An asphalt mixture, an asphalt composition, a production method and an application

Abstract

The application provides an asphalt mixture, an asphalt composition, a preparation method and application, and components of the asphalt mixture include, by mass fraction, 60-75 parts of steel slag, 15-25 parts of fine aggregate, 6-10 parts of mineral powder and 4-6.5 parts of modified asphalt; raw materials of the modified asphalt include, by mass ratio, asphalt:water:cationic surfactant=100:(1-3):(0.3-0.6). The asphalt mixture prepared by the preparation method provided by the application can more easily fill open surface pores of the steel slag and coat the steel slag, thereby effectively preventing the occurrence of phenomena that water directly contacts with the steel slag 'white material' without being coated with asphalt or water slowly penetrates into the open surface pores of the steel slag during the subsequent use of the asphalt mixture, and damage of the road surface caused by the volume expansion of the steel slag is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of asphalt pavement materials, in particular to an asphalt mixture, an asphalt composition, a preparation method and application. BACKGROUND

[0002] In recent years, sand and gravel aggregates are facing a major gap in the supply end. Steel slag, as a byproduct of steelmaking, its output is 10% to 15% of the crude steel output, the annual steel slag output in China is about 100 million tons, and the steel slag occupies a large amount of land. The application of steel slag instead of natural aggregate in asphalt mixture can reduce the mining of stone materials and save land occupation.

[0003] Steel slag has the characteristics of firmness, wear resistance, and small needle and flake content, and can replace basalt, diabase and other high-quality aggregates to be applied to the upper and middle layers of high-grade highway asphalt pavement to realize high-value utilization of steel slag. However, the conventional asphalt pavement prepared by mixing steel slag and asphalt is prone to water damage.

[0004] In summary, there is an urgent need for an asphalt mixture, an asphalt composition, a preparation method and application to solve the problems existing in the prior art. SUMMARY

[0005] The main purpose of the present application is to provide an asphalt mixture, an asphalt composition, a preparation method and application to solve the technical problems of reducing production efficiency, greatly increasing energy consumption and production cost in related technologies.

[0006] To achieve the above purpose, the present application provides an asphalt mixture, which comprises the following components in parts by mass: steel slag 60-75 parts, fine aggregate 15-25 parts, mineral powder 6-10 parts and modified asphalt 4-6.5 parts; the raw materials of the modified asphalt comprise, by mass ratio: asphalt: water: cationic surfactant = 100: (1-3): (0.3-0.6).

[0007] Preferably, the modified asphalt further comprises an adhesion promoter, which comprises one or more of fatty amide and polyacrylamide; the adhesion promoter is added in an amount of 0.03%-0.1% of the mass of asphalt.

[0008] Preferably, the asphalt comprises SBS modified asphalt or road petroleum asphalt.

[0009] Preferably, when the asphalt is road petroleum asphalt, the raw materials of the modified asphalt comprise, by mass ratio: road petroleum asphalt: water: cationic surfactant: adhesion promoter = 100: 1.5: 0.3: 0.08.

[0010] Preferably, when the asphalt is SBS modified asphalt, the raw materials of the modified asphalt include, by mass ratio, SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100: 2.5: 0.5: 0.05.

[0011] Preferably, the cationic surfactant includes a basic group.

[0012] Preferably, the cationic surfactant includes one or more of cetyl trimethyl ammonium bromide, dialkyldimethylammonium chloride, and octadecyl trimethyl ammonium chloride.

[0013] Preferably, the steel slag has an aging time of 6 months or more.

[0014] Preferably, the steel slag includes a first steel slag, a second steel slag, and a third steel slag; the first steel slag has a gradation of 85-100% passing through a 19mm sieve, and 10-20% passing through a 13.2mm sieve; the second steel slag has a gradation of 85-100% passing through a 13.2mm sieve, and 10-20% passing through a 9.5mm sieve; and the third steel slag has a gradation of 85-100% passing through a 9.5mm sieve, and 10-20% passing through a 4.75mm sieve.

