Semi-flexible pavement height difference repairing material, preparation method and application thereof

Abstract

The application provides a semi-flexible pavement height difference repairing material and a preparation method and application thereof. The repairing material comprises cement-based dry powder mortar, SBR-SiO2 composite modified emulsified asphalt mixture, aggregate and water in a mass ratio of 1000:(40-140):(800-1000):(110-130). The SBR-SiO2 composite modified emulsified asphalt mixture comprises 124-170 parts of SBR-SiO2 composite modified emulsified asphalt, 1-5 parts of carbon nanofiber, 1-5 parts of carbon nanotube and 0.2-0.4 parts of methyl potassium silicate. The SBR-SiO2 composite modified emulsified asphalt is obtained by modifying base asphalt by SBR and nano-SiO2. The method comprises SBR-SiO2 composite modified emulsified asphalt mixture preparation, cement-based dry powder mortar preparation and semi-flexible pavement height difference repairing material preparation. The compressive strength and durability of the repairing material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pavement materials, in particular to a semi-flexible pavement height difference repairing material, a preparation method and application thereof. BACKGROUND

[0002] In recent years, the expressway in China has developed rapidly, and the road has gradually changed from construction-oriented to maintenance-oriented. In road maintenance, local height difference of asphalt pavement appears at bridge expansion joints, climbing sections of expressways, around cistern covers and uneven settlement of bridge heads, etc. The appearance of height difference may cause jumping and impact when vehicles pass, affecting the comfort and safety of driving, increasing the noise when vehicles pass, and even greatly reducing the passing speed of vehicles, which also causes additional impact load on the pavement and bridge, affecting the service life of the bridge. Therefore, once the pavement height difference occurs, reasonable and scientific prevention and control measures need to be taken to deal with it.

[0003] At present, typical height difference diseases at bridge expansion joints, around cistern covers and uneven settlement of bridge heads are generally repaired by hot material repair, cement repair, cold material repair and other repair methods. Hot material has strong bonding performance with the original pavement and good effect, but hot material repair is usually suitable for large-area construction, and the cost of local repair is high, which is prone to problems in mixing, paving and construction organization. The strength and durability of cement repair material are outstanding, but it has the disadvantages of long construction and maintenance period and poor bonding with the original pavement. Cold material repair is convenient to construct and widely used, but the material itself has the durability problems of poor bonding with the old pavement interface and poor resistance to water damage. In addition, once the height difference disease site is formed, the stress and strain response under the action of vehicle load is complex, and the application of traditional repair materials is easy to cause secondary damage and height difference disease, which is difficult to restore the flatness of the pavement and ensure the safety of driving. Therefore, there is an urgent need for a new type of height difference repairing material which is convenient to construct, has good bonding with the original pavement, strong deformation coordination ability and excellent durability.

[0004] In order to solve the above problems, a new type of pavement material and construction method-semi-flexible pavement material has been adopted in the new generation of road traffic construction. Semi-flexible pavement material has the characteristics of both cement and asphalt, and can synergistically exert the advantages of cement, such as large rigidity and strong bearing capacity, and asphalt, such as good flexibility and strong load transmission capacity. Therefore, the application and development prospect of semi-flexible pavement material are broad. However, in semi-flexible pavement material, asphalt is oleophilic, and there is a repulsion between asphalt and cement mortar, which leads to poor compatibility between cement slurry and asphalt slurry when applied to pavement height difference repair, thereby reducing the compressive strength of the pavement and causing poor volume stability of the pavement. SUMMARY

[0005] The application provides a semi-flexible pavement height difference repairing material and a preparation method and application thereof, and aims to solve the above problems mentioned in the background art.

[0006] In one aspect, the application provides a semi-flexible pavement height difference repairing material, which comprises cement-based dry powder mortar, SBR-SiO2 composite modified emulsified asphalt mixture, aggregate and water with mass ratios of 1000:(40-140):(800-1000):(110-130) respectively.

[0007] The cement-based dry powder mortar comprises, by weight, 350-400 parts of fast-hardening sulphoaluminate cement, 20-40 parts of ordinary portland cement, 15-30 parts of silica fume, 20-35 parts of gypsum, 1-10 parts of fly ash, 520-580 parts of quartz sand, 10-20 parts of glue powder, 2-4 parts of water reducing agent, 0.0-1.0 parts of lithium carbonate, 0.2-3 parts of boric acid, 0.35-0.85 parts of water-absorbing resin, 0.5-1.0 parts of defoaming agent, 0.3-1.5 parts of water-retaining agent and 0.1-0.8 parts of expanding agent.

[0008] The SBR-SiO2 composite modified emulsified asphalt mixture comprises 124-170 parts of SBR-SiO2 composite modified emulsified asphalt, 1-5 parts of carbon nanofiber, 1-5 parts of carbon nanotube and 0.2-0.4 parts of methyl potassium silicate.

[0009] The SBR-SiO2 composite modified emulsified asphalt is obtained by modifying base asphalt with SBR and nano-SiO2.

[0010] The nano-SiO2 increases the compatibility between substances, improves the bonding capacity of SBR and asphalt interface and the performance of emulsified asphalt; the carbon nanofiber and nano-silicon dioxide improve the relative dynamic modulus of the material, reduce the internal micro-cracks of the material and the mass loss rate after freezing and thawing, improve the frost resistance and enhance the durability.

[0011] The water reducing agent is selected as a powdery polycarboxylic acid type water reducing agent, which has excellent water reducing rate, fluidity and permeability, and can also enhance the strength of the cement mortar. The defoaming agent can reduce the voids in the repair material and improve the compactness and strength of the repaired pavement by destroying the surface tension of the bubbles and making the bubbles dissipate rapidly. The defoaming agent can be any suitable defoaming agent, and is preferably an organic silicon defoaming agent such as dimethyl silicone oil or methyl silicone oil. The water retaining agent can improve the fluidity and plasticity of the concrete, making it easier to process and form, thereby improving the construction efficiency during repair. Preferably, the water retaining agent is selected as a cellulose ether. The expansive agent generates expansive crystals by hydration, compensates for the shrinkage of cement during hydration, prevents material cracking, and also enhances the waterproof performance of the structure of the repair material. The expansive agent is preferably selected from calcium sulphoaluminate type expansive agents such as alunite expansive agent and CSA expansive agent.

[0012] Optionally, the fast-hardening sulphoaluminate cement is R.SAC42.5 or R.SAC52.5, and the ordinary portland cement is P.O.42.5 or P.O.52.5.

[0013] Optionally, the aggregate is selected from at least one of limestone, sandstone and granite.

[0014] Optionally, the aggregate has a particle size grading of 0-3 mm, 3-5 mm, 5-10 mm and 10-15 mm, and the aggregate is selected from one or more of the above particle size gradings.

[0015] Optionally, the rubber powder is at least one of ethylene-vinyl acetate copolymer rubber powder, acrylic polymer rubber powder, polyethylene oxide rubber powder, styrene-acrylate rubber powder and styrene-butadiene rubber powder.

[0016] Optionally, the quartz sand has a particle size grading of 10-20 mesh, 20-40 mesh, 40-70 mesh and 70-140 mesh, wherein the weight fraction of the quartz sand with a particle size grading of 10-20 mesh is 385-387 parts, the weight fraction of the quartz sand with a particle size grading of 20-40 mesh is 100-106 parts, the weight fraction of the quartz sand with a particle size grading of 40-70 mesh is 60-65 parts, and the weight fraction of the quartz sand with a particle size grading of 70-140 mesh is 49-52 parts.

