Suspension dense polyurethane finish composition and pavement structure

Abstract

This invention relates to the field of road materials, providing a suspended dense polyurethane surface layer composition and a road surface structure. Road surfaces paved with the surface layer composition of this invention not only have a low permeability coefficient and high splitting strength after freeze-thaw cycles, but also exhibit good dynamic stability and 16-hour Marshall stability, enabling rapid traffic opening. The surface layer composition comprises a mixture and a curing agent; the mixture comprises the following components in parts by weight: 86.5-92.0 parts of aggregate, 4.9-7.0 parts of single-component polyurethane adhesive, 3-6 parts of mineral powder, and 0.1-0.5 parts of lignin fiber; the curing agent is a 2-35 wt% aqueous solution of a triol, wherein the triol is selected from one or more of glycerol and trimethylolpropane.

Description

Technical Field

[0001] This invention relates to the field of road materials, specifically to a suspended dense polyurethane surface layer composition and a road surface structure. Background Technology

[0002] Asphalt is one of the most commonly used binders in road engineering, typically used as a cementing material mixed with aggregates to form road surfaces. Asphalt pavements are widely used in my country and globally, offering advantages such as lower cost and driving comfort. However, asphalt is a temperature-sensitive material, making it prone to rutting in high summer temperatures and brittleness in low winter temperatures. Furthermore, the physical adhesion between asphalt and aggregates leads to defects such as rutting, potholes, loosening, and cracking under vehicle pressure and rainwater immersion. Polyurethane, as a high-molecular adhesive, possesses high bonding strength, highly designable molecular structure, and good durability. After chemical bonding with aggregates, the resulting mixture exhibits extremely high strength while also possessing excellent low-temperature deformation resistance, making it an ideal alternative to asphalt for road paving.

[0003] The publication number CN118063131A provides a "rigid base polyurethane mixture pavement structure and its paving method". The pavement structure consists of a porous modified cement concrete base layer and a multi-crushed polyurethane concrete surface layer laid on the roadbed from bottom to top. It has the advantages of good overall stability, high interlayer bonding strength and obvious cost-effectiveness, but it has the problems of surface water seepage and long opening time to traffic.

[0004] CN116240768A discloses a "paving structure and method for single-component polyurethane noise-reducing pavement," providing a noise-reducing pavement paving structure including a polyurethane mixture anti-skid wear layer and a polyurethane mixture OGFC noise-reducing and drainage layer. This structure simultaneously provides noise reduction and drainage functions, effectively preventing debris from clogging the noise-reducing and drainage layer, thus ensuring both noise reduction and drainage effects. However, this invention also suffers from drawbacks such as slow curing of the polyurethane mixture layer, long opening time to traffic, high cost, and generally poor interlayer adhesion.

[0005] How to effectively solve the problems of rutting, potholes, loosening and / or cracking that exist in current asphalt pavements, as well as the high water permeability coefficient and long open-to-traffic time of existing polyurethane pavement technology, is one of the technical challenges that urgently need to be overcome in this field. Summary of the Invention

[0006] This invention provides a suspended dense polyurethane surface layer composition and a road structure. The surface layer of the road surface paved with the surface layer composition of this invention not only has a low permeability coefficient and a high splitting strength after freeze-thaw, but also has good dynamic stability and 16h Marshall stability, which can achieve the effect of rapid opening to traffic.

[0007] To achieve its objective, the present invention provides the following technical solution:

[0008] This invention provides a suspended dense polyurethane topcoat composition, the topcoat composition comprising a mixture and a curing agent; the mixture comprises the following components in parts by weight:

[0009]

[0010] The curing agent is a 2-35 wt% aqueous solution of a triol, wherein the triol is selected from one or more of glycerol and trimethylolpropane.

[0011] In another aspect, the present invention provides a surface layer for a road structure, wherein the surface layer is paved using the surface layer composition described above; preferably, the thickness of the surface layer is 3-8 cm, more preferably 4-7 cm, and more preferably 5-6 cm.

[0012] Another aspect of the present invention provides a method for paving the surface layer of the road structure described above, comprising the following steps:

[0013] The mixture is spread to form a precast surface layer, and then the curing agent is applied to the surface of the precast surface layer. After 5-15 minutes, it is compacted to obtain the surface layer of the road structure.

[0014] Preferably, the compaction includes: using a road roller to sequentially perform initial compaction, intermediate compaction, and final compaction on the precast surface layer to which the curing agent has been applied; preferably, the initial compaction, intermediate compaction, and final compaction are each performed once or multiple times;

[0015] More preferably, the initial compaction is performed using a 13-ton double-drum roller to remove static pressure and allow for vibration, the secondary compaction is performed using a 26-ton rubber-tired roller, and the final compaction is performed using a 13-ton double-drum roller for static compaction.

[0016] In another aspect, the present invention provides a rigid-flexible composite polyurethane pavement structure, wherein the pavement structure comprises, from bottom to top, a subbase and a surface layer, wherein the surface layer is the surface layer described above or the surface layer obtained by the paving method described above.

[0017] The technical solution provided by this invention has the following beneficial effects:

[0018] The surface layer composition provided by this invention is a composition particularly suitable for use in paving road surface layers. The road surface layer constructed using the surface layer composition of this invention has a low permeability coefficient and a high splitting strength after freeze-thaw cycles, while also having good dynamic stability and 16-hour Marshall stability, enabling rapid traffic opening and possessing anti-rutting characteristics. It is applicable to paving of various levels of roads, including expressways / first-class highways, national and provincial highways, and municipal roads. Detailed Implementation

[0019] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0021] This invention provides a suspended dense polyurethane topcoat composition, the topcoat composition comprising a mixture and a curing agent; the mixture comprises the following components in parts by weight:

[0022] Stone material, 86.5-92.0 parts.

[0023] 4.9-7.0 parts of one-component polyurethane adhesive.

