Airport pavement asphalt layer in-situ thermal regeneration and stepped reinforcement comprehensive construction method

Abstract

The invention relates to the technical field of road engineering and airport pavement maintenance, in particular to an airport pavement asphalt layer in-situ thermal regeneration and stepped reinforcement comprehensive construction method. The invention discloses an airfield pavement asphalt layer in-situ thermal regeneration and stepped reinforcement comprehensive construction method, which comprises the following steps of: firstly, acquiring pavement structure state data by using multi-source nondestructive testing means such as a drop weight deflectometer, a ground penetrating radar and infrared thermal imaging; and constructing a three-dimensional decision matrix of an interlayer damage type-modulus attenuation-reinforcement strategy according to a diagnosis result, and formulating a stepped reinforcement scheme in a targeted manner. And then, in the same construction, infrared heating equipment is used for heating the pavement, and grouting, raking regeneration and paving procedures are synchronously completed, so that heating-grouting-paving one-time forming construction is realized. And finally, integrally paving a newly prepared high-performance asphalt wearing layer to realize synchronous completion of pavement structure repair and function improvement.

Description

Technical Field

[0001] This invention relates to the fields of road engineering and airport pavement maintenance technology, specifically to a comprehensive construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layers. Background Technology

[0002] Asphalt pavements at civil airports bear heavy takeoff and landing loads and are affected by environmental aging. Common types of damage include pavement cracks, ruts, loosening, subsidence, and base layer delamination and strength reduction caused by rainwater infiltration. If these damages are not addressed promptly and accurately, they can not only affect flight safety but may also lead to premature pavement failure.

[0003] Some existing solutions attempt to use high-viscosity, high-elasticity modified asphalt or warm-mix recycling agents. For example, CN119912826A discloses a high-viscosity, high-elasticity modified asphalt and its preparation method. The raw materials for this high-viscosity, high-elasticity modified asphalt, by weight, include: 100 parts base asphalt, 4-5 parts styrene-butadiene-styrene block copolymer, 1-2 parts polypropylene particles, 1-2 parts TMC modifier, 1.5-3 parts compatibilizer, 0.5-1.5 parts amide wax, 0.3-0.5 parts nano-montmorillonite, 0.5-1 part toughening agent, and 0.1-0.2 parts stabilizer. The resulting product has a high softening point (60℃). It exhibits good viscosity and elastic recovery, as well as excellent water resistance, aging resistance, weather resistance, and high-temperature stability, with low kinematic viscosity at 170℃. CN118725499A discloses a warm-mix recycling agent, asphalt mixture, and its preparation method, comprising the following components by weight percentage: 10%~20% modified polymer emulsion, 2%~5% nano-titanium dioxide, 5%~10% waste rubber powder, 10%~20% recycled oil, and the remainder as solvent. The technical effect is that by introducing nanotechnology, nano-titanium dioxide is cleverly added to the warm-mix recycling agent, significantly improving the material's reflectivity and thus significantly reducing the heat absorption of the asphalt mixture. However, these solutions have failed to systematically solve the core problems of structural diagnostic ambiguity, uneven material performance recovery, and long-term interlayer adhesion.

[0004] In summary, how to innovate a construction method that can accurately diagnose and identify structural layer problems, and then implement layered and step-by-step targeted reinforcement to simultaneously improve the durability and functionality of pavement structures has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a comprehensive construction method for in-situ thermal recycling and stepped reinforcement of airport pavement asphalt layers, so as to solve the technical problems of insufficient diagnostic accuracy, coarse reinforcement strategies and weak interlayer interfaces in the prior art.

[0006] The specific technical solution is as follows:

[0007] The integrated construction method of in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer first constructs a three-dimensional decision matrix of interlayer damage type, modulus attenuation and reinforcement strategy, then achieves one-time molding construction of heating-grouting-paving in the same construction, and finally paves a newly prepared high-performance asphalt wearing course, so as to achieve the simultaneous completion of pavement structure repair and improvement of anti-icing, anti-skid and noise reduction functions.

