduction to the pavement layer, bringing significant vibration and noise reduction benefits to bridge deck pavement, aligning with the development concept of green transportation. Silica fume, as an ultrafine filler, further densifies the structure and participates in interfacial reactions. The six-grade composite aggregate system ensures the densest packing, significantly improving the density, compressive strength (≥80MPa), and impact resistance of the concrete. The synergistic effect of the silane coupling agent and silica fume greatly enhances the interfacial adhesion between the resin matrix and various aggregates (especially inorganic aggregates).

[0021] 3. The reactive entanglement agent added in this invention is a PEI-based core framework that connects two functional groups through a chemical reaction: one is a small molecule containing catechol groups attached to some of its amino sites, and the other is an HTPB molecular chain attached to the remaining amino sites. This molecular chain, after IPDI modification, carries reactive -NCO groups at its ends. The catechol groups can react with metal ions (Fe2+) on the surface of aggregates such as ceramsite and basalt in multi-stage composite materials. 3+ Al 3+ The reactive entanglement agent formed coordination bonds (e.g., amine curing agents) to achieve chemical anchoring and solve the problem of easy aggregate debonding. The terminal reactive -NCO groups react with the amine curing agent in the system during concrete construction to form urea bonds, chemically integrating into the polyurethane network. Simultaneously, its long-chain HTPB portion can physically entangle with the polyurethane matrix. The reactive entanglement agent provided by this invention can form a triple interfacial reinforcement between aggregates and resin, consisting of chemical anchoring, reactive integration, and physical entanglement. This significantly improves the interlayer bond strength of concrete, enhances the fracture toughness, fatigue resistance, and durability of the material, and achieves a balance between high elasticity and high strength, high adhesion and high toughness. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to specific embodiments.

[0023] Example 1 A polyurethane high-elasticity concrete for steel bridge decks, comprising component A and component B; By weight, component A comprises the following raw materials: 90 parts polyurethane prepolymer, 8 parts reactive plasticizer, 2 parts UV stabilizer composition, 0.5 parts defoamer, and 1.2 parts nanoscale rheology modifier; By weight, component B comprises the following raw materials: 100 parts of multi-grade composite aggregate, 5 parts of composite latent curing agent system, 1.2 parts of reactive entanglement agent, 0.8 parts of silane coupling agent, and 7 parts of solvent I; The polyurethane prepolymer is a prepolymer obtained by reacting poly(ε-caprolactone) diol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I. The reactive entanglement agent is prepared by the following steps: (1) 100 parts by weight of hydroxyl-terminated polybutadiene II and 200 parts by weight of anhydrous toluene were mixed at 65°C. Under an inert atmosphere, 0.2 parts by weight of dibutyltin dilaurate were added, followed by the dropwise addition of 22 parts by weight of isophorone diisocyanate II. The reaction was carried out at 78°C for 3.5 h. After the reaction was completed, an isocyanate-terminated polybutadiene solution was obtained. The hydroxyl value of hydroxyl-terminated polybutadiene II was 54 mg KOH / g. (2) Under an inert atmosphere, 10 parts by weight of hyperbranched polyethyleneimine were dissolved in 150 parts by weight of anhydrous N,N-dimethylformamide, and 22 parts by weight of 3,4-dihydroxybenzoic acid were added. The mixture was reacted at 150℃ and -0.09MPa for 6 hours to obtain a catechol-modified hyperbranched polyethyleneimine solution. (3) Place the catechol-modified hyperbranched polyethyleneimine solution in an ice-salt bath at 0-5℃, and then add isocyanate-terminated polybutadiene solution dropwise. During the dropwise addition, control the temperature to <10℃. After the dropwise addition is completed, react at 5℃ for 2 hours, and then raise the temperature to 25℃ for 8 hours to obtain the reaction solution. (4) Pour the reaction solution into the mixed solvent to precipitate, collect the precipitate, wash it with anhydrous diethyl ether 3-5 times, and dry it under vacuum at 35°C for 48h to obtain the reactive entanglement agent; wherein, the mixed solvent is composed of ice diethyl ether and n-hexane in a volume ratio of 1:1.

