Emulsified asphalt steel slag ultra-thin overlay mixture, preparation method and application thereof

Abstract

The application discloses an emulsified asphalt steel slag ultrathin surface mixture and a preparation method and application thereof, and relates to the technical field of road building materials. The emulsified asphalt steel slag ultrathin surface mixture comprises mineral aggregate, emulsified asphalt and cement; the mineral aggregate comprises 5-10mm modified steel slag aggregate with a proportion of 30-35%, 0-5mm limestone aggregate with a proportion of 60-70% and limestone powder with a proportion of 1-3%; the preparation of the modified steel slag comprises the following steps: firstly, the steel slag is preliminarily treated by CO2 gas; secondly, the steel slag is soaked by cement slurry; thirdly, the steel slag is soaked by mercapto silane coupling agent; fourthly, the surface of the steel slag is sprayed by methyl phenyl silicone resin so that the steel slag is coated with hydrophobicity; and finally, the steel slag is sprayed by epoxy soybean oil. The steel slag is modified, and the mineral aggregate gradation is optimized, so that the ultrathin surface mixture prepared by the emulsified asphalt steel slag ultrathin surface mixture is durable, anti-skid, anti-cracking, waterproof, stable in structure and strong in overall cohesion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road construction materials, in particular to an emulsified asphalt steel slag ultra-thin overlay mixture and a preparation method and application thereof. BACKGROUND

[0002] Under the repeated action of load, cracks, lack of fine aggregate, and different degrees of disease such as wear of coarse aggregate will appear on the pavement. In order to further inhibit the development of the disease and prevent the occurrence of structural disease, preventive maintenance techniques such as ultra-thin overlay and micro-surfacing are generally used for pre-maintenance to prolong the service life of the road and save maintenance costs.

[0003] Steel slag is a product of primary steel smelting process and is a steel smelting industrial waste. The annual output in China exceeds 100 million tons, but the comprehensive utilization rate is only about 20%. A large amount of accumulated steel slag not only causes resource waste but also causes environmental pollution. Steel slag is generally alkaline, has a rough and porous structure, is rich in corners, and has high strength and wear resistance, so it is a road construction material with high utilization value. In order to improve the comprehensive utilization rate of steel slag, there is currently a method of using steel slag to replace natural high-quality aggregate and applying it to asphalt concrete. This method not only solves the use of steel slag waste but also reduces the amount of natural stone resources used, which is an ideal substitute for natural aggregate. However, the utilization efficiency of steel slag in road construction is still not high enough. The main reason is that it contains a certain amount of free calcium oxide and magnesium oxide, which can easily expand in water and cause cracking of the asphalt pavement, which limits the efficient use of steel slag.

[0004] In the prior art, there are many methods to solve the water swelling of steel slag. For example, patent CN 114835439 B discloses soaking steel slag in a silicone waterproof agent to coat the surface of the steel slag with a hydrophobic film, and patent CN 113563010 B discloses treating steel slag with epoxy resin, long-chain diluent, polyether amine, polyurethane-based prepolymer, and curing agent to coat the surface of the steel slag with a hydrophobic film to solve the water absorption and swelling problem. However, if the hydrophobic film is used for a long time, the amount of water is large, or the steel slag is soaked in water for a long time, the calcium oxide and magnesium oxide in the steel slag will absorb water and dissolve, causing the film to expand and break, which will affect the use effect. At the same time, some hydrophobic films will also reduce the bonding performance of steel slag and asphalt, especially in the construction of cold-mixed and cold-paved ultra-thin overlay, which is prone to engineering problems such as insufficient adhesion of asphalt-aggregate and difficulty in compaction of the mixture, resulting in loose and rutting diseases in the early stage of opening to traffic of the asphalt pavement. Therefore, it is necessary to modify and optimize the emulsified asphalt steel slag ultra-thin overlay mixture to enhance the durability of the road performance and use performance of the cold-mixed and cold-paved ultra-thin overlay. SUMMARY

[0005] In view of the above deficiencies, the present application provides an emulsified asphalt steel slag ultra-thin overlay mixture and a preparation method and application thereof, the ultra-thin overlay mixture prepared by the mixture is durable, anti-skid, anti-cracking, waterproof, structurally stable, and has strong overall cohesion. The specific technical solutions are as follows.