[0015] The present application has the following advantages:

[0016] The asphalt mixture provided by the present application includes steel slag, fine aggregate, mineral powder, and modified asphalt. The asphalt is caused to expand in volume by the combined action of an alkaline foaming agent and water, and the modified asphalt is obtained. The modified asphalt has low surface tension and viscosity, and has good ability to wrap the steel slag and long half-life. Therefore, the asphalt mixture requires a short mixing time during preparation. Moreover, water is not easily transmitted through the asphalt film to the interior of the steel slag to react with free calcium oxide contained in the steel slag, and therefore the asphalt mixture has good stability and good water damage resistance.

[0017] The present application also provides an asphalt composition for preparing the above asphalt mixture, which includes, by mass parts, 60-75 parts of steel slag, 15-25 parts of fine aggregate, 6-10 parts of mineral powder, 4-6.5 parts of asphalt, 0.04-0.195 parts of water, and 0.012-0.024 parts of cationic surfactant; more preferably, the mass of the water is 1-3% of the mass of the asphalt, and the mass of the cationic surfactant is 0.3-0.6% of the mass of the asphalt.

[0018] The asphalt composition provided by the present application can be used to prepare the above asphalt mixture.

[0019] The present application also provides a preparation method for preparing the above asphalt mixture, which includes:

[0020] After mixing the water and the cationic surfactant, the modified asphalt is obtained by mixing and foaming the asphalt heated to 150-170 DEG C;

[0021] The steel slag and the fine aggregate are heated to 145-160 DEG C; the modified asphalt and the mineral powder are added to obtain the asphalt mixture.

[0022] Preferably, the adding process of the modified asphalt and the mineral powder comprises spraying the modified asphalt into the mixture of the steel slag and the fine aggregate, stirring for 10-15 s; adding the mineral powder, stirring for 10-15 s to obtain the asphalt mixture.

[0023] Preferably, the mixing process of the water and the cationic surfactant further comprises adding an adhesion promoter, the adhesion promoter comprising one or more of fatty amide and polyacrylamide.

[0024] Preferably, the raw materials of the modified asphalt comprise, by mass fraction, 100 parts of asphalt, 1-3 parts of water, 0.3-0.6 parts of cationic surfactant and 0.03-0.1 parts of adhesion promoter.

[0025] The present application has the following beneficial effects:

[0026] In the present application, the modified asphalt is added into the asphalt mixture, and the cationic surfactant is added into the modified asphalt to reduce the surface tension of the asphalt, so that the modified asphalt is in a relatively stable state, the decay rate of the modified asphalt is reduced, the half-life of the modified asphalt is prolonged, and there is sufficient time to wrap the steel slag and sufficiently fill the open pore on the surface of the steel slag.

[0027] The present application further provides an application of the asphalt mixture or the asphalt mixture prepared by the preparation method in preparing an asphalt pavement, comprising spreading the asphalt mixture on a surface layer and rolling and forming at 110-130 DEG C.

[0028] The present application has the following beneficial effects:

[0029] Compared with the asphalt in the related art for preparing an asphalt pavement, the mixing, spreading and rolling temperature of the asphalt mixture provided by the present application is reduced by about 20 DEG C than the conventional hot-mixed asphalt mixture, which is beneficial to reduce the construction energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on the drawings shown.

[0031] Figure 1 The effect diagram of foaming of asphalt, water, cationic surfactant and adhesion promoter in an embodiment of the present application.

[0032] Figure 2 The volume attenuation curve of modified asphalt prepared in an embodiment of the present application and Comparative Example 3.

[0033] Figure 3 The effect diagram of coating of steel slag by modified asphalt in Comparative Example 7 of the present application;

[0034] Figure 4 The effect diagram of coating of steel slag by modified asphalt in an embodiment of the present application.