[0024] The polyurethane high-elasticity concrete for the steel bridge deck described above is prepared by the following steps: S1.1: Under nitrogen protection, poly(ε-caprolactone) glycol (Mn=2000) and hydroxyl-terminated polybutadiene I (Mn=2800) were mixed and dehydrated at 110℃ and -0.098MPa vacuum for 2.5h; then the temperature was lowered to 75℃, and isophorone diisocyanate I was slowly added dropwise, controlling the addition time to about 1h, during which the temperature was <85℃; after the addition was completed, the reaction was carried out at 80℃ for 3.5h, during which the NCO content was measured at regular intervals until it reached 10.2%, at which point the reaction was stopped to obtain polyurethane prepolymer; wherein, the mass ratio of poly(ε-caprolactone) glycol, hydroxyl-terminated polybutadiene I and isophorone diisocyanate I was 50:15:18.5; S1.2: Cool the above polyurethane prepolymer to 60°C, maintain a vacuum of -0.09 MPa, and add the reactive plasticizer (tris(2-ethylhexyl)trimethicone), the UV stabilizer composition (UV-1130 and Tinuvin 770 in a 2:1 ratio), the modified polysiloxane-polyether copolymer defoamer (TEGO Foamex 825), and the nanoscale rheology modifier (AEROSIL R812) in sequence. Stir for 2 hours at 60°C and a vacuum of -0.09 MPa to obtain component A. S2.1: An interface treatment solution is obtained by mixing and diluting a silane coupling agent, a reactive entanglement agent and anhydrous ethanol; wherein the silane coupling agent is a mixture of 3-glycidyl etheroxypropyltriethoxysilane and 3-aminopropyltriethoxysilane in a weight ratio of 1:1. S2.2: Prepare multi-graded composite aggregates (parts by weight) according to the following proportions: 20 parts of 3-5mm high-strength ceramsite, 25 parts of 1.18-3mm modified basalt fragments, 20 parts of 0.6-1.18mm sintered bauxite particles, 15 parts of 0.3-0.6mm quartz manufactured sand, 12 parts of 0.075-0.3mm graded rubber powder, and 8 parts of <0.075mm silica fume. Dry, cool, and mix all aggregates. Then, spray the interface treatment liquid onto the aggregate surface, and add the composite latent curing agent system. Stir and mix to ensure uniform powder dispersion, obtaining component B. The composite latent curing agent system consists of a modified amine-epoxy adduct (Ancamine) at a weight ratio of 1.2:1. ® It was obtained by combining 2489) and 4,4'-methylenebis(2-ethyl-6-methylaniline).

[0025] S3: The steel bridge deck is shot-blasted to Sa3.0 grade with a roughness Ry≈75μm, and then coated with an epoxy zinc-rich primer (dry film thickness 70μm). Using a two-component high-temperature and high-pressure paver, component A and component B are mixed at a weight ratio of 1:5, mixed for 12 seconds at 50℃ and 18MPa pressure, and then quickly spread onto the treated bridge surface. Immediately, it is leveled using a screed with infrared heating function. After curing for 8 hours at an ambient temperature of 25℃ and relative humidity of 45%, the pavement is fully cured and can be opened to traffic.

