Low-emission environment-friendly odorless asphalt mixture and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, in particular to a low-emission environment-friendly odorless asphalt mixture and a preparation method thereof. The low-emission environment-friendly odorless asphalt mixture is prepared from the following raw materials: 3.5 to 7 parts of environment-friendly modified asphalt, 0.8 to 1.2 parts of odorless smoke suppressant, 0.15 to 0.3 part of viscosity reduction type warm mixing agent, 78 to 87 parts of aggregate, 4 to 10 parts of filler and 0.2 to 0.5 part of polyester fiber. The low-emission environment-friendly odorless asphalt mixture prepared in the invention has excellent environmental protection performance, construction performance and pavement performance, is especially suitable for urban road construction and tunnel construction, and can effectively improve the construction environment and improve the road quality.

Description

Technical Field

[0001] This application relates to the technical field of road engineering materials, and particularly relates to a low-emission environmentally friendly odorless asphalt mixture and a preparation method thereof. Background Art

[0002] Asphalt is a blackish-brown complex mixture composed of hydrocarbon compounds with different molecular weights and their non-metallic derivatives. It is a kind of high-viscosity organic liquid, in a liquid state, black on the surface, and soluble in carbon disulfide. Asphalt is a waterproof, moisture-proof and anti-corrosion organic cementing material, which can be mainly divided into three types: coal tar asphalt, petroleum asphalt and natural asphalt. Among them, coal tar asphalt is a by-product of coking, petroleum asphalt is the residue after crude oil distillation, and natural asphalt is stored underground, some of which form ore layers or accumulate on the earth's crust surface.

[0003] Asphalt is often heated and used for paving roads, repairing houses or as an anti-corrosion coating. However, existing asphalt will emit a large amount of asphalt fumes when heated. Asphalt fumes and dust can cause severe problems through the respiratory tract and skin, resulting in symptoms such as dermatitis, blurred vision, conjunctivitis, chest tightness, palpitations and headaches. Research has shown that 3,4-benzopyrene contained in asphalt and asphalt fumes is the main cause of skin cancer, lung cancer and esophageal cancer, and living in air polluted by asphalt will also lead to a decline in immunity.

[0004] With the development of transportation, the increase in traffic flow and the improvement of vehicle load, the paving and application of asphalt pavements have become increasingly widespread. However, when using asphalt, the quality and environmental protection issues of asphalt are worthy of our deep consideration. Ordinary asphalt has a high heating temperature, and a large amount of harmful substances will be generated during the heating process, with a lot of fumes and odors, causing irreversible damage to the human body and the environment. Moreover, ordinary asphalt is also relatively easy to age, and the replacement cost is high in the case of a short service life, which prolongs the construction time and results in poor performance of asphalt pavements.

[0005] For example, a modified asphalt and a preparation method thereof with the Chinese patent application number: CN106832976B. The preparation raw materials of the modified asphalt include asphalt, polyphosphoric acid, polymer and additives; among them, the dosage of polyphosphoric acid is 3-5 times the asphaltene content in the asphalt, and the mass ratio of polyphosphoric acid to additives is 1:1-1.3; the additives include maleic anhydride, styrene, diacetone acrylamide and 2,2-dimethylolpropionic acid. By blending asphaltene with polyphosphoric acid, the colloidal structure of asphalt is changed to a sol-gel type. The additives can not only undergo chemical reactions with the sol-gel type asphalt, but also copolymerize with the polymer to form a polymer, so that the asphalt is uniformly and stably dispersed in the polymer solution. Although this preparation method can prepare asphalt with a relatively high degree of polymerization and significantly enhance the performance of asphalt, it still causes a large amount of pollution and endangers human health.

[0006] Therefore, how to significantly enhance the performance of asphalt while ensuring its environmental protection and achieving the goal of smokeless and odorless has become an urgent technical problem to be solved. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present application provides a low-emission environmentally friendly odorless asphalt mixture and a preparation method thereof. The low-emission environmentally friendly odorless asphalt mixture prepared by the present application reduces the emissions and malodor degree of asphalt fumes in the asphalt mixture through technical means such as adsorption, chemical reaction, and reducing the production and construction temperature. It has the advantages of moderate construction temperature, low emissions of asphalt fumes, low concentration, and light odor. Moreover, the mixture has high dynamic stability, strong rutting resistance, good water stability, excellent road performance, and is suitable for urban road construction and tunnel construction.