[0017] In another aspect, the application provides a preparation method of a semi-flexible pavement height difference repair material, which is used to prepare the semi-flexible pavement height difference repair material described above, and the preparation method comprises:

[0018] (1) Preparation of SBR-SiO2 composite modified emulsified asphalt mixture:

[0019] (101) Preparation of emulsified asphalt: heat base asphalt to 140-150℃ to obtain hot melt asphalt, add an aqueous emulsifier solution and a stabilizer to the hot melt asphalt, and mechanically disperse to obtain emulsified asphalt;

[0020] (102) Preparation of SBR modified emulsified asphalt: SBR is added to the emulsified asphalt, the temperature is kept at 140-150℃, and stirring is carried out at a speed of 5000-5500 r / min for 10-15 min to obtain the SBR modified emulsified asphalt;

[0021] (103) Preparation of SBR-SiO2 composite modified emulsified asphalt: nano-silicon dioxide is added to the SBR modified emulsified asphalt, the temperature is kept at 140-150℃, and stirring is carried out at a speed of 5000-5500 r / min for 10-15 min to obtain the SBR-SiO2 composite modified emulsified asphalt;

[0022] (104) Preparation of mixture: carbon nanofiber, carbon nanotube and methyl potassium silicate are added to the SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 140-150℃, and stirring is carried out at a speed of 5000-5500 r / min for 10-15 min to obtain the SBR-SiO2 composite modified emulsified asphalt mixture;

[0023] (2) Preparation of cement-based dry powder mortar: quick-hardening sulphoaluminate cement, ordinary Portland cement, silica fume, gypsum, fly ash, quartz sand, glue powder, water reducing agent, lithium carbonate, boric acid, water-absorbing resin, defoaming agent, water-retaining agent and expanding agent are added to a container in parts by weight, and are uniformly stirred and mixed at a speed of 150-200 r / min for 15-20 min to obtain the cement-based dry powder mortar, which is then sealed in a moisture-proof packaging bag.

[0024] (3) Preparation of semi-flexible pavement height difference repairing material: the cement-based dry powder mortar is added to a stirrer in parts by weight, and is stirred at a speed of 60-70 r / min for 45-60 s, then water and the SBR-SiO2 composite modified emulsified asphalt mixture are added and stirred at a speed of 150-200 r / min for 120 s, and finally the aggregate is added and stirred at a speed of 200-1000 r / min for 3-10 min to obtain the semi-flexible pavement height difference repairing material.

[0025] Optionally, the amount of base asphalt is 100 parts by weight, the amount of the water solution of emulsifier is 20-60 parts by weight, the amount of stabilizer is 2-10 parts by weight, the amount of SBR is 2-5 parts by weight, and the amount of nano-silicon dioxide is 2-5 parts by weight.

[0026] Optionally, in the preparation of emulsified asphalt, the mass concentration of emulsifier in the water solution of emulsifier is 1%-30%, and the emulsifier is selected from an anionic emulsifier or a cationic emulsifier.

[0027] In still another aspect, the application provides a use of a semi-flexible pavement height difference repairing material in repairing a height difference of a road or bridge, wherein the height difference repairing material is the semi-flexible pavement height difference repairing material described above, or is prepared by the method described above.

[0028] The application provides a semi-flexible pavement height difference repairing material, a preparation method and application thereof, realizes preparation and application of the pavement height difference repairing material, and has the following beneficial effects compared with the prior art:

[0029] (1) The application has the characteristics of both cement and asphalt, can synergistically exert the advantages of large rigidity, strong bearing capacity of cement and good flexibility, strong load transmission capacity of asphalt, has the semi-flexible and semi-rigid characteristics of the repairing material, effectively solves the repairing of the height difference pavement, improves the compatibility between the asphalt material and the cement material, has good adhesion to the old pavement, makes the repaired pavement have strong compressive strength and volume stability, improves the anti-rutting capacity of the pavement, reduces the bumping and vibration of the vehicle during driving, improves the comfort and safety of driving, greatly improves the durability of the pavement, and is safe and environmentally friendly without toxic gas emission. Meanwhile, the room temperature mixing has the advantages of energy saving and high efficiency, the mixing is easy during construction, the operation is simple, the adhesion to the old pavement is good, the whole process does not need heating, the environment is protected, and the cost of the pavement material is reduced, and the application is suitable for pavement height difference repairing of various grades of highways.

[0030] (2) First, the base asphalt is heated and melted to obtain hot melt asphalt. The base asphalt is modified by adding SBR to obtain SBR modified emulsified asphalt, and then nano silicon dioxide is added for further modification to obtain SBR-SiO2 composite modified emulsified asphalt. Finally, carbon nanofibers, carbon nanotubes and potassium methyl silicate are added to obtain SBR-SiO2 composite modified emulsified asphalt mixture. In the preparation step of the cement-based dry powder mortar, the required components are stirred and mixed according to the weight parts to obtain the cement-based dry powder mortar, and the cement-based dry powder mortar is sealed in a moisture-proof packaging bag to prevent moisture in the air from entering and prevent the cement from caking. When in use, the cement-based dry powder mortar is added to a stirrer and stirred at a speed of 60-70 r / min for 45-60 s, the cement-based dry powder mortar is first broken up to facilitate uniform mixing with the subsequent components. Then water and SBR-SiO2 composite modified emulsified asphalt mixture are added and stirred, and finally aggregate is added to obtain the semi-flexible pavement height difference repairing material. The nano SiO2 increases the compatibility between substances, improves the bonding capacity of the SBR and asphalt interface, and improves the performance of the emulsified asphalt; and the carbon nanofiber and nano silicon dioxide improve the relative dynamic modulus of the material, reduce the internal microcracks of the material and reduce the mass loss rate after freezing and thawing, improve the frost resistance, and enhance the durability.

[0031] (3) The height difference repairing material provided by the application is suitable for repairing the height difference of roads of various grades, and no toxic gas is discharged, which is safe and environmentally friendly. When the height difference repairing material is used for repairing the height difference of roads, it only needs to be mixed at room temperature, has the advantages of energy saving and high efficiency, is easy to mix and operate during construction, has good adhesion to the old road surface, and does not need to be heated throughout the process, thereby protecting the environment and reducing the cost of road materials, and the traffic can be opened in 2 hours. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application are clearly and completely described below. Obviously, the described embodiments are some but not all of the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0033] In one aspect, the application provides a semi-flexible road height difference repairing material, which comprises cement-based dry powder mortar, SBR-SiO2 composite modified emulsified asphalt mixture, aggregate and water, and the mass ratio of the cement-based dry powder mortar, the SBR-SiO2 composite modified emulsified asphalt mixture, the aggregate and the water is 1000:(40-140):(800-1000):(110-130) respectively.

[0034] The cement-based dry powder mortar comprises, by weight, 350-400 parts of fast-hardening sulphoaluminate cement, 20-40 parts of ordinary Portland cement, 15-30 parts of silica fume, 20-35 parts of gypsum, 1-10 parts of fly ash, 520-580 parts of quartz sand, 10-20 parts of glue powder, 2-4 parts of water reducing agent, 0.0-1.0 parts of lithium carbonate, 0.2-3 parts of boric acid, 0.35-0.85 parts of water-absorbing resin, 0.5-1.0 parts of defoaming agent, 0.3-1.5 parts of water-retaining agent, and 0.1-0.8 parts of expanding agent.

[0035] The SBR-SiO2 composite modified emulsified asphalt mixture comprises 124-170 parts of SBR-SiO2 composite modified emulsified asphalt, 1-5 parts of carbon nanofiber, 1-5 parts of carbon nanotube, and 0.2-0.4 parts of methyl potassium silicate.

[0036] The SBR-SiO2 composite modified emulsified asphalt is obtained by modifying base asphalt with SBR and nano-SiO2.