[0026] Example 2 A polyurethane high-elasticity concrete for steel bridge decks, comprising component A and component B; By weight, component A comprises the following raw materials: 95 parts polyurethane prepolymer, 12 parts reactive plasticizer, 3 parts UV stabilizer composition, 0.8 parts defoamer, and 2 parts nanoscale rheology modifier. By weight, component B comprises the following raw materials: 100 parts of multi-grade composite aggregate, 7 parts of composite latent curing agent system, 2 parts of reactive entanglement agent, 1 part of silane coupling agent, and 10 parts of solvent I; The polyurethane prepolymer is a prepolymer obtained by reacting poly(ε-caprolactone) diol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I. The reactive entanglement agent is prepared by the following steps: (1) 100 parts by weight of hydroxyl-terminated polybutadiene II and 210 parts by weight of anhydrous N,N-dimethylformamide were mixed at 70°C. Under an inert atmosphere, 0.3 parts by weight of bismuth isooctanoate was added, followed by the dropwise addition of 24 parts by weight of isophorone diisocyanate II. The reaction was carried out at 80°C for 3 hours. After the reaction was completed, an isocyanate-terminated polybutadiene solution was obtained. The hydroxyl value of hydroxyl-terminated polybutadiene II was 56 mg KOH / g. (2) Under an inert atmosphere, 12 parts by weight of hyperbranched polyethyleneimine were dissolved in 155 parts by weight of anhydrous N,N-dimethylformamide, and 25 parts by weight of 3,4-dihydroxybenzoic acid were added. The mixture was reacted at 160℃ and -0.08MPa for 5 h to obtain a catechol-modified hyperbranched polyethyleneimine solution. (3) Place the catechol-modified hyperbranched polyethyleneimine solution in an ice-salt bath at 0-5℃, and then add isocyanate-terminated polybutadiene solution dropwise. During the dropwise addition, control the temperature to <10℃. After the dropwise addition is completed, react at 10℃ for 1.5h, and then raise the temperature to 27℃ for 7h to obtain the reaction solution. (4) Pour the reaction solution into the mixed solvent to precipitate, collect the precipitate, wash it 5 times with anhydrous diethyl ether, and dry it under vacuum at 40°C for 46 h to obtain the reactive entanglement agent; wherein, the mixed solvent is a mixture of ice diethyl ether and n-hexane in a volume ratio of 1:1.

[0027] The polyurethane high-elasticity concrete for the steel bridge deck described above is prepared by the following steps: S1.1: Under nitrogen protection, poly(ε-caprolactone) glycol (Mn=2000) and hydroxyl-terminated polybutadiene I (Mn=2800) were mixed and dehydrated at 115℃ and -0.1MPa vacuum for 3 hours; then the temperature was lowered to 80℃, and isophorone diisocyanate I was slowly added dropwise, controlling the addition time to about 1 hour, during which the temperature was <85℃; after the addition was completed, the reaction was carried out at 82℃ for 3 hours, during which the NCO content was measured at regular intervals until it reached 10.8%, at which point the reaction was stopped to obtain a polyurethane prepolymer; wherein, the mass ratio of poly(ε-caprolactone) glycol, hydroxyl-terminated polybutadiene I and isophorone diisocyanate I was 52:17:19; S1.2: Cool the above polyurethane prepolymer to 60°C, maintain a vacuum of -0.09MPa, and sequentially add a reactive plasticizer (di(2-butoxyethyl adipic acid)), a UV stabilizer composition (UV-1130 and Tinuvin 770 in a 2:1 ratio), a modified polysiloxane-polyether copolymer defoamer (BYK-024), and a nanoscale rheology modifier (CAB-O-SIL TS-720). Stir for 1.5 h at 65°C and a vacuum of -0.095MPa to obtain component A. S2.1: The interface treatment solution is obtained by mixing and diluting the silane coupling agent, the reactive entanglement agent and anhydrous isopropanol; wherein the silane coupling agent is composed of 3-glycidyl etheroxypropyltriethoxysilane and 3-aminopropyltriethoxysilane in a weight ratio of 1:1. S2.2: Prepare multi-graded composite aggregates (parts by weight) according to the following proportions: 25 parts of 3-5mm high-strength ceramsite, 30 parts of 1.18-3mm modified basalt fragments, 15 parts of 0.6-1.18mm sintered bauxite particles, 10 parts of 0.3-0.6mm quartz manufactured sand, 15 parts of 0.075-0.3mm graded rubber powder, and 5 parts of <0.075mm silica fume. Dry, cool, and mix all aggregates. Then, spray the interface treatment liquid onto the aggregate surface, and add the composite latent curing agent system. Stir and mix to ensure uniform powder dispersion, obtaining component B. The composite latent curing agent system consists of a modified amine-epoxy adduct (Ancamine) at a weight ratio of 1.5:1. ® It was obtained by combining 2368) and 4,4'-methylenebis(2-ethyl-6-methylaniline).

