Local repair technology for asphalt pavement

Abstract

The invention belongs to the technical field of asphalt pavement repairing, and particularly relates to a local repairing technology of an asphalt pavement, which comprises the following specific contents: detecting a disease range by adopting ground three-dimensional laser scanning or ground penetrating radar, determining a repairing boundary, sampling and detecting the aging degree, the moisture content and the grading type of the asphalt of the original pavement, and determining the repairing quality of the asphalt pavement. According to the method, the bonding strength of the repairing material and the asphalt layer of the original pavement is enhanced by heating and activating the interface of the original pavement and emulsifying the asphalt bonding layer, and matching the repairing material with the shrinkage coefficient of the original pavement and reinforcing and compacting the edge, so that the condition that the repaired position is cracked, loosened and damaged in a short time is avoided; warm-mixed asphalt is adopted, the heating temperature is reduced by 40-60 DEG C, cold-mixed emulsified asphalt is popularized, and the asphalt does not need to be heated, so that release of a large amount of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and dust is effectively avoided, and air pollution is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of asphalt pavement repair, in particular to a local repair technology for asphalt pavement. BACKGROUND

[0002] Asphalt pavement refers to various types of pavements constructed by mixing road asphalt material into mineral material. The asphalt binder improves the ability of the paving granules to resist the damage of driving and natural factors to the pavement, so that the pavement is flat, less dusty, water-tight and durable. Therefore, asphalt pavement is a kind of senior pavement most widely used in road construction. The pit and groove repair is mainly for the repair and reinforcement of pit and groove, local net cracking, and alligator cracking, and can also repair the diseases such as heave, local subsidence and slip crack. However, the existing local repair technology still has the following technical problems when repairing the pavement: (1) The bonding strength of the repair material and the original pavement asphalt layer is insufficient, and the "two-layer skin" phenomenon is easy to occur. Due to the difference between the aging degree, water content and new paving material of the original pavement asphalt, the cold and hot shrinkage coefficients are not matched, and under the action of temperature cycle or vehicle load, cracks and loose are easy to occur at the interface, resulting in the damage of the repair area again in a short period of time; (2) When hot-mix asphalt is constructed, the asphalt needs to be heated to 160-180℃, and a large amount of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and dust are released during the process, polluting the air; at the same time, a large amount of fuel (such as diesel oil) is consumed, and the carbon emission is high.

[0003] Therefore, the present application provides a local repair technology for asphalt pavement to solve the above-mentioned problems. SUMMARY

[0004] The purpose of the present application is to provide a local repair technology for asphalt pavement to solve the problems mentioned in the background.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a local repair technology for asphalt pavement, the specific content of which is as follows: Step one, preliminary preparation: detect the disease range by using ground three-dimensional laser scanning or ground penetrating radar, determine the repair boundary, sample and detect the aging degree, water content and gradation type of the original pavement asphalt, and record the temperature shrinkage coefficient; Step two, selection of repair material: select the repair material with strong compatibility with the original asphalt, if the original asphalt is seriously aged, use modified warm-mix asphalt; if the water content of the original pavement is high, select the water damage resistant warm-mix asphalt; use warm-mix asphalt technology, reduce the heating temperature of asphalt from 160-180℃ to 120-150℃ by adding organic warm-mixing agent or inorganic nano warm-mixing agent, or directly use emulsified asphalt cold-mixing material; Step three, disease area milling cleaning: use a small milling machine to mill the disease area into a regular rectangle or trapezoid, use high pressure air to blow the milling surface to remove loose particles; if the surface has oil stains, use an environmentally friendly solvent to wipe it, and then use a hot air gun to dry it to a moisture content of <2%; Step four, original pavement interface activation treatment: heat the surface of the milled original pavement with an infrared heating plate for 30-60 seconds to soften and activate the surface layer 5-10 mm of asphalt, evenly spray the emulsified asphalt binder layer, and immediately spread the repair material after demulsification; Step five, repair material paving: if it is warm mix asphalt, use a small paver or manual paving to control the paving temperature, if it is cold mix emulsified asphalt, directly manual paving, and use a screed to level; Step six, layered compaction and interface fusion: first, use a small vibrating compactor to press 1-2 times with a pressure of 0.3-0.5 MPa to ensure that the material is initially attached to the original pavement, then vibrate and compact 2-3 times, focusing on compacting the edges to achieve a compaction degree of ≥96%, and finally, static pressure 1 time to eliminate wheel marks; Step seven, post-maintenance: if warm mix material is selected, maintain for 1-2 hours before opening traffic, if the temperature is low, cover the insulation blanket to extend the maintenance time to 3-4 hours; if cold mix material is selected, promote emulsified asphalt demulsification and solidification by watering, and limit heavy vehicle traffic within 7 days; Step eight, interface monitoring: after maintenance, use a portable bond strength instrument to detect the interface bond strength, and if there is a local deficiency, inject modified asphalt adhesive to reinforce it.

