Regenerated microsurfacing mixture and method for its preparation

Abstract

The application discloses a kind of recycled micro-surfacing mixture and preparation method thereof, including fine separation mineral aggregate, regenerant, cementing material, water, modified emulsified asphalt, also including at least one of nanoscale reinforcing material, high modulus fiber and microcapsule self-repairing agent.Fine separation mineral aggregate is activated pretreatment by old asphalt mixture, and is obtained by fine separation again.Regenerant is composite active regenerant or aromatic hydrocarbon oil type regenerant, and composite active regenerant is compounded by fatty acid ester compound and surfactant.Cementing material is ordinary Portland cement, fast-setting sulphoaluminate cement or geopolymer cementing material.Modified emulsified asphalt contains warm mix agent, and warm mix agent is fatty acid salt type warm mix agent.The application not only realizes effective reuse of old asphalt mixture, reduces micro-surfacing technology cost, reduces the pollution of mineral aggregate to environment, but also significantly improves the crack resistance, fatigue resistance, high-temperature stability and self-repairing ability of micro-surfacing.

Description

Technical Field

[0001] This invention belongs to the technical field of asphalt pavement maintenance materials, specifically relating to a recycled micro-surfacing mixture and its preparation method. Background Technology

[0002] Highway development requires a balance between construction and maintenance. The designed lifespan of asphalt pavement is generally 10-15 years. However, some pavements, due to unreasonable early design, show varying degrees of damage after only 3-5 years. Furthermore, increasing traffic volume further reduces the lifespan of asphalt pavements. Therefore, improving highway maintenance measures is extremely important. Micro-surfacing is the highest level of emulsified asphalt slurry overlay, a preventative maintenance technique developed based on slurry seal. Micro-surfacing technology uses micro-surfacing mixtures as fillers and is applied using specialized paving equipment. When filling ruts on highways, it can quickly restore and improve the smoothness of the original asphalt pavement, featuring fast construction speed and rapid reopening to traffic. Using finely separated old asphalt mixtures as micro-surfacing aggregates has advantages such as reduced costs, resource conservation, and less pollution. However, existing micro-surfacing mixtures lack sufficient resistance to rutting deformation, resulting in generally poor skid resistance and wear resistance after filling with existing micro-surfacing mixtures, making rutting prone to recurrence and leading to unsatisfactory filling effects. How to prepare high-quality micro-surfacing using old asphalt mixtures is a question worthy of in-depth research. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a regenerated micro-surfacing mixture and its preparation method, which addresses the shortcomings of the prior art.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A recycled micro-surfaced mixture, comprising any one of the following (1) to (6):

[0006] (1) Finely separated mineral materials, nano-scale reinforcing materials, high modulus fibers, regenerators, cementitious materials, water, modified emulsified asphalt and microcapsule self-healing agents, wherein the regenerator is a composite active regenerator and the cementitious materials are fast-setting sulfoaluminate cement or geopolymer cementitious materials;

[0007] (2) Finely separate mineral materials, high modulus fibers, regenerators, cementitious materials, water, modified emulsified asphalt and microcapsule self-healing agents, wherein the regenerator is a composite active regenerator and the cementitious materials are fast-setting sulfoaluminate cement or geopolymer cementitious materials;

[0008] (3) Finely separate mineral materials, nano-scale reinforcing materials, regenerators, cementitious materials, water, modified emulsified asphalt and microcapsule self-healing agents, wherein the regenerator is a composite active regenerator and the cementitious materials are fast-setting sulfoaluminate cement or geopolymer cementitious materials;

[0009] (4) Finely separate mineral materials, nano-scale reinforcing materials, high-modulus fibers, regenerators, cementitious materials, water and modified emulsified asphalt, wherein the regenerator is a composite active regenerator and the cementitious material is fast-setting sulfoaluminate cement or geopolymer cementitious material;

[0010] (5) Finely separated mineral materials, nano-level reinforcing materials, high-modulus fibers, regenerators, cementitious materials, water, modified emulsified asphalt and microcapsule self-healing agents, wherein the regenerator is a composite active regenerator and the cementitious material is ordinary silicate cement;

[0011] (6) Finely separated mineral materials, nano-level reinforcing materials, high-modulus fibers, regenerators, cementitious materials, water, modified emulsified asphalt and microcapsule self-healing agents, wherein the regenerator is an aromatic oil-type regenerator and the cementitious material is a fast-setting sulfoaluminate cement or a geopolymer cementitious material.

[0012] Preferably, in the above-mentioned recycled micro-surfaced mixture, the finely separated aggregate is obtained by activating and pretreating old asphalt mixture to remove the aged asphalt film on the surface of the aggregate, followed by fine separation; the high-modulus fiber has a tensile modulus ≥70GPa and a length of 3mm~12mm; the composite active regenerator is composed of fatty acid ester compounds and surfactants, with a mass ratio of fatty acid ester compounds to surfactants of 2~4∶1; the rapid-setting sulfoaluminate cement has an initial setting time ≥15 minutes and a final setting time ≤180 minutes; the geopolymer cementitious material is a composition containing aluminosilicate raw materials and an alkaline activator; the modified emulsified asphalt contains a warm mix agent, which is a fatty acid salt warm mix agent.

[0013] Preferably, in the above-mentioned regenerated micro-surfacing mixture, the fatty acid ester compound is a long-chain fatty acid ester with C16-C22 carbon atoms or a polyunsaturated fatty acid ester with no more than 2 double bonds; the long-chain fatty acid ester is a low-carbon alcohol ester with C1-C4 carbon atoms in the alcohol portion; and the surfactant is a sorbitan fatty acid ester surfactant.