[0028] S3: The steel bridge deck is shot-blasted to Sa3.0 grade with a roughness Ry≈75μm, and then coated with an epoxy zinc-rich primer (dry film thickness 70μm). Using a two-component high-temperature, high-pressure paver, component A and component B are mixed at a weight ratio of 1:6, mixed for 8 seconds at 55℃ and 20MPa pressure, and then quickly spread onto the treated bridge surface. Immediately, it is leveled using a screed equipped with infrared heating. After curing for 8 hours at an ambient temperature of 25℃ and relative humidity of 45%, the pavement is fully cured and can be opened to traffic.

[0029] Example 3 A polyurethane high-elasticity concrete for steel bridge decks, comprising component A and component B; By weight, component A comprises the following raw materials: 85 parts polyurethane prepolymer, 5 parts reactive plasticizer, 1 part UV stabilizer composition, 0.2 parts defoamer, and 0.5 parts nanoscale rheology modifier; By weight, component B comprises the following raw materials: 100 parts of multi-grade composite aggregate, 4 parts of composite latent curing agent system, 0.5 parts of reactive entanglement agent, 0.3 parts of silane coupling agent, and 3 parts of solvent I; The polyurethane prepolymer is a prepolymer obtained by reacting poly(ε-caprolactone) diol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I. The reactive entanglement agent is prepared by the following steps: (1) 100 parts by weight of hydroxyl-terminated polybutadiene II and 190 parts by weight of anhydrous toluene were mixed at 60°C. Under an inert atmosphere, 0.1 parts by weight of dibutyltin dilaurate was added, followed by the dropwise addition of 20 parts by weight of isophorone diisocyanate II. The reaction was carried out at 75°C for 4 hours. After the reaction was completed, an isocyanate-terminated polybutadiene solution was obtained. The hydroxyl value of hydroxyl-terminated polybutadiene II was 50 mg KOH / g. (2) Under an inert atmosphere, 8 parts by weight of hyperbranched polyethyleneimine were dissolved in 145 parts by weight of anhydrous N,N-dimethylformamide, and 20 parts by weight of 3,4-dihydroxybenzoic acid were added. The mixture was reacted at 140℃ and -0.1MPa for 8 hours to obtain a catechol-modified hyperbranched polyethyleneimine solution. (3) Place the catechol-modified hyperbranched polyethyleneimine solution in an ice-salt bath at 0-5℃, and then add isocyanate-terminated polybutadiene solution dropwise. During the dropwise addition, control the temperature to <10℃. After the dropwise addition is completed, react at 0℃ for 2.5h, and then raise the temperature to 22℃ for 9h to obtain the reaction solution. (4) Pour the reaction solution into the mixed solvent to precipitate, collect the precipitate, wash it three times with anhydrous diethyl ether, and dry it under vacuum at 30°C for 50 h to obtain the reactive entanglement agent; wherein, the mixed solvent is a mixture of ice diethyl ether and n-hexane in a volume ratio of 1:1.

