Construction method of low-carbon penetration type pavement structure

Abstract

The invention relates to the technical field of road construction, and discloses a construction method of a low-carbon penetration type pavement structure, which comprises the following steps: heating aggregate, preserving heat, uniformly mixing the aggregate with polyurethane at normal temperature to uniformly disperse the polyurethane on the surface of the aggregate, carrying out curing reaction on the polyurethane to form an elastic network structure to be adhered between coarse aggregates, and after the polyurethane is cured, carrying out curing to obtain the low-carbon penetration type pavement structure. Uniformly spreading premixed cement paste on the surface of the cured mixture under set pressure, applying vibration through a vibratory roller to promote the cement paste to deeply penetrate into gaps of the mixture, filling the gaps among the mixture and wrapping the mixture. The composite pavement structure layer with high strength and good integrity is formed through tight locking and embedding of the aggregate and full permeation and wrapping of double cementing materials of polyurethane and cement paste, heavy traffic loads can be borne, polyurethane has hydrophobicity and forms a compact composite structure with the aggregate and the cement paste, water invasion can be effectively blocked, and the service life of the pavement is prolonged. And the risk of water damage can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of road construction technology, specifically relating to a construction method for a low-carbon penetration pavement structure. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Currently, the most common road surface structures are asphalt concrete pavement and cement concrete pavement. Although these two pavement structures are technologically mature, they generate a large amount of carbon. For example, the core binder of asphalt concrete pavement is petroleum asphalt, which consumes a large amount of energy during production (refining), storage, transportation, and mixing (which requires heating to above 160°C), and directly or indirectly produces high emissions of greenhouse gases (such as CO2) and harmful smoke gases (such as VOCs). The binder of cement concrete pavement is cement, and the "limestone decomposition" and "high-temperature calcination (up to 1450°C)" during cement production directly generate a large amount of CO2; producing 1 ton of cement emits 0.6-1 ton of CO2.

[0004] In addition, asphalt concrete pavement is prone to rutting at high temperatures and cracking at low temperatures, resulting in a relatively short service life. Frequent maintenance further increases carbon emissions. Cement concrete pavement, on the other hand, has high rigidity, poor driving comfort, and requires demolition and recasting after damage, making maintenance difficult, time-consuming, and costly.

[0005] To address the aforementioned technical problems, existing technology discloses a construction method for a cement-emulsified asphalt mortar-infiltrated semi-flexible pavement. Coarse aggregate crushed stone is spread on the underlying layer, leveled, and compacted. Then, the mixed cement-emulsified asphalt mortar is infiltrated into the gaps between the coarse aggregate crushed stone. After curing and compaction, the semi-flexible pavement is formed. Construction can be carried out at room temperature, and the semi-flexible pavement exhibits good rutting resistance and is easy to maintain.

[0006] However, the above solution still has the following drawbacks: The production and preparation of the above-mentioned composite binder of emulsified asphalt and cement still consumes non-renewable petrochemical resources and poses risks of high carbon emissions and potential release of pollutants. The bonding interface between the asphalt film formed after the emulsified asphalt breaks down and the aggregate and cement is not dense enough, and water can easily penetrate into the aggregate gaps, leading to water damage such as peeling and loosening of the road surface. Its applicability is limited in rainy and humid areas. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a construction method for a low-carbon penetration pavement structure, which can solve the technical problems of high carbon emissions and poor water damage resistance of asphalt-based pavements in the prior art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A construction method for a low-carbon penetration pavement structure is provided, the specific steps of which include: Aggregates of various particle size ranges are screened and heated; the heated aggregates are divided into several specifications according to particle size and stored in the corresponding hot aggregate bins for insulation. The insulated aggregate in the hot silo is added to a mixer at room temperature and mixed with polyurethane. The aggregate is then arranged into aggregate according to the set gradation requirements. The mixed material is transported to the paving site, and mechanical paving equipment is used to evenly spread it to the designed thickness and compact it to form the road surface skeleton; After the polyurethane has cured, the pre-mixed cement slurry is evenly sprayed onto the surface of the cured mixture under a set pressure. Vibration is applied by a vibratory roller to promote the cement slurry to penetrate deeply into the gaps between the mixtures, fill the voids between the mixtures and wrap the mixtures. Traffic is opened after the set curing time.