[0024] 3-6 parts mineral powder

[0025] 0.1-0.5 parts of lignin fiber;

[0026] The curing agent is a 2-35 wt% aqueous solution of a triol, wherein the triol is selected from one or more of glycerol and trimethylolpropane.

[0027] The surface layer composition provided by this invention is a composition particularly suitable for use in paving road surface layers. The road surface layer constructed using the surface layer composition of this invention has a low permeability coefficient and a high splitting strength after freeze-thaw cycles, while also having good dynamic stability and 16-hour Marshall stability, enabling rapid traffic opening and possessing anti-rutting characteristics. It is applicable to paving of various levels of roads, including expressways / first-class highways, national and provincial highways, and municipal roads.

[0028] Furthermore, the mixture is used to spread and form a precast surface layer, and the curing agent is used to apply to the surface of the precast surface layer and cause a curing reaction; specifically, the curing agent can be sprayed onto the surface of the precast surface layer mechanically or manually.

[0029] This invention comprises a surface layer composition that combines aggregate, a one-component polyurethane adhesive, mineral powder, and lignin fibers to form a mixture, using a triol aqueous solution as a curing agent. The hydroxyl groups on the surface of the lignin fibers can chemically react with the active NCO groups in the one-component polyurethane mixture, forming a strong chemical bond and improving the strength of the molded mixture. Furthermore, the lignin fibers effectively fill the voids between the aggregates in the polyurethane mixture, reducing the permeability coefficient of the polyurethane pavement. Simultaneously, during the compaction process of the polyurethane pavement, the carbon dioxide gas generated by the reaction between the one-component polyurethane adhesive and the triol aqueous curing agent can diffuse along the surface of the lignin fibers, creating an "air-entraining effect," reducing the curing expansion of the polyurethane mixture and thus lowering the permeability coefficient of the pavement. The air-entraining and filling effects of the lignin fibers work synergistically to reduce the permeability coefficient of the polyurethane pavement. This invention, by applying a triol aqueous curing agent to the surface of the paved polyurethane mixture, provides a suitable allowance for compaction while simultaneously accelerating pavement curing and facilitating rapid traffic reopening. In addition, unlike the method of thoroughly mixing the curing agent and polyurethane mixture on the construction site, the present invention preferably adopts the method of spraying the curing agent, which has the advantages of simple operation, easy parameter control, low energy consumption, and good effect. Therefore, it has the characteristics of easy construction, no need for special equipment, and strong scalability.

[0030] In some examples, the mass fraction of the aggregate in the mixture is 86.5 parts, 87 parts, 89 parts, 90 parts, 92 parts, etc.; the mass fraction of the single-component polyurethane adhesive is 4.9 parts, 5.5 parts, 6.0 parts, 6.5 parts, 7.0 parts, etc.; the mass fraction of the mineral powder is 3 parts, 4 parts, 5 parts, 6 parts, etc.; and the mass fraction of the lignin fiber is 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, etc.

[0031] Preferably, the amount of curing agent applied to the surface of the precast surface layer is 0.6-2.0 kg / m². 2 The preferred concentration is 0.8-1.6 kg / m³. 2 More preferably 1.0-1.2 kg / m 2 .

[0032] In some examples, the concentration of the triol aqueous solution used as a curing agent is, for example, 2 wt%, 5 wt%, 12 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, etc.; preferably, the concentration of the triol aqueous solution is 5-25 wt%. Using a triol aqueous solution within the preferred concentration range as a curing agent not only achieves a reasonable construction allowance time, but also significantly reduces the permeability coefficient compared to higher or lower triol concentrations, while also maintaining good dynamic stability, 16-hour Marshall stability, and post-freeze-thaw splitting strength. Further preferably, the concentration of the triol aqueous solution is 5-20 wt%. More preferably, the concentration of the triol aqueous solution is 10-15 wt%. Using this more preferred triol concentration allows for a lower permeability coefficient and higher post-freeze-thaw splitting strength, while also maintaining excellent dynamic stability and 16-hour Marshall stability, thus facilitating the acquisition of a pavement structure with superior overall performance.

[0033] Preferably, the stone material is a stone combination formed by mixing stones of different particle sizes, and more preferably, the gradation of the stone combination is AC10 or AC13 type; preferably, the material of the stone combination is one or more of limestone and basalt; preferably, the weight percentage of the stone combination in the mixture is 86.5-92.0%, such as 86.5%, 87%, 89%, 90%, 92%, etc., more preferably 87.0-91.0%, and more preferably 88.0-90.0%;

[0034] Preferably, the NCO content of the single-component polyurethane adhesive is 6-12 wt%, more preferably 7-11 wt%, and even more preferably 8-10 wt%; preferably, the weight percentage of the single-component polyurethane adhesive in the mixture is 4.9-7.0%, for example 4.9%, 5.5%, 6.0%, 6.5%, 7.0%, etc., preferably 5.5-6.5%, and even more preferably 5.8-6.2%;

[0035] Preferably, the mineral powder accounts for 3-6% by weight in the mixture, such as 3%, 4%, 5%, 6%, etc., more preferably 4-5%; preferably, the mineral powder is a powder of hydrophobic stone, such as hydrophobic stone obtained by grinding limestone or strong basic rocks in igneous rocks;

[0036] Preferably, the lignin fiber accounts for 0.1-0.5% by weight in the mixture, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc., more preferably 0.15-0.4%, and more preferably 0.2-0.3%.