[0030] The polyurethane high-elasticity concrete for the steel bridge deck described above is prepared by the following steps: S1.1: Under nitrogen protection, poly(ε-caprolactone) glycol (Mn=2000) and hydroxyl-terminated polybutadiene I (Mn=2800) were mixed and dehydrated at 105℃ and -0.09MPa vacuum for 3 hours; then the temperature was lowered to 70℃, and isophorone diisocyanate I was slowly added dropwise, controlling the addition time to about 1 hour, during which the temperature was <85℃; after the addition was completed, the reaction was carried out at 78℃ for 4 hours, during which the NCO content was measured at regular intervals until it reached 9.5%, at which point the reaction was stopped to obtain a polyurethane prepolymer; wherein, the mass ratio of poly(ε-caprolactone) glycol, hydroxyl-terminated polybutadiene I and isophorone diisocyanate I was 48:13:18; S1.2: Cool the above polyurethane prepolymer to 60°C, maintain a vacuum of -0.09MPa, and add the reactive plasticizer (tris(2-ethylhexyl)trimethicone), the UV stabilizer composition (UV-1130 and Tinuvin 770 in a 2:1 ratio), the modified polysiloxane-polyether copolymer defoamer (TEGO Foamex 825), and the nanoscale rheology modifier (AEROSIL R812) in sequence. Stir for 2.5 hours at 55°C and a vacuum of -0.085MPa to obtain component A. S2.1: An interface treatment solution is obtained by mixing and diluting a silane coupling agent, a reactive entanglement agent and anhydrous ethanol; wherein the silane coupling agent is a mixture of 3-glycidyl etheroxypropyltriethoxysilane and 3-aminopropyltriethoxysilane in a weight ratio of 1:1. S2.2: Prepare multi-graded composite aggregates (parts by weight) according to the following proportions: 15 parts of 3-5mm high-strength ceramsite, 20 parts of 1.18-3mm modified basalt fragments, 25 parts of 0.6-1.18mm sintered bauxite particles, 20 parts of 0.3-0.6mm quartz manufactured sand, 15 parts of 0.075-0.3mm graded rubber powder, and 5 parts of <0.075mm silica fume. Dry, cool, and mix all aggregates. Then, spray the interface treatment liquid onto the aggregate surface, and add the composite latent curing agent system. Stir and mix to ensure uniform powder dispersion, obtaining component B. The composite latent curing agent system consists of a modified amine-epoxy adduct (Ancamine) in a 1:1 weight ratio. ® It was obtained by combining 2489) and 4,4'-methylenebis(2-ethyl-6-methylaniline).

[0031] S3: The steel bridge deck is shot-blasted to Sa3.0 grade with a roughness Ry≈75μm, and then coated with an epoxy zinc-rich primer (dry film thickness 70μm). Using a two-component high-temperature and high-pressure paver, component A and component B are mixed at a weight ratio of 1:4, mixed for 15 seconds at 45℃ and 15MPa pressure, and then quickly spread onto the treated bridge surface. Immediately, it is leveled using a screed equipped with infrared heating. After curing for 8 hours at an ambient temperature of 25℃ and relative humidity of 45%, the pavement is fully cured and can be opened to traffic.

[0032] Example 4 It is basically the same as Example 1, except that: In component A, the polyurethane prepolymer is obtained by reacting poly(ε-caprolactone) glycol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I in a mass ratio of 49:14:18, with an NCO content of 9%. In step S2.2, the multi-graded composite aggregate (parts by weight) consists of: 18 parts of 3-5mm high-strength ceramsite, 28 parts of 1.18-3mm modified basalt fragments, 22 parts of 0.6-1.18mm sintered bauxite particles, 16 parts of 0.3-0.6mm quartz manufactured sand, 10 parts of 0.075-0.3mm graded rubber powder, and 6 parts of <0.075mm silica fume. In step S3, component A and component B are mixed in a weight ratio of 1:4.5.

[0033] Example 5 It is basically the same as Example 1, except that: In component A, the polyurethane prepolymer is obtained by reacting poly(ε-caprolactone) glycol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I in a mass ratio of 51:16:19, with an NCO content of 11.5%. In step S2.2, the multi-graded composite aggregate (parts by weight) consists of: 22 parts of 3-5mm high-strength ceramsite, 22 parts of 1.18-3mm modified basalt fragments, 18 parts of 0.6-1.18mm sintered bauxite particles, 18 parts of 0.3-0.6mm quartz manufactured sand, 14 parts of 0.075-0.3mm graded rubber powder, and 6 parts of <0.075mm silica fume. In step S3, component A and component B are mixed in a weight ratio of 1:5.5.

[0034] Comparative Example 1 It is basically the same as Example 1, except that no reactive entanglement agent is added.

[0035] Comparative Example 2 The process is basically the same as in Example 1, except that the reactive entanglement agent is obtained through physical mixing, and the amounts of each component are the same as in Example 1. The steps are as follows: (1) Hydroxyl-terminated polybutadiene II and anhydrous toluene were mixed, and isophorone diisocyanate II was added to obtain dispersion A; (2) Next, the hyperbranched polyethyleneimine was dispersed in anhydrous N,N-dimethylformamide, and 3,4-dihydroxybenzoic acid was added to mix and obtain dispersion B; (3) Mix and stir dispersion A and dispersion B to form a reactive entanglement agent.