[0037] Specifically, the patching material provided by the application comprises cement-based dry powder mortar, SBR-SiO2 composite modified emulsified asphalt mixture, aggregate and water. The cement-based dry powder mortar provides cementation, and can form a slurry after stirring with water. The slurry can harden in air or water, so that the components in the patching material are firmly cemented together to form a strong whole. The patching material not only has good strength and density, but also can improve the durability of the patching material. The emulsified asphalt can form a nearly seamless waterproof layer on the repaired surface, effectively preventing water penetration and erosion, thereby prolonging the service life of the pavement. At the same time, the emulsified asphalt can fill the pores of the cement structure, enhance the bearing capacity and strength of the cement-based dry powder mortar, and improve the crack resistance. The SBR-SiO2 composite modified emulsified asphalt mixture provided by the application is obtained by modifying base asphalt after emulsification through SBR and nano-SiO2. SBR is a copolymer of butadiene and styrene, has a porous structure, can absorb small molecules and oil in asphalt, and contains part of light components. When the patching material is laid on a high-difference pavement, the light components are slowly released into the asphalt, so that the deformation capacity of the asphalt at low temperature is enhanced. The deformation of the asphalt can absorb a large part of the energy released by the expansion of free water freezing, so the frost resistance of the emulsified asphalt mortar is improved.

[0038] Since asphalt is a high polymer, it has strong hydrophobicity, and the adhesion and compatibility between asphalt and cement-based mortar are weak, which reduces the compressive strength of the road surface and leads to poor volume stability of the road surface. The nano-silicon dioxide increases the compatibility between substances, improves the binding capacity of SBR and the asphalt interface, improves the compatibility of emulsified asphalt and cement mortar, and improves the uniformity of the repair material, thereby improving the compactness of the internal structure of the repair material and enhancing the compressive strength. The present application also adds carbon nanofibers and carbon nanotubes to improve the compatibility between the cement-based mortar and the emulsified asphalt material. The incorporation of carbon nanofibers can significantly improve the relative dynamic elastic modulus of the emulsified asphalt mortar and reduce the mass loss rate. The carbon nanofibers overlap with each other in the asphalt to form a good network structure. When the stress is transmitted from the cement mortar matrix to the emulsified asphalt, the carbon nanofibers can play a role in linking and transmitting, and absorb most of the stress, so that the stress is released and the occurrence of cracks is prevented, thereby significantly improving the compressive strength of the repair material. The carbon nanotubes can convert the thin hexagonal plate-shaped calcium hydroxide crystals between the cement-based mortar and the asphalt interface into hexagonal prismatic crystals, increase the compactness of the interface, and the carbon nanotubes penetrating through the asphalt and cement stone also increase the adhesion of the interface. The enhancement of the interface between the cement stone and the asphalt reduces the internal defects of the cement asphalt mortar and improves the synergistic deformation performance between the two, which is beneficial to enhancing the anti-deformation performance of the cement emulsified asphalt mortar and the volume stability of the road surface. It can also improve the compatibility and adhesion between the repair material and the base material, improve the compressive strength and durability of the repair material, and the carbon nanotubes dispersed in the asphalt can hinder the free movement of the asphalt polymer chain segment, to a certain extent, improve the anti-deformation ability of the repair material. And in the presence of cement-based dry powder mortar, carbon nanofibers and carbon nanotubes can react with Ca(OH)2 to generate more C-S-H gel, occupy the void space, and increase the density of the interface transition zone. Therefore, the incorporation of carbon nanofibers and carbon nanotubes into emulsified asphalt will help to produce more cement hydrates, which can absorb free asphalt, thereby helping to improve the compatibility between asphalt and cement and improve the compressive strength of the repair material.

[0039] The fast hardening sulphoaluminate cement, ordinary Portland cement and silica fume in the cement-based dry powder mortar provide early strength of the repair material, the fast hardening sulphoaluminate cement and ordinary Portland cement mainly play a role in forming cement stone gel body, bonding other components together to form a whole and improving the strength of the repair material. At the same time, the two kinds of cement and other components can form a good space structure to provide excellent durability. The specific surface area of the silica fume is 20000 m 2 / kg, which helps the compatibility and mixing between components, helps to build a more compact and solid space structure between components, and further improves the compressive strength and durability of the repair material and the volume stability of the road surface.

[0040] The gypsum can delay the setting time of the repairing material, the gypsum and the methyl potassium silicate jointly act, can improve the hardness and the compactness of the repairing material, the methyl potassium silicate has the hydrophobic effect, reduces the contact range of the gypsum particles and water, reduces the SO4 2- Ion concentration, thereby reducing the influence degree of excessive SO4 2- Ion on the hydration process of C3A in cement. At the same time, the gypsum recrystallization of the dissolved gypsum crystal reduces, so that the internal structure of the semi-flexible repairing material is more compact, thereby improving the compressive strength of the pavement, and the mechanical properties are obviously improved. The methyl potassium silicate is a water solution with a solid content of 40wt%.

[0041] At the same time, the combined effect of lithium carbonate and boric acid and the synergistic effect with cement form a ternary system, further improving the durability of the repairing material.

[0042] The application has the characteristics of both cement and asphalt materials, and can synergistically exert the advantages of high rigidity, high bearing capacity of cement and good flexibility, high load transmission capacity of asphalt. The semi-flexible and semi-rigid characteristics of the repairing material provided by the application not only effectively solve the repair of high-difference pavements, improve the compatibility between asphalt materials and cement materials, and have good adhesion performance with old pavements, but also make the repaired pavement have strong compressive strength and volume stability, improve the anti-rutting ability of the pavement, reduce the bumping and vibration of the vehicle during driving, improve the comfort and safety of driving, and greatly improve the durability of the pavement. In addition, the application has no toxic gas emission, is safe and environmentally friendly. At the same time, the room temperature mixing also has the advantages of energy saving and high efficiency, and the mixing is easy and simple to operate during construction. The adhesion performance with the old pavement is good, and the whole process does not need heating, which protects the environment and reduces the cost of pavement materials, and is suitable for pavement repair of various grades of highways.

[0043] Optionally, the fast-hardening sulphoaluminate cement is R.SAC42.5 or R.SAC52.5, and the ordinary Portland cement is P.O.42.5 or P.O.52.5.

[0044] Specifically, the fast-hardening sulphoaluminate cement has the characteristics of rapid setting, reduces the opening time of traffic, minimizes the influence on traffic, thereby simplifying the process flow and reducing the production cost. The fast-hardening sulphoaluminate cement concrete still has high strength and frost resistance at low temperature. The ordinary Portland cement can tightly bond various components together to form a concrete structure with certain strength, but the setting time is long and the early strength is lower than that of the fast-hardening sulphoaluminate cement. By mixing the fast-hardening sulphoaluminate cement and the ordinary Portland cement, the setting time of the repairing material is reduced, and the early strength of the repairing material is enhanced, thereby improving the compressive strength of the repairing material.

[0045] Meanwhile, the two kinds of cement improve the mixing uniformity of the cement-based dry powder mortar and the modified emulsified asphalt mixture through a special combination of weights, and the SBR-SiO2 modified emulsified asphalt mixture can better enter the voids of the cement-based dry powder mortar, so that the spatial structure of the repair material is more compact, thereby improving the compressive strength of the repair material.

[0046] Optionally, the aggregate is selected from at least one of limestone, sandstone, and granite.

[0047] Optionally, the aggregate has a particle size grading of 0-3mm, 3-5mm, 5-10mm, and 10-15mm, and the aggregate is selected from one or more of the above particle size gradings.

[0048] Specifically, the aggregate can increase the strength and stiffness of the repair material and reduce the shrinkage and expansion of the concrete. After the aggregate is mixed with the cement-based dry powder mortar, a solid hardened system is formed, thereby improving the compressive strength and tensile strength of the repair material and increasing the load-bearing capacity and durability of the repair material.