[0008] Furthermore, the three-dimensional decision matrix is ​​constructed using the falling weight deflectometer (FWD) rebound modulus E, ground penetrating radar (GPR) vacuolation amplitude anomaly ΔA, and infrared surface temperature difference ΔT as three dimensions, and is constructed on a 0.5m × 0.5m grid. Its output is a discrete code: E < 500MPa and ΔA ≥ +6dB and ΔT ≥ 2℃ are marked as the base grouting zone, 500MPa ≤ E < 3000MPa and ΔA < +6dB and ΔT < 2℃ are marked as the middle layer regeneration zone, and E ≥ 3000MPa and ΔA < +3dB and ΔT < 1℃ are marked as the surface overlay zone. It also automatically generates centimeter-level CAD vector boundaries for construction navigation.

[0009] Furthermore, the heating-grouting-paving one-time molding construction involves completing infrared heating in the same thermal chain, followed by grouting of the base layer using residual heat for curing. Then, the hot old material is loosened on-site by the same machine, and high-viscosity asphalt and polyester fiber are added and mixed for backfilling. Finally, epoxy rubber adhesive is sprayed to pave an ultra-thin wear layer in one go. The temperature decreases controllably throughout the process, with zero milling, zero cold joints, and one-time molding.

[0010] Furthermore, the high-performance asphalt wear layer is composed of four components: aggregate, epoxy modified asphalt, mineral powder, and lignin fiber. It is laid in one go at the end of the same heat chain to form an ultra-thin structure of 3-4 cm. Its cross-section is asphalt mastic aggregate (SMA) gradation, and it is incorporating optional phase change microcapsules or conductive fibers. It has anti-skid, noise reduction, and fuel resistance functions. In winter, it can actively melt snow through phase change heat release or external low-voltage electricity. At the same time, it uses a conductive network to monitor strain in real time, realizing the integration of structure and function.

[0011] The integrated construction method of in-situ hot recycling and stepped reinforcement of airport pavement asphalt layers includes the following steps:

[0012] S1: Before construction, FWD is used to collect deflection basin data every 5m longitudinally and every 2m transversely along the runway and to invert the resilient modulus of the top surface of the base layer. At the same time, ground penetrating radar is used to scan for interlayer void amplitude anomalies and infrared thermal imager is used to record surface temperature anomalies, thereby constructing a three-dimensional decision matrix of layer damage type and modulus attenuation.

[0013] S2: The variable-amplitude infrared heating wall is activated to heat the old pavement surface layer in three temperature steps, maintaining the overall integrity of the surface layer. It utilizes the residual heat conducted downwards, while maintaining a stable speed for the heating vehicle and achieving closed-loop control using the onboard infrared temperature measurement system. Subsequently, based on the damaged areas identified by the constructed three-dimensional decision matrix, the heated pavement surface is precisely loosened by raking.

[0014] S3: After the surface temperature decreases, grouting is performed using the residual heat within the layer, which is still ≥90℃. A two-component gradient grout is injected using a pre-mounted array micro-grouting machine, and the grout is preheated and cured to form a reinforcing layer, thus completing the base layer reinforcement. Subsequently, a 4-6cm layer of hot recycled material is loosened in situ using a rear-mounted twin-shaft mixer, and then a special recycling agent, high-viscosity modified asphalt, and polyester fiber are added and mixed to obtain a high-toughness recycled mixture, which is then laid back onto the intermediate layer to complete in-situ hot recycling.

[0015] S4: Epoxy rubber binder is sprayed using an intelligent sprayer to form an interlayer transition. Aggregates, epoxy-modified asphalt, mineral powder, and lignin fibers are taken and laid in one go using a paver to form an ultra-thin wearing course. After double vibration preloading and real-time control by a laser flatness meter, a three-in-one airport runway pavement composite structure with seamless interlayer connections is obtained, consisting of a base course, a recycled layer, and a functional layer.

[0016] Furthermore, the variable amplitude infrared heating wall mentioned in S2 has a power of 160~200kW; the old pavement has a depth of 6~8cm; and the heating vehicle travels at a speed of 2~4m / min.