[0009] Preferably, after screening aggregates of each particle size range, the screened aggregates of each particle size range are classified according to their particle size and placed in their respective independent cold aggregate bins. The gradation of the aggregates should meet the requirements of the upper and lower limits of the gradation, so that the porosity of the aggregates is between 14% and 20%.

[0010] Preferably, the aggregates from the cold silo are arranged into aggregates according to a set gradation and conveyed by a belt conveyor to a rotary drying drum for heating and drying into hot aggregates.

[0011] Preferably, the hot aggregate is sent to a vibrating screen for further screening via an elevator. The vibrating screen further classifies the hot aggregate according to particle size and stores them in the corresponding hot aggregate bins.

[0012] Preferably, the amount of polyurethane is controlled at 3% of the total weight of the aggregate, and the polyurethane is added to the mixer at room temperature and mixed with the heat-insulated and dried hot aggregate.

[0013] Preferably, the pure mixing time of the mixture composed of polyurethane and thermal aggregate is not less than 40 seconds, of which the wet mixing time is not less than 35 seconds and the dry mixing time is not less than 5 seconds.

[0014] Preferably, the mixture is initially compacted after paving according to the number of compaction passes verified in the test section.

[0015] Preferably, the cement slurry is composed of ordinary Portland cement, water and a set amount of additives, and the water-cement ratio is controlled between 0.4 and 0.6.

[0016] Preferably, the additive is one or more of the following: high-efficiency water-reducing agent, expansive agent, early-strength agent, or cellulose ether. The amount of high-efficiency water-reducing agent added is 1.0%-1.8% of the mass of cement paste, the amount of expansive agent added is 6%-10% of the mass of cement paste, the amount of early-strength agent added is 2%-4% of the mass of cement paste, and the amount of cellulose ether added is 0.05%-0.1% of the mass of cement paste.

[0017] Preferably, the curing film is covered on the surface of the mixture during curing, and cured at room temperature for 24-48 hours.

[0018] Compared with the prior art, the advantages and positive effects of this invention are: This invention involves heating and insulating aggregates, then uniformly mixing them with polyurethane at room temperature to disperse the polyurethane evenly on the aggregate surface. The polyurethane undergoes a curing reaction, forming an elastic network structure that adheres to the spaces between the coarse aggregates. After the polyurethane has cured, pre-mixed cement slurry is evenly sprayed onto the cured mixture surface under a set pressure. Vibration is then applied using a vibratory roller to force the cement slurry to penetrate deeply into the gaps between the aggregates, filling the voids and encapsulating the mixture. This invention, through the tight interlocking of aggregates and the thorough penetration and encapsulation of the polyurethane and cement slurry dual binders, forms a high-strength, high-integration composite pavement structure capable of withstanding heavy traffic loads. Furthermore, the hydrophobic nature of polyurethane, combined with the aggregates and cement slurry to form a dense composite structure, effectively prevents moisture intrusion, reducing the risk of water damage (such as spalling and loosening), especially advantageous in rainy and humid areas. In addition, the use of polyurethane to form an elastic network structure between the aggregates not only reduces energy consumption compared to asphalt, but also provides better temperature adaptability, effectively mitigating high-temperature rutting and low-temperature cracking, thus extending service life. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a schematic diagram of a low-carbon penetrating pavement structure according to an embodiment of the present invention; Figure 2 This is a comparison chart of aggregate proportioning curves for low-carbon penetrating pavement structures according to embodiments of the present invention. In the picture: 1. Road surface layer; 2. Waterproof layer; 3. Stabilizing layer. Detailed Implementation

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, 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.

[0022] The present invention will now be described in detail with reference to the accompanying drawings.

[0023] This embodiment discloses a construction method for a low-carbon penetration pavement structure, the specific steps of which include: S1. Screen aggregates within each particle size range and heat the aggregates to remove moisture. It should be noted that screening aggregates within each particle size range involves selecting aggregates that meet design specifications. This screening can be done using planar screening equipment or airflow screening technology, such as standard sieves or rotary screens. The main purpose is to construct a skeleton structure with interconnected voids. In this embodiment, heating the aggregates is primarily to eliminate internal moisture or surface moisture, thereby preventing residual moisture from interfering with subsequent bonding reactions, ensuring the aggregate surface is clean and dry, laying the foundation for a uniform and stable skeleton void structure, and ensuring the uniformity of the subsequent mixing process.