[0006] Preferably, in step one, the scope of road surface detection and judgment includes pits, loose, cracks; the repair boundary is 5-10 cm beyond the disease edge; the aging degree of the asphalt inside is determined by measuring the complex modulus with a dynamic shear rheometer; and the temperature shrinkage coefficient is measured and recorded by a thermal dilatometer.

[0007] Preferably, in step two, the selected modified warm mix asphalt internally adds SBS or rubber modifier; if the original pavement has a high water content, the selected water damage resistant warm mix asphalt internally adds an anti-stripping agent; the selected organic warm mix agent is polysorbate; and the selected inorganic nano warm mix agent is nano calcium carbonate.

[0008] Preferably, in step three, the milling depth of the small milling machine is ≥ the thickness of the original disease layer + 1 cm; the slope gradient of the trapezoidal disease area milling is 1:4; when using high pressure air to blow the milling surface, the pressure of the high pressure air is 0.6-0.8 MPa, and the environmentally friendly solvent used is biodiesel; and the hot air temperature of the hot air gun is controlled at 80-100℃.

[0009] Preferably, in the fourth step, the infrared heating plate is heated at a temperature of 120-140 DEG C, and the amount of sprayed emulsified asphalt is 0.3-0.5 kg / m 2 .

[0010] Preferably, in the fifth step, the paving thickness of the small paver is greater than or equal to 2 cm, and the paving temperature is 110-140 DEG C.

[0011] Preferably, in the sixth step, the tonnage of the small vibratory roller is 1-3 t.

[0012] Preferably, in the seventh step, the maintenance environment temperature before opening the traffic is greater than or equal to 15 DEG C, and the water spraying maintenance is ensured 2-3 times per day for 2-3 days.

[0013] Preferably, in the eighth step, the injection modified asphalt adhesive is epoxy asphalt.