[0017] Furthermore, after the surface temperature of the S3 layer decreases, its temperature drops to 80~120℃; the grouting machine has an injection pressure of 0.2~0.4MPa; the preheating curing to form a reinforcing layer is carried out under the condition of curing to 1.5~3.0Gpa within 20~30 minutes; the special recycling agent, high viscosity modified asphalt, and polyester fiber have a mass composition of 0.3~0.5 parts special recycling agent, 5~10 parts high viscosity modified asphalt, and 0.2~0.4 parts polyester fiber; the mixing temperature is 140~150℃.

[0018] Furthermore, the special regenerant described in S3 includes 60% to 70% petroleum-based soft distillate oil, 15% to 20% styrene-butadiene-styrene triblock copolymer (SBS) or styrene-butadiene rubber (SBR) polymer elastomer, 10% to 15% organophosphate ester or silane coupling agent, and 3% to 5% hindered phenolic composite oxidant.

[0019] Furthermore, the epoxy rubber adhesive sprayed in S4 has a spraying range of 0.30~0.40 kg / m³. 2 The ultra-thin wear layer is laid in one go using a paver, and the paving temperature is 160~170℃.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) Precise diagnosis and prevention: By combining three methods, FWD, GPR and infrared thermography, we can comprehensively grasp the damage information of the pavement structure inside and on the surface. Compared with methods that rely solely on visual inspection or single detection, this method greatly improves the accuracy and depth of diagnosis, and can promptly detect hidden problems such as base layer delamination and asphalt peeling, preventing the omission of defects.

[0022] (2) Targeted reinforcement, economical and efficient: Targeted treatment measures are taken according to the specific types of defects in different layers, avoiding unnecessary waste caused by traditional uniform milling and overlay. This not only saves materials and construction costs, but also reduces disturbance to undamaged structures and improves reinforcement efficiency.

[0023] (3) One-time molding, shortening the construction period: This invention organically connects the processes of grouting, in-situ hot recycling and integral paving, and completes them in the same construction unit or in the same closure. Therefore, there is no need for repeated closure and construction, which greatly reduces the curing time.

[0024] (4) Dense interlayer structure, durable and reliable: By spraying high-performance adhesive material under hot conditions, the newly laid wear layer and the underlying layer form a strong chemical-thermal bond, overcoming the problem of low bonding strength in traditional cold laying. In addition, the base layer grouting restores support to the loose layer, and thermal regeneration eliminates interlayer inclusions and interface pollution. These measures comprehensively ensure the integrity of the pavement structure. Attached Figure Description

[0025] Figure 1 This is a flowchart of the integrated construction method for in-situ thermal recycling and stepped reinforcement of airport pavement asphalt layers according to the present invention.

[0026] Figure 2 This is a schematic diagram of the composite structure of the airport pavement in Embodiment 1 of the present invention.

[0027] Figure 3 This is a comparative graph showing the experimental results of interlayer shear strength, recycled material utilization rate, time to open to traffic, structural depth, and carbon emission reduction in Experiment Example 1 of this invention. Detailed Implementation

[0028] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0029] The technical solution designed by this invention to solve the existing problems includes the following key points:

[0030] 1. Precise Zoning Based on Three-Source Data Fusion

[0031] This invention differs from traditional pavement condition assessment methods that rely on superficial surveys and random sampling. It proposes a precise assessment and regional division technique for pavement structural conditions based on multi-source information fusion. Traditional methods, lacking precise understanding of hidden defects and the spatial heterogeneity of structural performance, easily lead to blurred maintenance boundaries and inaccurate intervention measures. This invention constructs a spatial distribution model of internal pavement structural damage and material performance degradation by simultaneously collecting and fusing three types of heterogeneous data: mechanical deflection basin, electromagnetic wave reflection signals, and infrared thermal radiation fields. The model uses a falling weight deflectometer (FWD) to collect basin data and invert the resilient modulus E of the base course surface. Ground penetrating radar simultaneously scans interlayer void maps to obtain amplitude anomalies ΔA, and an infrared thermal imager records the surface temperature difference ΔT. These three parameters are used to construct a three-dimensional decision matrix using a 0.5m × 0.5m grid: E < 500MPa with ΔA ≥ +6dB and ΔT ≥ 2℃ are automatically marked as base course grouting zones; 500MPa ≤ E < 3000MPa with ΔA < +6dB and ΔT < 2℃ are marked as mid-layer regeneration zones; and E ≥ 3000MPa with ΔA < +3dB and ΔT < 1℃ are marked as surface overlay zones. Centimeter-level CAD vector boundaries are output for subsequent construction navigation. This model enables the identification, location, and quantification of typical defects such as base course support failure, interlayer bond loss, and surface material aging, thus providing a scientific basis for delineating differentiated repair areas and formulating targeted reinforcement strategies.