[0008] In the first aspect, the present application provides a low-emission environmentally friendly odorless asphalt mixture, adopting the following technical solutions: A low-emission environmentally friendly odorless asphalt mixture, by mass, comprises the following raw materials for preparation: 3.5 - 7 parts of environmentally friendly modified asphalt, 0.8 - 1.2 parts of odorless smoke suppressant, 0.15 - 0.3 parts of viscosity-reducing warm mix agent, 78 - 87 parts of aggregate, 4 - 10 parts of filler, and 0.2 - 0.5 parts of polyester fiber.

[0009] By adopting the above technical solutions, the environmentally friendly modified asphalt forms physical and chemical crosslinks by adding SBS modifier, sulfur stabilizer, and ammonium polyphosphate to 70# base asphalt, improving the performance of the asphalt mixture, such as enhancing its high-temperature stability, low-temperature crack resistance, and adhesion. At the same time, the volatilization of light components in the asphalt is inhibited through chemical reactions, thereby reducing the emissions of asphalt fumes. When used in combination with the odorless smoke suppressant and the viscosity-reducing warm mix agent, the comprehensive performance of the asphalt mixture is further enhanced, such as reducing the construction temperature and harmful gas emissions. The odorless smoke suppressant is prepared by mixing zinc ricinoleate, expanded graphite, and zinc oxide. Through its extremely large specific surface area and special structure, it realizes strong physical adsorption and chemical reactions on asphalt fumes, effectively reducing the concentration and malodor degree of asphalt fumes, and purifying the asphalt fumes. Acting together with the environmentally friendly modified asphalt and the viscosity-reducing warm mix agent, it further reduces the harmful gas emissions during the construction process and improves the environmental performance of the mixture. The viscosity-reducing warm mix agent reduces the viscosity of the asphalt mixture at high temperatures, reduces the mixing and construction temperature, thereby effectively reducing CO, CO2, NO xEmissions of pollutants such as soot and dust are reduced. At the same time, the viscosity of the mixture at low temperatures is maintained to ensure good construction performance. When used in combination with environmentally friendly modified asphalt and odorless and smoke-suppressing agents, it not only reduces the construction temperature but also significantly reduces the emissions of harmful gases, improving the overall environmental performance and road performance of the mixture. Aggregates, as the main aggregates of the mixture, provide strength and stability, while improving the gradation of the mixture, enhancing its density and compressive strength. Acting together with other components, the overall mechanical properties and durability of the mixture are improved. Fillers fill the voids between aggregates, increasing the density and stability of the mixture and improving its micro-structure. Acting together with other components, the impermeability and water stability of the mixture are enhanced. Polyester fibers, through their high strength and high elastic modulus, improve the crack resistance and fatigue resistance of the mixture, enhancing its overall strength and durability. Acting together with other components, the comprehensive mechanical properties and road performance of the mixture are improved. In summary, through their unique roles and synergistic effects, each component in the low-emission environmentally friendly odorless asphalt mixture jointly enhances the environmental performance and road performance of the mixture, making it perform excellently in urban road construction and tunnel construction.

[0010] Preferably, the environmentally friendly modified asphalt, by mass parts, comprises the following preparation raw materials: 100 parts of 70# base asphalt, 5 - 8 parts of SBS modifier, 1 - 3 parts of diisononyl phthalate, 0.1 - 0.16 parts of sulfur stabilizer, and 0.1 - 0.3 parts of ammonium polyphosphate.