[0014] Compared with the prior art, the beneficial effects of the present application are: 1) The present application activates the original pavement interface by heating and forms a bonding layer with emulsified asphalt, and the shrinkage coefficient of the repair material is matched with the original pavement and the edge is reinforced and compacted, so as to enhance the bonding strength of the repair material and the original pavement asphalt layer, and avoid the situation that the repaired position will not appear cracks, loose and damage in a short period of time. 2) The present application uses warm mix asphalt, the heating temperature is reduced by 40-60 DEG C, and the cold mix emulsified asphalt is popularized, which does not need to be heated, so as to effectively avoid the release of a large amount of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and dust, and avoid air pollution. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The step flow chart of the present application. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0017] Embodiment: Please refer to Figure 1 , the present application provides a technical solution: A local repair technology for asphalt pavement, the specific content of the local repair technology for asphalt pavement is as follows: Step one, preparation: use ground three-dimensional laser scanning or ground penetrating radar to detect disease range, determine the repair boundary, sample and test the aging degree, moisture content and gradation type of the original pavement asphalt, record its temperature shrinkage coefficient, and provide the basis for subsequent material selection and interface treatment through accurate analysis of the characteristics of the original pavement, to avoid bonding failure due to mismatch of material performance; Step two, repair material selection: choose repair materials with strong compatibility with the original asphalt. If the original asphalt is severely aged, use modified warm mix asphalt. If the moisture content of the original pavement is high, choose water damage resistant warm mix asphalt. Use warm mix asphalt technology, add organic or inorganic nano warm mix additives to reduce the heating temperature of asphalt from 160-180℃ to 120-150℃, or directly use emulsified asphalt cold mix material, adjust the oil stone ratio, and ensure that the difference between the temperature shrinkage coefficients of the repair material and the original pavement is less than 5x10 -6 / ℃ through indoor test to reduce the interface stress under temperature cycle; Step three, disease area milling cleaning: use a small milling machine to mill the disease area into a regular rectangle or trapezoid to avoid stress concentration caused by sharp corners, and use high-pressure air to blow the milling surface to remove loose particles. If there is oil on the surface, use an environmentally friendly solvent to wipe it off, and then use a hot air gun to dry it until the moisture content is less than 2%. Remove loose and contaminated layers to ensure a clean interface and provide a good adhesion foundation for the subsequent bonding layer. Step four, original pavement interface activation treatment: heat the original pavement surface after milling for 30-60 seconds with an infrared heating plate to soften and activate the surface layer 5-10 mm of asphalt, and evenly spray the emulsified asphalt bonding layer. Immediately after demulsification, spread the repair material. By heating and activating the original pavement asphalt, a gradient transition interface is formed with the bonding layer to enhance the intermolecular forces between new and old materials and solve the two-layer problem. Step five, repair material paving: if it is a warm mix asphalt material, use a small paving machine or manual paving to control the paving temperature to avoid the failure of warm mix additives due to high temperature. If it is a cold mix emulsified asphalt material, directly use manual paving and use a screed to ensure that it is flush with the original pavement. The low temperature characteristics of warm / cold mix materials reduce VOCs (more than 50% lower than hot mix) and polycyclic aromatic hydrocarbon emissions, and avoid secondary aging of the original pavement caused by high temperature. Step six, layered compaction and interface fusion: first, use a small vibrating compactor to press 1-2 times with a pressure of 0.3-0.5 MPa to ensure that the material is initially attached to the original pavement. Second, vibratory compaction is performed 2-3 times, with a focus on edge compaction (eliminate interface gaps through "oblique rolling") to achieve a compaction degree of ≥96%. Finally, static pressure is applied for 1 pass to eliminate wheel marks and avoid interface loosening caused by excessive vibration. Layered compaction ensures the density of the repair material, while edge compaction enhances the mechanical interlocking force of the interface, forming a "chemical bonding + mechanical interlocking" double combination with the pre-bonding layer to solve the problem of insufficient bonding strength. Step seven, post-curing: If warm mix material is selected, maintain for 1-2 hours before opening to traffic, if the temperature is low, cover the insulation blanket and extend the curing time to 3-4 hours; if cold mix material is selected, promote the demulsification and solidification of emulsified asphalt by watering, and limit heavy vehicle traffic (load ≤10t) within 7 days; Step eight, interface monitoring: After curing, use a portable bond strength instrument to detect the interface bond strength, if local is insufficient, inject modified asphalt adhesive to reinforce, through curing to ensure that the material is fully solidified, monitor the reinforcement to further eliminate interface hidden dangers and prolong the repair life.

[0018] In step one, the range of road surface detection and judgment includes pit, loose, crack; the repair boundary exceeds the disease edge by 5-10 cm; the aging degree of the inside asphalt is judged by measuring the complex modulus through a dynamic shear rheometer; the temperature shrinkage coefficient is measured and recorded by a thermal dilatometer.