[0006] An emulsified asphalt steel slag ultra-thin overlay mixture, comprising the following components by mass fraction: 100 parts of mineral aggregate, 7-11 parts of emulsified asphalt, and 1-3 parts of cement;

[0007] When the mineral aggregate passes through 9.5mm, 4.75mm, 2.36mm, 1.18mm, 0.6mm, 0.3mm, 0.15mm, and 0.075mm aperture departmental standard square hole sieves, the corresponding passing ratios are 100%, 70%-90%, 45%-70%, 28%-50%, 19%-34%, 12%-25%, 7%-18%, 7%-18%, and 6%-12%, respectively.

[0008] The mineral aggregate is divided into three groups of materials according to particle size: the first group is 5-10mm modified steel slag aggregate; the second group is 0-5mm limestone aggregate; and the third group is limestone powder; the first group of aggregate accounts for 30-35% of the mass of the mineral aggregate, the second group of aggregate accounts for 60-70% of the mass of the mineral aggregate, and the third group of powder accounts for 1-3% of the mass of the mineral aggregate.

[0009] Further, the preparation method of the modified steel slag aggregate is as follows:

[0010] Step 1, first immerse the steel slag aggregate in water, heat to 60-70℃ after complete immersion, then stir while introducing carbon dioxide into the water, react for 3-5h, filter, immerse the filtered steel slag aggregate in a cement slurry with a mass concentration of 30-40% for 1-2h, filter, and obtain pretreated steel slag aggregate;

[0011] Step 2, first immerse the pretreated steel slag aggregate in a mercapto silane coupling agent ethanol solution for 20-30min, dry at 60-70℃ until the water content is 5-8%, then spray methyl phenyl silicone resin with a solid content of 10-20%, and cure at 150-180℃ for 10-15min to obtain steel slag aggregate coated with a hydrophobic layer;

[0012] Step 3, spray epoxy soybean oil on the steel slag aggregate coated with a hydrophobic layer to obtain the modified steel slag aggregate.

[0013] Further, in step 1, the carbon dioxide concentration is 20-30%, and the flow rate is 2-5L / min.

[0014] Further, in step 2, the mass concentration of the mercapto silane coupling agent ethanol solution is 5-9wt%.

[0015] Further, in step 3, the amount of the epoxy soybean oil is 0.1-0.5% of the weight of the steel slag aggregate coated with the hydrophobic layer.

[0016] Further, the emulsified asphalt comprises the following components by weight percentage: 80-90% of base asphalt, 1-3% of SBS modifier, 1-3% of emulsifier, 6-8% of SBR latex, 0.2-0.5% of NaCl stabilizer and 2-3% of warm-mixing agent.

[0017] Further, the preparation method of the emulsified asphalt is as follows:

[0018] (1) each component is weighed by weight percentage, the emulsifier is added into water at 60-70℃ and stirred, hydrochloric acid is added to adjust pH to 2-3 while stirring, after the emulsifier is completely dissolved, the SBR latex is added and mixed, pH is continuously adjusted to 2-3, and a soap solution is obtained;

[0019] (2) the base asphalt is heated to 180-200℃, the SBS modifier is added, high-speed shearing is carried out at 3000-5000 revolutions / min for 30-40 min, and then the modified asphalt is developed at 180-200℃ for 3-5 h;

[0020] (3) the soap solution, the modified asphalt, the NaCl stabilizer and the warm-mixing agent are added into a colloid mill for shearing and grinding, and then the emulsified asphalt is obtained after cooling.

[0021] The application further provides a preparation method of the emulsified asphalt steel slag ultra-thin surface mixture, which comprises the following steps: the mineral aggregate, the emulsified asphalt and the cement are weighed by weight percentage and uniformly mixed, and 5-8% of water by weight of the mineral aggregate is added and mixed for 80-90 s, and the emulsified asphalt steel slag ultra-thin surface mixture is obtained.

[0022] The application further provides an application of the emulsified asphalt steel slag ultra-thin surface mixture in road maintenance.