[0037] Preferably, the one-component polyurethane adhesive is a prepolymer obtained by reacting polyether polyol with isocyanate and then diluted with a plasticizer; the NCO content of the one-component polyurethane adhesive is 6-12 wt%; the amount of polyether polyol is 40-55 wt%, the amount of isocyanate is 32-45 wt%, and the amount of plasticizer is 10-20 wt%; the plasticizer is selected from one or more of dioctyl phthalate, dibutyl phthalate, diisodecyl phthalate, palm oil, rapeseed oil, soybean oil, and biodiesel. The polyether polyol is, for example, one or more of Wanol C2020, C2010, and C2040 produced by Wanhua Chemical Group, and the isocyanate is, for example, one or more of Wannate PM-8215, MDI-100, and MDI-50 produced by Wanhua Chemical Group. Using the above-mentioned preferred one-component polyurethane adhesive in the surface layer mixture helps to obtain a pavement structure with excellent comprehensive performance. In some specific examples, the reaction temperature for the polyether polyol and the isocyanate to obtain the prepolymer is, for example, 60-80°C. After the prepolymer is obtained, a plasticizer is added, stirred and mixed, and then cooled to obtain the one-component polyurethane adhesive.

[0038] In another aspect, the present invention provides a surface layer for a road structure, wherein the surface layer is paved using the surface layer composition described above; preferably, the thickness of the surface layer is 3-8 cm, more preferably 4-7 cm, and more preferably 5-6 cm.

[0039] Another aspect of the present invention provides a method for paving the surface layer of the road structure described above, comprising the following steps:

[0040] The mixture is spread to form a precast surface layer, for example, by using industry-standard paving equipment to spread the mixture onto the underlying layer; then the curing agent is applied to the surface of the precast surface layer, for example, by spraying the curing agent onto the surface of the precast surface layer; after standing for 5-15 minutes, some of the carbon dioxide gas generated by the reaction between the water in the curing agent and the single-component polyurethane adhesive is released, avoiding excessive gas retention and mixing expansion caused by direct rolling; after standing for the above time, rolling is performed to obtain the surface layer of the road structure.

[0041] Preferably, the compaction includes: using a road roller to sequentially perform initial compaction, secondary compaction, and final compaction on the precast surface layer to which the curing agent has been applied; preferably, the initial compaction, secondary compaction, and final compaction are each performed once or multiple times;

[0042] More preferably, the initial compaction is performed using a 13-ton double-drum roller to remove static pressure and allow for vibration, the secondary compaction is performed using a 26-ton rubber-tired roller, and the final compaction is performed using a 13-ton double-drum roller for static compaction.

[0043] In another aspect, the present invention provides a rigid-flexible composite polyurethane pavement structure, wherein the pavement structure comprises, from bottom to top, a subbase and a surface layer, wherein the surface layer is the surface layer described above or the surface layer obtained by the paving method described above.

[0044] Furthermore, the underlying layer comprises, from bottom to top, a semi-rigid base layer, a sealing layer, a stress-absorbing layer, and an adhesive layer.

[0045] Preferably, the semi-rigid base layer is a cement-stabilized crushed stone base layer. Preferably, the binder in the stress-absorbing layer is modified asphalt, and the binder of the stress-absorbing layer contains embedded stones. The stress-absorbing layer gradation type is preferably AC5, and the thickness of the stress-absorbing layer is, for example, 2 cm or 3 cm. Specifically, the stress-absorbing layer is formed by mixing and compacting modified asphalt and stones, wherein the mass ratio of modified asphalt to stones is between 8-10%. The modified asphalt in the stress-absorbing layer is, for example, SBS modified asphalt. Preferably, the sealing layer is an emulsified asphalt crushed stone sealing layer. Preferably, the tack coat is made of one of emulsified asphalt, SBR modified emulsified asphalt, SBS modified hot asphalt, or ordinary hot asphalt. By combining a semi-rigid base course, a flexible stress-absorbing layer, and a polyurethane surface layer, the pavement becomes a rigid-flexible composite structure. The flexible stress-absorbing layer can reduce stress concentration in localized areas between the upper and lower semi-rigid structures, improving the durability of the pavement structure. Because the stress-absorbing layer is rich in asphalt and completely impermeable, it can solve the problem of relying solely on sealing layers for waterproofing in ordinary pavement structures, and effectively protect the semi-rigid cement-stabilized crushed stone base course from water damage.

[0046] The pavement structure, which combines a preferred subbase structure with the surface layer of this invention, uses a triol aqueous solution as a curing agent during surface layer construction, along with the surface layer mixture provided by this invention. The resulting pavement structure exhibits superior performance, effectively solving the problems of high-temperature rutting and low-temperature brittleness in traditional asphalt pavements. The resulting rigid-flexible composite polyurethane pavement structure has a low permeability coefficient, for example, as low as 20 ml / min; high splitting strength after freeze-thaw cycles; excellent rutting resistance; and can be opened to traffic quickly, for example, 16 hours after paving. It is also easy to construct and has strong applicability.

[0047] Further, the emulsified asphalt chip seal comprises emulsified asphalt and chipped stone, preferably PC-2 type slow-setting cationic emulsified asphalt, and preferably 3-6mm chipped stone; preferably, the amount of emulsified asphalt in the emulsified asphalt chip seal is 0.7-1.2 L / m³. 2 The preferred concentration is 0.8-1.1 L / m³. 2 More preferably 0.9-1.0 L / m 2 The amount of crushed stone used in the emulsified asphalt macadam seal layer is 5.0-8.0 kg / m³.2 The preferred concentration is 5.5-7.5 kg / m³. 2 More preferably 6.0-7.0 kg / m 2 ;

[0048] Furthermore, the tack coat is made of one of the following: emulsified asphalt, SBR-modified emulsified asphalt, SBS-modified hot asphalt, or ordinary hot asphalt; ordinary hot asphalt refers to asphalt that has not undergone any modification. Preferably, the amount of emulsified asphalt in the tack coat is 0.3-0.8 L / m³. 2 The preferred concentration is 0.4-0.7 L / m. 2 More preferably 0.5-0.6 L / m 2 Preferably, the amount of SBR-modified emulsified asphalt used in the tack coat is 0.3-0.8 L / m³. 2 The preferred concentration is 0.4-0.7 L / m. 2 More preferably 0.5-0.6 L / m 2 Preferably, the amount of SBS-modified hot asphalt used in the tack coat is 0.7-1.2 L / m. 2 The preferred concentration is 0.8-1.1 L / m³. 2 More preferably 0.9-1.0 L / m 2 Preferably, the amount of ordinary hot asphalt in the tack coat is 0.7-1.2 L / m. 2 The preferred concentration is 0.8-1.1 L / m³. 2 More preferably 0.9-1.0 L / m 2 .