[0019] In step two, SBS or rubber modifier is added inside the selected modified warm mix asphalt to improve the elastic recovery rate to >70%; if the original pavement has a high water content, anti-stripping agent such as amine compounds is added inside the selected water damage resistant warm mix asphalt to make the adhesion level ≥5 levels); the selected organic warm mix agent is polysorbate; the selected inorganic nano warm mix agent is nano calcium carbonate.

[0020] The role of adding SBS or rubber modifier in modified warm mix asphalt: Improve material compatibility and deformation resistance: SBS (styrene-butadiene-styrene block copolymer) or rubber modifier (such as waste tire rubber powder) can combine with asphalt through chemical or physical action, significantly improving the high and low temperature performance of asphalt: at high temperature, it enhances the anti-rutting ability of asphalt, avoiding excessive deformation of the repair area due to vehicle load; at low temperature, it improves the flexibility of asphalt, reduces the stress difference caused by temperature shrinkage and the original pavement, and reduces the risk of interface cracking; it has better compatibility with aged original asphalt, which can reduce the difference in temperature shrinkage coefficient between the two, and reduce the "two-layer skin" phenomenon from the material essence; The role of adding anti-stripping agent in water damage resistant warm mix asphalt: enhance the water resistance of interface bonding: when the original pavement has a high water content, water will weaken the adhesion between asphalt and aggregate (or original pavement), leading to interface loosening. Anti-stripping agent (such as amine, amide compounds) can form a chemical adsorption layer on the surface of aggregate, replacing water molecules and combining with asphalt, improving the adhesion strength between asphalt and aggregate; resist the erosion of water penetration to the interface, even in a humid environment, it can maintain the stable bonding between the repair material and the original pavement, avoiding early damage caused by the difference in water content; The role of the organic warm mix agent selected from polysorbate is to reduce the construction temperature, reduce pollution and energy consumption; polysorbate is a non-ionic surfactant, and its mechanism of action is to insert between the asphalt molecular chains, reduce the viscosity and surface tension of asphalt, so that the asphalt can reach the required fluidity at 120-150°C (instead of 160-180°C), reduce VOCs, PAHs volatilization and fuel consumption during the heating process; improve the wrapping of asphalt and aggregate, ensure uniform paving at low temperature, and balance the construction performance and environmental protection, directly solve the problem of high pollution and high carbon emission of hot mix asphalt; The role of the inorganic nano warm mix agent selected from nano calcium carbonate is to synergistically reduce the temperature and enhance the interface stability; nano calcium carbonate has the following functions due to its small particle size (usually <100 nm) and large specific surface area: filling the intermolecular gap of asphalt, reducing the high temperature viscosity of asphalt through physical lubrication, assisting the warm mix agent to reduce the construction temperature to 120-150°C, reducing heating energy consumption and pollution; forming a nano reinforced structure with asphalt, improving the compressive strength and anti-aging performance of the repaired material, and at the same time enhancing the mechanical interlocking effect with the original pavement milling interface, reducing the difference in shrinkage coefficient between new and old materials; the hydrophilic surface can better combine with the emulsified asphalt binder layer, further improving the interface bonding strength and reducing the risk of “two-layer skin”.

[0021] In step three, the milling depth of the small milling machine is ≥ the thickness of the original disease layer + 1 cm; the slope gradient ratio of the trapezoidal slope of the disease area is 1:4; when the milling surface is blown with high-pressure air, the pressure of the high-pressure air is 0.6-0.8 MPa, and the environmentally friendly solvent used is biodiesel; the hot air temperature of the hot air gun is controlled at 80-100°C.

[0022] In step four, the heating temperature of the selected infrared heating plate is 120-140°C; the amount of emulsified asphalt sprayed is 0.3-0.5 kg / m 2 .