[0023] Further, when the mixture is used for road maintenance, the construction temperature is normal temperature, the compaction thickness is 0.7-1.0 cm, the mixture is paved for 2 hours, and then the pavement is rolled 1-3 times by a rubber-tired road roller, and the traffic can be opened.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] The present application is related to the standards and technical requirements of preventive maintenance seal coat, by modifying the steel slag, optimizing the preparation method of emulsified asphalt, the ultra-thin overlay prepared by the mixture is durable anti-skid, anti-cracking waterproof, stable structure and strong overall cohesion. Among them, the compatibility of each material in the emulsified asphalt is improved by the combination of high-speed shearing and colloid mill, so that the prepared emulsified asphalt has good stability and high viscosity, and the bonding performance with the mineral aggregate is improved; at the same time, when the steel slag aggregate is modified, carbon dioxide is introduced into the mixture of steel slag and water, part of the free calcium oxide in the steel slag is changed into calcium carbonate which does not absorb water, the volume expansion rate of the steel slag is reduced, and the film rupture caused by water absorption expansion is prevented, then the steel slag is soaked in cement slurry, the pores in the steel slag are filled and closed, the water absorption of the steel slag aggregate is reduced, after the pretreatment of the steel slag, the steel slag aggregate is coated with mercapto silane coupling agent and methyl phenyl silicone resin, which further reduces the water absorption of the steel slag aggregate, then the epoxy soybean oil is sprayed on the surface of the steel slag, one end of the epoxy soybean oil is connected with the hydrophobic film, and the other end is anchored with asphalt through van der waals force, which improves the cohesion between asphalt and steel slag aggregate, and solves the problems of insufficient adhesion of asphalt-hydrophobic modified steel slag aggregate and difficulty in compaction of the mixture. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the following embodiment description will be briefly introduced.

[0027] Figure 1 The present application is related to the standards and technical requirements of preventive maintenance seal coat, by modifying the steel slag, optimizing the preparation method of emulsified asphalt, the ultra-thin overlay prepared by the mixture is durable anti-skid, anti-cracking waterproof, stable structure and strong overall cohesion. Among them, the compatibility of each material in the emulsified asphalt is improved by the combination of high-speed shearing and colloid mill, so that the prepared emulsified asphalt has good stability and high viscosity, and the bonding performance with the mineral aggregate is improved; at the same time, when the steel slag aggregate is modified, carbon dioxide is introduced into the mixture of steel slag and water, part of the free calcium oxide in the steel slag is changed into calcium carbonate which does not absorb water, the volume expansion rate of the steel slag is reduced, and the film rupture caused by water absorption expansion is prevented, then the steel slag is soaked in cement slurry, the pores in the steel slag are filled and closed, the water absorption of the steel slag aggregate is reduced, after the pretreatment of the steel slag, the steel slag aggregate is coated with mercapto silane coupling agent and methyl phenyl silicone resin, which further reduces the water absorption of the steel slag aggregate, then the epoxy soybean oil is sprayed on the surface of the steel slag, one end of the epoxy soybean oil is connected with the hydrophobic film, and the other end is anchored with asphalt through van der waals force, which improves the cohesion between asphalt and steel slag aggregate, and solves the problems of insufficient adhesion of asphalt-hydrophobic modified steel slag aggregate and difficulty in compaction of the mixture. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be described in detail below, but it should be understood that the protection scope of the present application is not limited by the specific embodiments.

[0029] I. Preparation of emulsified asphalt

[0030] 1. Preparation of materials: the raw materials for preparing emulsified asphalt are: base asphalt (70# road petroleum asphalt), SBS modifier, LX811G emulsifier, LX65 cationic SBR latex, NaCl stabilizer and warm mixing agent (sasobit warm mixing agent).

[0031] (1) The technical indexes of base asphalt are shown in Table 1:

[0032] Table 1 Test results of base asphalt

[0033]

[0034] (2) The technical indexes of SBS modifier are shown in Table 2:

[0035] Table 2 Technical indexes of SBS modifier

[0036]

[0037] (3) The technical indexes of SBR latex are shown in Table 3:

[0038] Table 3 Technical indexes of SBR latex

[0039]

[0040] 2. Preparation method of emulsified asphalt:

[0041] (1) Each component is weighed by percentage by weight, the emulsifier is added into water at 60-70℃ and stirred, hydrochloric acid is added to adjust pH to 2-3 while stirring, after the emulsifier is completely dissolved, SBR latex is added and stirred, and pH is continuously adjusted to 2-3, to obtain a soap solution;

[0042] (2) The base asphalt is heated to 180-200℃, the SBS modifier is added, and after high-speed shearing at 3000-5000 rpm for 30-40 min, the modified asphalt is developed at 180-200℃ for 3-5 h;

[0043] (3) The soap solution, modified asphalt, NaCl stabilizer and warm-mixing agent are added into a colloid mill for shearing and grinding, and cooled to obtain emulsified asphalt.