[0049] The rigid-flexible composite polyurethane pavement structure provided by this invention has a low surface permeability coefficient and high splitting strength after freeze-thaw cycles; at the same time, it can balance good Marshall stability and dynamic stability after 16 hours of compaction and curing, allowing for rapid opening to traffic.

[0050] The paving of the subbase layer of the road surface structure can be carried out with reference to the following steps:

[0051] On a roadbed that meets the specifications, a semi-rigid base course is laid, such as a cement-stabilized crushed stone base course; its total thickness is, for example, 48-52cm, and it is laid, compacted, and cured in three stages, with all process parameters following industry-standard practices.

[0052] After the cement-stabilized crushed stone base course is cured, a sealing layer is laid according to industry-standard practices, such as laying the required amount of emulsified asphalt crushed stone sealing layer; then a stress-absorbing layer of the required thickness is laid, such as laying an AC5 modified asphalt stress-absorbing layer, where the modified asphalt is, for example, SBS modified asphalt.

[0053] Apply the required amount of adhesive layer to the already laid stress-absorbing layer using industry-standard equipment. Then, lay the topcoat layer on the underlying layer.

[0054] The present invention will be further illustrated by the following embodiments, but it should not be construed as the present invention being limited to these embodiments.

[0055] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0056] Raw material information:

[0057] Stone composition: The stone particle size and gradation method comply with the provisions of "JTG F40-2004 Technical Specification for Construction of Highway Asphalt Pavement", and the stone is produced by Yantai Qixia Xingshan Stone Factory;

[0058] The mineral powder conforms to the "JTG F40-2004 Technical Specification for Construction of Highway Asphalt Pavement" and is produced by Yantai Qixia Xingshan Stone Factory.

[0059] The lignin fiber conforms to the "JTG F40-2004 Technical Specification for Construction of Highway Asphalt Pavement" and is produced by Taian Hongtong New Materials Co., Ltd.

[0060] Curing agent: glycerol aqueous solution, wherein the water is ordinary tap water; glycerol, industrial grade, Jintenglong Chemical Co., Ltd.

[0061] PC-2 type slow-cracking cationic emulsified asphalt: Shandong Yuebo Construction Engineering Co., Ltd.

[0062] Equipment and testing method description:

[0063] Fully automatic mixture pressure testing machine, Shanghai Changji, SYD-0730A;

[0064] Multifunctional Automatic Rutting Tester, Shanghai Changji, SYD-0719C-2;

[0065] Permeability coefficient meter, Shandong Luda, HHDS-II.

[0066] The permeability coefficient shall be implemented in accordance with T 0971 of the "Specifications for Field Testing of Highway Subgrade and Pavement";

[0067] The test methods for Marshall stability, splitting tensile strength after freeze-thaw, and dynamic stability shall be performed in accordance with T0709, T0716, and T0719 of the "JTG E20-2011 Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering".

[0068] In the following examples and comparative examples, the pavement structure was laid on a roadbed that meets the requirements of the "JTG / T F20-2015 Technical Specifications for Construction of Highway Pavement Base Course".

[0069] Example 1:

[0070] S1, Subgrade Paving:

[0071] On a roadbed meeting the specifications, a 49cm thick semi-rigid base course, specifically a cement-stabilized crushed stone base course, is laid. This base course is laid in three layers, with thicknesses of 16cm, 16cm, and 17cm from bottom to top. After a 28-day curing period, an emulsified asphalt crushed stone seal layer is applied to the surface of the semi-rigid base course using a synchronous crushed stone seal vehicle. The emulsified asphalt in the crushed stone seal layer is PC-2 type slow-setting cationic emulsified asphalt, and the application rate of emulsified asphalt in this seal layer is 1.2L / m². 2 The application rate of 3-6mm gravel is 8.0 kg / m³. 2 ;

[0072] Then, a 3cm thick AC5 modified asphalt stress-absorbing layer is laid. The modified asphalt in this stress-absorbing layer is SBS modified asphalt, and the mass ratio of modified asphalt to aggregate is between 8-10%. Next, an SBR modified emulsified asphalt is applied to the stress-absorbing layer using a tack coat distributor at a rate of 0.3L / m². 2 This forms an adhesive layer;

[0073] S2, Production of Suspension-Dense Polyurethane Blends:

[0074] Suspension-compact polyurethane mixtures are produced using an asphalt mixing plant. The aggregate gradation type is controlled to be AC13. The aggregate (limestone), single-component polyurethane adhesive, mineral powder, and lignin fiber are mixed in the following proportions: 90 parts by weight, 5 parts by weight, 4.5 parts by weight, and 0.5 parts by weight, respectively, to obtain the polyurethane mixture. The polyurethane mixture is then transported to the construction site using a transport vehicle.

[0075] The preparation steps of the single-component polyurethane adhesive are as follows: Place a three-necked flask in a 70°C oil bath, and add 41 parts by weight of polyether polyol (Wanol C2020) and 44 parts by weight of isocyanate (Wannate PM-8215) to the three-necked flask in the same amount. Stirring is started at the same time. When the temperature of the mixture rises to 70°C, start timing and react for 1.5 hours. Add 15 parts by weight of palm oil, stir for 10 minutes, and then cool down to 50°C. Discharge the material to obtain a single-component polyurethane adhesive with an NCO content of 12wt%.