[0023] In step five, the paving thickness of the small paver is ≥2 cm, and the paving temperature is 110-140°C. Its role is as follows: The role of paving thickness ≥2 cm is: Ensure the structural strength and bearing capacity: the local repair of asphalt pavement needs to bear the repeated action of vehicle load, and paving thickness ≥2 cm can ensure that the repair layer has sufficient mechanical strength, avoid the rapid appearance of secondary diseases such as depression and cracking in the repair area due to insufficient thickness under the action of load, and ensure that the repaired pavement can cooperate with the original pavement to bear; Reduce the influence of temperature stress on the interface: Thicker paving layers can reduce the direct impact of temperature changes (such as day-night temperature difference, seasonal alternation) on the interface between the repair layer and the original pavement. Thin repair layers are prone to have large differences in temperature contraction / expansion with the original pavement, leading to stress concentration at the interface, while a thickness of ≥2 cm can buffer part of the stress through its own structure, reducing the occurrence of "two-layer skin" phenomenon; Compaction effect of the evidence material: Asphalt mixture needs to be compacted to achieve the design density (compaction degree ≥96%). Thin paving layers are prone to "over-rolling" during compaction, leading to material particle breakage or loose structure. A thickness of ≥2 cm can provide sufficient space for compaction work, ensuring that the material is fully compacted and improving overall stability.

[0024] The role of paving temperature at 110-140℃: Matching the performance requirements of warm mix asphalt: The warm mix asphalt selected in this technology reduces the heating temperature to 120-150℃ by adding warm mix additives, and the paving temperature is set to 110-140℃, which not only ensures that the asphalt mixture is still in a plastic state during paving (avoiding hardening of the material due to too low temperature, making it difficult to pave and flatten), but also meets the core advantage of warm mix technology "low temperature construction", reducing the emission of VOCs and harmful gases at high temperature, and reducing energy consumption; Promote the fusion with the interface of the original pavement: The original pavement surface layer asphalt has been softened and activated by infrared heating in step four, and the paving temperature of 110-140℃ can ensure that the newly paved warm mix asphalt still maintains a certain heat when it contacts the original pavement, avoiding rapid cooling of the interface and reducing the adhesion due to too large temperature difference. At the same time, the appropriate temperature can make the emulsified asphalt adhesive layer and the newly paved material better infiltrate and fuse, improve the interface adhesion strength, and reduce the risk of two-layer skin.

[0025] In step six, the tonnage of the small vibrating roller selected is 1-3t.

[0026] In step seven, the maintenance environment temperature is ≥15℃ before opening to traffic, and water spraying maintenance is ensured 2-3 times a day for 2-3 days.

[0027] In step eight, the injection modified asphalt adhesive selected is epoxy asphalt; its role is as follows: Enhance the interface adhesion strength: Epoxy asphalt is made of epoxy resin and asphalt, and has excellent adhesion performance. When the detection finds that the interface adhesion strength of the repair area and the original pavement is locally insufficient, the injection of epoxy asphalt can penetrate into the interface gap, form a high-strength adhesive layer through curing reaction, effectively improve the integrity of the interface, avoid the intensification of two-layer skin phenomenon, and reduce secondary damage such as cracks and looseness caused by insufficient adhesion; Improve anti-aging and durability: the three-dimensional network structure formed after the curing of epoxy asphalt has strong stability, excellent high and low temperature resistance, can resist the erosion of environmental factors such as temperature cycle and ultraviolet radiation, and has good resistance to the repeated action of vehicle load, prolonging the service life of the repaired area; Excellent water damage resistance: epoxy asphalt is water-tight after curing, and has good compatibility with the original pavement asphalt layer and the repair material, which can block water from seeping into the base through the interface gap, avoiding the destruction of the pavement structure caused by water damage, especially suitable for high water content original pavement repair scenarios.