[0035] The purposes, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise that the embodiments in the present application fall within the scope of protection of the present application.

[0037] It should be noted that all directional indications, such as up, down, …, in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0038] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features.

[0039] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0040] The surface porous characteristics of the steel slag affect the wrapping and bonding between the asphalt and the steel slag interface, if the steel slag is not completely wrapped by the asphalt or the open pores on the surface of the steel slag are not sufficiently filled by the asphalt mortar, water is likely to directly contact the steel slag (white material) without asphalt wrapping or slowly penetrate the asphalt film into the open pores on the surface of the steel slag, and then react with the free calcium oxide in the steel slag, causing the volume expansion of the steel slag, thereby causing water damage to the road surface.

[0041] To solve the above problems, the user often prolongs the wet mixing time of the steel slag and the asphalt or optimizes the mixing process to improve the wrapping effect of the asphalt on the steel slag and ensure that the asphalt mortar can sufficiently fill the open pores of the steel slag. However, this treatment method reduces the production efficiency and greatly increases the energy consumption and production cost.

[0042] The present application provides an asphalt mixture to solve the above problems, which comprises, by mass fraction: 60-75 parts of steel slag, 15-25 parts of fine aggregate, 6-10 parts of mineral powder and 4-6.5 parts of modified asphalt; the raw materials of the modified asphalt comprise, by mass ratio: asphalt: water: cationic surfactant = 100: (1-3): (0.3-0.6). Among them, the fine aggregate refers to natural sand, artificial sand (including machine-made sand) and stone chips with a particle size of less than 2.36 mm; the mineral powder refers to the powder obtained by crushing and processing the mined ore.

[0043] The steel slag in the present application has the characteristics of being strong, wear-resistant and having a small content of needle-like particles, and can replace basalt, diabase and other high-quality aggregate in the asphalt mixing components in related technologies and be applied to the upper and middle surface layers of high-grade highway asphalt pavement, so as to realize high-value utilization of the steel slag.

[0044] The cationic surfactant is added to the asphalt mixture provided by the present application, which improves the bonding strength between the asphalt and the steel slag, the alkaline groups in the cationic surfactant and the acidic substances such as SiO2, P2O5 and SO3 contained in the steel slag have a chemical adsorption effect, which enhances the bonding strength between the asphalt and the steel slag and effectively improves the water damage resistance of the steel slag asphalt mixture.

[0045] In the asphalt mixture provided by the present application, the viscosity of the asphalt is significantly reduced after the addition of the cationic surfactant and the mechanical foaming synergistic treatment, which improves the workability of the mixture, thereby reducing the mixing and compaction temperature and greatly reducing the energy consumption and carbon emissions in the production link.

[0046] The asphalt mixture provided by the present application has uniform steel slag, fine aggregate, mineral powder and modified asphalt, solves the technical problem of reducing production efficiency and greatly increasing energy consumption and production cost in the related art, wherein the volume of the asphalt expands sharply under the combined action of the cationic surfactant and water, temporarily reduces the surface tension and viscosity of the asphalt, improves the ability of the asphalt to wrap the steel slag, so that the modified asphalt obtained under the premise of not prolonging the mixing time can more easily fill the open pore on the surface of the steel slag and coat the steel slag, thereby effectively preventing the occurrence of the phenomenon that water directly contacts the steel slag "white material" without asphalt or water slowly penetrates the asphalt film into the open pore on the surface of the steel slag in the subsequent use process of the asphalt mixture, and avoiding the damage of the road surface caused by the volume expansion of the steel slag.

[0047] In some embodiments, the modified asphalt further comprises an adhesion promoter, the adhesion promoter comprises one or more of fatty amide, polyacrylamide; the adhesion promoter is added in an amount of 0.03% to 0.1% of the mass of the asphalt. By adding the adhesion promoter such as fatty amide and polyacrylamide, since the adhesion promoter is rich in non-metallic elements with free electron pairs, such as N (nitrogen), and according to the electron coordination theory, Fe 3+ in the steel slag is a good electron acceptor, by the combination of the non-metallic elements rich in free electron pairs in the adhesion promoter and Fe 3+ in the steel slag, the adhesion between the asphalt and the steel slag is improved, so that the asphalt can firmly coat the steel slag.