[0076] S3, Suspended dense polyurethane compound surface layer paving:

[0077] Using paving equipment, the polyurethane mixture is spread onto the subbase obtained in step S1 to a thickness of 6 cm, forming a precast surface layer. Then, a curing agent is evenly sprayed onto the precast surface layer at a dosage of 2.0 kg / m².2 The curing agent is a 35wt% aqueous solution of glycerol; after standing for about 10 minutes, use a 13-ton double-drum roller for two passes of initial compaction with static and vibration, use a 26-ton rubber-tired roller for two passes of secondary compaction, and use a 13-ton double-drum roller for two passes of static compaction. After curing for 16 hours, a rigid-flexible composite polyurethane pavement is obtained.

[0078] Example 2:

[0079] S1, Subgrade Paving:

[0080] On a roadbed meeting the specifications, a 50cm thick semi-rigid base course is laid, specifically a cement-stabilized crushed stone base course. This base course is laid in three layers, with thicknesses of 16cm, 17cm, and 17cm from bottom to top. After a 28-day curing period, an emulsified asphalt crushed stone seal layer is applied to the surface of the semi-rigid base course using a synchronous crushed stone seal vehicle. The emulsified asphalt in the crushed stone seal layer is PC-2 type slow-setting cationic emulsified asphalt, and the application rate of emulsified asphalt in this seal layer is 0.8L / m². 2 The application rate of 3-6mm gravel is 5.5 kg / m³. 2 ;

[0081] Then, a 2cm thick AC5 modified asphalt stress-absorbing layer is laid. The modified asphalt in this stress-absorbing layer is SBS modified asphalt, and the mass ratio of modified asphalt to aggregate is between 8-10%. Next, an SBS modified hot asphalt is applied to the stress-absorbing layer using a tack coat distributor at a rate of 0.7L / m². 2 This forms an adhesive layer;

[0082] S2, Production of Suspension-Dense Polyurethane Blends:

[0083] Suspension-compact polyurethane mixtures are produced using an asphalt mixing plant. The aggregate gradation type is controlled to be AC10. The aggregate (basalt stone), single-component polyurethane adhesive, mineral powder, and lignin fiber are mixed in the following proportions: 92 parts by weight, 5.5 parts by weight, 3 parts by weight, and 0.1 parts by weight, respectively, to obtain the polyurethane mixture. The polyurethane mixture is then transported to the construction site using a transport vehicle.

[0084] The preparation steps of the single-component polyurethane adhesive are as follows: Place a three-necked flask in a 70°C oil bath, and add 46 parts by weight of polyether polyol (Wanol C2010), 10 parts by weight of isocyanate (MDI-100), and 24 parts by weight of isocyanate (PM-8215) to the three-necked flask in the following order. At the same time, start stirring and start timing when the temperature of the mixture rises to 70°C. React for 1.5 hours, add 20 parts by weight of dioctyl phthalate, stir for 10 minutes, and then cool down to 50°C. Discharge the material to obtain a single-component polyurethane adhesive with an NCO content of 7wt%.

[0085] S3, Suspended dense polyurethane compound surface layer paving:

[0086] Using paving equipment, the polyurethane mixture is spread onto the subbase obtained in step S1 to a thickness of 3 cm, forming a precast surface layer. Then, a curing agent is evenly sprayed onto the precast surface layer at a dosage of 0.8 kg / m². 2 The curing agent is a 2wt% aqueous solution of glycerol; let it stand for about 10 minutes; use a 13-ton double-drum roller for two passes of initial compaction with static and vibration, use a 26-ton rubber-tired roller for one pass of secondary compaction, use a 13-ton double-drum roller for one pass of static compaction, and cure for 16 hours to obtain a rigid-flexible composite polyurethane pavement.

[0087] Example 3:

[0088] S1, Subgrade Paving:

[0089] On a roadbed meeting the specifications, a 51cm thick semi-rigid base course, specifically a cement-stabilized crushed stone base course, is laid. This base course is laid in three layers, with thicknesses of 17cm, 17cm, and 17cm from bottom to top. After a 28-day curing period, an emulsified asphalt crushed stone seal layer is applied to the surface of the semi-rigid base course using a synchronous crushed stone seal vehicle. The emulsified asphalt in the crushed stone seal layer is PC-2 type slow-setting cationic emulsified asphalt, and the application rate of emulsified asphalt in this seal layer is 1.0L / m². 2 The application rate of 3-6mm gravel is 7.0 kg / m³. 2 ;

[0090] Then, a 2cm thick AC5 modified asphalt stress-absorbing layer is laid. The modified asphalt in this stress-absorbing layer is SBS modified asphalt, and the mass ratio of modified asphalt to aggregate is between 8-10%. Then, ordinary hot asphalt is sprayed onto the stress-absorbing layer using a tack coat distributor at a rate of 1.0L / m². 2 This forms an adhesive layer;

[0091] S2, Production of Suspension-Dense Polyurethane Blends:

[0092] Suspension-compact polyurethane mixtures are produced using an asphalt mixing plant. The aggregate gradation type is controlled to be AC13. The aggregate (limestone), single-component polyurethane adhesive, mineral powder, and lignin fiber are mixed in the following proportions: 90 parts by weight, 6.2 parts by weight, 4 parts by weight, and 0.2 parts by weight, respectively, to obtain the polyurethane mixture. The polyurethane mixture is then transported to the construction site using a transport vehicle.

[0093] The preparation steps of the single-component polyurethane adhesive are as follows: Place a three-necked flask in a 70°C oil bath, and add 55 parts by weight of polyether polyol (Wanol C2040), 10 parts by weight of isocyanate (MDI-100), and 25 parts by weight of isocyanate (PM-8215) to the three-necked flask in the following order. Stirring is started at the same time, and the reaction is started when the temperature of the mixture rises to 70°C. After reacting for 1.5 hours, 10 parts by weight of dibutyl phthalate are added, and the mixture is stirred for 10 minutes. Then, the temperature is lowered to 50°C, and the single-component polyurethane adhesive with an NCO content of 10 wt% is obtained by discharging the product.

