阅读说明：本技术 一种磁粉改性沥青混合料及其制备方法 (Magnetic powder modified asphalt mixture and preparation method thereof ) 是由 不公告发明人 于 2020-08-06 设计创作，主要内容包括：本发明公开了一种磁粉改性沥青混合料及其制备方法,即将传统沥青混合料中的部分矿粉和细集料组分采用磁粉替代而制成,其各组分质量分数为：磁粉0.1％～50.0％,沥青2.0％～15.0％,集料40.0％～95.0％,矿粉0.0％～40.0％,纤维0.0％～1.0％,表面活性剂0.0％～1.0％。本发明的磁粉改性沥青混合料主要用于钢桥面铺装,并与防腐层、防水粘结层和缓冲层等共同组成铺装体系。铺装完成后,通过外加磁场对磁粉充磁使混合料铺装层磁化,以达到磁致硬化效果,从而在传统铺装体系物化粘结的基础上,额外增加铺装层混合料与钢桥面板之间的磁力粘结,并降低刚度差异,增强钢桥面铺装体系的层间结合和变形追从性。该磁粉改性沥青混合料还可用于路面内部缺陷自诊断等技术。(The invention discloses a magnetic powder modified asphalt mixture and a preparation method thereof, namely, the magnetic powder modified asphalt mixture is prepared by replacing part of mineral powder and fine aggregate components in the traditional asphalt mixture by magnetic powder, and the mass fractions of the components are as follows: 0.1 to 50.0 percent of magnetic powder, 2.0 to 15.0 percent of asphalt, 40.0 to 95.0 percent of aggregate, 0.0 to 40.0 percent of mineral powder, 0.0 to 1.0 percent of fiber and 0.0 to 1.0 percent of surfactant. The magnetic powder modified asphalt mixture is mainly used for paving steel bridge surfaces, and forms a paving system together with an anticorrosive layer, a waterproof bonding layer, a buffer layer and the like. After pavement is finished, the magnetic powder is magnetized through the external magnetic field, so that the mixed material pavement layer is magnetized, the magneto-hardening effect is achieved, the magnetic adhesion between the mixed material of the pavement layer and the steel bridge deck is additionally increased on the basis of the physical and chemical adhesion of a traditional pavement system, the rigidity difference is reduced, and the interlayer bonding and deformation following performance of the steel bridge deck pavement system are enhanced. The magnetic powder modified asphalt mixture can also be used for the self-diagnosis of the internal defects of the pavement and other technologies.)

1. The magnetic powder modified asphalt mixture is characterized in that: the method comprises the following steps of substituting part of mineral powder and fine aggregate components in the traditional asphalt mixture by magnetic powder to prepare a magnetic powder modified asphalt mixture, wherein the mass fractions of the components are as follows: 0.1 to 50.0 percent of magnetic powder, 2.0 to 15.0 percent of asphalt, 40.0 to 95.0 percent of aggregate, 0.0 to 40.0 percent of mineral powder, 0.0 to 1.0 percent of fiber and 0.0 to 1.0 percent of surfactant.

2. The magnetic powder modified asphalt mixture according to claim 1, wherein: the magnetic powder is one or more of millimeter-scale, micron-scale or nanometer-scale neodymium iron boron magnetic powder, barium ferrite magnetic powder, strontium ferrite magnetic powder, ferroferric oxide magnetic powder, carbonyl iron powder and alnico magnetic powder, which can be uniformly dispersed in asphalt and asphalt mixture thereof, and is magnetic after magnetization and magnetic particles which are not easy to demagnetize.

3. The magnetic powder modified asphalt mixture according to claim 1, wherein: the asphalt can be any one or more of asphalt of common road petroleum asphalt, polymer modified asphalt, natural asphalt modified asphalt and composite modified asphalt.

4. The magnetic powder modified asphalt mixture according to claim 1, wherein: the fiber can be any one or more of lignin fiber, acrylic fiber, polyester fiber and mineral fiber, and is suitable for asphalt mixture with stabilizing and reinforcing effects.

5. The magnetic powder modified asphalt mixture according to claim 1, wherein: the surfactant is any one or more of coupling agent, stearic acid surfactant, fatty acid surfactant or emulsion.

6. The magnetic powder according to claim 2, wherein: after the magnetic powder is activated by the surfactant, the magnetic powder can be uniformly dispersed into the asphalt and the asphalt mixture thereof to form activated magnetic powder.