[0048] In some embodiments, the asphalt comprises road petroleum asphalt or SBS modified asphalt;

[0049] When the asphalt is road petroleum asphalt, the raw materials of the modified asphalt comprise, by mass ratio: road petroleum asphalt: water: cationic surfactant: adhesion promoter = 100: 1.5: 0.3: 0.08;

[0050] When the asphalt is SBS modified asphalt, the raw materials of the modified asphalt comprise, by mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100: 2.5: 0.5: 0.05.

[0051] By controlling the ratio of road petroleum asphalt (or SBS modified asphalt), water, cationic surfactant and adhesion promoter, most of the asphalt can form a stable chemical connection structure with the steel slag under the combined action of water, cationic surfactant and adhesion promoter, improve the adhesion between the asphalt and the steel slag, that is, the coating effect of the asphalt on the steel slag, and improve the water damage resistance and service life of the asphalt mixture.

[0052] In some embodiments, the cationic surfactant comprises a basic group. By the combination of the basic group in the cationic surfactant with the acidic substances such as SiO2, P2O5 and SO3 contained in the steel slag, the adhesion strength between the asphalt and the steel slag is enhanced, and the acid corrosion caused by the strong acidic substances such as phosphoric acid, sulfuric acid, phosphate and sulfate generated by the reaction between the acidic substances such as SiO2, P2O5 and SO3 and the rainwater after the asphalt mixture is applied to the road construction is reduced.

[0053] In some embodiments, the cationic surfactant comprises one or more of hexadecyl trimethyl ammonium bromide, dialkyldimethyl ammonium chloride and octadecyl trimethyl ammonium chloride.

[0054] The hexadecyl trimethyl ammonium bromide has hygroscopicity, generates a large amount of foam when shaken, and has excellent properties of penetration, softening, emulsification, antistatic, biodegradability and sterilization and algae killing.

[0055] The octadecyl trimethyl ammonium chloride has excellent properties of stability, surface activity, emulsification, sterilization, disinfection, softening and antistatic.

[0056] The dialkyldimethyl ammonium chloride is a colorless or light yellow paste, can be dissolved in non-polar solvents, is generally insoluble in water, has excellent properties of softening and antistatic, and is used as a fabric softener and a textile auxiliary. The dialkyldimethyl ammonium chloride has a certain biodegradability.

[0057] In the present application, the cationic surfactant is not limited, as long as it belongs to the cationic surfactant, can provide a basic group (such as an amino group) to combine with the acidic substances such as SiO2, P2O5 and SO3 in the steel slag, and can reduce the surface tension and viscosity of the asphalt.

[0058] In some embodiments, the aging time of the steel slag is greater than or equal to 6 months. After aging for at least 6 months, the steel slag is broken into different particle sizes, and according to the requirements of subsequent preparation work, the steel slag with a required particle size can be selected for recycling, so that mechanical crushing is avoided and energy consumption is reduced.

[0059] In some embodiments, the steel slag comprises a first steel slag, a second steel slag and a third steel slag; the gradation of the first steel slag is that the passing rate of a 19 mm sieve is 85-100%, and the passing rate of a 13.2 mm sieve is 10-20%; the gradation of the second steel slag is that the passing rate of a 13.2 mm sieve is 85-100%, and the passing rate of a 9.5 mm sieve is 10-20%; and the gradation of the third steel slag is that the passing rate of a 9.5 mm sieve is 85-100%, and the passing rate of a 4.75 mm sieve is 10-20%.