[0094] S3, Suspended dense polyurethane compound surface layer paving:

[0095] The polyurethane mixture is spread onto the subbase obtained in step S1 using paving equipment, with a thickness of 8 cm, to form a precast surface layer. Then, a curing agent is evenly sprayed onto the precast surface layer at a dosage of 1.2 kg / m². 2 The curing agent is a 20wt% aqueous solution of glycerol; after standing for about 10 minutes, use a 13-ton double-drum roller for initial compaction with static and vibration, use a 26-ton rubber-tired roller for secondary compaction, and use a 13-ton double-drum roller for static compaction twice. After curing for 16 hours, a rigid-flexible composite polyurethane pavement is obtained.

[0096] Example 4:

[0097] S1, Subgrade Paving:

[0098] On a roadbed meeting the specifications, a 52cm thick semi-rigid base course, specifically a cement-stabilized crushed stone base course, is laid. This base course is laid in three layers, with thicknesses of 17cm, 17cm, and 18cm from bottom to top. After a 28-day curing period, an emulsified asphalt crushed stone seal layer is applied to the surface of the semi-rigid base course using a synchronous crushed stone seal vehicle. The emulsified asphalt in the crushed stone seal layer is PC-2 type slow-setting cationic emulsified asphalt, and the application rate of emulsified asphalt in this seal layer is 0.9L / m². 2 The application rate of 3-6mm gravel is 6.0 kg / m³. 2 ;

[0099] Then, a 3cm thick AC5 modified asphalt stress-absorbing layer is laid. The modified asphalt in this stress-absorbing layer is SBS modified asphalt, and the mass ratio of modified asphalt to aggregate is between 8-10%. Next, an SBS modified hot asphalt is applied to the stress-absorbing layer using a tack coat distributor at a rate of 1.2L / m². 2 This forms an adhesive layer;

[0100] S2, Production of Suspension-Dense Polyurethane Blends:

[0101] Suspension-compact polyurethane mixtures are produced using an asphalt mixing plant. The aggregate gradation type is controlled to be AC13. The aggregate (limestone), single-component polyurethane adhesive, mineral powder, and lignin fiber are mixed in the following proportions: 88 parts by weight, 5.8 parts by weight, 5 parts by weight, and 0.3 parts by weight, respectively, to obtain the polyurethane mixture. The polyurethane mixture is then transported to the construction site using a transport vehicle.

[0102] The preparation steps of the single-component polyurethane adhesive are as follows: Place a three-necked flask in a 70°C oil bath, and add 55 parts by weight of polyether polyol (Wanol C2020), 10 parts by weight of isocyanate (MDI-50), and 22 parts by weight of isocyanate (PM-8215) to the three-necked flask in the following order. Stirring is started at the same time, and the reaction is started when the temperature of the mixture rises to 70°C. After 1.5 hours, 13 parts by weight of soybean oil are added, and the mixture is stirred for 10 minutes. Then, the temperature is lowered to 50°C, and the single-component polyurethane adhesive with an NCO content of 8 wt% is obtained by discharging the product.

[0103] S3, Suspended dense polyurethane compound surface layer paving:

[0104] Using paving equipment, the polyurethane mixture is spread onto the subbase obtained in step S1 to a thickness of 5 cm, forming a precast surface layer. Then, a curing agent is evenly sprayed onto the precast surface layer at a dosage of 1.6 kg / m². 2 The curing agent is a 25wt% aqueous solution of glycerol. After standing for about 10 minutes, use a 13-ton double-drum roller for two passes of initial compaction with static and vibration, use a 26-ton rubber-tired roller for one pass of secondary compaction, and use a 13-ton double-drum roller for one pass of static compaction. After curing for 16 hours, a rigid-flexible composite polyurethane pavement is obtained.

[0105] Example 5:

[0106] S1, Subgrade Paving:

[0107] On a roadbed meeting the specifications, a 50cm thick semi-rigid base course is laid, specifically a cement-stabilized crushed stone base course. This base course is laid in three layers, with thicknesses of 16cm, 17cm, and 17cm from bottom to top. After a 28-day curing period, an emulsified asphalt crushed stone seal layer is applied to the surface of the semi-rigid base course using a synchronous crushed stone seal vehicle. The emulsified asphalt in the crushed stone seal layer is PC-2 type slow-setting cationic emulsified asphalt, and the application rate of emulsified asphalt in this seal layer is 1.1L / m². 2 The application rate of 3-6mm gravel is 7.5 kg / m³. 2 ;

[0108] Then, a 3cm thick AC5 modified asphalt stress-absorbing layer is laid. The modified asphalt in this stress-absorbing layer is SBS modified asphalt, and the mass ratio of modified asphalt to aggregate is between 8-10%. Then, ordinary hot asphalt is sprayed onto the stress-absorbing layer using a tack coat distributor at a rate of 0.7L / m². 2 This forms an adhesive layer;

[0109] S2, Production of Suspension-Dense Polyurethane Blends:

[0110] Suspension-compact polyurethane mixtures are produced using an asphalt mixing plant. The aggregate gradation type is controlled to be AC13. The aggregate (limestone), single-component polyurethane adhesive, mineral powder, and lignin fiber are mixed in the following proportions: 91 parts by weight, 6.5 parts by weight, 6 parts by weight, and 0.4 parts by weight, respectively, to obtain the polyurethane mixture. The polyurethane mixture is then transported to the construction site using a transport vehicle.

[0111] The preparation steps of the single-component polyurethane adhesive are as follows: Place a three-necked flask in a 70°C oil bath, and add 43 parts by weight of polyether polyol (Wanol C2020), 18 parts by weight of isocyanate MDI-50, and 22 parts by weight of isocyanate PM-8215 to the three-necked flask, respectively. At the same time, start stirring. Start timing when the temperature of the mixture rises to 70°C and react for 1.5 hours. Add 17 parts by weight of biodiesel, stir for 10 minutes, and then cool down to 50°C. Discharge the material to obtain a single-component polyurethane adhesive with an NCO content of 11 wt%.