[0032] 2. Heating-reinforcing-laying within the same temperature chain

[0033] This invention addresses the problem of weakened interlayer bonding caused by temperature discontinuities during the phased construction of multi-layer pavement structures by proposing a collaborative construction process based on continuous temperature field control. Unlike traditional processes where temperature interruptions and reheating occur during the construction of each structural layer, this invention precisely controls heat input and process connections, placing key steps such as heating the old pavement, mixing recycled materials, forming the reinforcement layer, and laying the new wearing course within a continuous and controlled temperature decay chain. It utilizes the residual heat conducted downwards to trigger a rapid polymerization reaction of the grout injected into defective areas of the base layer. During on-site construction, the residual heat window of the pavement (135°C to 95°C) allows the grout to reach and maintain a suitable low viscosity. This low viscosity allows for full penetration into micro-cracks in the base layer under pressure. Subsequently, triggered by the absorbed residual heat, the grout releases heat through its own polymerization reaction, completing curing within 25 minutes. Core drilling shows a seamless interface between the reinforcement layer and the base layer, confirming that residual heat curing and gradient strength formation occur within the construction heat chain. This process ensures that the materials of each structural layer are bonded within their optimal bonding temperature window, maximizes the utilization of heat energy between processes, and promotes molecular diffusion and interlocking of asphalt materials between different layers, thereby fundamentally guaranteeing the integrity of the pavement structure and the reliability of interlayer bonding after repair.

[0034] 3. High-value utilization of recycled materials and zero-milling

[0035] This invention abandons the traditional linear processing model of "milling-waste-replacement" and designs a high-value resource utilization method for old asphalt mixtures based on in-situ thermal recycling. The core of this method lies in achieving on-site upgrading and reconstruction of the original pavement material through controlled temperature field softening, performance restoration of special recycling agents, and, when necessary, the addition of new materials. The process achieves systematic value enhancement through three key steps: First, a controlled temperature field softening technique is used to soften the old pavement through stepped infrared heating, aiming to physically activate the aged asphalt and restore its workability. Next, a specialized recycling agent and necessary new materials are precisely incorporated into the loosened old material. Through the chemical composition harmonization and structural repair effects of the recycling agent, and the composite material reinforcement effect brought by the new materials, the performance of the old material is restored and upgraded. The recycled mixture undergoes systematic verification, and its volumetric and mechanical properties, such as porosity, stability, flow value, and dynamic modulus, all meet the technical requirements for new surface layer materials in MH / T5010-2025 "Design Specification for Asphalt Pavement of Civil Airports," thus ensuring the reliability and high performance of the renovated old material. Finally, the recycled core layer and the new functional wearing course are synergistically compacted, completing its transformation from waste material to high-value core raw material. This process ensures that the performance indicators of the recycled mixture are no lower than those of new construction, thus transforming the old material from waste awaiting treatment into a core raw material that meets high-grade road performance requirements.

[0036] Example 1

[0037] The integrated construction method of in-situ hot recycling and stepped reinforcement of airport pavement asphalt layers includes the following steps:

[0038] S1: Before construction, FWD was used to collect deflection basin data every 5m longitudinally and every 2m transversely along the runway and to invert the resilient modulus of the top surface of the base layer. At the same time, 1.5GHz ground penetrating radar was used to scan for interlayer void amplitude anomalies and infrared thermal imager was used to record surface temperature anomalies, thereby constructing a three-dimensional decision matrix of layer damage type and modulus attenuation.

[0039] S2: The 180kW variable-amplitude infrared heating wall is activated to raise the temperature of the 7cm layer of the old pavement to 135℃ in three stages: 150℃, 130℃, and 110℃, maintaining the integrity of the surface layer. The residual heat is conducted downwards, while the heating vehicle maintains a speed of 3m / min and uses an onboard infrared temperature measurement system for closed-loop control. Subsequently, based on the damaged areas identified by the constructed three-dimensional decision matrix, the heated pavement is precisely loosened by raking.