[0014] Preferably, in the above-mentioned regenerated micro-surfacing mixture, the long-chain fatty acid ester is a monounsaturated fatty acid ester, and the monounsaturated fatty acid ester is an oleate or an erucic acid ester; the polyunsaturated fatty acid ester is ethyl linoleate; the dehydrated sorbitan fatty acid ester surfactant is selected from at least one of Span-40, Span-60, and Span-80; and the nanoscale reinforcing material is nano-silica.

[0015] Preferably, in the above-mentioned recycled micro-surfaced compound, the length of the high-modulus fiber is 5mm to 8mm, and the high-modulus fiber is at least one of basalt fiber, carbon fiber, high-silica glass fiber, and ultra-high modulus polyethylene fiber. The high-silica glass fiber has a silica content of 96% to 99.8% and a tensile modulus of 75GPa to 85GPa, and the ultra-high modulus polyethylene fiber has a tensile modulus of 100GPa to 120GPa.

[0016] Preferably, in the above-mentioned regenerated micro-surface treatment mixture, the aromatic oil-type regenerator has a closed-cup flash point ≥180℃, a viscosity of 15mPa·s~40 mPa·s at 25℃, a moisture content ≤0.1%, and an ash content ≤0.05%.

[0017] Preferably, in the above-mentioned recycled microsurface treatment mixture, the microcapsule self-healing agent is a urea-formaldehyde resin microcapsule encapsulated with epoxy resin.

[0018] Preferably, in the above-mentioned regenerated micro-surfacing mixture, the fatty acid salt in the fatty acid salt warm mixing agent is a saturated fatty acid salt; the carbon chain length of the fatty acid portion of the fatty acid salt is C12-C18; and the cation of the fatty acid salt is an alkali metal cation or an alkaline earth metal cation.

[0019] Preferably, in the above-mentioned recycled micro-surfaced mixture, the specific surface area of ​​the geopolymer cementitious material is ≥380m² / kg, the moisture content is ≤1.0%, the 3h compressive strength is ≥12MPa, the 28d compressive strength is ≥35MPa, and the 28d flexural strength is ≥5.0MPa.

[0020] Preferably, in the above-mentioned recycled micro-surfacing mixture, the modified emulsified asphalt further includes a water-based epoxy curing system and SBR emulsified asphalt, wherein the mass ratio of the water-based epoxy curing system to the SBR emulsified asphalt is 1-5:50, the water-based epoxy curing system includes a water-based epoxy resin emulsion and a curing agent; the mass ratio of the water-based epoxy resin emulsion to the curing agent is 2-2.87:1; the modified emulsified asphalt is obtained by mixing the water-based epoxy curing system with the SBR emulsified asphalt, then adding a fatty acid salt warm mix agent, and stirring, wherein the mass of the fatty acid salt warm mix agent is 1.5%-3.0% of the mass of the SBR emulsified asphalt.

[0021] Preferably, in the above-mentioned recycled micro-surfacing mixture, the finely separated mineral material, by mass percentage, comprises: 40%–50% finely separated mineral material with a particle size of 0–2.36 mm, 28%–38% finely separated mineral material with a particle size of 2.36 mm–4.75 mm, 8%–15% finely separated mineral material with a particle size of 4.75 mm–7.2 mm, and 8%–15% finely separated mineral material with a particle size of 7.2 mm–9.5 mm.

[0022] Preferably, in the above-mentioned recycled micro-surfacing mixture, the mass ratio of the finely separated mineral aggregate, regenerator, modified emulsified asphalt, cementitious material, water, nano-scale reinforcing material, high-modulus fiber, and microcapsule self-healing agent is 1:0.5%~2.0%:6%~10%:1.0%~2.0%:5%~12%:0.1%~0.5%:0.1%~0.5%:0.3%~0.8%.

[0023] As a general technical concept, the present invention also provides a method for preparing the above-mentioned recycled micro-surfacing mixture, which, when the components are group (1), group (5) or group (6), includes the following steps:

[0024] S1. Dry mixing and preheating stage: Add nano-level reinforcing materials and high-modulus fibers to finely separated mineral materials, dry mix, then add regenerator, continue stirring, and finally add the cementitious material. Mix and blend at 50℃~60℃ to obtain mixed mineral materials.

[0025] S2, Wet mixing emulsification stage: Water and modified emulsified asphalt are added to the mixed aggregate and stirred evenly at 45℃~55℃ to obtain water-mixed aggregate;

[0026] S3, Shearing Strengthening Stage: The microcapsule self-healing agent is added to the water-mixed mineral material and sheared at a speed of 2000 rpm to 3000 rpm to form a stable slurry, thus obtaining the regenerated micro-surfaced mixture.

[0027] When the composition is group (2), no nanoscale reinforcing material is used in step S1;

[0028] When the composition is group (3), high modulus fiber is not used in step S1;

[0029] When the composition is group (4), step S3 is: shear strengthening stage: the water-mixed mineral material is sheared at a speed of 2000rpm~3000rpm to form a stable slurry, thus obtaining the regenerated micro-surfaced mixture.

[0030] In the above-mentioned method for preparing the recycled micro-surfaced mixture, preferably, the rotation speed used in the dry mixing preheating stage is 500 rpm to 1000 rpm, the dry mixing time is 1 min to 2 min, the continued stirring time is 1.5 min to 2.5 min, and the mixing time is 2 min to 3 min.