[0044] II. Preparation of emulsified asphalt steel slag ultra-thin overlay mixture

[0045] 1. Preparation: The emulsified asphalt steel slag ultra-thin overlay mixture comprises the following components by mass fraction: 100 parts of mineral aggregate, 7-11 parts of emulsified asphalt and 1-3 parts of cement. The mineral aggregate is divided into three groups of materials according to particle size: the first group is 5-10 mm modified steel slag aggregate; the second group is 0-5 mm limestone aggregate; and the third group is limestone powder; the first group of aggregate accounts for 30-35% of the mass of the mineral aggregate, the second group of aggregate accounts for 60-70% of the mass of the mineral aggregate, and the third group of powder accounts for 1-3% of the mass of the mineral aggregate.

[0046] (1) The density of 0-5 mm limestone aggregate is shown in Table 4:

[0047] Table 4 Test results of water absorption rate and density

[0048]

[0049] (2) The gradation of 5-10 mm modified steel slag aggregate and 0-5 mm limestone aggregate is shown in Table 5:

[0050] Table 5 Sieving results of aggregate gradation

[0051]

[0052] (3) Limestone powder, the screening test results of which are shown in Table 6:

[0053] Table 6 Screening test results of the mineral materials

[0054]

[0055] (4) The cement used is PM brand PO42.5 ordinary portland cement.

[0056] (5) The gradation of the mixture is shown in Table 7 and Table 8: Figure 1

[0057] Table 7 Gradation of the mixture

[0058]

[0059] 2. The preparation method of the emulsified asphalt steel slag ultra-thin overlay mixture is as follows: the mineral materials, emulsified asphalt and cement are weighed and mixed uniformly, and 5-8% of water by mass of the mineral materials is added and mixed for 80-90s, to obtain the emulsified asphalt steel slag ultra-thin overlay mixture.

[0060] Example 1

[0061] Preparation method of emulsified asphalt:

[0062] (1) The base asphalt (70# road petroleum asphalt) 87.5%, SBS modifier 2%, LX811G emulsifier 2%, LX65 cationic SBR latex 6.8%, NaCl stabilizer 03% and sasobit warm-mixing agent 2.5% are weighed according to the weight percentage, the emulsifier is added into water at 70℃ and stirred, hydrochloric acid is added while stirring to adjust the pH to 3, after the emulsifier is completely dissolved, the SBR latex is added and mixed, and the pH is continuously adjusted to 3, to obtain a soap solution;

[0063] (2) The base asphalt is heated to 190℃, the SBS modifier is added, and after high-speed shearing at 4000r / min for 35min, the modified asphalt is obtained by developing at 190℃ for 4h;

[0064] (3) The soap solution, modified asphalt, NaCl stabilizer and warm-mixing agent are added into a colloid mill for shearing and grinding, and cooled to obtain the emulsified asphalt.

[0065] The three indexes of the remaining amount on the screen, Engler viscosity and evaporation residue of the prepared emulsified asphalt are tested, and the test results are shown in Table 8:

[0066] Table 8 Technical indexes of emulsified asphalt

[0067]

[0068] ​From the above table, the emulsified asphalt prepared by the application has strong high-temperature stability and low-temperature ductility, and SBR and SBS modifiers form a continuous structure in the emulsified asphalt, the softening point of which can reach 65.3 DEG C, and the 5 DEG C ductility can reach 36.0 cm, and the performance index can meet the specification requirements.