[0024] S2. The heated aggregate is divided into several sizes according to particle size and stored in corresponding hot aggregate bins for insulation. It should be noted that the aggregate, after being heated and dehydrated, is further classified according to particle size and stored in the corresponding hot aggregate bins for insulation because the aggregate may reabsorb or adhere moisture after the temperature drops, which would affect the subsequent mixing and bonding reaction. In addition, the secondary screening of the hot aggregate is to achieve more precise gradation control, so that aggregates of different particle sizes can achieve void connectivity during paving, providing a stable penetration path for subsequent material infiltration.

[0025] S3. Add the insulated aggregate and polyurethane from the hot aggregate bin to a mixer at room temperature and mix. The aggregate is then sized according to the set gradation requirements. It should be noted that the insulated aggregate and polyurethane are thoroughly mixed in the mixer at room temperature, with the polyurethane evenly dispersed on the aggregate surface. The polyurethane undergoes a curing reaction, forming an elastic network structure that adheres between the coarse aggregates. Using polyurethane to form an elastic network structure between the aggregates not only reduces energy consumption compared to using asphalt, but also provides better temperature adaptability, effectively mitigating the problems of high-temperature rutting and low-temperature cracking.

[0026] In this embodiment, polyurethane is applied using a room-temperature mixing process, unlike asphalt mixtures which require high-temperature heating (above 160°C) for mixing and paving, thus avoiding energy consumption and CO2 emissions. Furthermore, polyurethane is resistant to common road de-icing agents (such as chlorides) and oil stains, helping to maintain stable road surface performance.

[0027] S4. Transport the mixed asphalt to the paving site, and use mechanical paving equipment to evenly spread it to the designed thickness, then compact it to form the road surface framework. Specifically, after the asphalt is transported to the site, as follows: Figure 1 As shown, the mixture is spread on the waterproof layer 2 and compacted to form the road surface layer 1. The stabilizing layer 3 is located below the waterproof layer 2.

[0028] The material is evenly laid to a set thickness (6-8 cm in this embodiment) using mechanical paving equipment and compacted to form a high-strength initial skeleton. This skeleton structure remains stable after the polyurethane cures, providing reliable support for the penetration of cement slurry.

[0029] S5. After the polyurethane has cured, the pre-mixed cement slurry is evenly sprayed onto the surface of the cured mixture under a set pressure. Vibration is applied by a vibratory roller to promote the cement slurry to penetrate deeply into the gaps between the mixtures, fill the voids between the mixtures and wrap the mixture.

[0030] It is understandable that polyurethane is uniformly dispersed on the surface of aggregates. After the polyurethane undergoes a curing reaction, it forms an elastic network structure between the aggregates. Since the aggregates are composed of various particle sizes, there are voids / gaps between the aggregates. Even after the polyurethane is fully cured, voids / gaps will still exist between the mixtures. Pre-prepared cement slurry is uniformly sprayed onto the surface of the mixture at a pressure of 0.5 MPa. A vibratory roller is used to apply mechanical vibration to drive the cement slurry to flow and diffuse in the voids. This causes the cement slurry to break through the surface tension under the action of kinetic energy and deeply penetrate into the gaps between the mixtures, achieving complete filling of the voids in the mixture and complete encapsulation of the mixture (or aggregates). This significantly improves the bonding strength of the interface between the mixtures and also enhances the water erosion resistance of the pavement structure.

[0031] It is also understandable that the tight interlocking of aggregates in the aggregates and the full penetration and encapsulation of polyurethane and cement grout as dual binders form a high-strength, high-integration composite pavement structure layer capable of withstanding heavy traffic loads. In addition, polyurethane itself is hydrophobic and forms a dense composite structure with aggregates and cement grout, which can effectively prevent water intrusion and reduce the risk of water damage (such as spalling and loosening), especially in rainy and humid areas.