[0049] The size, shape, surface characteristics, and coarseness of the aggregate directly affect the plasticity and moldability of the repair material. For example, larger aggregate can increase the protrusions formed on the surface of the concrete, thereby increasing the skid resistance of the concrete, while smaller aggregate can increase the density and porosity of the concrete. The aggregate can also reduce the permeability of the repair material, preventing the infiltration of water and air molecules in the repair material, thereby increasing the durability of the pavement. In the repair material of the present application, any one or more particle size gradings of aggregate can be selected (such as using 3-5mm aggregate or a combination of 0-3mm aggregate when the height difference is ≤2cm, preferably using 5-10mm aggregate or a combination of 0-3mm aggregate when the height difference is 2-5cm, and preferably using 10-15mm aggregate or a combination of 0-3mm aggregate, 3-5mm aggregate when the height difference is >5cm), which meets the specifications of JTG 3420-2020 “Test Code for Highway Engineering Cement and Cement Concrete” according to the actual working conditions, which is not particularly limited here. Among them, 0mm in 0-3mm aggregate means no aggregate is used.

[0050] Optionally, the rubber powder is at least one of ethylene-vinyl acetate copolymer rubber powder, acrylic polymer rubber powder, polyethylene oxide rubber powder, styrene-acrylate rubber powder, and styrene-butadiene rubber powder. The rubber powder can improve the toughness of the repair material.

[0051] Optionally, the particle size grading of the quartz sand is 10-20 mesh, 20-40 mesh, 40-70 mesh, and 70-140 mesh, wherein the weight parts of the quartz sand with a particle size of 10-20 mesh is 385-387 parts, the weight parts of the quartz sand with a particle size of 20-40 mesh is 100-106 parts, the weight parts of the quartz sand with a particle size of 40-70 mesh is 60-65 parts, and the weight parts of the quartz sand with a particle size of 70-140 mesh is 49-52 parts.

[0052] Specifically, the quartz sand can improve the compressive strength of the repair material, reduce shrinkage cracks, improve durability, and improve work performance. By adding quartz sand with different particle sizes, it can help to fill the voids in the concrete, increase the density of the repair material, and thus reduce the occurrence of shrinkage cracks. At the same time, the quartz sand has high hardness and good durability, which can reduce the aging rate of the repair material and prolong the service life of the pavement.

[0053] Preferably, the SBR-SiO2 composite modified emulsified asphalt mixture further comprises 0.15-0.26 parts by weight of kojic acid, 0.3-0.85 parts by weight of methyl butynol, and 0.56-1.5 parts by weight of potassium cinnamate. When the repair material is laid, the hydroxyl group of kojic acid and the carboxyl group on potassium cinnamate are easy to react with the active groups on nano-silicon dioxide, so that the six-membered heterocyclic ring contained in kojic acid and the benzene ring at the other end of the structure of potassium cinnamate can also be grafted onto the surface of nano-silicon dioxide. The modification of emulsified asphalt by silicon dioxide not only further disperses kojic acid and potassium cinnamate in the repair material with emulsified asphalt, but also improves the mechanical strength of the repair material, thereby improving the compressive strength and durability of the repair material. Methyl butynol can bond with the active groups of carbon nanofibers and carbon nanotubes, improve the dispersibility and stability of carbon nanofibers and carbon nanotubes, and thus improve the reaction of carbon nanofibers and carbon nanotubes with Ca(OH)2 to generate more C-S-H gel, occupy the void space, and increase the density of the interface transition zone. More cement hydrates are produced, thereby also helping to improve the compatibility between asphalt and cement and the compressive strength of the repair material. The three work together to further improve the compressive strength of the repair material.

[0054] On the other hand, the present application provides a preparation method of a semi-flexible pavement height difference repair material, which is used to prepare the semi-flexible pavement height difference repair material described above, and the preparation method comprises:

[0055] (1) SBR-SiO2 composite modified emulsified asphalt mixture preparation:

[0056] (101) Emulsified asphalt preparation: heat the base asphalt to 140-150℃ to obtain hot melt asphalt, add an aqueous emulsifier solution and a stabilizer to the hot melt asphalt, and mechanically disperse for 10-15 min to prepare emulsified asphalt;

[0057] (102) Preparation of SBR modified emulsified asphalt: SBR is added to the emulsified asphalt, the temperature is kept at 140-150℃, and stirring is carried out at a speed of 5000-5500 r / min for 10-15 min to obtain the SBR modified emulsified asphalt;

[0058] (103) Preparation of SBR-SiO2 composite modified emulsified asphalt: nano silicon dioxide is added to the SBR modified emulsified asphalt, the temperature is kept at 140-150℃, and stirring is carried out at a speed of 5000-5500 r / min for 10-15 min to obtain the SBR-SiO2 composite modified emulsified asphalt;

[0059] (104) Preparation of mixture: carbon nanofiber, carbon nanotube and potassium methyl silicate are added to the SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 140-150℃, and stirring is carried out at a speed of 5000-5500 r / min for 10-15 min to obtain the SBR-SiO2 composite modified emulsified asphalt mixture;

[0060] (2) Preparation of cement-based dry powder mortar: quick-hardening sulphoaluminate cement, ordinary portland cement, silica fume, gypsum, fly ash, quartz sand, powder, water reducing agent, lithium carbonate, boric acid, water absorbing resin, defoaming agent, water retaining agent and expanding agent are added to a container in parts by weight, and are uniformly stirred and mixed at a speed of 150-200 r / min for 15-20 min to obtain the cement-based dry powder mortar, which is sealed in a moisture-proof packaging bag.

[0061] (3) Preparation of semi-flexible pavement height difference repair material: the cement-based dry powder mortar is added to a mixer in parts by weight, and is stirred at a speed of 60-70 r / min for 45-60 s, then water and the SBR-SiO2 composite modified emulsified asphalt mixture are added, and are stirred at a speed of 150-200 r / min for 120 s, finally the aggregate is added, and is stirred at a speed of 200-1000 r / min for 3-10 min to obtain the semi-flexible pavement height difference repair material.

[0062] The application realizes the preparation of the semi-flexible pavement height difference repair material. First, the base asphalt is heated to 140-150℃ to melt the asphalt to obtain hot melt asphalt. Then SBR is added to modify the base asphalt to obtain SBR modified emulsified asphalt, and nano silicon dioxide is further added to modify the SBR modified emulsified asphalt to obtain SBR-SiO2 composite modified emulsified asphalt. Finally, carbon nanofiber, carbon nanotube and potassium methyl silicate are added to obtain the SBR-SiO2 composite modified emulsified asphalt mixture.

[0063] In the preparation step of the cement-based dry powder mortar, the required components are mixed according to the weight parts, and the cement-based dry powder mortar is obtained and stored in a moisture-proof packaging bag to avoid the entry of moisture in the air and the cement clumping. When used, the cement-based dry powder mortar is added to a mixer and stirred at a speed of 60-70 r / min for 45-60 s, the cement-based dry powder mortar is first broken up to facilitate uniform mixing with the subsequent components. Then, water and SBR-SiO2 composite modified emulsified asphalt mixture are added and stirred, and finally, the aggregate is added to obtain the semi-flexible pavement differential height repair material.

[0064] In the formula, the SBR binding rate is 23.5%, the solid content is 64%, the pH value is 6, the Brookfield viscosity is 500-1500, and the particle charge is positive charge. The length of the carbon nanofiber is 10-30 um, the diameter is 160-200 nm, and the specific surface area is 2000 m 2 / g.

[0065] Optionally, the amount of base asphalt is 100 parts by weight, the amount of emulsifier aqueous solution is 20-60 parts by weight, the amount of stabilizer is 2-10 parts by weight, the amount of SBR is 2-5 parts by weight, and the amount of nano-silicon dioxide is 2-5 parts by weight.