[0040] S3: When the surface temperature drops to 95℃, grouting is performed using the residual heat within the layer, which is still ≥90℃. A two-component gradient grout consisting of 10 parts epoxy resin component A and 10 parts pre-urethane prepolymer component B is injected at a pressure of 0.3MPa using a pre-array micro-grouting machine. The grout is cured into a 2.3Gpa reinforcing layer within 25 minutes by preheating, thus completing the base layer reinforcement. Subsequently, 100 parts of 4~6cm hot recycled material are loosened in situ using a rear-mounted twin-shaft mixer. Then, 0.4 parts of special recycling agent, 8 parts of high-viscosity modified asphalt, and 0.3 parts of polyester fiber are added and mixed at 145℃ for 25 seconds to obtain a high-toughness recycled mixture, which is then laid back onto the intermediate layer to complete in-situ hot recycling.

[0041] S4: Using an intelligent sprayer truck at 0.35kg / m 2 Spray 5 parts of epoxy rubber binder to form a 1.2MPa interlayer transition. Take 100 parts of aggregate, 6 parts of epoxy modified asphalt, 8 parts of mineral powder and 0.4 parts of lignin fiber, and pave them in one go at 165℃ to form a 3-4m ultra-thin wearing layer. After double vibration pre-compaction and real-time control with a laser flatness tester for 4-6 hours, a three-in-one airport runway pavement composite structure with seamless interlayer connection of base layer-recycled layer-functional layer is obtained.

[0042] Example 2

[0043] The preparation method is the same as in Example 1, except that:

[0044] S2: The 180kW variable amplitude infrared heating wall is replaced with a 120kW variable amplitude infrared heating wall; the 7cm layer heating of the old pavement is replaced with a 6cm layer heating of the old pavement; the heating vehicle travel speed of 3m / min is replaced with a heating vehicle travel speed of 2m / min;

[0045] S3: The surface temperature dropping to 95℃ is replaced with the surface temperature dropping to 80℃; 0.3MPa pressure is replaced with 0.2MPa pressure; curing to 2.3Gpa reinforcement layer within 25 minutes is replaced with curing to 1.5Gpa reinforcement layer within 20 minutes; 0.4 parts special recycling agent, 8 parts high-viscosity modified asphalt, and 0.3 parts polyester fiber are replaced with 0.3 parts special recycling agent, 5 parts high-viscosity modified asphalt, and 0.2 parts polyester fiber; mixing at 145℃ is replaced with mixing at 140℃.

[0046] S4: 0.35kg / m 2 Replace the spraying with 0.30 kg / m³ 2 Spraying; replace the paver used at 165℃ with the paver used at 160℃;

[0047] All other steps are the same.

[0048] Example 3

[0049] The preparation method is the same as in Example 1, except that:

[0050] S2: The 180kW variable amplitude infrared heating wall is replaced with a 200kW variable amplitude infrared heating wall; the 7cm layer heating of the old pavement is replaced with an 8cm layer heating of the old pavement; the heating vehicle travel speed of 3m / min is replaced with a heating vehicle travel speed of 4m / min;

[0051] S3: The surface temperature dropping to 95℃ is replaced with the surface temperature dropping to 120℃; 0.3MPa pressure is replaced with 0.5MPa pressure; curing to a 2.3Gpa reinforcement layer within 25 minutes is replaced with curing to a 2.5Gpa reinforcement layer within 30 minutes; 0.4 parts of special recycling agent, 8 parts of high-viscosity modified asphalt, and 0.3 parts of polyester fiber are replaced with 0.5 parts of special recycling agent, 10 parts of high-viscosity modified asphalt, and 0.4 parts of polyester fiber; mixing at 145℃ is replaced with mixing at 150℃.

[0052] S4: 0.35kg / m 2 Replace the spraying with 0.40 kg / m³ 2 Spraying; replace the paver used at 165℃ with the paver used at 170℃;

[0053] All other steps are the same.