[0060] The steel slag of different gradations is obtained by screening through sieves with different diameters, and is used to replace stone to prepare asphalt mixture, and in the application, the asphalt mixture obtained by selection of the steel slag gradation can be effectively embedded, extruded and compacted when applied to pavement, and the wear resistance and service life of the pavement are improved.It is worth noting that the ratio of the steel slag in each particle size range in the application only needs to meet the specified gradation range (see Table 1, AC represents asphalt concrete).

[0061] Table 1 Steel slag asphalt mixture gradation range

[0062]

[0063] The application also provides an asphalt composition for preparing the above-mentioned asphalt mixture, which comprises, by mass fraction, 60-75 parts of steel slag, 15-25 parts of fine aggregate, 6-10 parts of mineral powder, 4-6.5 parts of asphalt, 0.04-0.195 parts of water and 0.012-0.024 parts of cationic surfactant; in some embodiments, the mass of the water is 1%-3% of the mass of the asphalt, and the mass of the cationic surfactant is 0.3%-0.6% of the mass of the asphalt.

[0064] The application provides an asphalt composition, which can be used to prepare the above-mentioned asphalt mixture.

[0065] The application also provides a preparation method of the above-mentioned asphalt mixture, which comprises:

[0066] The water and the cationic surfactant are mixed, and then are mixed with the asphalt heated to 150-170 DEG C to obtain modified asphalt by foaming;

[0067] The steel slag and the fine aggregate are heated to 145-160 DEG C, and then the modified asphalt and the mineral powder are added to obtain the asphalt mixture.

[0068] In the application, the modified asphalt is added to the asphalt mixture, and the cationic surfactant is added to the modified asphalt to reduce the surface tension of the asphalt, so that the modified asphalt is in a relatively stable state, the decay rate of the modified asphalt is reduced, the half-life of the modified asphalt is prolonged, and when the modified asphalt is subsequently mixed with the steel slag, there is sufficient time to wrap the steel slag, and the surface open pores of the steel slag are sufficiently filled, so that water is effectively prevented from directly contacting the steel slag with no asphalt wrapped thereon or slowly penetrating into the surface open pores of the steel slag through the asphalt film during the use of the subsequent asphalt mixture.

[0069] In the modified asphalt preparation process, the asphalt is heated to 150-170℃, when the heated asphalt is mixed with a small amount of water, the water exchanges heat with the asphalt in the hot atmosphere, rapidly vaporizes, and the water vapor escapes in all directions due to the non-directionality of the gas, causing the asphalt to rapidly expand to tens of times, reducing the surface tension and viscosity of the asphalt, and cooperating with the cationic surfactant to enable the obtained modified asphalt to fully wrap the steel slag and fully fill the open surface pores of the steel slag, effectively preventing water from directly contacting the steel slag (white material) without asphalt or slowly penetrating the asphalt film into the open surface pores of the steel slag during subsequent use of the asphalt mixture.

[0070] Before the modified asphalt is subsequently mixed with the steel slag and fine aggregate, the steel slag and fine aggregate are first mixed uniformly and heated to 145-160℃, so that when the modified asphalt is mixed with the steel slag and fine aggregate, the system temperature does not decrease sharply, thereby avoiding the phenomenon of the surface tension and viscosity of the modified asphalt rising due to the sharp decrease in temperature, causing the modified asphalt to be unable to fully wrap the steel slag or to be unable to fully fill the open surface pores of the steel slag.

[0071] Preferably, the modified asphalt and the addition process of the mineral powder include spraying the modified asphalt into the mixture of the steel slag and the fine aggregate, stirring for 10-15s; adding the mineral powder, stirring for 10-15s, to obtain the asphalt mixture.

[0072] In this way, the asphalt mixture with uniform mixing can be obtained.

[0073] In some embodiments, the mixing process of the water and the cationic surfactant further includes adding an adhesion promoter, and the adhesion promoter includes one or more of fatty amides and polyacrylamide.