[0066] Specifically, the base asphalt uses any commonly used base asphalt in the industry, and preferably, ordinary 70# base asphalt is used. The emulsifier is used to emulsify the base asphalt, which helps the modification of SBR and SiO2 to the base asphalt. The stabilizer helps to maintain the stability of the emulsified asphalt during emulsification of the base asphalt, and at the same time, it is beneficial to maintain the uniform suspension of the solution during subsequent modification, improve the stability of the SBR-SiO2 composite modified emulsified asphalt mixture, and improve the stability of the repair material. It helps the repair material to play the maximum role in repairing the high-differential pavement, improves the compressive strength and durability of the pavement, and improves the compressive strength and durability of the pavement. Preferably, the stabilizer uses calcium chloride or magnesium chloride.

[0067] Optionally, in the preparation step of the emulsified asphalt, the mass concentration of the emulsifier in the emulsifier aqueous solution is 1%-30%, and the emulsifier is selected from anionic emulsifiers or cationic emulsifiers.

[0068] Specifically, the emulsifier can effectively inhibit the clumping of particles and reduce the cohesion, thereby increasing the flowability of the repair material, which makes the repair material flow and fill more easily during construction. More preferably, the emulsifier uses sodium dodecyl benzene sulfonate.

[0069] In another aspect, the application provides another application of the semi-flexible pavement differential height repair material in the repair of road and bridge differential height, which is the semi-flexible pavement differential height repair material described above or obtained by the method described above.

[0070] Specifically, the height difference repairing material provided by the application is suitable for repairing the height difference of roads of various grades, and no toxic gas is discharged, which is safe and environmentally friendly. Meanwhile, the height difference repairing material only needs to be mixed at room temperature when used for repairing the height difference of roads, which is energy-saving and efficient. The mixing is easy and the operation is simple during construction. The height difference repairing material has good adhesion to the old road surface and does not need to be heated throughout the process, which protects the environment and reduces the cost of road materials. Meanwhile, the traffic can be opened in 2 hours.

[0071] It should be noted that in the present application and the following examples, the concentrations, ratios and the like not specifically stated are weight concentrations, weight ratios and the like, and the "%" represents the weight percentage, and the "part" represents the weight part, which is the writing habit commonly used by those skilled in the art, and therefore will not be described in detail in the present application.

[0072] The application will be further described in detail below in combination with the examples. However, it should be understood that the examples are only for illustrative purposes and are not intended to limit the scope of the application.

[0073] Example 1

[0074] Preparation of SBR-SiO2 composite modified emulsified asphalt mixture:

[0075] (101) Preparation of emulsified asphalt: 100 parts by weight of base asphalt is heated to 145 DEG C to obtain hot melt asphalt, 40 parts by weight of emulsifier aqueous solution and 6 parts by weight of stabilizer are added to the hot melt asphalt, and mechanical dispersion is carried out to prepare emulsified asphalt;

[0076] (102) Preparation of SBR modified emulsified asphalt: 3 parts by weight of SBR is added to the emulsified asphalt, the temperature is kept at 145 DEG C, and stirring is carried out at a speed of 5000-5500 r / min for 15 min to prepare SBR modified emulsified asphalt;

[0077] (103) Preparation of SBR-SiO2 composite modified emulsified asphalt: 3 parts by weight of nano-silicon dioxide is added to the SBR modified emulsified asphalt, the temperature is kept at 145 DEG C, and stirring is carried out at a speed of 5000-5500 r / min for 15 min to prepare SBR-SiO2 composite modified emulsified asphalt;

[0078] (104) Preparation of mixture: 3 parts by weight of carbon nanofiber, 3 parts by weight of carbon nanotube, 0.3 parts by weight of potassium methyl silicate, 0.2 parts by weight of kojic acid, 0.4 parts by weight of methyl butynol and 0.8 parts by weight of potassium cinnamate are added to 140 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 145 DEG C, and stirring is carried out at a speed of 5000-5500 r / min for 15 min to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0079] Comparative Example 1

[0080] SBR-SiO2 composite modified emulsified asphalt mixture preparation:

[0081] The difference from Example 1 is that:

[0082] (104) Mixture preparation: 3 parts by weight of carbon nanofibers, 3 parts by weight of carbon nanotubes, 0.3 parts by weight of potassium methyl silicate, 0.4 parts by weight of methyl butynol and 0.8 parts by weight of potassium cinnamate were added to 140 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature was kept at 145°C, and stirring was carried out at a speed of 5000-5500 r / min for 15 min to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0083] Comparative Example 2

[0084] SBR-SiO2 composite modified emulsified asphalt mixture preparation:

[0085] The difference from Example 1 is that:

[0086] (104) Mixture preparation: 3 parts by weight of carbon nanofibers, 3 parts by weight of carbon nanotubes, 0.3 parts by weight of potassium methyl silicate, 0.2 parts by weight of kojic acid, 0.8 parts by weight of potassium cinnamate were added to 140 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature was kept at 145°C, and stirring was carried out at a speed of 5000-5500 r / min for 15 min to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0087] Comparative Example 3

[0088] SBR-SiO2 composite modified emulsified asphalt mixture preparation:

[0089] The difference from Example 1 is that:

[0090] (104) Mixture preparation: 3 parts by weight of carbon nanofibers, 3 parts by weight of carbon nanotubes, 0.3 parts by weight of potassium methyl silicate, 0.2 parts by weight of kojic acid, 0.4 parts by weight of methyl butynol were added to 140 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature was kept at 145°C, and stirring was carried out at a speed of 5000-5500 r / min for 15 min to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0091] Experimental Example 1

[0092] According to JTGF40-2011 “Technical Specification for Construction of Highway Asphalt Pavement”, the performance of SBR-SiO2 composite modified emulsified asphalt mixture was detected, 3 parallel tests were set for each test group, and the average value was taken. The detection results and specific detection methods are shown in Table 1:

[0093] Table 1

[0094]

[0095]

[0096] As can be seen from Table 1, by the technical method provided in the present application, the SBR-SiO2 composite modified emulsified asphalt mixture can be successfully prepared, and all indexes meet or are even better than the values specified in the Technical Specification for Construction of Highway Asphalt Pavement. Among them, the hydroxyl group of kojic acid and the carboxyl group on potassium cinnamate are easy to react with the active groups on nano-silica, so that the six-membered heterocyclic ring contained in kojic acid and the benzene ring at the other end of the structure of potassium cinnamate can also be grafted on the surface of nano-silica, and the emulsified asphalt is modified by silica, which further enables kojic acid and potassium cinnamate to be dispersed in the repair material with emulsified asphalt, and the active groups of carbon nanofibers and carbon nanotubes can be bonded with methyl acetylenic alcohol, thereby improving the dispersibility and stability of carbon nanofibers and carbon nanotubes, improving the storage stability of asphalt, and further improving the stability of the repair material.

[0097] Example 2

[0098] A preparation method of a semi-flexible pavement height difference repair material, comprising the following steps:

[0099] (1) Preparation of SBR-SiO2 composite modified emulsified asphalt mixture:

[0100] (101) Preparation of emulsified asphalt: 100 parts by weight of base asphalt is heated to 140°C to obtain hot melt asphalt, 20 parts by weight of emulsifier aqueous solution and 2 parts by weight of stabilizer are added to the hot melt asphalt, and mechanical dispersion is carried out for 10 min to prepare emulsified asphalt;

[0101] (102) Preparation of SBR modified emulsified asphalt: 2 parts by weight of SBR is added to the emulsified asphalt, the temperature is kept at 140°C, and stirring is carried out at a speed of 5000-5500 r / min for 10 min to prepare SBR modified emulsified asphalt;

[0102] (103) Preparation of SBR-SiO2 composite modified emulsified asphalt: 2 parts by weight of nano-silica is added to the SBR modified emulsified asphalt, the temperature is kept at 140°C, and stirring is carried out at a speed of 5000-5500 r / min for 10 min to prepare SBR-SiO2 composite modified emulsified asphalt;