[0112] S3, Suspended dense polyurethane compound surface layer paving:

[0113] Using paving equipment, the polyurethane mixture is spread onto the subbase obtained in step S1 to a thickness of 4 cm, forming a precast surface layer. Then, a curing agent is evenly sprayed onto the precast surface layer at a dosage of 1.0 kg / m². 2 The curing agent is a 30wt% aqueous solution of glycerol. After standing for about 10 minutes, use a 13-ton double-drum roller for two passes of initial compaction with static and vibration, use a 26-ton rubber-tired roller for one pass of secondary compaction, and use a 13-ton double-drum roller for two passes of static compaction. After curing for 16 hours, a rigid-flexible composite polyurethane pavement is obtained.

[0114] Example 6

[0115] The procedure was carried out in accordance with Example 4, except that the amount of curing agent used was 1.2 kg / m². 2 The glycerol concentration in the curing agent is 10 wt%.

[0116] Example 7

[0117] The procedure was carried out in accordance with Example 4, except that the amount of curing agent used was 1.2 kg / m².2 The concentration of glycerol in the curing agent is 13 wt%.

[0118] Comparative Example 1:

[0119] S1, Subgrade Paving:

[0120] On a roadbed meeting the specifications, a 50cm thick semi-rigid base course is laid, specifically a cement-stabilized crushed stone base course. This base course is laid in three layers, with thicknesses of 16cm, 17cm, and 17cm from bottom to top. After a 28-day curing period, an emulsified asphalt crushed stone seal layer is applied to the surface of the semi-rigid base course using a synchronous crushed stone seal vehicle. The emulsified asphalt in the crushed stone seal layer is PC-2 type slow-setting cationic emulsified asphalt, and the application rate of emulsified asphalt in this seal layer is 0.8L / m². 2 The application rate of 3-6mm gravel is 5.5 kg / m³. 2 ;

[0121] Then, a 2cm thick AC5 modified asphalt stress-absorbing layer is laid. The modified asphalt in this stress-absorbing layer is SBS modified asphalt, and the mass ratio of modified asphalt to aggregate is between 8-10%. Next, an SBS modified hot asphalt is applied to the stress-absorbing layer using a tack coat distributor at a rate of 0.7L / m². 2 This forms an adhesive layer;

[0122] S2, Production of Suspension-Dense Polyurethane Blends:

[0123] Suspension-compact polyurethane mixtures are produced using an asphalt mixing plant. The aggregate gradation type is controlled to be AC10. The aggregate (basalt stone), single-component polyurethane adhesive, mineral powder, and lignin fiber are mixed in the following proportions: 92 parts by weight, 5.5 parts by weight, 3 parts by weight, and 0 parts by weight, respectively, to obtain the polyurethane mixture. The polyurethane mixture is then transported to the construction site using a transport vehicle.

[0124] The preparation steps of the single-component polyurethane adhesive are as follows: Place a three-necked flask in a 70°C oil bath, and add 46 parts by weight of polyether polyol Wanol C2010, 10 parts by weight of isocyanate MDI-100, and 24 parts by weight of isocyanate PM-8215 to the three-necked flask in the following order. At the same time, start stirring and start timing when the temperature of the mixture rises to 70°C. React for 1.5 hours, add 20 parts by weight of dioctyl phthalate, stir for 10 minutes, and then cool down to 50°C. Discharge the material to obtain a single-component polyurethane adhesive with an NCO content of 7wt%.

[0125] S3, Suspended dense polyurethane compound surface layer paving:

[0126] The polyurethane mixture is spread onto the subbase obtained in step S1 using paving equipment, with a thickness of 3 cm, to form a precast surface layer. Then, a curing agent is evenly sprayed onto the precast surface layer at a dosage of 0.8 kg / m². 2 Add water with 0% glycerol in the curing agent; let stand for about 10 minutes; use a 13-ton double-drum roller for two passes of initial compaction with static and vibration, use a 26-ton rubber-tired roller for one pass of secondary compaction, use a 13-ton double-drum roller for one pass of static compaction, and cure for 16 hours to obtain a rigid-flexible composite polyurethane pavement.

[0127] Comparative Example 2:

[0128] The procedure was carried out in accordance with Example 7, except that the weight of lignin fiber was 0.

[0129] Comparative Example 3:

[0130] The procedure was carried out in accordance with Example 7, except that the weight of lignocellulose was 1.0 part.

[0131] Comparative Example 4:

[0132] The procedure was carried out in accordance with Example 7, except that the lignin fibers were replaced with carboxymethyl cellulose.

[0133] Comparative Example 5:

[0134] The test was conducted according to Example 7, except that glycerol in the curing agent was replaced with ethylene glycol. Performance test data for the comparative example and the actual examples are shown in Table 1 below:

[0135] Table 1

[0136]

[0137] The experimental results above show that the rigid-flexible composite polyurethane pavement structure obtained based on the suspended dense polyurethane surface layer composition of the present invention has a significantly lower permeability coefficient and significantly better splitting strength after freeze-thaw cycles compared with the comparative example; it also achieves good dynamic stability (>20,000 cycles / mm) and 16h Marshall stability (≥15KN), exhibiting better overall performance. A comparison of Examples 6 and 7 with other examples shows that using a triol solution of a preferred concentration as a curing agent can further significantly reduce the permeability coefficient and improve the splitting strength after freeze-thaw cycles, while simultaneously achieving excellent dynamic stability and 16h Marshall stability.

[0138] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom remain within the scope of protection of this invention.

Claims

1. A suspended dense polyurethane surface layer composition, characterized in that, The surface layer composition comprises a mixture and a curing agent; the mixture comprises the following components in parts by weight: Stone material, 86.5-92.0 parts. 4.9-7.0 parts of one-component polyurethane adhesive. 3-6 parts mineral powder 0.1-0.5 parts of lignin fiber; The curing agent is a 2-35 wt% aqueous solution of a triol, wherein the triol is selected from one or more of glycerol and trimethylolpropane.