[0074] In some embodiments, the raw materials of the modified asphalt include, by mass fraction, 100 parts of asphalt, 1-3 parts of water, 0.3-0.6 parts of cationic surfactant, and 0.03-0.1 parts of adhesion promoter.

[0075] The application also provides an application of the asphalt mixture or the asphalt mixture prepared by the above preparation method in preparing an asphalt pavement, including spreading the asphalt mixture on a surface layer of the asphalt pavement and rolling and forming at 110-130℃. Compared with the asphalt in the related art for preparing an asphalt pavement, the asphalt mixture provided by the application has a lower construction temperature, and the temperature in the mixing, spreading and rolling links can be reduced by 20℃, which is beneficial to reducing the construction energy consumption.

[0076] Embodiment 1

[0077] The preparation method of the asphalt mixture includes:

[0078] The water, cationic surfactant (hexadecyl trimethyl ammonium bromide) and adhesion promoter (fatty amide) are mixed, and then mixed with the SBS modified asphalt heated to 165-170℃ in a foaming device (referring to the related technology) to obtain the modified asphalt.

[0079] The steel slag and fine aggregate are heated to 155-160℃ and dry mixed for 10s; the modified asphalt is sprayed into the mixture of the steel slag and fine aggregate through the nozzle of the foaming device, and stirred for 10s; finally, the mineral powder is added and stirred for 10s to obtain the asphalt mixture.

[0080] In this embodiment, the components of the asphalt mixture include, by mass fraction: 71 parts of steel slag, 18 parts of fine aggregate, 7 parts of mineral powder and 5 parts of modified asphalt. The raw materials of the modified asphalt include, by mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100: 2.5: 0.5: 0.05.

[0081] In this embodiment, the aging time of the steel slag is greater than or equal to 6 months; the steel slag includes first steel slag, second steel slag and third steel slag; the gradation of the first steel slag is: 85-100% passing through a 19mm sieve, and 10-20% passing through a 13.2mm sieve; the gradation of the second steel slag is: 85-100% passing through a 13.2mm sieve, and 10-20% passing through a 9.5mm sieve; the gradation of the third steel slag is: 85-100% passing through a 9.5mm sieve, and 10-20% passing through a 4.75mm sieve.

[0082] In this embodiment, the fine aggregate is 0-4.75mm limestone fine aggregate.

[0083] In this embodiment, the mineral powder is finely ground limestone.

[0084] Example 2: Different from Example 1, the components of the asphalt mixture include, by mass fraction: 60 parts of steel slag, 25 parts of fine aggregate, 10 parts of mineral powder and 6.5 parts of modified asphalt.

[0085] Example 3: Different from Example 1, the components of the asphalt mixture include, by mass fraction: 75 parts of steel slag, 15 parts of fine aggregate, 6 parts of mineral powder and 4 parts of modified asphalt.

[0086] Example 4: Different from Example 1, the modified asphalt does not include fatty amide.

[0087] Example 5: Different from Example 1, the raw materials of the modified asphalt include, by mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100: 1.5: 0.6: 0.08.

[0088] Example 6: Different from Example 1, the raw materials of the modified asphalt include, by mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100:3:0.3:0.03.

[0089] Example 7: Different from Example 1, the raw materials of the modified asphalt include, by mass ratio: road petroleum asphalt: water: cationic surfactant: adhesion promoter = 100:1:0.3:0.1.

[0090] Comparative Example 1: Different from Example 1, the components of the asphalt mixture include, by mass parts: steel slag 50 parts, fine aggregate 25 parts, mineral powder 10 parts, and modified asphalt 6.5 parts.

[0091] Comparative Example 2: Different from Example 1, the components of the asphalt mixture include, by mass parts: steel slag 80 parts, fine aggregate 15 parts, mineral powder 6 parts, and modified asphalt 3.5 parts.

[0092] Comparative Example 3: Different from Example 1, the cetyl trimethyl ammonium bromide is not included in the modified asphalt.