[0103] (104) Preparation of mixture: Add 1 part by weight of carbon nanofiber, 1 part by weight of carbon nanotube and 0.2 parts by weight of potassium methylsilicate to 124 parts by weight of SBR-SiO2 composite modified emulsified asphalt, keep the temperature at 140℃, stir at a speed of 5000-5500r / min for 10min to obtain SBR-SiO2 composite modified emulsified asphalt mixture;

[0104] (2) Preparation of cement-based dry mortar: Mix 350 parts by weight of rapid-hardening sulfoaluminate cement, 20 parts by weight of ordinary Portland cement, 15 parts by weight of silica fume, 20 parts by weight of gypsum, 1 part by weight of fly ash, and 520 parts by weight of quartz sand (385 parts by weight of 10-20 mesh quartz sand, 100 parts by weight of 20-40 mesh quartz sand, 60 parts by weight of 40-70 mesh quartz sand, and 70- Add 49 parts by weight of 140-mesh quartz sand, 10 parts by weight of adhesive powder, 2 parts by weight of water-reducing agent, 0.2 parts by weight of boric acid, 0.35 parts by weight of water-absorbing resin, 0.5 parts by weight of defoamer, 0.3 parts by weight of water-retaining agent and 0.1 parts by weight of expansion agent to a container, and stir and mix at a speed of 150-200 r / min for 15 minutes to obtain cement-based dry powder mortar, and seal it in a moisture-proof packaging bag.

[0105] The rapid-hardening sulfoaluminate cement is R.SAC42.5, and the ordinary silicate cement is PO42.5.

[0106] (3) Preparation of semi-flexible pavement elevation difference repair material: Add cement-based dry powder mortar to the mixer according to the weight parts, and stir at a speed of 60-70 r / min for 45-60s. Then add water and SBR-SiO2 composite modified emulsified asphalt mixture, and stir at a speed of 150-200 r / min for 120s. Finally, add aggregate and stir at a speed of 200-1000 r / min for 3-10min to obtain semi-flexible pavement elevation difference repair material.

[0107] The mass ratio of cement-based dry powder mortar, SBR-SiO2 composite modified emulsified asphalt mixture, aggregate and water is 1000:40:800:110, and the aggregate is selected from 5-10mm limestone.

[0108] Example 3

[0109] A method for preparing a semi-flexible pavement elevation difference repair material includes the following steps:

[0110] (1) Preparation of SBR-SiO2 composite modified emulsified asphalt mixture:

[0111] (101) Preparation of emulsified asphalt: 100 parts by weight of base asphalt is heated to 145℃ to obtain hot melt asphalt, 40 parts by weight of emulsifier aqueous solution and 6 parts by weight of stabilizer are added to the hot melt asphalt, and mechanical dispersion is carried out for 12 min to obtain emulsified asphalt;

[0112] (102) Preparation of SBR modified emulsified asphalt: 3 parts by weight of SBR is added to the emulsified asphalt, the temperature is kept at 145℃, and stirring is carried out at a speed of 5000-5500 r / min for 12 min to obtain SBR modified emulsified asphalt;

[0113] (103) Preparation of SBR-SiO2 composite modified emulsified asphalt: 3 parts by weight of nano silicon dioxide is added to the SBR modified emulsified asphalt, the temperature is kept at 145℃, and stirring is carried out at a speed of 5000-5500 r / min for 12 min to obtain SBR-SiO2 composite modified emulsified asphalt;

[0114] (104) Preparation of mixture: 3 parts by weight of carbon nanofiber, 3 parts by weight of carbon nanotube, and 0.3 parts by weight of potassium methyl silicate are added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 145℃, and stirring is carried out at a speed of 5000-5500 r / min for 12 min to obtain SBR-SiO2 composite modified emulsified asphalt mixture;

[0115] (2) Preparation of cement-based dry powder mortar: 380 parts by weight of fast-hardening sulphoaluminate cement, 30 parts by weight of ordinary portland cement, 25 parts by weight of silica fume, 25 parts by weight of gypsum, 6 parts by weight of fly ash, 550 parts by weight of quartz sand (386 parts by weight of 10-20 mesh quartz sand, 103 parts by weight of 20-40 mesh quartz sand, 62 parts by weight of 40-70 mesh quartz sand, and 50 parts by weight of 70-140 mesh quartz sand), 15 parts by weight of rubber powder, 3 parts by weight of water reducing agent, 0.6 parts by weight of lithium carbonate, 2.2 parts by weight of boric acid, 0.55 parts by weight of water-absorbing resin, 0.7 parts by weight of defoaming agent, 1.2 parts by weight of water-retaining agent, and 0.5 parts by weight of expanding agent are added to a container, and uniform stirring and mixing are carried out at a speed of 150-200 r / min for 12 min to obtain the cement-based dry powder mortar, which is then sealed in a moisture-proof packaging bag.

[0116] The fast-hardening sulphoaluminate cement is R.SAC42.5, and the ordinary portland cement is P.O.42.5.

[0117] (3) Preparation of the semi-flexible pavement high-differential repair material: the cement-based dry powder mortar is added into a mixer according to the weight parts, stirred at a speed of 60-70 r / min for 45-60 s, then the water and the SBR-SiO2 composite modified emulsified asphalt mixture is added, stirred at a speed of 150-200 r / min for 120 s, finally the aggregate is added, stirred at a speed of 200-1000 r / min for 3-10 min, to obtain the semi-flexible pavement high-differential repair material.

[0118] The mass ratio of the cement-based dry powder mortar, the SBR-SiO2 composite modified emulsified asphalt mixture, the aggregate and the water is 1000:90:900:120 respectively, and the aggregate is selected from 5-10 mm limestone.

[0119] Example 4

[0120] A preparation method of a semi-flexible pavement high-differential repair material, comprising the following steps:

[0121] (1) Preparation of the SBR-SiO2 composite modified emulsified asphalt mixture:

[0122] (101) Preparation of the emulsified asphalt: 100 parts by weight of base asphalt is heated to 150℃ to obtain hot melt asphalt, 60 parts by weight of an emulsifier aqueous solution and 10 parts by weight of a stabilizer are added into the hot melt asphalt, and mechanical dispersion is carried out for 15 min to prepare the emulsified asphalt;

[0123] (102) Preparation of the SBR modified emulsified asphalt: 5 parts by weight of SBR is added into the emulsified asphalt, the temperature is kept at 150℃, and stirring is carried out at a speed of 5000-5500 r / min for 15 min to prepare the SBR modified emulsified asphalt;

[0124] (103) Preparation of the SBR-SiO2 composite modified emulsified asphalt: 5 parts by weight of nano silicon dioxide is added into the SBR modified emulsified asphalt, the temperature is kept at 150℃, and stirring is carried out at a speed of 5000-5500 r / min for 15 min to prepare the SBR-SiO2 composite modified emulsified asphalt;

[0125] (104) Preparation of the mixture: 5 parts by weight of carbon nanofiber, 5 parts by weight of carbon nanotube and 0.4 parts by weight of methyl potassium silicate are added into 170 parts by weight of the SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 150℃, and stirring is carried out at a speed of 5000-5500 r / min for 15 min to prepare the SBR-SiO2 composite modified emulsified asphalt mixture;

[0126] (2) Preparation of the cement-based dry powder mortar: 400 parts by weight of fast-hardening sulphoaluminate cement, 40 parts by weight of ordinary Portland cement, 30 parts by weight of silica fume, 35 parts by weight of gypsum, 10 parts by weight of fly ash, 580 parts by weight of quartz sand (387 parts by weight of quartz sand of 10-20 mesh, 106 parts by weight of quartz sand of 20-40 mesh, 65 parts by weight of quartz sand of 40-70 mesh, and 52 parts by weight of quartz sand of 70-140 mesh), 20 parts by weight of wood flour, 4 parts by weight of water reducing agent, 1.0 part by weight of lithium carbonate, 3 parts by weight of boric acid, 0.85 parts by weight of water-absorbing resin, 1.0 part by weight of defoaming agent, 1.5 parts by weight of water-retaining agent, and 0.8 part by weight of expanding agent are added into a container, and stirred and mixed at a speed of 150-200 r / min for 20 min to obtain the cement-based dry powder mortar, which is then sealed in a moisture-proof packaging bag.