7. The method for preparing a magnetic powder modified asphalt mixture according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:

s1, preparing a surfactant into a solution according to a mass ratio, wherein a solvent can be absolute ethyl alcohol, kerosene, a hydrocarbon solvent, turpentine or an acetone solvent;

s2, putting the magnetic powder into the prepared surfactant solution according to the mass ratio, uniformly stirring, and ensuring that the surface of the magnetic powder is fully and uniformly wrapped by the surfactant to form a mixed solution of the magnetic powder and the surfactant solution;

s3, putting the magnetic powder mixed solution into a dryer for drying to constant weight to obtain activated magnetic powder;

s4, drying the aggregate to ensure that the water content of the dried aggregate is not more than 1%;

s5, uniformly mixing the activated magnetic powder and mixed filler consisting of mineral powder according to a mass ratio;

s6, heating the aggregate and the mixed filler at the temperature of 155-190 ℃;

s7, heating the asphalt at the temperature of 135-175 ℃ to a molten state;

s8, dry-mixing the aggregate in a mixer at a temperature of 140-175 ℃ according to the mass ratio;

s9, pouring melted asphalt into the stirred aggregate according to the mass ratio and uniformly stirring;

s10, according to the mass ratio, adding the granular fibers into the aggregate in the step S8 to be dry-mixed together with the aggregate, and adding the flocculent fibers into the aggregate in the step S9 to be wet-mixed together with the asphalt;

s11, adding the mixed filler preheated in the step S6 into the mixed material according to the mass ratio and stirring to obtain a magnetic powder modified asphalt mixture;

s12, magnetizing the prepared magnetic powder modified asphalt mixture to prepare the magnetic powder modified asphalt mixture.

8. The method for preparing a magnetic powder modified asphalt mixture according to claim 7, wherein the method comprises the following steps: the magnetizing mode in step S12 may be implemented by a capacitive pulse magnetizing apparatus, a pulse magnetizing apparatus without energy storage, or a constant current magnetizing apparatus.

Technical Field

The invention relates to a magnetic powder modified asphalt mixture and a preparation method thereof, which can be applied to an asphalt mixture pavement layer of a steel bridge deck pavement system and also can be applied to asphalt mixtures with technical requirements on self-diagnosis of internal defects of asphalt pavements and the like, and belongs to the technical field of building materials.

Background

With the rapid development of the traffic industry in China, the construction of large-span bridges is more and more. The orthotropic steel bridge deck plate box girder system has the advantages of light dead weight, strong lateral wind resistance, convenience in transportation and erection, better spatial structure stress performance, shorter construction period and the like, and is widely applied to modern bridge construction, particularly large-span bridge construction. Meanwhile, the pavement of the steel bridge deck is one of key technologies for the construction of the large-span steel box girder bridge, and is always highly concerned and valued by the academic and engineering communities at home and abroad.

The asphalt concrete has the advantages of light weight, strong deformation coordination capability, good bonding performance with the steel bridge deck, convenient maintenance, comfortable driving and the like, and becomes a preferred pavement system form of the orthotropic steel bridge deck. The steel bridge surface asphalt concrete pavement system is directly paved on an orthotropic steel bridge deck, and because the orthotropic steel bridge deck has high flexibility, under the combined action of natural factors such as travelling load, temperature change, wind load, earthquake and the like, the stress and deformation of the steel bridge surface asphalt concrete pavement system are much more complicated than the stress and deformation of the steel bridge surface asphalt concrete pavement system under the combined action of natural factors such as travelling load, temperature change, wind load, earthquake and the like, and the working environment is more severe, so that the early damage phenomena such as pushing, rutting, delamination, fatigue cracking and the like of an asphalt pavement layer of the steel bridge surface are easily generated. Therefore, the steel bridge deck asphalt pavement technology is still a worldwide technical problem which is not well solved so far.

The steel bridge deck asphalt pavement system generally comprises an anticorrosive layer, a waterproof bonding layer, a buffer layer and an asphalt mixture pavement layer, and is directly paved on a steel bridge roof. A large number of researches and applications show that the cohesiveness and rigidity difference between the steel bridge deck asphalt pavement layer and the steel bridge deck are key factors influencing the deformation following performance between the steel bridge deck asphalt pavement layer and the steel bridge deck, so that the asphalt pavement layer is required to have good adaptability for following the deformation of the steel bridge deck and cannot generate excessive displacement deformation under the action of high temperature and driving load. Therefore, the selection of the asphalt pavement layer mixture with excellent performance has important significance for preventing the damage of an asphalt pavement system of a steel bridge deck.