[0054] Comparative Example 1

[0055] The preparation method is the same as in Example 1, except that:

[0056] S1: The steps of scanning the interlayer void map with ground penetrating radar and recording the surface temperature difference anomaly with infrared thermal imager, as well as constructing the three-dimensional decision matrix, are omitted. The decision is made based solely on the empirical maximum deflection value of FWD.

[0057] All other steps are the same.

[0058] Comparative Example 2

[0059] The preparation method is the same as in Example 1, except that:

[0060] S3: The step of curing the 2.3Gpa reinforcing layer within 25 minutes by preheating is omitted and replaced with room temperature cold grouting;

[0061] All other steps are the same.

[0062] Comparative Example 3

[0063] S2, S3: Replace the steps of heating-grouting-loosening and recycling-fogging-paving within the same thermal chain with cold grouting and curing for 12 hours, followed by cold milling of 4cm, then spraying ordinary emulsified asphalt tack coat, and finally cold paving of 4cm new asphalt.

[0064] All other steps are the same.

[0065] Comparative Example 4

[0066] The preparation method is the same as in Example 1, except that:

[0067] S3: Omit the step of loosening 100 parts of 4-6cm hot recycled material, then add 0.4 parts of special recycling agent, 8 parts of high-viscosity modified asphalt and 0.3 parts of polyester fiber, and replace them with new material of equal weight;

[0068] All other steps are the same.

[0069] Experimental Example 1

[0070] The airport runway pavement composite structures prepared in Examples 1-3 and Comparative Examples 1-4 were measured:

[0071] (1) Interlaminar shear strength: Referring to ISO 14130-1997 "Fiber-reinforced plastic composites - Determination of apparent interlaminar bond shear strength by short specimen method", Ø100mm double-layer core samples were drilled on site and cut into short beams with a width b of 10mm and a thickness h of 10mm according to the standard. The samples were sent to the laboratory and tested by the three-point bending method of short beams with a span-to-thickness ratio of 4~5 and a loading rate of 1mm / min. The maximum load h was recorded and calculated by the formula τ=0.75P / (b·h). The result was taken as the average value of 5 cores, and the target was ≥0.8MPa.

[0072] (2) Utilization rate of old materials: Based on the weighing record of the mixing plant, the formula is (amount of old materials entering the site / total amount of mixed materials) × 100%. Three truckloads of mixed materials are randomly selected on site for sieving and confirmation. The target is ≥ 95%, and the average value of the result is taken.

[0073] (3) Opening time for traffic: Infrared temperature measurement is started immediately after the last compaction is completed. The surface temperature is recorded every 50m. Timing stops when the temperature of the entire area is ≤80℃ for 30 minutes. The number of hours obtained is the actual opening time for traffic, which is used to verify the ≤6h commitment.

[0074] (4) Construction depth: Referring to GB / T 21989-2008 "Plastic polyvinyl chloride paste - Determination of apparent viscosity using Seers rheometer", after spreading and compacting for 2 hours, take 50mL of standard sand and 0.25m×0.25m board and measure according to the sand-filling method. Take one point every 200m and average the three points. The result of 0.7~1.0mm can be directly compared with the 0.5mm level of traditional SMA.

[0075] (5) Carbon emission reduction: The CO2 equivalent was calculated from the raw material entry to the site completion using the Life Cycle Assessment (LCA) method. The CO2 equivalent was calculated using the utilization rate of old materials, energy consumption and transportation mileage. The data of traditional milling and repaving of the same area was compared with the formula (1 - scheme emission amount / traditional emission amount) × 100%, with a target of ≥ 45%. Three average experiments were conducted, and the average value of the results was taken.

[0076] Table 1. Comparison of experimental results between Examples 1-3 and Comparative Examples 1-4

[0077]

[0078] The experimental results of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1. Figure 3 As shown, the airport pavement asphalt composite structure prepared by this invention is significantly superior to traditional schemes in five core indicators: interlayer shear strength, old material utilization rate, time to open to traffic, construction depth, and carbon emission reduction. Example 1 has an interlayer shear strength of 0.82 MPa, an old material utilization rate of 95.2%, can be opened to traffic within 5.5 hours at night, a construction depth of 0.88 mm, and a carbon emission reduction of 45.3%. It has balanced performance and moderate equipment power consumption and was determined to be the optimal implementation point.