[0031] In the above-mentioned method for preparing the recycled micro-surfaced mixture, preferably, the stirring speed during the wet mixing emulsification stage is 800 rpm to 1200 rpm, and the stirring time is 3 min to 5 min.

[0032] In the above-mentioned method for preparing the recycled micro-surfaced mixture, preferably, the shearing time in the shear strengthening stage is 1 min to 2 min.

[0033] The preferred method for preparing the above-mentioned recycled micro-surface treated mixture includes the following steps in preparing the finely separated mineral material:

[0034] S1.1 Pretreatment: Asphalt recycled material is collected by cold milling or mechanical excavation, and after removing impurities, it is activated by microwave heating or surface corona treatment to remove the aged asphalt film on the surface of the asphalt recycled material.

[0035] S1.2 Screening: The pretreated asphalt recycled material is separated and then screened to obtain particles of different sizes;

[0036] S1.3 Cleaning and Grading: The screened asphalt recycled material is cleaned, graded, and dried to obtain finely separated mineral material.

[0037] In the above-mentioned method for preparing the regenerated micro-surfaced mixture, preferably, the heating temperature for microwave activation is 120℃~150℃, and the heating time is 5min~10min.

[0038] The method for using recycled micro-surfacing mixture in micro-surfacing construction according to this embodiment includes the following steps:

[0039] A1. Pre-treatment: Clean the old road surface, remove debris and standing water, and treat the road surface by shot blasting or milling;

[0040] A2. Sealing layer: The micro-surfacing mixture is laid on the road surface in a segmented joint manner, with a single layer thickness of 3mm to 10mm, covering ruts. The joints include longitudinal joints and transverse joints, and the joints should overlap by 10cm to 15cm and be compacted.

[0041] A3. Wellness: Allow the mixture to naturally mature for 2-5 hours, and then open it to traffic after the mixture has solidified.

[0042] Compared with the prior art, the advantages of the present invention are as follows:

[0043] (1) The recycled micro-surfacing mixture of the present invention uses finely separated old asphalt mixtures obtained by sieving to obtain finely separated mineral aggregates in full proportion as raw materials. Activation pretreatment cleans the surface of the old mineral aggregates and improves the interfacial bonding strength with new asphalt. This not only realizes the effective reuse of old asphalt mixtures, reduces the cost of micro-surfacing technology, and reduces the pollution of mineral aggregates to the environment, but also significantly improves the crack resistance, fatigue resistance, high-temperature stability, and self-healing ability of micro-surfacing through specific component design, solving the problems of easy cracking and insufficient rutting resistance of traditional micro-surfacing. In particular, when using the full-component compounding of the present invention, micro-surfacing mixtures with excellent road performance can be obtained. Considering the cost-effectiveness, in actual engineering, the selection and dosage of nano-reinforcing materials, high-modulus fibers, regenerators, cementitious materials, and microcapsule self-healing agents can be adjusted according to climatic conditions and traffic load requirements to achieve the best performance-price ratio. In addition to full-component compounding, other preferred compounding schemes based on the research of the present invention can also obtain micro-surfacing mixtures with significantly better performance than traditional schemes.

[0044] (2) The recycled micro-surfacing mixture of the present invention has a synergistic effect when the components are compounded. The three-dimensional reinforcing network formed by filling the pores of the mineral aggregate with nano-scale reinforcing materials and high-modulus fibers significantly improves the crack resistance and high-temperature stability of the mixture. The fatty acid ester compounds in the composite active regenerator react chemically with the polar components in the aged asphalt to restore the viscoelasticity of the asphalt, which is different from the physical swelling effect of traditional regenerators. The microcapsule self-healing agent ruptures when the microcracks expand, releasing epoxy resin to repair the cracks and extend the service life of the pavement. Special cementitious materials such as fast-setting sulfoaluminate cement or geopolymer cementitious materials can shorten the time of opening to traffic and reduce the aging effect of alkaline environment on asphalt. The warm mix agent reduces the construction temperature by 10℃~15℃, reducing energy consumption and carbon emissions. The SBR emulsified asphalt is modified with water-based epoxy resin emulsion and cross-linked network is formed after adding curing agent, thereby effectively improving the adhesion of SBR emulsified asphalt, and thus effectively improving the density of the micro-surfacing mixture and the resistance to rutting deformation of the micro-surfacing mixture.

[0045] (3) The recycled micro-surfacing mixture of the present invention can be used for road surface repair, and it has excellent and stable anti-skid and wear-resistant properties, which can reduce the occurrence of ruts on the road after filling and repair, effectively reduce damage, extend the service life of asphalt pavement, and significantly improve the crack resistance, fatigue resistance and high temperature stability of the mixture, giving the mixture intelligent self-healing characteristics.

[0046] (4) The preparation method of the recycled micro-surfaced mixture of the present invention is based on the preferred compounding scheme of the present invention and the process innovation. The three-stage temperature-controlled stirring promotes the deep integration of the recycling agent and the old asphalt, refines the emulsified asphalt particles, and ensures the uniform dispersion of the reinforcing components through the high-speed shearing process to form a stable structure.

[0047] (5) The recycled micro-surface treatment prepared by the mixture of the present invention has the following advantages: rapid setting characteristics, the special cementitious material shortens the opening time to less than 4 hours; low temperature construction adaptability, the warm mixing agent allows the mixture to be constructed in an environment above 5℃; self-healing function, the microcapsules automatically repair micro-cracks during use and extend the curing cycle. Detailed Implementation

[0048] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the materials and reagents used in the following embodiments of the present invention are commercially available, and the equipment used is conventional equipment.