[0036] Comparative Example 3 The results are basically the same as in Example 1, except that the polyurethane prepolymer does not contain hydroxyl-terminated polybutadiene I, but is obtained by reacting poly(ε-caprolactone) diol and isophorone diisocyanate I.

[0037] Comparative Example 4 It is basically the same as Example 1, except that the multi-graded composite aggregate is replaced with a single aggregate, and all of them are 3.0-5.0mm high-strength ceramsite, with the same weight as the total weight of aggregate in Example 1.

[0038] Comparative Example 5 The conventional epoxy asphalt concrete formula (epoxy resin (bisphenol A type epoxy resin) and cured asphalt are mixed at a weight ratio of 1:0.5, and conventional aggregates are added) and its standard construction process are adopted.

[0039] The concrete prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests. The test results are shown in Tables 1 and 2.

[0040] Since there is currently no specific and unified testing standard for "polyurethane concrete" (PUC) in China or internationally, this invention relates to the performance testing of polyurethane high-elasticity concrete, and the following relevant standards are used as a reference for testing.

[0041] Tensile properties and elastic recovery rate were determined according to GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". A standard dumbbell-shaped (Type I) specimen was prepared and stretched at a constant speed of 500 mm / min on a tensile testing machine until fracture. The maximum tensile force (for calculating tensile strength) and the gauge length elongation at fracture (for calculating elongation at break) were recorded. The specimen was then stretched to a predetermined strain, held for 60 s, unloaded, and after waiting another 60 s, the residual strain (εr) was measured. The elastic recovery rate was calculated as: Elastic recovery rate = (1 - εr / 1.00) × 100%.

[0042] The bond strength was tested using a pull-out tester according to standard GB / T 5210 "Paints and Varnishes - Pull-out Adhesion Test". A steel plate-concrete composite specimen was prepared, and a standard pull-out test column was firmly bonded to its surface using a high-strength two-component epoxy adhesive. The bond strength was then tested using a digital pull-out tester.

[0043] Dynamic stability was assessed using standard JTG E20 2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (T0719, Rutting Test). The rutting test is a core method for evaluating the high-temperature stability of asphalt mixtures, directly reflecting the pavement's resistance to permanent deformation under high temperatures and heavy vehicle loads. 300x300x50mm plate-shaped specimens were placed in a 70℃ environmental chamber for at least 5 hours. A standard test wheel (0.7MPa wheel pressure) was used to compact the mixture at a speed of 42 cycles / min for 1 hour. The rutting depth was recorded at 45 minutes and 60 minutes, and the dynamic stability (cycles / mm) was calculated.

[0044] The -30℃ low-temperature bending strain test refers to T0715 (bending test) in the standard JTG E20 2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The low-temperature bending test is used to evaluate the low-temperature crack resistance of asphalt mixtures. The specimen is placed in a -30℃ environmental chamber for no less than 4 hours. Three-point bending loading is applied on a material testing machine with a mid-span loading rate of 50 mm / min. The maximum bending tensile strain (με) at the fracture of the specimen is recorded.

[0045] The anti-skid pendulum value is determined according to standard JTG E60-2008 "Specifications for Field Testing of Highway Subgrade and Pavement" T0964 (Pendulum Friction Coefficient Test). Test points are selected on the surface of the formed pavement layer, kept clean and dry, and tested using a pendulum friction coefficient measuring instrument. The pendulum value (BPN) indicated by the pointer when the pendulum swings back is read, and the average value is taken.

[0046] Salt spray resistance test: Place the steel plate-paving material bonded specimen into a salt spray chamber and conduct a 3000-hour neutral salt spray test (5% NaCl, 35℃) according to standard GB / T 1771 "Determination of resistance to neutral salt spray of paints and varnishes". Remove the specimen, clean it, and then test the bond strength using a pull-out tester according to GB / T 5210 "Paints and varnishes pull-out adhesion test" and calculate the strength retention rate.