[0127] The fast-hardening sulphoaluminate cement is R.SAC 42.5, and the ordinary Portland cement is P.O. 42.5.

[0128] (3) Preparation of the semi-flexible pavement height difference repairing material: the cement-based dry powder mortar is added into a mixer, stirred at a speed of 60-70 r / min for 45-60 s, then water and SBR-SiO2 composite modified emulsified asphalt mixture are added, stirred at a speed of 150-200 r / min for 120 s, and finally aggregate is added, stirred at a speed of 200-1000 r / min for 3-10 min to obtain the semi-flexible pavement height difference repairing material.

[0129] The mass ratio of the cement-based dry powder mortar, the SBR-SiO2 composite modified emulsified asphalt mixture, the aggregate, and the water is 1000:140:1000:130, and the aggregate is selected from 3-5 mm limestone.

[0130] Comparative Example 5

[0131] A preparation method of a semi-flexible pavement height difference repairing material, comprising the following steps:

[0132] The difference from Example 3 is that:

[0133] (1) Preparation of the SBR-SiO2 composite modified emulsified asphalt mixture:

[0134] (104) Preparation of the mixture: 0.4 parts by weight of methyl potassium silicate is added into 170 parts by weight of the SBR-SiO2 composite modified emulsified asphalt, stirred at a speed of 5000-5500 r / min for 15 min at a temperature of 150°C to obtain the SBR-SiO2 composite modified emulsified asphalt mixture.

[0135] Experimental Example 2

[0136] The performance of the semi-flexible pavement differential height repairing material provided by Examples 2 to 4 and Comparative Example 5 was detected according to JTG 3420-2020 “Test Code for Cement and Cement Concrete of Highway Engineering”, and 3 parallel tests were respectively arranged for each test group, and the average value was taken. The detection results are shown in Table 2:

[0137] Table 2

[0138]

[0139]

[0140] As shown in Table 2, the semi-flexible pavement differential height repairing material provided by the application has good compressive strength, and the compressive strength after 2 hours of maintenance is all above 23 MPa, which meets the open-to-traffic regulation, greatly shortens the pavement repairing time, and reduces the influence on traffic in the repairing process. Moreover, the semi-flexible pavement differential height repairing material has good flexural strength and dynamic elastic modulus, and the carbon nanofiber and carbon nanotube are added to improve the compatibility between the cement-based mortar and the emulsified asphalt material. The incorporation of the carbon nanofiber can obviously improve the relative dynamic elastic modulus of the emulsified asphalt mortar and reduce the mass loss rate. The carbon nanofiber is overlapped in the asphalt to form a good network structure. When the stress is transmitted from the cement mortar matrix to the emulsified asphalt, the carbon nanofiber can play a role of connection and transmission, and absorb most of the stress, so that the stress is released and the occurrence of cracks is prevented, thereby significantly improving the compressive strength of the repairing material.

[0141] Meanwhile, the cyclic frost resistance of the repairing material provided by the application is much higher than that of Comparative Example 4. The asphalt in the emulsified asphalt mortar is a viscoelastic material, and its modulus is much lower than that of cement. During the freezing and thawing process, the free water in the emulsified asphalt mortar expands due to ice formation. Due to the good deformation performance of the asphalt, part of the energy can be absorbed to prevent the frost heaving damage of the emulsified asphalt mortar. The carbon nanofiber and carbon nanotube are dispersed in the emulsified asphalt, and the two kinds of nanomaterials are overlapped in the emulsified asphalt to form a good network structure. When the stress is transmitted from the cement mortar matrix to the emulsified asphalt, the carbon nanofiber and carbon nanotube can absorb most of the stress, so that the stress is released and the occurrence of cracks in the emulsified asphalt mortar is prevented, thereby significantly improving the frost resistance of the emulsified asphalt mortar.

[0142] Example 5

[0143] A preparation method of a semi-flexible pavement differential height repairing material, comprising the following steps:

[0144] The difference from Example 3 is that:

[0145] (104) The mixture preparation: 3 parts by weight of carbon nanofiber, 3 parts by weight of carbon nanotube, 0.3 parts by weight of potassium methyl silicate, 0.2 parts by weight of kojic acid, 0.55 parts by weight of methyl butynol and 1.0 parts by weight of potassium cinnamate are added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 145℃, stirring at 5000-5500r / min for 12min, to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0146] Example 6

[0147] A preparation method of a semi-flexible pavement height difference repairing material, comprising the following steps:

[0148] The difference from example 3 is that:

[0149] (104) The mixture preparation: 3 parts by weight of carbon nanofiber, 3 parts by weight of carbon nanotube, 0.3 parts by weight of potassium methyl silicate, 0.26 parts by weight of kojic acid, 0.85 parts by weight of methyl butynol and 1.5 parts by weight of potassium cinnamate are added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 145℃, stirring at 5000-5500r / min for 12min, to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0150] Example 7

[0151] A preparation method of a semi-flexible pavement height difference repairing material, comprising the following steps:

[0152] The difference from example 3 is that:

[0153] (104) The mixture preparation: 3 parts by weight of carbon nanofiber, 3 parts by weight of carbon nanotube, 0.3 parts by weight of potassium methyl silicate, 0.26 parts by weight of kojic acid, 0.85 parts by weight of methyl butynol and 1.5 parts by weight of potassium cinnamate are added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature is kept at 145℃, stirring at 5000-5500r / min for 12min, to prepare SBR-SiO2 composite modified emulsified asphalt mixture.

[0154] Comparative example 6

[0155] The difference from example 6 is that:

[0156] (104) Preparation of the mixture: 3 parts by weight of carbon nanofibers, 3 parts by weight of carbon nanotubes, 0.3 parts by weight of potassium methyl silicate, 0.26 parts by weight of kojic acid, and 1.5 parts by weight of potassium cinnamate were added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature was kept at 145℃, and stirring was carried out at a speed of 5000-5500r / min for 12min to prepare the SBR-SiO2 composite modified emulsified asphalt mixture.

[0157] The difference from Example 6 is that:

[0158] (104) Preparation of the mixture: 3 parts by weight of carbon nanofibers, 3 parts by weight of carbon nanotubes, 0.3 parts by weight of potassium methyl silicate, 0.26 parts by weight of kojic acid, and 1.5 parts by weight of potassium cinnamate were added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature was kept at 145℃, and stirring was carried out at a speed of 5000-5500r / min for 12min to prepare the SBR-SiO2 composite modified emulsified asphalt mixture.

[0159] Comparative Example 7

[0160] The difference from Example 6 is that:

[0161] (104) Preparation of the mixture: 3 parts by weight of carbon nanofibers, 3 parts by weight of carbon nanotubes, 0.3 parts by weight of potassium methyl silicate, 0.26 parts by weight of kojic acid, and 1.5 parts by weight of potassium cinnamate were added to 150 parts by weight of SBR-SiO2 composite modified emulsified asphalt, the temperature was kept at 145℃, and stirring was carried out at a speed of 5000-5500r / min for 12min to prepare the SBR-SiO2 composite modified emulsified asphalt mixture.