[0011] By adopting the above technical solution, 70# base asphalt is used as the base material to provide the basic bonding performance and durability of the mixture. SBS modifier: SBS (styrene-butadiene-styrene block copolymer) is a thermoplastic elastomer that can significantly improve the elasticity and toughness of asphalt, and improve the high-temperature stability and low-temperature crack resistance of the mixture. Through physical crosslinking and chemical crosslinking, the overall performance of the asphalt mixture is enhanced, while the volatilization of light components is inhibited, and the emission of asphalt fumes is reduced. Diisononyl phthalate, as a plasticizer, can improve the dispersibility and compatibility of SBS modifier in asphalt, and further enhance the flexibility and processing performance of the mixture. It helps to reduce the high-temperature viscosity of the mixture and facilitate construction operations. Sulfur stabilizer can improve the stability of SBS modifier in asphalt, prevent SBS from decomposing at high temperatures, and extend the service life of modified asphalt. Through chemical reactions, a stable network structure is formed to enhance the bonding force and anti-aging performance of asphalt. Ammonium tetraphosphate not only has a flame-retardant effect, but also can react with light components in asphalt through chemical reactions to inhibit their volatilization, thereby reducing the emission of asphalt fumes. At the same time, it can also improve the antioxidant performance of asphalt and enhance the durability of the mixture. The SBS modifier and sulfur stabilizer work together to form a stable three-dimensional network structure through physical crosslinking and chemical crosslinking, significantly improving the mechanical properties and durability of the asphalt mixture. The SBS modifier, sulfur stabilizer and ammonium tetraphosphate work together synergistically, through physical adsorption and chemical reactions, to effectively inhibit the volatilization of light components in asphalt and reduce the emission of asphalt fumes. Diisononyl phthalate is used in combination with the SBS modifier to improve the processing performance and construction operability of the modified asphalt, while maintaining the low-temperature viscosity of the mixture and preventing low-temperature embrittlement. In summary, through the synergistic effect of each component, the environmentally friendly modified asphalt not only improves the comprehensive performance of the asphalt mixture, but also significantly reduces the emission of harmful gases during the construction process, achieving the dual goals of environmental protection and high performance.

[0012] Preferably, the SBS modifier is at least one of a linear SBS modifier and a star-shaped SBS modifier.

[0013] Preferably, the SBS modifier is prepared by mixing a linear SBS modifier and a star-shaped SBS modifier in a mass ratio of 4:1.

[0014] By adopting the above technical solutions, the SBS modifier enhances the cohesion and elasticity of asphalt through physical cross-linking and chemical cross-linking, thereby improving the dynamic stability, rutting resistance and water stability of asphalt mixtures, and making their road performance more excellent. The SBS modifier can effectively inhibit the volatilization of light components in asphalt, reduce the emissions of asphalt fumes, and reduce environmental pollution during construction. The linear SBS modifier has good compatibility and fluidity, can be evenly dispersed in the matrix asphalt, improve the ductility and low-temperature performance of asphalt, and prevent cracking. The star-shaped SBS modifier has a higher degree of branching and cross-linking density, can significantly improve the high-temperature stability and elastic recovery ability of asphalt, and enhance the rutting resistance of asphalt mixtures. The combined use of the linear SBS modifier and the star-shaped SBS modifier can significantly improve the high-temperature stability and elastic recovery ability of asphalt while maintaining good fluidity and low-temperature performance, making the asphalt mixture exhibit excellent performance under a wide range of temperature conditions. The synergistic effect of the linear SBS modifier and the star-shaped SBS modifier can promote physical cross-linking and chemical cross-linking in the matrix asphalt, form a more stable network structure, and further improve the cohesion and overall strength of asphalt mixtures. The high degree of branching of the star-shaped SBS modifier helps to better encapsulate the light components in asphalt, and together with the linear SBS modifier, effectively inhibits the volatilization of light components, thereby reducing the emissions of asphalt fumes and reducing environmental pollution during construction. In summary, the synergistic effect of the linear SBS modifier and the star-shaped SBS modifier not only improves the comprehensive performance of the environmentally friendly modified asphalt, but also effectively reduces the fume emissions during construction, making it an ideal material suitable for urban road and tunnel construction.

[0015] Preferably, the preparation method of the environmentally friendly modified asphalt is as follows: by mass, first heat the 70# matrix asphalt to 155-165 °C, then add diisononyl phthalate and stir for 15 min to obtain a mixed solution; then continue to heat the mixed solution to 170-180 °C, and evenly add the SBS modifier to the mixed solution during heating, stir and swell for 30 min, and then shear at 170-180 °C for 25-30 min; finally, add sulfur stabilizer and ammonium tetraphosphate and stir at low speed at 170-180 °C for 45-60 min to obtain the environmentally friendly modified asphalt, and keep it warm for standby.

[0016] Preferably, the odorless and smoke-suppressing agent is prepared by mixing zinc ricinoleate, expanded graphite and zinc oxide in a mass ratio of 5:3:2.