[0028] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0029] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A local repair technique for asphalt pavement, characterized in that, The specific details of the local repair technique for this asphalt pavement are as follows: Step 1: Preliminary preparation: Use ground-based three-dimensional laser scanning or ground-penetrating radar to detect the extent of the damage, determine the repair boundary, take samples to test the aging degree, moisture content and gradation type of the original pavement asphalt, and record its temperature shrinkage coefficient. Step 2: Selection of Repair Materials: Select repair materials with strong compatibility with the original asphalt. If the original asphalt is severely aged, use modified warm-mix asphalt; if the original pavement has a high moisture content, select water-resistant warm-mix asphalt; use warm-mix asphalt technology, by adding organic or inorganic nano-warm-mix agents to reduce the asphalt heating temperature from 160-180℃ to 120-150℃, or directly use emulsified cold-mix asphalt. Step 3: Milling and cleaning of the affected area: Use a small milling machine to mill the affected area into a regular rectangle or trapezoid, and use high-pressure air to blow away the milled surface to remove loose particles; if there is oil on the surface, wipe it with an environmentally friendly solvent, and then dry it with a hot air gun until the moisture content is <2%; Step 4: Activation treatment of the original road surface: Heat the milled original road surface with an infrared heating plate for 30-60 seconds to soften and activate the surface 5-10mm of asphalt. Spray an emulsified asphalt bonding layer evenly, and lay the repair material immediately after the emulsion breaks. Step 5: Repair material paving: If it is warm-mix asphalt, use a small paver or manual paving to control the paving temperature; if it is cold-mix emulsified asphalt, pave manually and level it with a scraper. Step 6, Layered Compaction and Interface Integration: First, use a small vibratory roller to statically compact the road 1-2 times with a pressure of 0.3-0.5MPa to ensure that the material initially adheres to the original road surface. Then, vibrate to compact 2-3 times, focusing on compacting the edges to achieve a compaction degree of ≥96%. Finally, statically compact once to eliminate wheel tracks. Step 7, Post-construction maintenance: If warm mix asphalt is used, maintain it for 1-2 hours before opening to traffic. If the temperature is low, cover it with an insulation blanket to extend the maintenance to 3-4 hours. If cold mix asphalt is used, promote the demulsification and solidification of emulsified asphalt by water spraying. Restrict the passage of heavy vehicles for 7 days. Step 8, Interface Monitoring: After curing, use a portable bond strength tester to test the interface bond strength. If there is insufficient bond strength in some areas, inject modified asphalt adhesive to reinforce it.

2. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step one, the scope of road surface inspection and judgment needs to include potholes, loose surfaces, and cracks; the repair boundary extends 5-10cm beyond the edge of the defect; the degree of aging of the asphalt inside is judged by measuring the complex modulus using a dynamic shear rheometer; and the temperature shrinkage coefficient is measured and recorded using a thermal expansion meter.

3. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step two, SBS or rubber modifiers are added to the modified warm mix asphalt; if the original pavement has a high moisture content, an anti-stripping agent is added to the selected water-damage resistant warm mix asphalt; the selected organic warm mix agent is polysorbate; and the selected inorganic nano warm mix agent is nano calcium carbonate.

4. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step three, the milling depth of the small milling machine is ≥ the original disease layer thickness + 1cm; the slope ratio of the trapezoidal slope of the diseased area is 1:4; when the milled surface is blown with high-pressure air, the pressure of the high-pressure air is 0.6-0.8MPa, and the environmentally friendly solvent used is biodiesel; the hot air temperature of the hot air gun is controlled at 80-100℃.

5. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step four, the infrared heating plate used has a heating temperature of 120-140℃; the amount of emulsified asphalt sprayed is 0.3-0.5 kg / m³. 2 .

6. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step five, the paving thickness of the small paver is ≥2cm, and the paving temperature is 110-140℃.

7. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step six, the selected small vibratory roller has a tonnage of 1-3t.

8. The local repair technology for asphalt pavement according to claim 1, characterized in that: In step seven, the ambient temperature for maintenance before opening to traffic must be ≥15℃, and watering maintenance must be carried out 2-3 times a day for 2-3 days.

9. The local repair technology for asphalt pavement according to claim 1, characterized in that: The injection-modified asphalt adhesive used in step eight is epoxy asphalt.

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