[0162] Experimental Example 3

[0163] By successfully preparing the semi-flexible pavement height difference repair material in Examples 5 to 7, taking Example 6 as an example, referring to JTG 3420-2020 “Highway Engineering Cement and Cement Concrete Test Regulations”, and testing the compressive strength of the repair materials obtained in Comparative Examples 6 to 8, 3 parallel tests were set for each test group, and the average value was taken. The test results are shown in Table 3:

[0164] Table 3

[0165]

[0166] The results show that the compressive strength of the repair material is obviously improved by adding kojic acid, methyl butynol and potassium cinnamate. This is because when repairing the pavement, the cement-based dry powder mortar and aggregate in the repair material and the SBR-SiO2 composite modified emulsified asphalt two materials play the advantages of cement rigidity, strong bearing capacity and asphalt flexibility, strong load transmission capacity, providing the main carrier for the repair material. The hydroxyl group of kojic acid and the carboxyl group of potassium cinnamate are easy to react with the active groups on nano-silicon dioxide, not only further dispersing kojic acid and potassium cinnamate with emulsified asphalt in the repair material, but also the six-membered heterocyclic ring and benzene ring can improve the mechanical strength of the repair material, thereby improving the compressive strength and durability of the repair material. Methyl butynol can bond with the active groups of carbon nanofibers and carbon nanotubes, improve the dispersibility and stability of carbon nanofibers and carbon nanotubes, and further improve the reaction of carbon nanofibers and carbon nanotubes with Ca(OH)2 to generate more C-S-H gel, occupy the void space and improve the density of the interface transition zone. More cement hydrates are produced, which helps to improve the compatibility between asphalt and cement and the compressive strength of the repair material. The three work together to further improve the compressive strength of the repair material.

[0167] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that; it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A semi-flexible pavement elevation difference repair material, characterized in that, The repair material comprises cement-based dry powder mortar, SBR-SiO2 composite modified emulsified asphalt mixture, aggregate and water in a mass ratio of 1000:(40-140):(800-1000):(110-130); The cement-based dry mortar comprises, by weight, 350-400 parts of rapid-hardening sulfoaluminate cement, 20-40 parts of ordinary Portland cement, 15-30 parts of silica fume, 20-35 parts of gypsum, 1-10 parts of fly ash, 520-580 parts of quartz sand, 10-20 parts of adhesive powder, 2-4 parts of water-reducing agent, 0.0-1.0 parts of lithium carbonate, 0.2-3 parts of boric acid, 0.35-0.85 parts of water-absorbing resin, 0.5-1.0 parts of defoamer, 0.3-1.5 parts of water-retaining agent, and 0.1-0.8 parts of expanding agent. The SBR-SiO2 composite modified emulsified asphalt mixture comprises: 124-170 parts by weight of SBR-SiO2 composite modified emulsified asphalt, 1-5 parts by weight of carbon nanofibers, 1-5 parts by weight of carbon nanotubes, 0.2-0.4 parts by weight of potassium methylsilicate, 0.15-0.26 parts by weight of kojic acid, 0.3-0.85 parts by weight of methylbutyninol and 0.56-1.5 parts by weight of potassium cinnamate; The SBR-SiO2 composite modified emulsified asphalt is obtained by modifying the base asphalt with SBR and nano-SiO2.

2. The semi-flexible pavement elevation difference repair material according to claim 1, characterized in that, The rapid-hardening sulfoaluminate cement is R.SAC42.5 or R.SAC52.5, and the ordinary silicate cement is PO42.5 or PO52.

5.

3. The semi-flexible pavement elevation difference repair material according to claim 1, characterized in that, The aggregate is selected from at least one of limestone, sandstone, and granite.

4. The semi-flexible pavement elevation difference repair material according to claim 3, characterized in that, The aggregate is classified into particle size grades of 0-3mm, 3-5mm, 5-10mm, and 10-15mm; and the aggregate is selected from one or more of the above particle size grades.

5. The semi-flexible pavement elevation difference repair material according to claim 1, characterized in that, The adhesive powder is at least one of ethylene-vinyl acetate copolymer adhesive powder, acrylic polymer adhesive powder, polyethylene oxide adhesive powder, styrene-acrylic adhesive powder, and styrene-butadiene adhesive powder.

6. The semi-flexible pavement elevation difference repair material according to claim 5, characterized in that, The quartz sand is graded by particle size as 10-20 mesh, 20-40 mesh, 40-70 mesh, and 70-140 mesh, wherein the weight parts of 10-20 mesh quartz sand are 385-387 parts, the weight parts of 20-40 mesh quartz sand are 100-106 parts, the weight parts of 40-70 mesh quartz sand are 60-65 parts, and the weight parts of 70-140 mesh quartz sand are 49-52 parts.

7. A method for preparing a semi-flexible pavement elevation difference repair material, characterized in that, The preparation method is used to prepare the semi-flexible pavement elevation difference repair material as described in any one of claims 1-6, and the preparation method includes: (1) Preparation of SBR-SiO2 composite modified emulsified asphalt mixture: (101) Preparation of emulsified asphalt: The base asphalt is heated to 140-150℃ to obtain hot melt asphalt. An emulsifier aqueous solution and a stabilizer are added to the hot melt asphalt and mechanically dispersed to obtain the emulsified asphalt. (102) Preparation of SBR modified emulsified asphalt: Add SBR to the emulsified asphalt, keep the temperature at 140-150℃, and stir for 10-15 minutes at a speed of 5000-5500r / min to obtain the SBR modified emulsified asphalt. (103) Preparation of SBR-SiO2 composite modified emulsified asphalt: Add nano silica to the SBR modified emulsified asphalt, keep the temperature at 140-150℃, and stir at a speed of 5000-5500r / min for 10-15min to obtain the SBR-SiO2 composite modified emulsified asphalt. (104) Preparation of mixture: Carbon nanofibers, carbon nanotubes, potassium methylsilicate, kojic acid, methylbutyninol and potassium cinnamate are added to the SBR-SiO2 composite modified emulsified asphalt. The temperature is maintained at 140-150℃ and the mixture is stirred at a speed of 5000-5500r / min for 10-15min to obtain the SBR-SiO2 composite modified emulsified asphalt mixture. (2) Preparation of cement-based dry powder mortar: The rapid-hardening sulfoaluminate cement, the ordinary silicate cement, the silica fume, the gypsum, the fly ash, the quartz sand, the adhesive powder, the water-reducing agent, the lithium carbonate, the boric acid, the water-absorbing resin, the defoamer, the water-retaining agent and the expansion agent are added to a container according to the weight parts, and stirred and mixed at a speed of 150-200r / min for 15-20min to obtain the cement-based dry powder mortar, and sealed in a moisture-proof packaging bag; (3) Preparation of semi-flexible pavement elevation difference repair material: The cement-based dry powder mortar is added to the mixer according to the weight parts and stirred at a speed of 60-70 r / min for 45-60s. Then the water and the SBR-SiO2 composite modified emulsified asphalt mixture are added and stirred at a speed of 150-200 r / min for 120s. Finally, the aggregate is added and stirred at a speed of 200-1000 r / min for 3-10min to obtain the semi-flexible pavement elevation difference repair material.

8. The method for preparing the semi-flexible pavement elevation difference repair material according to claim 7, characterized in that, The amount of the base asphalt is 100 parts by weight, the amount of the emulsifier aqueous solution is 20-60 parts by weight, the amount of the stabilizer is 2-10 parts by weight, the amount of the SBR is 2-5 parts by weight, and the amount of the nano silica is 2-5 parts by weight.

9. The preparation method of the semi-flexible pavement elevation difference repair material according to claim 8, characterized in that, In the emulsified asphalt preparation step, the mass concentration of the emulsifier in the emulsifier aqueous solution is 1%-30%, and the emulsifier is selected from anionic emulsifiers or cationic emulsifiers.

10. The application of a semi-flexible pavement elevation difference repair material in road and bridge deck elevation difference repair, characterized in that, The elevation difference repair material is the semi-flexible pavement elevation difference repair material according to any one of claims 1-6, or the elevation difference repair material prepared by the method according to any one of claims 7-9.

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