At present, asphalt mixtures for paving steel bridge decks at home and abroad are widely applied to asphalt mastic macadam mixtures (SMA), cast asphalt mixtures (GA) and epoxy asphalt mixtures (EA). Therefore, the magnetic powder is doped into the steel bridge deck pavement asphalt mixture to prepare a magnetic powder modified asphalt mixture pavement layer, so that the performance of the asphalt mixture is improved, and the rigidity of the pavement layer is improved; meanwhile, the magnetic powder is magnetized through an external magnetic field, the magnetic bonding effect is increased, the bonding force between the asphalt mixture pavement layer and the steel bridge deck is enhanced, the rigidity of the pavement layer is further improved by utilizing the magnetic hardening effect, the integrity, the interlayer bonding strength and the deformation following performance of the traditional steel bridge deck asphalt pavement structure are further improved under the combined enhancement effect of the magnetic bonding and the magnetic hardening, and the pavement performance and the durability of the traditional steel bridge deck asphalt pavement structure are improved.

Disclosure of Invention

In order to achieve the above purpose, the invention adopts the following technical scheme:

the invention relates to a magnetic powder modified asphalt mixture prepared from magnetic powder, asphalt, mineral aggregate and the like, which is characterized in that: the method comprises the following steps of substituting part of mineral powder and fine aggregate components in the traditional asphalt mixture by magnetic powder to prepare a magnetic powder modified asphalt mixture, wherein the mass fractions of the components are as follows: 0.1 to 50.0 percent of magnetic powder, 2.0 to 15.0 percent of asphalt, 40.0 to 95.0 percent of aggregate, 0.0 to 40.0 percent of mineral powder, 0.0 to 1.0 percent of fiber and 0.0 to 1.0 percent of surfactant.

Furthermore, the magnetic powder is one or more of millimeter-scale, micron-scale or nanometer-scale neodymium iron boron magnetic powder, barium ferrite magnetic powder, strontium ferrite magnetic powder, ferroferric oxide magnetic powder, carbonyl iron powder and alnico magnetic powder, which can be uniformly dispersed in asphalt and asphalt mixture thereof, and is magnetic after magnetization and magnetic particles which are not easy to demagnetize.

Further, the asphalt can be any one or more of asphalt of common road petroleum asphalt, polymer modified asphalt, natural asphalt modified asphalt and composite modified asphalt.

Furthermore, the fiber can be any one or more of lignin fiber, acrylic fiber, polyester fiber and mineral fiber, and is suitable for asphalt mixture fibers with stabilizing and reinforcing functions.

Further, the surfactant is any one or more combined surfactants of a coupling agent, a stearic acid surfactant, a fatty acid surfactant or an emulsion.

Furthermore, the magnetic powder can be uniformly dispersed into asphalt and asphalt mixture thereof after being subjected to surface modification and activation by a surfactant and the like to form activated magnetic powder.

The preparation method of the magnetic powder modified asphalt mixture comprises the following steps:

s1, preparing a surfactant into a solution according to a mass ratio, wherein a solvent can be absolute ethyl alcohol, kerosene, a hydrocarbon solvent, turpentine or an acetone solvent;

s2, putting the magnetic powder into the prepared surfactant solution according to the mass ratio, uniformly stirring, and ensuring that the surface of the magnetic powder is fully and uniformly wrapped by the surfactant to form a mixed solution of the magnetic powder and the surfactant solution;

s3, putting the magnetic powder mixed solution into a dryer for drying to constant weight to obtain activated magnetic powder;

s4, drying the aggregate to ensure that the water content of the dried aggregate is not more than 1%;

s5, uniformly mixing the activated magnetic powder and mixed filler consisting of mineral powder according to a mass ratio;

s6, heating the aggregate and the mixed filler at the temperature of 155-190 ℃;

s7, heating the asphalt at the temperature of 135-175 ℃ to a molten state;

s8, dry-mixing the aggregate in a mixer at a temperature of 140-175 ℃ according to the mass ratio;

s9, pouring melted asphalt into the stirred aggregate according to the mass ratio and uniformly stirring;

s10, according to the mass ratio, adding the granular fibers into the aggregate in the step S8 to be dry-mixed together with the aggregate, and adding the flocculent fibers into the aggregate in the step S9 to be wet-mixed together with the asphalt;

s11, adding the mixed filler preheated in the step S6 into the mixed material according to the mass ratio and stirring to obtain a magnetic powder modified asphalt mixture;

s12, magnetizing the prepared magnetic powder modified asphalt mixture to prepare the magnetic powder modified asphalt mixture.