[0032] In this embodiment, the high-strength three-dimensional network structure formed by the curing of polyurethane and the composite formed by the cement grout possess both elasticity and rigidity, which can improve the high-temperature stability of the pavement. Under high-temperature and heavy-load traffic conditions in summer, it can effectively resist permanent deformation (rutting), maintain pavement smoothness, and ensure driving safety. It is also less prone to thermal shrinkage cracks in low-temperature environments. In addition, the high toughness and high elasticity of polyurethane material itself endow the pavement structure with excellent resistance to repeated bending deformation. The fatigue life of the polyurethane-cement grout hybrid structure far exceeds that of traditional asphalt pavement, effectively inhibiting the generation and propagation of microcracks, significantly extending the service life of the pavement, and reducing early damage caused by fatigue cracking.

[0033] S6. Open to traffic after the set curing time. This means that traffic will be opened after the cement slurry has completed its hydration reaction and formed a dense structure, ensuring that the road surface has reached its service strength.

[0034] Understandably, the stable skeleton formed by polyurethane and cement grout improves the temperature adaptability of the pavement, inhibits high-temperature deformation and low-temperature brittleness, and extends its service life. The deep penetration of cement grout enhances interfacial adhesion and water erosion resistance, thus effectively solving the problems of high carbon emissions, insufficient mechanical properties, and limited water damage resistance caused by the construction of existing pavement structures.

[0035] In this embodiment, after screening aggregates of each particle size range, the screened aggregates of each particle size range are classified according to their particle size and placed in their respective independent cold storage bins. The screening pass rate of aggregates of each particle size range is shown in Table 1.

[0036] Table 1. Aggregate Screening Pass Rate

[0037] It should be noted that the aggregate gradation should meet the requirements of the upper and lower limits of gradation, so that the porosity of the aggregate is between 14% and 20%. In this embodiment, three sets of gradations are set according to the requirements of the upper and lower limits of gradation, namely synthetic gradation 1, synthetic gradation 2, and synthetic gradation 3. The specific upper and lower limits of gradation, as well as the proportions of synthetic gradation 1, synthetic gradation 2, and synthetic gradation 3 are shown in Table 2. Figure 2 As shown, the proportioning curves of synthetic gradation 1, synthetic gradation 2, and synthetic gradation 3 lie between the upper limit curve and the lower limit curve of the gradation, which meets the gradation requirements. The optimal gradation should be a gradation close to the median value of the gradation.

[0038] Table 2. Aggregate Proportioning Table

[0039] In this embodiment, all aggregates from the cold aggregate bins are transported by belt conveyor to a rotary drying drum according to a predetermined gradation to be heated and dried into hot aggregates. The predetermined gradation is any one of the three composition gradations in Table 2. Specifically, inside the rotary drying drum, high-temperature flue gas is generated by burning fuel oil (generally heavy oil or diesel), which comes into countercurrent contact with the aggregates, heating them to a predetermined temperature range. In this embodiment, this predetermined temperature range is 150-180°C (it should be noted that the specific heating temperature depends on the ambient temperature during construction, and no specific limitation is made here). The rotation of the rotary drying drum uniformly heats the aggregates, ensuring uniform contact between the aggregates and the heat source, improving heat utilization efficiency, and removing moisture from the aggregates to avoid affecting the subsequent bonding effect of polyurethane and the stability of the pavement skeleton.

[0040] Understandably, cold aggregate bins are independent storage units used to store aggregates of different particle sizes after screening. They can be steel or concrete silos, the purpose of which is to maintain the independence of aggregate particle size classification, avoid particle size mixing, and prevent affecting the accuracy of aggregate proportioning. The set proportion is actually a gradation relationship of aggregates determined based on the strength requirements of the pavement skeleton, ensuring uniform distribution of voids between aggregates and providing a stable structural foundation for subsequent cement slurry penetration.

[0041] In this embodiment, the heated aggregate is conveyed to a vibrating screen for further screening via an elevator. The vibrating screen further classifies the heated aggregate according to particle size and stores them in corresponding hot aggregate bins. The hot aggregate bins are used to store the heated aggregate and can be metal or concrete bins with insulation layers. The purpose is to maintain the temperature and dryness of the aggregate, prevent external moisture intrusion, and ensure stable bonding with polyurethane after subsequent mixing. Furthermore, the secondary screening of the heated aggregate enables more precise gradation control, which is a crucial step in ensuring the quality of the mixture.