[0049] Example 1

[0050] The present invention provides a recycled micro-surfacing mixture comprising finely separated mineral aggregates, nanoscale reinforcing materials, high-modulus fibers, a regenerating agent, a cementing material, water, modified emulsified asphalt, and a microcapsule self-healing agent.

[0051] Among them, the finely separated aggregate is obtained by activating and pretreating the old asphalt mixture to remove the aged asphalt film on the surface of the aggregate, and then finely separating it.

[0052] The nano-reinforcing material specifically uses nano-silica, purchased from Keneng (Xi'an) Materials Technology Co., Ltd., model KN-SiO2 series (KN-SiO2-01, KN-SiO2-02, etc.). Of course, other nano-silica with an average particle size of 10nm-50nm, an effective component purity of ≥98%, impurity (such as metal oxides, moisture) content of ≤2%, and dispersion uniformity in modified emulsified asphalt of ≥90% can also be used.

[0053] The high modulus fiber has a tensile modulus ≥70GPa. Specifically, basalt fiber is used, purchased from Sichuan Qianyi Composite Materials Co., Ltd., model 613 series basalt chopped fiber, or 702U series basalt ply untwisted roving can also be used.

[0054] The regenerator is a composite active regenerator, which is composed of fatty acid ester compounds and surfactants. In this embodiment, ethyl oleate and sorbitol monooleate are compounded at a mass ratio of 3:1. The sorbitol monooleate is purchased from Jiangsu Haian Petrochemical Plant, and the model is Span-80. The alternative is industrial grade Span-80 from Shanghai Yuanye Biotechnology Co., Ltd.

[0055] The cementitious material is rapid-setting sulfoaluminate cement, purchased from Jiangxi Yinsong Supermaterial Technology Co., Ltd., model 42.5 (code R.SAC425). Alternatively, other special cementitious materials with an initial setting time ≥15 minutes and a final setting time ≤180 minutes, as tested according to the "Standard Consistency Water Requirement, Setting Time and Soundness Test Methods for Cement" (GB / T 1346-2011), can also be used.

[0056] In this embodiment, the modified emulsified asphalt contains a warm mix agent, which is a fatty acid salt warm mix agent, specifically potassium palmitate.

[0057] In this embodiment, the modified emulsified asphalt further includes a water-based epoxy curing system and SBR emulsified asphalt, with a mass ratio of 2:50 between the water-based epoxy curing system and SBR emulsified asphalt. The water-based epoxy curing system includes a water-based epoxy resin emulsion and a curing agent, with a mass ratio of 5:2 between the water-based epoxy resin emulsion and the curing agent. The modified emulsified asphalt is obtained by mixing the water-based epoxy curing system with SBR emulsified asphalt, then adding a fatty acid salt warm mix agent and stirring. The mass of the fatty acid salt warm mix agent is 2% of the mass of the SBR emulsified asphalt.

[0058] The microcapsule self-healing agent was purchased from Liyang Ruipu New Materials Co., Ltd., and the model is RP type self-healing anti-fouling and anti-corrosion microcapsule.

[0059] In this embodiment, the gradation of the finely separated mineral material is as follows: 45% of the mass of the 0-2.36mm grade, 35% of the mass of the 2.36mm-4.75mm grade, 10% of the mass of the 4.75mm-7.2mm grade, and 10% of the mass of the 7.2mm-9.5mm grade.

[0060] In this embodiment, the mass ratio of finely separated mineral materials, regenerator, modified emulsified asphalt, cementitious materials, water, nanoscale reinforcing materials, high-modulus fibers, and microcapsule self-healing agents is 1:1.0%:7%:1.5%:6%:0.2%:0.3%:0.5%.

[0061] The preparation method of the recycled micro-surfacing mixture in this embodiment includes the following steps:

[0062] S1. Dry mixing and preheating stage: Weigh 1000g of finely separated mineral material, add 2g of nano-silica and 3g of basalt fiber, dry mix at 800rpm for 1min, add 10g of composite active regenerator, continue mixing at 800rpm for 1.5min, add 15g of fast-setting sulfoaluminate cement, dry mix at 55℃ and 800rpm for 2.5min to obtain mixed mineral material;

[0063] S2, Wet mixing emulsification stage: Add 60g of water to the mixed aggregate, stir for 1 minute, then add 70g of modified emulsified asphalt, wet mix at 50℃ and 1000rpm for 4 minutes to obtain water-mixed aggregate;

[0064] S3, Shear Strengthening Stage: Add 5g of microcapsule self-healing agent to the water-mixed mineral material and shear at 2500rpm for 1.5min to form a stable slurry, thus obtaining the regenerated micro-surfaced mixture.

[0065] In this embodiment, the preparation steps of finely separated mineral materials include:

[0066] S1.1 Pretreatment: Asphalt recycled material is collected by cold milling and impurities are removed. Then, microwave heating activation pretreatment (130℃, 8min) is used to remove the aged asphalt film on the surface of the asphalt recycled material.

[0067] S1.2 Screening: The pretreated asphalt recycled material is separated and then screened to obtain particles of different sizes;

[0068] The primary function of separation is to transform waste asphalt mixtures into effective raw materials that meet the requirements of micro-surfacing; to eliminate the "contamination layer" (impurities, aged asphalt film) on the surface of the old aggregate, ensuring that the aggregate is tightly bonded with new components such as modified emulsified asphalt and cement; to prevent impurities or oversized particles from interfering with the mixing process, ensuring that the functional components such as recycling agents, nanomaterials, and fibers mixed in the subsequent process are evenly dispersed; and to screen the asphalt recycled material into four grades with particle sizes of 0-2.36mm, 2.36mm-4.75mm, 4.75mm-7.2mm, and 7.2mm-9.5mm respectively.