[0017] Preferably, the preparation method of the odorless and smoke-suppressing agent is as follows: by mass, mix zinc ricinoleate, expanded graphite, zinc oxide with an appropriate amount of deionized water, stir at 60 °C for 30-40 minutes, and then dry and grind to obtain the odorless and smoke-suppressing agent.

[0018] By adopting the above technical scheme, zinc ricinoleate can react chemically with harmful gases in asphalt, converting them into harmless or low-toxic substances, thereby reducing the concentration of harmful gases in asphalt fume. Expanded graphite and zinc oxide have super large specific surface area and special layered structure, which can effectively adsorb harmful gases and particulate matter in asphalt fume and reduce their emissions. Expanded graphite expands rapidly when heated to form a barrier to prevent the escape of harmful gases. There is a significant synergistic effect between zinc ricinoleate, expanded graphite and zinc oxide. Zinc ricinoleate captures harmful gases through chemical reactions, while expanded graphite and zinc oxide further reduce the concentration of harmful gases through physical adsorption. This synergistic effect makes the odor-free smoke suppressant perform well in reducing the emission and odor of asphalt fume. In summary, the odor-free smoke suppressant effectively reduces the emission and odor of asphalt fume through the dual mechanisms of chemical reaction and physical adsorption, and works together with environmentally friendly modified asphalt and other additives to make asphalt mixture more environmentally friendly and safe during construction, while maintaining excellent road performance.

[0019] Preferably, the viscosity-reducing warm-mix agent is composed of C40-C64 alkane components and has an average molecular weight of 720.

[0020] By adopting the above technical solution, the viscosity-reducing warm mix agent is composed of C40-C64 alkane components with an average molecular weight of 720. This warm mix agent can significantly reduce the viscosity of the asphalt mixture at high temperature without affecting the low-temperature viscosity. This helps to improve the workability of the mixture, making it easier to mix and compact, especially under construction conditions with lower temperatures, which can effectively improve construction efficiency. Since the viscosity-reducing warm mix agent can reduce the high-temperature viscosity of the asphalt mixture, it can be mixed and constructed at lower temperatures. This not only saves energy, but also reduces the emission of asphalt fumes and other harmful gases caused by high-temperature construction, such as CO, CO2, NO xAnd soot, etc., thus realizing environmental protection construction. There is a significant synergistic effect between the viscosity-reducing warm mix agent and other components: 1) Synergistic effect with environmentally friendly modified asphalt: The environmentally friendly modified asphalt improves the performance of the mixture and inhibits the volatilization of light components through the addition of SBS modifier, sulfur stabilizer and ammonium polyphosphate. The viscosity-reducing warm mix agent further reduces the high-temperature viscosity of the mixture, making the modified asphalt easier to operate during construction while maintaining good road performance. 2) Synergistic effect with odor and smoke suppressant: The odor and smoke suppressant effectively reduces the concentration and malodor degree of asphalt fumes through chemical reactions and physical adsorption. The viscosity-reducing warm mix agent reduces the generation amount of fumes by lowering the construction temperature. The combined action of the two further improves the environmental protection performance of the mixture. 3) Synergistic effect with aggregate, filler and polyester fiber: These components work together to improve the dynamic stability, rutting resistance and water stability of the mixture, ensuring excellent road performance of the mixture in practical applications. In summary, the viscosity-reducing warm mix agent not only realizes energy conservation and emission reduction by reducing high-temperature viscosity and construction temperature in the low-emission environmentally friendly odorless asphalt mixture, but also improves the overall performance and environmental protection effect of the mixture through the synergistic effect with other components.

[0021] Preferably, the aggregate is at least one of basalt aggregate, diabase aggregate and limestone aggregate; the filler is prepared by mixing mineral powder and steel slag fine powder in a mass ratio of 2:1, and the particle size of the steel slag fine powder is 200-300 mesh.