[0042] In this embodiment, the amount of polyurethane is controlled at 3% of the total aggregate weight. The polyurethane is added to the mixer at room temperature and mixed with the heated and dried aggregate to ensure uniform mixing. It should be noted that controlling the amount of polyurethane to 3% of the total aggregate weight ensures that the polyurethane fully coats the aggregate to form a continuous bonding network, while avoiding increased costs and potential performance degradation caused by excessive use. Adding at room temperature means pouring the polyurethane into the heated and dried aggregate under ambient temperature conditions. This utilizes the residual heat of the hot aggregate to promote the flow and initial wetting of the polyurethane, while avoiding damage to the polyurethane molecular structure caused by high temperature environment, ensuring uniform distribution of the mixture and long-term service stability.

[0043] In this embodiment, a polyurethane containing urethane groups and / or isocyanate groups in its molecular chain is used. The technical specifications of the polyurethane are shown in Table 3.

[0044] Table 3. Technical Specifications of Polyurethane

[0045] In this embodiment, Type I polyurethane is a high-strength, fast-drying type with higher tensile strength requirements (≥18 MPa) and a shorter surface drying time (3-5 hours), suitable for applications requiring large loads and rapid delivery. Type II polyurethane is a standard-strength, standard-drying type with slightly lower tensile strength requirements (≥15 MPa), but offers a longer surface drying time (5-8 hours), higher construction tolerance, and more relaxed operation.

[0046] In this embodiment, the pure mixing time of the mixture of polyurethane and thermal aggregate is not less than 40 seconds, of which the wet mixing time is not less than 35 seconds and the dry mixing time is not less than 5 seconds. It should be noted that the mixing time of polyurethane and aggregate is set to 40 seconds or longer to ensure that the polyurethane fully penetrates into the gaps between the aggregates, forms a stable distribution and coats the surface of the aggregates, and avoids the occurrence of local aggregates not being coated with polyurethane due to short-time mixing.

[0047] It should be noted that the wet mixing time is the wetting and mixing stage after the polyurethane is added with the aggregate, which can last for more than 35 seconds to ensure that the polyurethane liquid has enough time to wet the aggregate surface and build a continuous adhesive film, thereby enhancing the bonding strength between aggregates and avoiding insufficient density of the bonding interface. The dry mixing time refers to the initial integration time of the aggregate before the addition of polyurethane, which is set to more than 5 seconds to initially disperse the aggregate, reduce aggregate accumulation and uneven voids, thereby optimizing the aggregate distribution and creating ideal mixing and penetration conditions for the wet mixing stage.

[0048] In one specific embodiment, during the mixing process, the aggregate is first dry-mixed in the mixer for more than 5 seconds to achieve uniform distribution; then, polyurethane is added and wet-mixed for more than 35 seconds to ensure that the polyurethane fully coats the aggregate surface, thus ensuring the uniformity of the mixture. This avoids the problem of uneven polyurethane distribution, enhances the density of the bonding interface, reduces the path of water intrusion, lowers the risk of water damage such as pavement peeling, and improves the uniformity of the mixture and the long-term durability of the pavement structure.

[0049] In this embodiment, after paving, the mixture is initially compacted according to the number of compaction passes verified in the test section, specifically one static compaction and two vibratory compaction passes. It is understood that the test section is a representative road section selected on-site for testing to scientifically determine the number of compaction operations, with the aim of ensuring compaction strength.

[0050] Static compaction refers to a compaction method that applies uniform pressure without vibration. It can be carried out by a double-drum roller traveling at a low and uniform speed. The purpose is to eliminate unevenness of the mixture surface and segregation of coarse and fine aggregates, quickly form preliminary structural stability, reduce the risk of particle displacement, and ensure the overall smoothness of the paving layer. Vibratory compaction refers to a compaction method that uses controlled vibration energy to make aggregate particles tightly interlocked. It can be carried out by a vibratory roller operating at a fixed amplitude and frequency. The purpose is to improve the density of the pavement skeleton. At the same time, the number of vibration compaction passes is limited to two to balance the compaction effect and aggregate protection, avoid aggregate breakage or structural weakening caused by repeated vibration, and thus jointly build a uniform and stable pavement skeleton.