[0069] S1.3 Cleaning and Grading: The screened asphalt recycled material is cleaned, graded, and dried to obtain finely separated mineral material.

[0070] In this embodiment, the preparation steps of the modified emulsified asphalt include:

[0071] S2.1. Take 100g of epoxy resin, 15g of emulsifier and 90g of purified water and mix them. Stir at 60℃ and 800rpm for 30min to obtain an aqueous epoxy resin emulsion.

[0072] S2.2. Take 100g of the waterborne epoxy resin emulsion obtained in step S2.1 and mix it with 40g of curing agent. Stir at 50℃ and 800rpm for 20min to obtain a waterborne epoxy curing system.

[0073] S2.3. Take 4g of the water-based epoxy curing system obtained in step S2.2 and mix it with 100g of SBR emulsified asphalt. Add 2g of fatty acid salt warm mix agent and stir at 45℃ and 800rpm for 15min to obtain modified emulsified asphalt.

[0074] The epoxy resin was purchased from Evonik Industries, specifically the nano-silica modified waterborne epoxy resin NANOPOX E470. The alternative was the bisphenol A type waterborne epoxy resin EXA-835LV from DIC Corporation.

[0075] The emulsifier in step S2.1 was purchased from Jiangsu Jinyang New Material Technology Co., Ltd.; model JY-R3T1 (cationic slow-crack emulsifier); the alternative is Dongguan Aoda Environmental Protection New Material Co., Ltd., model AD-EM01.

[0076] The curing agent was purchased from Huntsman, specifically the modified amine curing agent Aradur 3229. The alternative was the fatty amine modified curing agent T31 from Shanghai Kaiyin Chemical Co., Ltd.

[0077] The SBR emulsified asphalt was purchased from Dongguan Aoda Environmental Protection New Materials Co., Ltd., model AD 5010 (the core component of SBR emulsified asphalt is carboxylated styrene-butadiene latex); the alternative was Shandong Hanlian Energy Co., Ltd., model SBR II-B (SBR modified emulsified asphalt).

[0078] The fatty acid salt warm mix agent was purchased from Jiangsu Qiangsheng Functional Chemical Co., Ltd., model QSS-88 (potassium palmitate, a C16 saturated fatty acid salt); the alternative was industrial grade sodium stearate (a C18 saturated fatty acid salt) from Shanghai Yuanye Biotechnology Co., Ltd.

[0079] The method for using recycled micro-surfacing mixture in micro-surfacing construction according to this embodiment includes the following steps:

[0080] A1. Pre-treatment: Clean the old road surface, remove debris and standing water, and treat the road surface by shot blasting or milling;

[0081] A2. Sealing layer: The micro-surfacing mixture is laid on the road surface in a segmented joint manner, with a single layer thickness of 6mm, covering ruts. The joints include longitudinal joints and transverse joints, and the joints should overlap by 12cm and be compacted.

[0082] A3. Wellness: Allow the mixture to naturally mature for 3 hours before opening it to traffic.

[0083] The performance tests are shown in Table 1. Through various road performance tests, it can be seen that the recycled micro-surfacing performance obtained by using the mixture prepared by the raw material and reagent combination, ratio and process of this embodiment is the best.

[0084] Example 2

[0085] The present invention provides a recycled micro-surfacing mixture, the raw material composition and ratio of which are basically the same as those in Example 1, the only difference being that it does not contain nanoscale reinforcing materials.

[0086] The preparation method of the recycled micro-surface treated mixture in this embodiment is basically the same as the preparation method of the recycled micro-surface treated mixture in Example 1, except that nano-silica is not added in step S1.

[0087] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0088] Example 3

[0089] The present invention provides a recycled micro-surfacing mixture, the raw material composition and ratio of which are basically the same as those in Example 1, the only difference being that it does not contain high-modulus fibers.

[0090] The preparation method of the recycled micro-surfacing mixture in this embodiment is basically the same as the preparation method of the recycled micro-surfacing mixture in Example 1, except that basalt fiber is not added in step S1.

[0091] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0092] Example 4

[0093] The present invention provides a regenerated micro-surfacing mixture, the raw material components and proportions of which are basically the same as those in Example 1, the only difference being that it does not contain microcapsule self-healing agents.

[0094] The preparation method of the regenerated micro-surfacing mixture in this embodiment is basically the same as the preparation method of the regenerated micro-surfacing mixture in Example 1, except that the microcapsule self-repairing agent is not added in step S3.

[0095] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0096] Example 5

[0097] The present invention provides a recycled micro-surfaced mixture, the raw material composition and proportions of which are basically the same as those in Example 1, the only difference being that the cementing material used is ordinary Portland cement.

[0098] The preparation method of the recycled micro-surfaced mixture in this embodiment is basically the same as the preparation method of the recycled micro-surfaced mixture in Example 1, except that the cementitious material used in step S1 is ordinary Portland cement.

[0099] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is basically the same as that in Embodiment 1, except that the curing time is 5 hours.

[0100] Example 6

[0101] The present invention provides a regenerated micro-surface treatment mixture, the raw material composition and ratio of which are basically the same as those in Example 1, the only difference being that the regenerator used is a physical regenerator, specifically an aromatic oil-type regenerator.