Furthermore, the magnetic powder modified asphalt mixture can be magnetized by adopting a capacitive pulse magnetizing machine, a non-energy-storage pulse magnetizing machine or a constant-current magnetizing machine.

Compared with the prior art, the invention has the advantages that:

the magnetic powder modified asphalt mixture is prepared and applied to the asphalt pavement layer of the steel bridge deck, and the preparation process is reasonable, economical and durable. Compared with the traditional steel bridge deck asphalt pavement mixed material layer, the invention can comprehensively improve the performance of the asphalt mixed material pavement layer and improve the overall strength of the pavement layer; meanwhile, the magnetizing machine is used for magnetizing the magnetic powder through an external magnetic field, the magnetic bonding effect is increased, the bonding force between the asphalt mixture pavement layer and the steel bridge deck is enhanced, the powder modification and magnetic hardening effects are utilized to further improve the rigidity of the pavement layer, so that the integrity, the interlayer bonding strength and the deformation following performance of the traditional steel bridge deck asphalt pavement structure are further improved under the comprehensive enhancement effect of the powder modification, the magnetic bonding and the magnetic hardening, and the pavement performance and the durability of the traditional steel bridge deck asphalt pavement structure are improved. Meanwhile, according to the performance characteristics of the magnetic powder modified asphalt mixture, the magnetic powder modified asphalt mixture can also be used for the self-diagnosis of the internal defects of the pavement and other technologies.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a preparation process of the magnetic powder modified asphalt mixture and the preparation method thereof.

Detailed Description

The present invention will be described in detail with reference to examples, which are only preferred embodiments of the present invention and are not intended to limit the present invention.

Fig. 1 shows an embodiment of a magnetic powder modified asphalt mixture and a preparation method thereof, and the magnetic powder modified asphalt mixture of the embodiment is characterized in that: the grading type is SMA-10; the selected magnetic powder is neodymium iron boron magnetic powder with the particle size of 100 microns; the surfactant is a silane coupling agent Si 69; the asphalt is SBS modified asphalt; the aggregate is diabase aggregate: the particle size of the fine aggregate is 0-3 mm, and the particle size of the coarse aggregate is 3-5 mm and 5-10 mm; the mineral powder is limestone mineral powder; the fiber is lignin fiber.

According to Marshall test design, the optimal asphalt dosage of the SMA-10 is determined to be 6.0%, 2.0% of neodymium iron boron magnetic powder is adopted to replace mineral powder, the SMA-10 neodymium iron boron magnetic powder modified asphalt mixture is manufactured and magnetized according to the optimal asphalt dosage, and meanwhile, the performance of the SMA-10 modified asphalt mixture is compared with that of the SMA-10 modified asphalt mixture which is not doped with magnetic powder.

The SMA-10 modified asphalt mixture A not doped with the magnetic powder comprises the following raw materials in parts by mass: 6.0 percent of SBS modified asphalt, 15.9 percent of fine aggregate with the thickness of 0-3 mm, 20.6 percent of coarse aggregate with the thickness of 3-5 mm, 47.7 percent of coarse aggregate with the thickness of 5-10 mm, 9.4 percent of mineral powder and 0.4 percent of lignin fiber. The SMA-10 NdFeB magnetic powder modified asphalt mixture B comprises the following raw materials in percentage by mass: 1.83% of neodymium iron boron magnetic powder, 690.04% of silane coupling agent, 6.0% of SBS modified asphalt, 15.9% of fine aggregate with the thickness of 0-3 mm, 20.6% of coarse aggregate with the thickness of 3-5 mm, 47.7% of coarse aggregate with the thickness of 5-10 mm, 7.53% of mineral powder and 0.4% of lignin fiber.