[0047] Table 1

[0048] Table 2

[0049] As can be seen from Tables 1 and 2, the polyurethane high-elasticity concrete prepared in Examples 1-5 of the present invention is comprehensively and significantly superior to traditional epoxy asphalt concrete in terms of tensile strength, elasticity, bond strength, high and low temperature performance, durability and functionalization (noise reduction). In particular, it performs exceptionally well in terms of high elasticity and high temperature stability, and fully meets the requirements of modern long-span steel bridge deck paving.

[0050] As can be seen from the comparative examples, Example 1, which uses a chemically grafted entanglement agent, has a bond strength far exceeding that of Comparative Example 2 (5.2 MPa) which uses only physical mixing and Comparative Example 1 (4.0 MPa) which does not use any chemically grafted entanglement agent, demonstrating the necessity of reactive entanglement agents. Comparative Example 3 lacks HTPB segments, resulting in the material becoming harder and more brittle, manifested as a decrease in elongation at break and elastic recovery rate, and poor low-temperature crack resistance. Comparative Example 4 uses a single gradation, and its tensile strength, dynamic stability, and anti-slip value are all significantly reduced.

[0051] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A polyurethane high-elasticity concrete for steel bridge decks, characterized in that, Includes component A and component B; By weight, component A comprises the following raw materials: 85-95 parts of polyurethane prepolymer, 5-12 parts of reactive plasticizer, 1-3 parts of UV stabilizer composition, 0.2-0.8 parts of defoamer, and 0.5-2 parts of nano-rheology modifier; By weight, component B comprises the following raw materials: 100 parts of multi-grade composite aggregate, 4-7 parts of composite latent curing agent system, 0.5-2 parts of reactive entanglement agent, 0.3-1 parts of silane coupling agent, and 3-10 parts of solvent I; The polyurethane prepolymer is a prepolymer obtained by reacting poly(ε-caprolactone) diol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I. The reactive entanglement agent is prepared by the following steps: (1) Mix hydroxyl-terminated polybutadiene II and solvent II, add catalyst under an inert atmosphere, and then add isophorone diisocyanate II dropwise to react. After the reaction is completed, an isocyanate-terminated polybutadiene solution is obtained. (2) Under an inert atmosphere, hyperbranched polyethyleneimine was dissolved in anhydrous N,N-dimethylformamide, and 3,4-dihydroxybenzoic acid was added to react and obtain catechol-modified hyperbranched polyethyleneimine solution. (3) The isocyanate-terminated polybutadiene solution is added dropwise to the catechol-modified hyperbranched polyethyleneimine solution to obtain a reaction solution; (4) Pour the reaction solution into a mixed solvent to precipitate, collect the precipitate, and wash and dry it to obtain the reactive entanglement agent.

2. The polyurethane high-elasticity concrete for steel bridge decks according to claim 1, characterized in that, The reactive entanglement agent comprises the following components by weight: 100 parts of hydroxyl-terminated polybutadiene II, 190-210 parts of solvent II, 0.1-0.3 parts of catalyst, 20-24 parts of isophorone diisocyanate II, 8-12 parts of hyperbranched polyethyleneimine, 145-155 parts of anhydrous N,N-dimethylformamide, and 20-25 parts of 3,4-dihydroxybenzoic acid.

3. The polyurethane high-elasticity concrete for steel bridge decks according to claim 2, characterized in that, Solvent II is anhydrous toluene or anhydrous N,N-dimethylformamide; the catalyst is one of dibutyltin dilaurate and bismuth isooctanoate; the hydroxyl-terminated polybutadiene II has a hydroxyl value of 50-56 mg KOH / g; the mixed solvent is a mixture of icy diethyl ether and n-hexane in a volume ratio of 1:

1.

4. The polyurethane high-elasticity concrete for steel bridge decks according to claim 1, characterized in that, In step (1), the mixing temperature is 60-70℃, the reaction temperature is 75-80℃, and the reaction time is 3-4h; in step (2), the reaction is carried out at 140-160℃ and -0.08 to -0.1MPa for 5-8h.