[0102] The preparation method of the recycled micro-surface treated mixture in this embodiment is basically the same as the preparation method of the recycled micro-surface treated mixture in Example 1. The only difference is that the regenerator used in step S1 is an aromatic oil-type regenerator.

[0103] The aromatic oil-based regenerant has a closed-cup flash point ≥180℃, a viscosity of 15 mPa·s~40 mPa·s at 25℃, a moisture content ≤0.1%, and an ash content ≤0.05%. Specifically, it is an aromatic oil-based regenerant purchased from Shandong Furunda Chemical Co., Ltd., model FRD-AR-01. The flash point refers to the closed-cup flash point measured according to GB / T 261-2021 standard.

[0104] Of course, ordinary aromatic oil regenerators, RA-type aromatic oil regenerators, high-purity aromatic oil regenerators, or warm-mixed high-dosage aromatic oil regenerators that meet the above performance parameters can also be used.

[0105] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0106] Example 7

[0107] The present invention provides a recycled micro-surfacing mixture, the raw material composition and proportions of which are basically the same as those in Example 1, the only difference being that the gradation of the finely separated mineral materials is different, with the 0-2.36mm grade accounting for 48% of the mass, the 2.36-4.75mm grade accounting for 32% of the mass, the 4.75-7.2mm grade accounting for 12% of the mass, and the 7.2-9.5mm grade accounting for 8% of the mass.

[0108] The preparation method of the recycled micro-surfaced mixture in this embodiment is the same as the preparation method of the recycled micro-surfaced mixture in Example 1.

[0109] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0110] Example 8

[0111] The present invention provides a regenerated micro-surfacing mixture with the same raw material composition and proportion as in Example 1. The only difference is the amount of nano-reinforcing material, i.e., nano-silica, added in this example is 0.1% of the finely separated mineral material.

[0112] The preparation method of the recycled micro-surfaced mixture in this embodiment is the same as the preparation method of the recycled micro-surfaced mixture in Example 1.

[0113] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0114] Example 9

[0115] The present invention provides a recycled micro-surfacing mixture with the same raw material composition and proportion as in Example 1, except that the amount of high modulus fiber, i.e. basalt fiber, is different. In this example, the amount of high modulus fiber added is 0.1% of the finely separated mineral material.

[0116] The preparation method of the recycled micro-surfaced mixture in this embodiment is the same as the preparation method of the recycled micro-surfaced mixture in Example 1.

[0117] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0118] Example 10

[0119] The present invention provides a regenerated micro-surfacing mixture with the same raw material composition and proportion as in Example 1, except that the amount of microcapsule self-healing agent is different. In this example, the amount of microcapsule self-healing agent added is 0.3% of the finely separated mineral material.

[0120] The preparation method of the recycled micro-surfaced mixture in this embodiment is the same as the preparation method of the recycled micro-surfaced mixture in Example 1.

[0121] The method of using the recycled micro-surfacing mixture in this embodiment for micro-surfacing construction is the same as that in Embodiment 1.

[0122] Comparative Example 1

[0123] A traditional recycled micro-surfaced mixture is formulated using finely separated mineral aggregates without microwave pretreatment, ordinary silicate cement, water, SBR emulsified asphalt without warm mix additives, and an aromatic oil-based recycler. The mass ratios of the finely separated mineral aggregates, ordinary silicate cement, water, SBR emulsified asphalt, and aromatic oil-based recycler are 1:1.5%:6%:7%:0.5%.

[0124] The preparation method of the recycled micro-surfaced mixture in this comparative example includes the following steps:

[0125] S1. Weigh 1000g of finely separated mineral material that has not undergone microwave pretreatment;

[0126] S2. Add 15g of ordinary Portland cement and dry mix at room temperature for 1 minute.

[0127] S3. Add 60g of water, stir for 1 minute, then add 70g of ordinary SBR emulsified asphalt (without warm mix additive).

[0128] S4. Add 5g of aromatic oil-based regenerator and stir at room temperature for 3 minutes.

[0129] The method of using the recycled micro-surfacing mixture in this comparative example for micro-surfacing construction is basically the same as that in Example 1, except that the curing time is 6 hours.

[0130] Compared with Example 1, Comparative Example 1 did not use the key innovative components of this invention (nano-silica, basalt fiber, microcapsule self-healing agent, composite active regenerator), but only used traditional components (ordinary SBR emulsified asphalt, aromatic oil-based physical regenerator, ordinary silicate cement). The performance comparison with Example 1 shows that the innovative components of this invention have a synergistic effect: they can significantly improve the crack resistance and high temperature stability of the mixture, extend the service life of the pavement, and make the recycling depth and effect better.

[0131] Comparative Example 1 uses traditional base materials, contrasting with the "upgraded materials" of Example 1, demonstrating the improvement in construction efficiency resulting from material selection. The comprehensive performance differences between Comparative Example 1 (traditional solution) and Example 1 (inventive solution) (e.g., 81% improvement in high-temperature stability, 56% improvement in low-temperature crack resistance, and 50% reduction in curing time) clearly demonstrate the technological breakthrough of this invention in "performance improvement, efficiency optimization, and cost reduction" (utilizing old asphalt mixtures + reducing material waste), representing an advancement compared to traditional micro-surfacing technologies.

[0132] Comparative Example 1 uses "simple stirring at room temperature" (without temperature control or high-speed shearing), which contrasts with the three-stage process of "dry mixing preheating - wet mixing emulsification - shear enhancement" in Example 1, highlighting the value of process innovation.