The preparation method of the SMA-10 NdFeB magnetic powder modified asphalt mixture B comprises the following steps:

s1, the dosage of the Si69 silane coupling agent is 2 percent of the dosage of the neodymium iron boron magnetic powder, and the Si69 silane coupling agent is added according to the mass ratio m₁(Si69 silane coupling agent): m₂(water) m₃(ethanol) is fully hydrolyzed for 2 hours at the ratio of 1: 20 to prepare a coupling agent solution;

s2, mixing the neodymium iron boron magnetic powder according to a mass ratio m₄M of neodymium-iron-boron magnetic powder₁(Si69 silane coupling agent) is put into the prepared silane coupling agent solution at the ratio of 50: 1, and is stirred uniformly, so that the surface of the neodymium iron boron magnetic powder is fully and uniformly wrapped by the coupling agent, and mixed solution of the neodymium iron boron magnetic powder and the coupling agent solution is formed;

s3, putting the mixed liquid of the neodymium iron boron magnetic powder into a dryer to be dried to constant weight, and obtaining activated neodymium iron boron magnetic powder;

s4, drying the coarse and fine aggregates to ensure that the water content of the dried aggregates is not more than 1%;

s5, uniformly mixing the activated neodymium-iron-boron magnetic powder and mixed filler consisting of mineral powder according to a mass ratio;

s6, heating the aggregate and the mixed filler at the temperature of 180 ℃;

s7, heating SBS modified asphalt at 175 ℃ to be in a melting state;

s8, dry-mixing the coarse aggregate and the fine aggregate in a mixer according to the mass ratio at the temperature of 170 ℃;

s9, adding SBS modified asphalt and lignin fiber into the stirred aggregate according to the mass ratio for wet mixing;

s10, adding the mixed filler preheated in the step S6 into the mixed material according to the mass ratio and uniformly stirring to obtain an SMA neodymium iron boron magnetic powder modified asphalt mixture B;

s11, magnetizing the prepared SMA neodymium iron boron magnetic powder modified asphalt mixture B by using a high-pressure pulse type magnetizer to prepare a magnetic SMA neodymium iron boron magnetic powder modified asphalt mixture C.

The preparation method of the SMA-10 modified asphalt mixture A not doped with the magnetic powder comprises the following steps:

s1, drying coarse and fine aggregates to ensure that the water content of the dried aggregates is not more than 1%;

s2, heating the coarse and fine aggregates and the mineral powder at the temperature of 180 ℃;

s3, heating SBS modified asphalt at 175 ℃ to be in a melting state;

s4, dry-mixing the coarse aggregate and the fine aggregate in a mixer according to the mass ratio at the temperature of 170 ℃;

s5, adding SBS modified asphalt and lignin fiber into the stirred aggregate according to the mass ratio for wet mixing;

s6, adding the mineral powder preheated in the step S2 into the mixed material and uniformly stirring to obtain the SMA modified asphalt mixture A without the magnetic powder.

The tests of rutting, soaking Marshall, freeze-thaw splitting, low-temperature bending, flexural tensile modulus, water seepage, construction depth, drawing and shearing of a steel bridge deck pavement model and the like are respectively carried out on the SMA modified asphalt mixture A, B and the C test piece, and the corresponding test results are shown in Table 1.

Table 1 performance test data for three SMA-10 modified asphalt mixtures according to the examples of the present invention.

As can be seen from Table 1, after the neodymium iron boron magnetic powder is mixed into the SMA-10 modified asphalt mixture instead of the mineral powder, the high-temperature performance, the water stability, the mechanical property and the bonding property of the neodymium iron boron magnetic powder are obviously improved, the anti-permeability and anti-skid properties are not changed greatly, but the low-temperature performance is reduced. Meanwhile, compared with the performance of the asphalt mixture B before magnetization, the performance of the SMA-10 NdFeB magnetic powder modified asphalt mixture C after magnetization has similar improvement effect, and the improvement effect is obviously improved, particularly the bonding performance is improved by about 50%, and the effect is obvious. The magnetic powder can replace the mineral powder to be mixed into the asphalt mixture, and can play the roles of powder modification, magnetic bonding and magnetic hardening, and can be used for an asphalt pavement layer of a steel bridge deck, and the bonding performance and the deformation following performance of the asphalt pavement layer can be obviously improved.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Any person skilled in the art can make many possible variations to the technical solution of the present invention using the technical contents disclosed above without departing from the scope of the technical solution of the present invention, such as changing the asphalt type and the grading type of the asphalt mixture and changing the type, the blending ratio and the mode of the magnetic powder, etc., which are common variations of the present invention, and the detailed description is not repeated here. Therefore, any simple modification of the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical solution of the present invention.