[0069] Example 2

[0070] Preparation method of emulsified asphalt steel slag ultra-thin overlay mixture:

[0071] (1) Preparation of modified steel slag aggregate:

[0072] Step 1, first immerse the steel slag aggregate in water, heat to 65 DEG C after completely immersed, then stir while introducing carbon dioxide with a concentration of 25% into the water, the carbon dioxide flow is 4L / min, after 4h of reaction, filter, immerse the filtered steel slag aggregate in cement slurry with a mass concentration of 35% for 1.5h, filter, and obtain pretreated steel slag aggregate;

[0073] Step 2, first immerse the pretreated steel slag aggregate in an ethanol solution of mercapto silane coupling agent with a mass concentration of 7wt% for 25min, then dry at 65 DEG C until the water content is 6%, then spray methyl phenyl silicone resin with a solid content of 16%, and cure at 160 DEG C for 12min, to obtain steel slag aggregate coated with a hydrophobic layer;

[0074] Step 3, spray epoxy soybean oil on the steel slag aggregate coated with a hydrophobic layer, the amount of epoxy soybean oil is 0.3% of the weight of the steel slag aggregate coated with a hydrophobic layer, to obtain the modified steel slag aggregate.

[0075] (2) Preparation: emulsified asphalt steel slag ultra-thin overlay mixture, including the following components with mass fractions: 100 parts of mineral aggregate, 9.6 parts of emulsified asphalt prepared in Example 1, and 2.2 parts of cement. The mineral aggregate is divided into three groups of materials according to particle size: the first group is 5-10mm modified steel slag aggregate; the second group is 0-5mm limestone aggregate; and the third group is limestone powder; the first group of aggregate accounts for 33% of the mass of the mineral aggregate, the second group of aggregate accounts for 65% of the mass of the mineral aggregate, and the third group of powder accounts for 2% of the mass of the mineral aggregate; the synthesis gradation is shown in Table 9:

[0076] Table 9 Synthesis gradation of mixture

[0077]

[0078] (3) Preparation of emulsified asphalt steel slag ultra-thin overlay mixture: weigh the mineral aggregate, emulsified asphalt and cement, mix uniformly, add 7% of the mass of the mineral aggregate, and mix for 85s, to obtain the emulsified asphalt steel slag ultra-thin overlay mixture.

[0079] Example 3

[0080] Preparation method of emulsified asphalt steel slag ultra-thin overlay mixture

[0081] (1) Preparation of modified steel slag aggregate:

[0082] Step 1, first immerse the steel slag aggregate in water, heat to 70℃ after complete immersion, then stir while introducing carbon dioxide with a concentration of 30% into the water, carbon dioxide flow is 5L / min, after 5h of reaction, filter, immerse the filtered steel slag aggregate in cement slurry with a mass concentration of 40% for 2h, filter, obtain pretreated steel slag aggregate;

[0083] Step 2, first immerse the pretreated steel slag aggregate in an ethanol solution of mercapto silane coupling agent with a mass concentration of 9wt% for 30min, then dry at 70℃ until the water content is 8%, then spray methyl phenyl silicone resin with a solid content of 20%, cure at 180℃ for 15min, obtain steel slag aggregate coated with a hydrophobic layer;

[0084] Step 3, spray epoxy soybean oil on the steel slag aggregate coated with a hydrophobic layer, the amount of epoxy soybean oil is 0.5% of the weight of the steel slag aggregate coated with a hydrophobic layer, thus obtaining the modified steel slag aggregate.

[0085] (2) Preparation of emulsified asphalt steel slag ultra-thin overlay mixture, including the following components by mass fraction: 100 parts of mineral aggregate, 11 parts of emulsified asphalt prepared in Example 1 and 3 parts of cement. The mineral aggregate is divided into three groups of materials according to particle size: the first group is 5-10mm modified steel slag aggregate; the second group is 0-5mm limestone aggregate; the third group is limestone powder; the first group of aggregate accounts for 35% of the mass of the mineral aggregate, the second group of aggregate accounts for 70% of the mass of the mineral aggregate, and the third group of powder accounts for 3% of the mass of the mineral aggregate; the synthesis gradation is shown in Table 10:

[0086] Table 10 Synthesis gradation of mixture

[0087]

[0088] (3) Preparation of emulsified asphalt steel slag ultra-thin overlay mixture: weigh the mineral aggregate, emulsified asphalt and cement by weight fraction, mix uniformly, add 8% of the mass of the mineral aggregate, and mix for 90s, thus obtaining the emulsified asphalt steel slag ultra-thin overlay mixture.