2. The suspended dense polyurethane surface layer composition according to claim 1, characterized in that, The mixture is used to spread and form a precast surface layer, and the curing agent is used to apply to the surface of the precast surface layer and undergo a curing reaction; preferably, the curing agent is applied by spraying. Preferably, the amount of said solidifying agent applied to the surface of said preformed surface layer is 0.6-2.0 kg / m 2 , preferably 0.8-1.6 kg / m 2 , more preferably 1.0-1.2 kg / m 2 .

3. The suspended dense polyurethane surface layer composition according to claim 1 or 2, characterized in that, The concentration of the triol aqueous solution is 5-25 wt%, preferably 5-20 wt%, and more preferably 10-15 wt%.

4. The suspended dense polyurethane surface layer composition according to any one of claims 1-3, characterized in that, The stone material is a stone material combination formed by mixing stones of different particle sizes. Preferably, the gradation of the stone material combination is AC10 type or AC13 type. Preferably, the material of the stone material combination is one or more of limestone and basalt. Preferably, the weight ratio of the stone material combination in the mixture is 86.5-92.0%, more preferably 87.0-91.0%, and more preferably 88.0-90.0%. And / or, the NCO content of the single-component polyurethane adhesive is 6-12 wt%, preferably 7-11 wt%, more preferably 8-10 wt%; preferably, the weight percentage of the single-component polyurethane adhesive in the mixture is 4.9-7.0%, preferably 5.5-6.5%, more preferably 5.8-6.2%; And / or, the mineral powder accounts for 3-6% by weight in the mixture, preferably 4-5%; And / or, the lignin fiber accounts for 0.1-0.5% by weight in the mixture, preferably 0.15-0.4%, more preferably 0.2-0.3%.

5. The suspended dense polyurethane surface layer composition according to any one of claims 1-4, characterized in that, The one-component polyurethane adhesive is a prepolymer of polyether polyol and isocyanate diluted with a plasticizer; the NCO content of the one-component polyurethane adhesive is 6-12 wt%. The amount of the polyether polyol is 40-55 wt%, the amount of the isocyanate is 32-45 wt%, and the amount of the plasticizer is 10-20 wt%. The plasticizer is selected from one or more of dioctyl phthalate, dibutyl phthalate, diisodecyl phthalate, palm oil, rapeseed oil, soybean oil, and biodiesel.

6. A surface layer of a road structure, characterized in that, The surface layer is laid using the surface layer composition according to any one of claims 1-5; preferably, the thickness of the surface layer is 3-8cm, more preferably 4-7cm, and even more preferably 5-6cm.

7. The method for paving the surface layer of the road structure according to claim 6, characterized in that, Includes the following steps: The mixture is spread to form a precast surface layer, and then the curing agent is applied to the surface of the precast surface layer. After 5-15 minutes, it is compacted to obtain the surface layer of the road structure. Preferably, the compaction includes: using a road roller to sequentially perform initial compaction, intermediate compaction, and final compaction on the precast surface layer to which the curing agent has been applied; preferably, the initial compaction, intermediate compaction, and final compaction are each performed once or multiple times; More preferably, the initial compaction is performed using a 13-ton double-drum roller to remove static pressure and allow for vibration, the secondary compaction is performed using a 26-ton rubber-tired roller, and the final compaction is performed using a 13-ton double-drum roller for static compaction.

8. A rigid-flexible composite polyurethane pavement structure, characterized in that, The road structure comprises, from bottom to top, a subbase and a surface layer, wherein the surface layer is the surface layer described in claim 6 or the surface layer obtained by the paving method described in claim 7; Preferably, the underlying layer comprises, from bottom to top, a semi-rigid base layer, a sealing layer, a stress-absorbing layer, and an adhesive layer.

9. The road structure according to claim 8, characterized in that, The semi-rigid base layer is a cement-stabilized crushed stone base layer; And / or, the binder in the stress-absorbing layer is modified asphalt, the gradation type of the stress-absorbing layer is preferably AC5, and the thickness of the stress-absorbing layer is, for example, 2 cm or 3 cm; the modified asphalt in the stress-absorbing layer is preferably SBS modified asphalt; And / or, the seal is an emulsified bitumen chip seal.

10. The road structure according to claim 9, characterized in that, The emulsified asphalt chip seal comprises emulsified asphalt and chipped stone. Preferably, the emulsified asphalt is PC-2 type slow-setting cationic emulsified asphalt, and preferably, the chipped stone is 3-6mm chipped stone. Preferably, the amount of emulsified asphalt used in the emulsified asphalt chip seal is 0.7-1.2L / m³. 2 The preferred concentration is 0.8-1.1 L / m³. 2 More preferably 0.9-1.0 L / m 2 The amount of crushed stone used in the emulsified asphalt macadam seal layer is 5.0-8.0 kg / m³. 2 The preferred strength is 5.5-7.5 kg / m³. 2 More preferably 6.0-7.0 kg / m 2 ; And / or, the tack coat is made of one of emulsified asphalt, SBR-modified emulsified asphalt, SBS-modified hot asphalt, or ordinary hot asphalt; preferably, the amount of emulsified asphalt in the tack coat is 0.3-0.8 L / m³. 2 The preferred concentration is 0.4-0.7 L / m. 2 More preferably 0.5-0.6 L / m 2 Preferably, the SBR-modified emulsified asphalt content in the tack coat is 0.3-0.8 L / m³. 2 The preferred concentration is 0.4-0.7 L / m. 2 More preferably 0.5-0.6 L / m 2 Preferably, the amount of SBS-modified hot asphalt used in the tack coat is 0.7-1.2 L / m. 2 The preferred concentration is 0.8-1.1 L / m³. 2 More preferably 0.9-1.0 L / m 2 Preferably, the amount of ordinary hot asphalt in the tack coat is 0.7-1.2 L / m. 2 The preferred concentration is 0.8-1.1 L / m³. 2 More preferably 0.9-1.0 L / m 2 .

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