[0022] In a second aspect, the present application provides a preparation method of a low-emission environmentally friendly odorless asphalt mixture, adopting the following technical scheme: As a general technical concept, the present application also provides the preparation method of the above-mentioned low-emission environmentally friendly odorless asphalt mixture, including the following steps: S101. According to the mass parts, place the aggregate and the filler in an oven at 165-175°C for preheating for more than 6 hours respectively to obtain the preheated aggregate and the preheated filler, and set aside; S102. According to the mass parts, when heating the mixing pot to the mixing temperature of 160-170°C, first add the preheated aggregate into the mixing pot, add polyester fiber and mix for 15-20 s, then add the environmentally friendly modified asphalt and the viscosity-reducing warm mix agent and mix for 70-90 s, and finally add the odor and smoke suppressant and the preheated filler and mix for 70-90 s to prepare a low-emission environmentally friendly odorless asphalt mixture.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. Environmental protection performance: Reduction of asphalt fume emissions: Through the action of environmentally friendly modified asphalt, odorless smoke suppressants, and viscosity-reducing warm mix agents, the volatilization of light components in asphalt is effectively inhibited, the emissions and concentration of asphalt fumes are significantly reduced, and the emissions of harmful gases during construction are reduced.

[0024] Reduction of malodor level: The odorless smoke suppressant effectively purifies asphalt fumes through chemical reactions and physical adsorption, making the odor lighter and improving the construction environment.

[0025] Reduction of pollutant emissions: The viscosity-reducing warm mix agent reduces the high-temperature viscosity of asphalt mixtures, decreases the mixing and construction temperatures, and thus effectively reduces the emissions of pollutants such as CO, CO2, NO x and soot.

[0026] 2. Construction performance: Moderate construction temperature: Due to the action of the viscosity-reducing warm mix agent, asphalt mixtures can be mixed and constructed at lower temperatures, which not only saves energy but also improves construction efficiency.

[0027] Easy to construct: The reduction of the high-temperature viscosity of the mixture makes the construction operation more convenient and reduces the construction difficulty.

[0028] 3. Road performance: High dynamic stability: The environmentally friendly modified asphalt improves the dynamic stability of the mixture through physical crosslinking and chemical crosslinking, enhancing the anti-deformation ability of the road surface.

[0029] Strong rutting resistance: The addition of SBS modifier significantly improves the high-temperature stability of the mixture and effectively prevents the generation of ruts.

[0030] Good water stability: The optimized ratio of modified asphalt and filler improves the waterproof performance of the mixture and extends the service life of the road surface. Specific implementation methods

[0031] The implementation schemes of this application will be described in detail below in combination with examples. However, those skilled in the art will understand that the following examples are only used to illustrate this application and should not be regarded as limiting the scope of this application. For those not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0032] In the following examples and preparation examples, 1 part means 10 kg. The preferred model of linear SBS modifier is LG501; the preferred model of star-shaped SBS modifier is Dushanzi Petrochemical T161B; the viscosity-reducing warm mix agent is composed of alkane components with C40 - C64, and the average molecular weight is 720; the particle size of steel slag micropowder is 200 - 300 mesh.

[0033] Preparation Example 1: Preparation of Odorless and Smoke Suppressant The preparation method of the odorless and smoke suppressant is as follows: By mass fraction, 50 parts of zinc ricinoleate, 30 parts of expanded graphite, 20 parts of zinc oxide and 350 parts of deionized water are mixed, stirred at 60 °C for 35 minutes, and then dried and ground to obtain the odorless and smoke suppressant.

[0034] Example 1 A low-emission environmentally friendly odorless asphalt mixture, by mass fraction, comprises the following preparation raw materials: 3.5 parts of environmentally friendly modified asphalt, 0.8 part of odorless and smoke suppressant, 0.15 part of viscosity-reducing warm mix agent, 78 parts of aggregate, 4 parts of filler, 0.2 part of polyester fiber. Among them, the environmentally friendly modified asphalt, by mass fraction, comprises the following preparation raw materials: 100 parts of 70# base asphalt, 5 parts of SBS modifier, 1 part of diisononyl phthalate, 0.1 part of sulfur stabilizer, 0.1 part of ammonium tetraphosphate; the SBS modifier is a linear SBS modifier; the aggregate is basalt aggregate; the filler is prepared by mixing mineral powder and steel slag fine powder in a mass ratio of 2:1; The preparation method of the above low-emission environmentally friendly odorless asphalt mixture comprises the following steps: S100: Preparation of environmentally friendly modified asphalt. By mass fraction, first heat 70# base asphalt to 155 °C, then add diisononyl phthalate and stir for 15 min to obtain a mixed solution; continue to heat the mixed solution to 170 °C, and evenly add the SBS modifier to the mixed solution during heating, stir and swell for 30 min, then shear at 170 °C for 30 min; finally, add sulfur stabilizer and ammonium tetraphosphate and stir at low speed at 170 °C for 60 min to obtain environmentally friendly modified asphalt, and keep it warm for standby.