5. The polyurethane high-elasticity concrete for steel bridge decks according to claim 1, characterized in that, In step (3), the catechol-modified hyperbranched polyethyleneimine solution is placed in an ice-salt bath at 0-5℃ during the dropwise addition process, and the dropwise addition temperature is controlled to be <10℃. The reaction is first carried out at 0-10℃ for 1.5-2.5h, and then the temperature is raised to 22-27℃ for 7-9h. In step (4), the washing is carried out with anhydrous diethyl ether 3-5 times, and the drying is carried out under vacuum at 30-40℃ for 46-50h.

6. The polyurethane high-elasticity concrete for steel bridge decks according to claim 1, characterized in that, The mass ratio of poly(ε-caprolactone) diol, hydroxyl-terminated polybutadiene I, and isophorone diisocyanate I is 48-52:13-17:18-19; the NCO mass percentage of the polyurethane prepolymer is 9-11.5%; the reactive plasticizer is tris(2-ethylhexyl) trimellitate or di(2-butoxyethyl) adipic acid; the UV stabilizer composition is a compound of benzotriazole UV absorber and hindered amine light stabilizer in a weight ratio of 2:1; the defoamer is a modified polysiloxane-polyether copolymer defoamer; and the nanoscale rheology modifier is a product obtained by surface treatment of fumed silica with hexamethyldisilazane.

7. The polyurethane high-elasticity concrete for steel bridge decks according to claim 1, characterized in that, The multi-graded composite aggregate comprises the following components in parts by weight: 15-25 parts of 3-5mm high-strength ceramsite, 20-30 parts of 1.18-3mm modified basalt fragments, 15-25 parts of 0.6-1.18mm sintered bauxite particles, 10-20 parts of 0.3-0.6mm quartz manufactured sand, 5-15 parts of 0.075-0.3mm graded rubber powder, and 3-8 parts of <0.075mm silica fume.

8. The polyurethane high-elasticity concrete for steel bridge decks according to claim 1, characterized in that, The composite latent curing agent system is obtained by compounding a modified amine-epoxy adduct and 4,4'-methylenebis(2-ethyl-6-methylaniline) in a weight ratio of 1-1.5:1; the silane coupling agent is composed of a mixture of 3-glycidyl etheroxypropyltriethoxysilane and 3-aminopropyltriethoxysilane in a weight ratio of 1:1; the solvent I is selected from at least one of anhydrous ethanol and anhydrous isopropanol.

9. A method for preparing polyurethane high-elasticity concrete for steel bridge decks according to any one of claims 1-8, characterized in that, Includes the following steps: S1.1: Under an inert atmosphere, poly(ε-caprolactone) diol and hydroxyl-terminated polybutadiene I are mixed and dehydrated, and isophorone diisocyanate I is added dropwise. After the addition is complete, the reaction is carried out to obtain a polyurethane prepolymer. S1.2: A reactive plasticizer, a UV stabilizer composition, an antifoaming agent, and a nanoscale rheology modifier are added sequentially to the polyurethane prepolymer and mixed to obtain component A; S2.1: Mix and dilute the silane coupling agent, reactive entanglement agent and solvent I to obtain the interface treatment solution; S2.2: Spray the interface treatment liquid onto the surface of the multi-grade composite aggregate, and mix it with the composite latent curing agent system to obtain component B; S3: Mix component A and component B at a weight ratio of 1:4-6 to obtain a mixture, place the mixture on the steel bridge deck, level and cure to obtain polyurethane high-elasticity concrete for the steel bridge deck.

10. The method for preparing polyurethane high-elasticity concrete for steel bridge decks according to claim 9, characterized in that, In step S1.1, the dehydration is carried out at 105-115℃ and under a vacuum of -0.09 to -0.1MPa for 2-3 hours. When isophorone diisocyanate I is added dropwise, poly(ε-caprolactone) glycol and hydroxyl-terminated polybutadiene I are cooled to 70-80℃, and the temperature during the dropwise addition is <85℃. The reaction is carried out at 78-82℃ for 3-4 hours. In step S1.2, the mixing is carried out at 55-65℃ and under a vacuum of -0.085 to -0.095MPa for 1.5-2.5 hours. In step S3, the mixing is carried out at 45-55℃ and under a pressure of 15-20MPa for 8-15 seconds.

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