[0089] Example 4

[0090] Preparation method of emulsified asphalt steel slag ultra-thin overlay mixture

[0091] (1) Preparation of modified steel slag aggregate:

[0092] Step 1, first immerse the steel slag aggregate in water, after completely immersed, heated to 60℃, then stirring while the water into the concentration of 20% carbon dioxide reaction, carbon dioxide flow is 2L / min, after 3h, filter, the filtered steel slag aggregate immersed in the cement slurry with a mass concentration of 30% 1h, filter, get pretreated steel slag aggregate;

[0093] Step 2, first the pretreated steel slag aggregate is placed in the mass concentration of 5wt% mercapto silane coupling agent ethanol solution for 20min, dried at 60℃ to moisture content of 5%, then spray solid content of 10% methyl phenyl silicone resin, at 150℃ for 10min, get coated with hydrophobic layer of steel slag aggregate;

[0094] Step 3, to the coated with hydrophobic layer of steel slag aggregate on the spray epoxy soybean oil, the amount of epoxy soybean oil is 0.1% of the coated with hydrophobic layer of steel slag aggregate weight, namely the modified steel slag aggregate.

[0095] (2) material preparation: emulsified asphalt steel slag ultra-thin overlay mixture, including the following mass fraction of components: 100 parts of mineral aggregate, 7 parts of emulsified asphalt and 1 part of cement. The mineral aggregate is divided into three groups according to particle size: the first group: 5-10mm modified steel slag aggregate; the second group: 0-5mm limestone aggregate; the third group: limestone powder; the first group of aggregate accounts for 30% of the mass of the mineral aggregate, the second group of aggregate accounts for 60% of the mass of the mineral aggregate, and the third group of powder accounts for 1% of the mass of the mineral aggregate; the synthesis of the grading is shown in Table 11:

[0096] Table 11 synthesis of mixture grading

[0097]

[0098] (3) preparation of emulsified asphalt steel slag ultra-thin overlay mixture: the mineral aggregate, emulsified asphalt and cement are weighed and mixed uniformly, 5% of the mass of the mineral aggregate is added to the water and mixed for 80s, and then the mixture is obtained.

[0099] Comparative Example 1: In this comparative example, the steel slag material is not modified, and the other raw materials and preparation methods are the same as those of Example 4.

[0100] Comparative Example 2: In this comparative example, step 1 is not performed when preparing the modified steel slag aggregate, and the other raw materials and preparation methods are the same as those of Example 4.

[0101] Comparative Example 3: In this comparative example, step 3 is not performed when preparing the modified steel slag aggregate, and the other raw materials and preparation methods are the same as those of Example 4.

[0102] The mixture prepared by each of the examples 2 to 4 and the comparative examples 1 to 3 is subjected to a wet wheel abrasion test, a load wheel adhesion sand amount (LWT) and a rut deformation test, and an expansion test, wherein the wet wheel abrasion test is to study the abrasion resistance of the mixture under the conditions of immersion for 1 hour and immersion for 6 days; the expansion test is carried out according to the “Highway Engineering Aggregate Test Regulations (JTG E42-2005)”.

[0103] The wet wheel abrasion of the mixture prepared by each of the examples and the comparative examples is shown in Table 12:

[0104] Table 12 Wet wheel abrasion of each group of mixtures

[0105]

[0106] The load wheel adhesion sand amount of the mixture prepared by each of the examples and the comparative examples is shown in Table 13:

[0107] Table 13 Load wheel adhesion sand amount (LWT) of each group of mixtures

[0108]

[0109] The PLD unit width deformation rate of the mixture prepared by each of the examples and the comparative examples is shown in Table 14:

[0110] Table 14 PLD unit width deformation rate of each group of mixtures

[0111]

[0112] The PVD-unit thickness rut depth rate of the mixture prepared by each of the examples and the comparative examples is shown in Table 15:

[0113] Table 15 PVD-unit thickness rut depth rate of each group of mixtures

[0114]

[0115] The expansion results of the mixture prepared by each of the examples and the comparative examples are shown in Table 16:

[0116] Table 16 Immersion expansion rate of each group of mixtures

[0117]

[0118] From the wet wheel abrasion, load wheel adhesion sand amount (LWT), rut deformation test and expansion test results, it can be known that the steel slag is modified, the emulsified asphalt preparation method is optimized, so that the prepared mixture has the advantages of persistent anti-skid, anti-crack waterproof, stable structure, and strong overall cohesion.