[0051] In this embodiment, the cement slurry is composed of ordinary Portland cement, water, and a predetermined amount of additives, with the water-cement ratio controlled between 0.4 and 0.6. It should be noted that the water-cement ratio refers to the mass ratio of water to cement. Controlling the water-cement ratio within this range (0.4-0.6) prevents the cement slurry from becoming too viscous and failing to completely fill the gaps / voids in the mixture. It also avoids the risk of bleeding, segregation, and shrinkage cracking, thus ensuring that the cement slurry tightly coats the aggregate and enhances interfacial density, significantly improving resistance to water intrusion.

[0052] In this embodiment, the additive is a chemical component that improves the workability of the cement slurry. It can be one or more combinations of high-efficiency water-reducing agents, expanding agents, early-strength agents, or cellulose ethers. The purpose is to optimize the fluidity of the cement slurry, reduce bleeding, or compensate for shrinkage. The high-efficiency water-reducing agent is added at 1.0%-1.8% of the cement slurry mass, which optimizes the fluidity of the cement slurry, controlling the fluidity to above 280mm, and promoting the cement slurry to penetrate into the gaps / voids of the mixture. The expanding agent is added at 6%-10% of the cement slurry mass, providing sufficient shrinkage compensation capacity. After the cement slurry fills the gaps / voids of the mixture, it compensates for the shrinkage after cement curing, ensuring that the cured cement fills all the gaps / voids of the mixture. The early-strength agent is added at 2%-4% of the cement slurry mass, which can cure within 2-4 hours, resulting in high early strength of the pavement structure and accelerating the opening to traffic. The cellulose ether (HPMC) is added at 0.05%-0.1% of the cement slurry mass to retain water and prevent bleeding of the cement slurry.

[0053] In this embodiment, a curing film is placed over the surface of the mixture during curing, and the mixture is cured at room temperature for 24-48 hours.

[0054] In some of the embodiments described above in this application, a curing procedure is proposed to ensure that the cement slurry is fully cured and forms a stable structure. However, in the process of its implementation, conventional curing methods are prone to cause the surface moisture of the mixture to evaporate too quickly, resulting in insufficient hydration reaction of the cement slurry and reducing the overall strength of the pavement. At the same time, external moisture may penetrate into the bonding interface through pores, weakening the bonding force between the aggregate and the cement slurry, and causing water damage such as peeling and loosening, which is especially prominent in rainy or humidity-changing environments.

[0055] To address this, this application further proposes using a curing membrane to cover the surface of the mixture during curing, and curing at room temperature for 24-48 hours. It should be noted that the curing membrane refers to a covering material used to form a sealed barrier on the surface of the mixture. It can be a polyethylene film, polypropylene geotextile, or composite waterproof membrane. Its purpose is to inhibit the rapid loss of moisture due to airflow or dry environment, and to block the direct penetration of external rainwater or moisture, maintaining a stable humidity environment required for cement slurry hydration. This prevents insufficient hydration reaction caused by excessively rapid evaporation of moisture from the mixture surface, improving the overall strength of the pavement; at the same time, it avoids the weakening of the bonding interface caused by external moisture intrusion, significantly reducing the risk of water damage diseases such as spalling and loosening, especially improving the durability and water damage resistance of the pavement structure in rainy or humidity-changing environments.

[0056] It should be noted that the polyurethane cement penetration pavement in this embodiment has superior mechanical properties and is more environmentally friendly than traditional asphalt pavement. A detailed comparison is shown in Table 5.

[0057] Table 4. Comparison of key data between polyurethane cement penetration pavement and traditional asphalt pavement.