[0079] Example 2 has a lower power and a reduced heating depth of 6cm, resulting in insufficient heating of the old material. The shear strength and structural depth are slightly lower than those of Example 1. At the same time, the walking speed is slower and the grouting temperature window is lowered, forcing the opening time to be extended to 6 hours. Although the overall performance meets the standard, the margin is small and the equipment efficiency is not high. Although Example 3 has the best data, it uses a high power of 20kW and a heating depth of 8cm, which significantly increases energy consumption and power distribution load. The amount of high viscosity asphalt used is increased by 25%, and equipment wear and cost increase simultaneously. Moreover, the grouting pressure of 0.5MPa has higher requirements for the sealing of existing pipelines, and the long-term reliability verification is insufficient. The cost performance is not as good as that of Example 1.

[0080] Due to the lack of key technologies, the overall performance of Comparative Examples 1-4 was reduced to varying degrees compared to the Example. Comparative Example 1 omitted ground-penetrating radar and infrared thermography, relying solely on FWD maximum deflection experience for zoning, resulting in an excessively large grouting and regeneration area. The interlayer shear strength dropped to 0.58 MPa, and the carbon emission reduction was only 30.2%. Insufficient maintenance precision led to material waste, and the overall cost had no significant advantage. Comparative Example 2 used room-temperature cold grouting, requiring 12 hours of curing. There was a significant stiffness step between the grout and the surrounding base layer, and the interlayer shear strength was only 0.51 MPa. Temperature loss during curing interrupted the subsequent heat chain. Although the open time was short, the strength margin was small, and the carbon emission reduction also dropped to 28%. 4%, overall reliability decreased; Comparative Example 3 changed "one-time molding of the same hot chain" to first cold grouting and curing for 12 hours, then cold milling 4cm and cold laying of new material, the interlayer shear strength dropped to 0.41MPa, the utilization rate of old material was only 50%, the sealing time was extended to 24 hours, the carbon emissions were the same as the benchmark, and the advantages of speed and greenness were completely lost; Comparative Example 4, although retaining the hot chain construction, replaced all 100 parts of old material with new material, the utilization rate of old material was zero, resulting in an increase of 12.5% ​​in carbon emissions; Although the interlayer shear strength and structural depth were similar to Example 1, the advantages of circular economy were lost, the overall cost increased by about 25%, so the overall effect was far inferior to Example 1.

[0081] In summary, this invention achieves precise zoning through the fusion of FWD, GPR, and infrared three-source technology, utilizes infrared residual heat to drive gradient grouting and one-time molding in the same thermal chain, realizes 100% recycling of old materials, interlayer shear ≥0.8MPa, openness within 6 hours, and a 45% reduction in carbon emissions. It balances performance, speed, and environmental friendliness, and is significantly superior to traditional cold curing, cold laying, or full-section repaving solutions.

Claims

1. A comprehensive construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layers, including heating, loosening, grouting reinforcement, and paving, characterized in that... The construction method involves precisely delineating the maintenance area by constructing a three-dimensional decision matrix. Within the same thermal chain, the base course residual heat grouting reinforcement, the in-situ hot recycling of the middle and lower layers, and the single-pass paving of the ultra-thin functional wear layer are completed sequentially, forming a three-in-one airport runway composite structure with no cold joints, consisting of the base course, recycled layer, and functional layer. The three-dimensional decision matrix uses specialized equipment to measure the rebound modulus, void amplitude anomaly, and surface temperature difference as dimensions. It divides the airport pavement into grids and discretizes them, automatically generating centimeter-level vector boundaries to achieve precise positioning of the loosening target. The same thermal chain refers to the base course residual heat grouting reinforcement, the in-situ hot recycling of the middle and lower layers, and the single-pass paving of the ultra-thin functional wear layer being within a continuous and controlled temperature decay chain. The in-situ hot recycling involves loosening the old asphalt layer in situ within the same thermal chain, adding high-toughness recycled mixture, mixing, and re-laying to restore the material properties of the middle and lower layers.

2. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 1, characterized in that, The rebound modulus, void amplitude anomaly, and surface temperature difference are constructed using a 0.5m × 0.5m grid, integrating three detection data: the rebound modulus E of the top surface of the base layer, the void amplitude anomaly value ΔA between layers, and the surface temperature anomaly value ΔT. The output is a discrete code: E < 500MPa and ΔA ≥ +6dB and ΔT ≥ 2℃ are marked as the base layer grouting zone; 500MPa ≤ E < 3000MPa and ΔA < +6dB and ΔT < 2℃ are marked as the middle layer regeneration zone; and E ≥ 3000MPa and ΔA < +3dB and ΔT < 1℃ are marked as the surface layer overlay zone.

3. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 1, characterized in that, The base layer residual heat grouting reinforcement utilizes the heat conducted from top to bottom during the heating stage, and relies on the base layer voids and loose areas identified by the three-dimensional decision matrix to perform precise grouting. A two-component gradient grout is injected using a low-pressure grouting process. Through the penetration and solidification of the two-component gradient grout in the residual heat environment, a gradient transition structure with seamless interlayer bonding is formed.

4. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 1, characterized in that, The ultra-thin functional wear-resistant layer is laid in one go. The wear-resistant layer is made by centrally mixing 100 parts aggregate, 5-7 parts epoxy modified asphalt, 7-9 parts mineral powder and 0.3-0.5 parts fiber. The paving thickness is controlled at 3-4 cm during construction.

5. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 1, characterized in that, Includes the following steps: S1: Before construction, collect deflection basin data and invert the resilient modulus of the top surface of the base layer. At the same time, scan the abnormal amplitude of interlayer voids and record the abnormal surface temperature difference to construct a three-dimensional decision matrix of layer damage type and modulus attenuation. S2: The old pavement layer is heated in three steps, and closed-loop control is achieved by using an infrared temperature measurement system. Then, the heated pavement is precisely loosened based on the damaged areas identified by the constructed three-dimensional decision matrix. S3: When the surface temperature drops, the residual heat inside the layer is used for grouting. A two-component gradient grout is injected and cured by preheating to form a reinforcing layer, thus completing the base layer reinforcement. Then, the hot old material is loosened on the spot, and the high-toughness recycled mixture is added and spread back to the middle layer to complete the in-situ hot recycling. S4: Spray epoxy rubber adhesive on top of the intermediate layer to form an interlayer transition; take aggregate, epoxy modified asphalt, mineral powder and lignin fiber, and spread them into an ultra-thin wear layer in one go. After compaction and real-time leveling, a three-in-one airport runway pavement composite structure with seamless interlayer connection is obtained, consisting of base layer, recycled layer and functional layer.

6. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 5, characterized in that, S2 describes heating the old pavement surface layer using a three-stage temperature gradient, with a heating power of 160~200kW and a depth of 6~8cm; simultaneously, it utilizes an infrared temperature measurement system to achieve closed-loop control, with a control speed of 2~4m / min.

7. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 5, characterized in that, S3 states that when the surface temperature decreases, it drops to 80~120℃; the grouting pressure is 0.2~0.4MPa; the two-component gradient grout is a polyurethane polymer or modified epoxy resin. The reinforcement layer is cured by preheating, and the condition is that it is cured into a 1.5~3.0Gpa reinforcement layer within 20~30 minutes.

8. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 5, characterized in that, The mixing temperature described in S3 is 140~150℃; the high-toughness recycled mixture is composed of a special recycling agent, high-viscosity modified asphalt and polyester fiber, with a mass composition of 0.3~0.5 parts special recycling agent, 5~10 parts high-viscosity modified asphalt and 0.2~0.4 parts polyester fiber; the special recycling agent is a petroleum-based soft distillate oil rich in aromatics and cycloalkanes.

9. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 5, characterized in that, The epoxy rubber adhesive sprayed as described in S4 has a spraying range of 0.30~0.40 kg / m². 2 The ultra-thin wear layer is laid out in one go at a temperature of 160~170℃.

10. The integrated construction method for in-situ hot recycling and stepped reinforcement of airport pavement asphalt layer as described in claim 2, characterized in that, The airport runway pavement composite structure described in S4 has an interlayer shear strength ≥0.75MPa, a recycled material utilization rate ≥94.8%, an open traffic time ≤6.0h, a construction depth of 0.7~1.0mm, and a carbon emission reduction of ≥43.5%.

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