[0119] The foregoing description of specific exemplary embodiments of the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the application be limited not with this detailed description, but rather by the claims appended hereto.

Claims

1. An emulsified asphalt steel slag ultra-thin overlay mixture, characterized in that, Comprise the following components by mass fraction: 100 parts of mineral aggregate, 7-11 parts of emulsified asphalt and 1-3 parts of cement; The mineral aggregate is passed through 9.5mm, 4.75mm, 2.36mm, 1.18mm, 0.6mm, 0.3mm, 0.15mm and 0.075mm aperture standard square hole sieves, and the corresponding passing ratios are 100%, 70%-90%, 45%-70%, 28%-50%, 19%-34%, 12%-25%, 7%-18% and 6%-12% respectively; The mineral aggregate is divided into three groups according to particle size: the first group of aggregate is 5-10mm modified steel slag aggregate; the second group of aggregate is 0-5mm limestone aggregate; and the third group of aggregate is limestone powder; the first group of aggregate accounts for 30-35% of the mass of the mineral aggregate, the second group of aggregate accounts for 60-70% of the mass of the mineral aggregate, and the third group of aggregate accounts for 1-3% of the mass of the mineral aggregate; The preparation method of the modified steel slag aggregate is as follows: Step 1, first immerse the steel slag aggregate in water, and after complete immersion, heat to 60-70℃, then pass 2-5L / min of carbon dioxide with a concentration of 20-30% into the water while stirring, react for 3-5h, filter, immerse the filtered steel slag aggregate in a cement slurry with a mass concentration of 30-40% for 1-2h, filter, and obtain pretreated steel slag aggregate; Step 2, first immerse the pretreated steel slag aggregate in an ethanol solution of mercapto silane coupling agent with a mass concentration of 5-9wt% for 20-30min, then dry at 60-70℃ until the water content is 5-8%, then spray methyl phenyl silicone resin with a solid content of 10-20%, and cure at 150-180℃ for 10-15min to obtain steel slag aggregate coated with a hydrophobic layer; Step 3, spray epoxy soybean oil onto the steel slag aggregate coated with a hydrophobic layer to obtain the modified steel slag aggregate; The emulsified asphalt comprises the following components by weight percentage: 80-90% of base asphalt, 1-3% of SBS modifier, 1-3% of emulsifier, 6-8% of SBR latex, 0.2-0.5% of NaCl stabilizer and 2-3% of warm mixing agent; The preparation method of the emulsified asphalt is as follows: (1) weigh each component according to weight percentage, add the emulsifier into 60-70℃ water and stir, add hydrochloric acid while stirring to adjust pH to 2-3, after the emulsifier is completely dissolved, add SBR latex and mix evenly, continue to adjust pH to 2-3, and obtain soap solution; (2) heat the base asphalt to 180-200℃, add SBS modifier, high-speed shear at 3000-5000rpm for 30-40min, and develop at 180-200℃ for 3-5h to obtain modified asphalt; (3) add the soap solution, modified asphalt, NaCl stabilizer and warm mixing agent into a colloid mill for shearing and grinding, and cool to obtain emulsified asphalt.

2. The emulsified asphalt steel slag ultra-thin overlay mixture according to claim 1, characterized in that, In step 3, the amount of epoxy soybean oil is 0.1-0.5% of the weight of the steel slag aggregate coated with a hydrophobic layer.

3. A method for preparing the emulsified asphalt steel slag ultra-thin overlay mixture according to any one of claims 1 to 2, characterized in that, The emulsified asphalt steel slag ultra-thin surface mixture comprises the following steps: taking mineral aggregate, emulsified asphalt and cement by weight, mixing uniformly, adding water with a mass of 5-8% of the mineral aggregate, and mixing for 80-90 seconds to obtain the emulsified asphalt steel slag ultra-thin surface mixture.

4. Application of the emulsified asphalt steel slag ultra-thin surface mixture according to any one of claims 1 to 2 to road maintenance.

5. Use according to claim 4, characterized in that, When the emulsified asphalt steel slag ultra-thin surface mixture is used for road maintenance, the construction temperature is normal temperature, the compaction thickness is 0.7-1.0 cm, and the pavement is rolled 1-3 times by a rubber-tired road roller after the mixture is paved for 2 hours, so that the traffic can be opened.

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