[0093] Comparative Example 4: Different from Example 1, the cetyl trimethyl ammonium bromide and the fatty amide are not included in the modified asphalt.

[0094] Comparative Example 5: Different from Example 1, the raw materials of the modified asphalt include, by mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100:1:0.8:0.2.

[0095] Comparative Example 6: Different from Example 1, the raw materials of the modified asphalt include, by mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100:4:0.2:0.01.

[0096] Comparative Example 7: Different from Example 1, the water, the cetyl trimethyl ammonium bromide and the fatty amide are not included in the modified asphalt.

[0097] The asphalt mixtures prepared in Examples 1-7 and Comparative Examples 1-7 are respectively compacted into molded test pieces.

[0098] Performance test: The above test pieces are respectively subjected to immersion Marshall test and freeze-thaw splitting test according to the “Standard Test Methods of Bitumen and Bituminous Mixtures for Highway Engineering” (JTG E20-2011), and the test results are shown in Table 2.

[0099] Table 2 Evaluation of water damage resistance of the asphalt mixtures prepared in Examples 1-7 and Comparative Examples 1-7

[0100]

[0101]

[0102] As shown in Examples 1-3 and Comparative Examples 1-2, controlling the proportions of the various components in the asphalt mixture can effectively improve the coating effect of modified asphalt on steel slag. Under the same conditions, if the mass fraction of modified asphalt in the asphalt mixture is too high or too low compared to the steel slag, the performance of properties such as Marshall stability, standard Marshall stability, residual stability, splitting strength after freeze-thaw, standard splitting strength, and freeze-thaw splitting strength ratio will decrease significantly after immersion in water. This is because when the mass fraction of modified asphalt in the asphalt mixture is too low compared to the steel slag, the modified asphalt cannot fully coat the surface of the steel slag, which will not effectively prevent water from directly contacting the uncoated steel slag "white residue" or water from slowly penetrating the asphalt film into the open pores on the surface of the steel slag during the subsequent use of the asphalt mixture. The steel slag expands in volume under water erosion, causing the specimen to be damaged and the performance to decline. Conversely, when the mass fraction of modified asphalt in the asphalt mixture is too high compared to the steel slag, the density of the asphalt mixture decreases, leading to a decline in performance.

[0103] As demonstrated in Examples 1, 4, and Comparative Examples 3-4, cationic surfactants significantly influence the heating temperature of steel slag and fine aggregates, as well as the specimen molding temperature. This is because cationic surfactants temporarily reduce the surface tension and viscosity of asphalt, enhancing its ability to coat steel slag. Under the same mixing time, modified asphalt treated with cationic surfactants more easily fills the open pores on the surface of steel slag and coats it, eliminating the need for higher heating temperatures to reduce surface tension and viscosity. This results in better performance of the asphalt mixture. Meanwhile, adhesion promoters (fatty amides) have a certain effect on improving the Marshall stability, standard Marshall stability, residual stability, splitting tensile strength after freeze-thaw cycles, standard splitting tensile strength, and freeze-thaw splitting strength ratio of asphalt mixtures after immersion in water.

[0104] It can be seen from Example 1, Examples 5-7 and Comparative Examples 5-6 that by controlling the ratio between each raw material of the modified asphalt, the wrapping effect of the modified asphalt on the steel slag can be effectively improved. Under the same conditions, when the cationic surfactant and adhesion promoter are controlled within the set range, the wrapping effect of the prepared modified asphalt on the steel slag is better, and the Marshall stability, standard Marshall stability, residual stability, splitting strength after freezing and thawing, standard splitting strength and strength ratio of the freezing and thawing splitting test of the asphalt mixture after immersion are better. When the cationic surfactant is too high compared with the asphalt (SBS modified asphalt or road petroleum asphalt), the asphalt will be excessively foamed, although the volume expansion rate of the asphalt is high, but the half-life is short, and the performance is obviously decreased due to the insufficient wrapping of the steel slag. When the cationic surfactant is too low, the asphalt cannot be fully foamed, and the performance is obviously decreased due to the insufficient wrapping of the steel slag.