[0058] Understandably, this embodiment uses polyurethane instead of petroleum asphalt, reducing the consumption of non-renewable resources and decreasing dependence on petrochemical asphalt resources. Furthermore, it employs ambient temperature construction, avoiding the generation of harmful fumes and odors, thus improving air quality at the construction site and in the surrounding environment. Due to the rapid curing speed of polyurethane, combined with the rapid hydration of cement slurry, the pavement structure can reach the early strength required for opening to traffic after only 24-48 hours of ambient temperature curing, significantly shortening the long curing period required for cement concrete pavements (usually several days to several weeks), greatly reducing traffic disruption, and is particularly suitable for projects requiring rapid repair or reopening. In addition, the construction process in this embodiment mainly involves paving at ambient temperature, polyurethane injection / mixing, cement slurry spraying, compaction, and covering curing, eliminating the need for complex large-scale heated mixing equipment (such as asphalt mixing plants) or prolonged high-temperature curing measures. The process is relatively simplified, reducing equipment requirements.

[0059] Furthermore, the pavement structure of this embodiment possesses excellent durability (resistant to rutting, fatigue, and water damage), extending the service life of the pavement structure and reducing maintenance needs, thereby lowering the maintenance costs and resource consumption of the road throughout its entire life cycle.

[0060] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A construction method for a low-carbon penetration pavement structure, characterized in that, The specific steps include: Aggregates of various particle size ranges are screened and heated; the heated aggregates are divided into several specifications according to particle size and stored in corresponding hot material bins for insulation. The insulated aggregate in the hot material silo is added to a mixer at room temperature and mixed with polyurethane. The aggregate is then arranged into aggregate according to the set gradation requirements. The mixed material is transported to the paving site, and mechanical paving equipment is used to evenly spread it to the designed thickness and compact it to form the road surface skeleton; After the polyurethane has cured, the pre-mixed cement slurry is evenly sprayed onto the surface of the cured mixture under a set pressure. Vibration is applied by a vibratory roller to promote the cement slurry to penetrate deeply into the gaps in the mixture, fill the voids between the mixtures and encapsulate the mixture. Traffic is opened after the set curing time.

2. The construction method of a low-carbon penetration pavement structure as described in claim 1, characterized in that, After screening the aggregates in each particle size range, the aggregates in each particle size range are classified according to their particle size and placed in their respective independent cold aggregate bins. The gradation of the aggregates should meet the requirements of the upper and lower limits of the gradation, so that the porosity of the aggregates is between 14% and 20%.

3. The construction method of a low-carbon penetration pavement structure as described in claim 2, characterized in that, The aggregates from the cold silo are arranged according to a set gradation and transported by belt conveyor to a rotary drying drum for heating and drying into hot aggregates.

4. The construction method of a low-carbon penetration pavement structure as described in claim 3, characterized in that, The hot aggregate is sent to a vibrating screen for further screening via an elevator. The vibrating screen further classifies the hot aggregate according to particle size and stores them in the corresponding hot aggregate bins.

5. The construction method of a low-carbon penetration pavement structure as described in claim 4, characterized in that, The amount of polyurethane used is controlled at 3% of the total weight of the aggregate. The polyurethane is added to the mixer at room temperature and mixed with the heat-insulated and dried thermal aggregate.

6. The construction method of a low-carbon penetration pavement structure as described in claim 5, characterized in that, The pure mixing time of the mixture of polyurethane and thermal aggregate shall not be less than 40 seconds, of which the wet mixing time shall not be less than 35 seconds and the dry mixing time shall not be less than 5 seconds.

7. The construction method of a low-carbon penetration pavement structure as described in claim 6, characterized in that, After paving, the mixture is initially compacted according to the number of compaction passes verified in the test section.

8. The construction method of a low-carbon penetration pavement structure as described in claim 1, characterized in that, The cement slurry is composed of ordinary silicate cement, water and a set amount of additives, with the water-cement ratio controlled between 0.4 and 0.

6.

9. The construction method of a low-carbon penetration pavement structure as described in claim 8, characterized in that, The additive is one or more of the following: high-efficiency water-reducing agent, expansive agent, early-strength agent, or cellulose ether. The amount of high-efficiency water-reducing agent added is 1.0%-1.8% of the mass of cement paste, the amount of expansive agent added is 6%-10% of the mass of cement paste, the amount of early-strength agent added is 2%-4% of the mass of cement paste, and the amount of cellulose ether added is 0.05%-0.1% of the mass of cement paste.

10. The construction method of a low-carbon penetration pavement structure as described in claim 1, characterized in that, During curing, cover the surface of the mixture with a curing film and cure at room temperature for 24-48 hours.

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