[0133] Comparative Example 2

[0134] A conventional recycled micro-surface treatment mixture has the same raw material composition and proportions as in Example 1.

[0135] The main difference between the preparation method of the recycled micro-surfaced mixture in this comparative example and the preparation method of the recycled micro-surfaced mixture in Example 1 is that there is no three-stage temperature-controlled stirring, as detailed below:

[0136] S1: Weigh 1000g of finely separated mineral material, add 2g of nano-silica and 3g of basalt fiber, dry mix at 800rpm for 1min, add 10g of composite active regenerator, and continue stirring at 800rpm for 1.5min (at room temperature).

[0137] S2: Add all remaining components to the mixture from step S1 at once: 15g fast-setting sulfoaluminate cement, 60g water, 70g modified emulsified asphalt, and 5g microcapsule self-healing agent. Stir at room temperature and 800 rpm for 5 minutes (without high-speed shear).

[0138] The method of using the recycled micro-surfacing mixture in this comparative example for micro-surfacing construction is basically the same as that in Example 1, except that the curing time is 4 hours.

[0139] The performance of each embodiment and comparative example was tested in accordance with the "Technical Specification for Microsurfacing" (T / CECS G:M53-02-2020), and the specific data are shown below.

[0140] Table 1 - Performance Test Data Table

[0141]

[0142] As can be seen from the data in Table 1, the micro-surfacing obtained in Example 1 of this invention exhibits significantly better performance than the micro-surfacing obtained in Comparative Example 1 using conventional techniques. In particular, it shows significant improvements in high-temperature stability (81% increase), low-temperature crack resistance (56% increase), and self-healing ability (recovery rate as high as 85%, an increase of 183%). The initial anti-skid value is increased by 17%, the wear value is reduced by 33%, and the time to open traffic is shortened by 50%. Compared with Examples 2-10, the test results of Example 1 also show advantages, indicating that the optimal performance micro-surfacing can be obtained using the complete composition and proportions of this invention.

[0143] Compared with Comparative Example 2, the micro-surface prepared in Example 1 also has significant advantages in various properties. This is because the staged temperature-controlled shearing process plays a key role in component dispersion and interfacial bonding, which is conducive to obtaining micro-surfaces with excellent performance.

[0144] Compared with Comparative Examples 1-2, the properties of the micro-surfaces prepared in Examples 2-10 were significantly improved. However, Example 1 still showed significant advantages in certain properties compared with Examples 2-10, such as better initial anti-skid value, abrasion value, and high-temperature stability compared with Example 2. This indicates that nanoscale reinforcing materials are beneficial to improving the initial anti-skid value, abrasion resistance, and high-temperature stability of the micro-surfaces. Compared with Example 3, Example 1 showed significantly better abrasion value, high-temperature stability, and low-temperature crack resistance, indicating that high-modulus fibers are beneficial to improving the abrasion value, high-temperature stability, and low-temperature crack resistance of the micro-surfaces. Compared with Example 4, the most significant change in Example 1 was the strength recovery rate after crack self-healing, which increased by 70%, indicating that the microcapsule self-healing agent is beneficial to improving the strength recovery rate after crack healing. Compared with Example 5, Example 1 reduced the time to open traffic by 40%, indicating that fast-setting sulfoaluminate cement is very beneficial to shortening the time to open traffic. Compared to Example 6, Example 1 showed significant changes in abrasion value, high-temperature stability, and low-temperature crack resistance. This is because the composite active regenerator deeply repairs aged asphalt through chemical reaction, thereby improving abrasion value, high-temperature stability, and low-temperature crack resistance. Compared to Example 1, Example 7 adjusted the gradation of the finely separated mineral aggregate, Example 8 reduced the amount of nano-silica, Example 9 reduced the amount of basalt fiber, and Example 10 reduced the amount of microcapsule self-healing agent. All these results in a decrease in various properties (except during traffic opening hours), indicating that optimizing the mineral aggregate gradation and the amount of each component can further improve the various properties of micro-surfacing.

[0145] The recycled micro-surfacing mixture of this invention is particularly suitable for road maintenance in heavy-duty traffic areas, high-temperature regions, and cold regions, significantly extending road surface service life and reducing maintenance costs. In practical engineering, the dosage of nanoscale reinforcing materials, high-modulus fibers, and microcapsule self-healing agents can be adjusted according to climatic conditions and traffic load requirements to achieve the best performance-price ratio.

[0146] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A recycled micro-surfaced mixture, characterized in that, The ingredients include: finely separated mineral materials, nano-scale reinforcing materials, high-modulus fibers, regenerator, cementitious materials, water, modified emulsified asphalt, and microcapsule self-healing agent. The regenerator is a composite active regenerator, and the cementitious material is fast-setting sulfoaluminate cement or geopolymer cementitious material. The finely separated mineral aggregate is obtained by activating and pretreating old asphalt mixture to remove the aged asphalt film on the surface of the mineral aggregate, followed by fine separation. The composite active regenerator is composed of fatty acid ester compounds and surfactants, with a mass ratio of fatty acid ester compounds to surfactants of 2-4:

1. The fatty acid ester compounds are long-chain fatty acid esters with C16-C22 carbon atoms or polyunsaturated fatty acid esters with no more than 2 double bonds. The long-chain fatty acid esters are low-carbon alcohol esters with C1-C4 carbon atoms in the alcohol portion. The surfactant is a sorbitan fatty acid ester surfactant. The long-chain fatty acid ester is a monounsaturated fatty acid ester, which is an oleate or erucic acid ester. The polyunsaturated fatty acid ester is ethyl linoleate. The sorbitan fatty acid ester surfactant is selected from at least one of Span-40, Span-60, and Span-80. The modified emulsified asphalt comprises a warm mix agent, a water-based epoxy curing system, and SBR emulsified asphalt. The warm mix agent is a fatty acid salt-based warm mix agent. The water-based epoxy curing system comprises a water-based epoxy resin emulsion and a curing agent. The mass ratio of the water-based epoxy curing system to the SBR emulsified asphalt is 1–5:50, and the mass ratio of the water-based epoxy resin emulsion to the curing agent is 2–2.87:

1. The mass of the fatty acid salt-based warm mix agent is 1.5%–3.0% of the mass of the SBR emulsified asphalt. The microcapsule self-healing agent is a urea-formaldehyde resin microcapsule encapsulated with epoxy resin, and the mass ratio of the finely separated mineral material to the microcapsule self-healing agent is 1:0.3% to 0.8%. The mass ratio of the finely separated minerals, regenerator, modified emulsified asphalt, cementitious materials, water, nano-scale reinforcing materials, and high-modulus fibers is 1:0.5%–2.0%:6%–10%:1.0%–2.0%:5%–12%:0.1%–0.5%:0.1%–0.5%. The preparation steps of the recycled micro-surfacing mixture include: S1. Dry mixing and preheating stage: Add nano-level reinforcing materials and high-modulus fibers to finely separated mineral materials, dry mix, then add regenerator, continue stirring, and finally add the cementitious material. Mix and blend at 50℃~60℃ to obtain mixed mineral materials. S2, Wet mixing emulsification stage: Water and modified emulsified asphalt are added to the mixed aggregate and stirred evenly at 45℃~55℃ to obtain water-mixed aggregate; S3, Shearing Strengthening Stage: The microcapsule self-healing agent is added to the water-mixed mineral material and sheared at a speed of 2000 rpm to 3000 rpm to form a stable slurry, thus obtaining the regenerated micro-surfaced mixture.

2. The recycled micro-surfaced mixture according to claim 1, characterized in that, The high-modulus fiber has a tensile modulus ≥70GPa and a length of 3mm~12mm; the rapid-setting sulfoaluminate cement has an initial setting time ≥15 minutes and a final setting time ≤180 minutes; the geopolymer cementitious material is a composition containing aluminosilicate raw materials and an alkaline activator.

3. The recycled micro-surfacing mixture according to claim 2, characterized in that, The nanoscale reinforcing material is nano-silica; the length of the high-modulus fiber is 5mm to 8mm, and the high-modulus fiber is at least one of basalt fiber, carbon fiber, high-silica glass fiber, and ultra-high modulus polyethylene fiber. The high-silica glass fiber has a silica content of 96% to 99.8% and a tensile modulus of 75GPa to 85GPa, and the ultra-high modulus polyethylene fiber has a tensile modulus of 100GPa to 120GPa. The specific surface area of ​​the geopolymer cementitious material is ≥380m² / kg, the moisture content is ≤1.0%, the 3h compressive strength is ≥12MPa, the 28d compressive strength is ≥35MPa, and the 28d flexural strength is ≥5.0MPa.

4. The recycled micro-surfaced mixture according to claim 1, characterized in that, The modified emulsified asphalt is obtained by mixing a water-based epoxy curing system with SBR emulsified asphalt, then adding a fatty acid salt warm mix agent, and stirring.

5. The recycled micro-surfaced mixture according to claim 1, characterized in that, By mass percentage, the finely separated mineral material comprises: 40%–50% finely separated mineral material with a particle size of 0–2.36 mm, 28%–38% finely separated mineral material with a particle size of 2.36 mm–4.75 mm, 8%–15% finely separated mineral material with a particle size of 4.75 mm–7.2 mm, and 8%–15% finely separated mineral material with a particle size of 7.2 mm–9.5 mm.

6. The recycled micro-surfaced mixture according to any one of claims 1 to 5, characterized in that, The fatty acid salt in the warm mixing agent is a saturated fatty acid salt; the carbon chain length of the fatty acid portion of the fatty acid salt is C12-C18; the cation of the fatty acid salt is an alkali metal cation or an alkaline earth metal cation.

7. The recycled micro-surfaced mixture according to claim 1, characterized in that, The dry mixing preheating stage uses a rotation speed of 500 rpm to 1000 rpm, the dry mixing time is 1 min to 2 min, the continued stirring time is 1.5 min to 2.5 min, and the mixing time is 2 min to 3 min. The wet mixing emulsification stage uses a speed of 800 rpm to 1200 rpm and a stirring time of 3 min to 5 min; The shearing time during the shear strengthening stage is 1 min to 2 min.

8. The recycled micro-surfaced mixture according to claim 1, characterized in that, The preparation steps of the finely separated mineral material include: S1.1 Pretreatment: Asphalt recycled material is collected by cold milling or mechanical excavation, and after removing impurities, it is activated by microwave heating to remove the aged asphalt film on the surface of the asphalt recycled material. S1.2 Screening: The pretreated asphalt recycled material is separated and then screened to obtain particles of different sizes; S1.3 Cleaning and Grading: The screened asphalt recycled material is cleaned, graded, and dried to obtain finely separated mineral material.

9. The recycled micro-surfaced mixture according to claim 8, characterized in that, The microwave heating activation temperature is 120℃~150℃, and the heating time is 5min~10min.

Images