[0105] It can be seen from Example 1 and Comparative Example 7 that although the asphalt mixture obtained by directly mixing the asphalt without foaming treatment by the cationic surfactant with the components of the steel slag has good performance in the standard Marshall stability and standard splitting strength, the performance in the Marshall stability after immersion and the splitting strength after freezing and thawing is obviously decreased compared with Example 1. This is because under the same stirring time, the asphalt without foaming treatment by the cationic surfactant cannot effectively wrap the steel slag or cannot fully fill the open pore on the surface of the steel slag.

[0106] In the above technical solution of the present application, the above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method of producing an asphalt mixture, characterized in that, The application relates to a modified asphalt and a preparation method thereof. The water and the cationic surfactant are mixed, and then mixed with the asphalt heated to 150-170 DEG C to foam and obtain the modified asphalt; The steel slag and the fine aggregate are heated to 145-160 DEG C, the modified asphalt and the mineral powder are added to obtain the asphalt mixture; The asphalt mixture comprises the following components in parts by mass: 60-75 parts of the steel slag, 15-25 parts of the fine aggregate, 6-10 parts of the mineral powder and 4-6.5 parts of the modified asphalt; the raw materials of the modified asphalt comprise the following components in mass ratio: asphalt: water: cationic surfactant = 100: (1-3): (0.3-0.6). The raw materials of the modified asphalt further comprise an adhesion promoter, and the adhesion promoter comprises one or more of fatty amide and polyacrylamide; the adhesion promoter is added in an amount of 0.03%-0.1% of the mass of the asphalt.

2. The method of claim 1, wherein, The asphalt comprises road petroleum asphalt or SBS modified asphalt. When the asphalt is road petroleum asphalt, the raw materials of the modified asphalt comprise the following components in mass ratio: road petroleum asphalt: water: cationic surfactant: adhesion promoter = 100: 1.5: 0.3: 0.

08. When the asphalt is SBS modified asphalt, the raw materials of the modified asphalt comprise the following components in mass ratio: SBS modified asphalt: water: cationic surfactant: adhesion promoter = 100: 2.5: 0.5: 0.

05.

3. The method of claim 1, wherein the asphalt mixture is prepared by a method comprising: The cationic surfactant comprises an alkaline group.

4. The method of claim 3, wherein the asphalt mixture is prepared by a method comprising: The cationic surfactant comprises one or more of cetyltrimethylammonium bromide, dialkyldimethylammonium chloride and octadecyltrimethylammonium chloride.

5. The method of claim 1, wherein, The steel slag comprises a first steel slag, a second steel slag and a third steel slag; the first steel slag has a gradation of 85-100% of 19mm sieve hole passing rate and 10-20% of 13.2mm sieve hole passing rate; the second steel slag has a gradation of 85-100% of 13.2mm sieve hole passing rate and 10-20% of 9.5mm sieve hole passing rate; and the third steel slag has a gradation of 85-100% of 9.5mm sieve hole passing rate and 10-20% of 4.75mm sieve hole passing rate.

6. The method of claim 1, wherein, The adding process of the modified asphalt and the mineral powder comprises spraying the modified asphalt into the mixture of the steel slag and the fine aggregate, stirring for 10-15s, adding the mineral powder and stirring for 10-15s to obtain the asphalt mixture.

7. An asphalt mixture characterized in that, The asphalt mixture is prepared according to the preparation method of the asphalt mixture in any one of claims 1-6.

8. Use of the bituminous mixture prepared according to the process of any one of claims 1 to 6 for the preparation of bituminous pavements, characterized in that, The asphalt mixture is spread on a bituminous pavement surface layer and rolled and formed at 110-130 DEG C.

Images