[0035] S101: By mass fraction, place the aggregate and the filler in an oven at 165 °C and preheat for more than 6 h respectively to obtain the preheated aggregate and the preheated filler, and keep them for standby; S102: By mass fraction, when heating the mixing pot to the mixing temperature of 160 °C, first add the preheated aggregate to the mixing pot, add polyester fiber and mix for 15 s, then add the environmentally friendly modified asphalt and the viscosity-reducing warm mix agent and mix for 70 s, and finally add the odorless and smoke suppressant and the preheated filler and mix for 70 s to prepare the low-emission environmentally friendly odorless asphalt mixture.

[0036] Example 2 A low-emission and environmentally friendly odorless asphalt mixture, by mass parts, includes the following preparation raw materials: 7 parts of environmentally friendly modified asphalt, 1.2 parts of odorless and smoke-suppressing agent, 0.3 parts of viscosity-reducing warm mix agent, 87 parts of aggregate, 10 parts of filler, and 0.5 parts of polyester fiber. Among them, the environmentally friendly modified asphalt, by mass parts, includes the following preparation raw materials: 100 parts of 70# base asphalt, 8 parts of SBS modifier, 3 parts of diisononyl phthalate, 0.16 parts of sulfur stabilizer, and 0.3 parts of ammonium polyphosphate; the SBS modifier is a star-shaped SBS modifier; the aggregate is diabase aggregate; the filler is prepared by mixing mineral powder and steel slag fine powder in a mass ratio of 2:1; The preparation method of the above low-emission and environmentally friendly odorless asphalt mixture includes the following steps: S100. Preparation of environmentally friendly modified asphalt. According to mass parts, first heat 70# base asphalt to 165°C, then add diisononyl phthalate and stir for 15 min to obtain a mixed solution; continue to heat the mixed solution to 180°C, and uniformly add the SBS modifier to the mixed solution during the heating process, stir and swell for 30 min, and then shear at 180°C for 25 min; finally, add the sulfur stabilizer and ammonium polyphosphate and stir at a low speed at 180°C for 45 min to obtain environmentally friendly modified asphalt, and keep it warm for standby.

[0037] S101. According to mass parts, place the aggregate and the filler in an oven at 175°C and preheat for more than 6 h respectively to obtain the preheated aggregate and the preheated filler, and keep them for standby; S102. According to mass parts, when the mixing pot is heated to the mixing temperature of 170°C, first add the preheated aggregate to the mixing pot, add the polyester fiber and mix for 20 s, then add the environmentally friendly modified asphalt and the viscosity-reducing warm mix agent and mix for 90 s, and finally add the odorless and smoke-suppressing agent and the preheated filler and mix for 90 s to prepare the low-emission and environmentally friendly odorless asphalt mixture.

[0038] Example 3 A low-emission and environmentally friendly odorless asphalt mixture, by mass parts, includes the following preparation raw materials: 5.5 parts of environmentally friendly modified asphalt, 1 part of odorless and smoke-suppressing agent, 0.23 parts of viscosity-reducing warm mix agent, 82 parts of aggregate, 7 parts of filler, and 0.4 parts of polyester fiber. Among them, the environmentally friendly modified asphalt, by mass parts, includes the following preparation raw materials: 100 parts of 70# base asphalt, 7 parts of SBS modifier, 2 parts of diisononyl phthalate, 0.13 parts of sulfur stabilizer, and 0.2 parts of ammonium polyphosphate; the SBS modifier is a linear SBS modifier; the aggregate is limestone aggregate; the filler is prepared by mixing mineral powder and steel slag fine powder in a mass ratio of 2:1; The preparation method of the above low-emission and environmentally friendly odorless asphalt mixture includes the following steps: S100. Preparation of environment-friendly modified asphalt: By mass fraction, first heat 70# base asphalt to 160 °C, then add diisononyl phthalate and stir for 15 min to obtain a mixture; continue to heat the mixture to 175 °C, and evenly add SBS modifier to the mixture during heating, stir and swell for 30 min, then shear at 175 °C for 28 min; finally, add sulfur stabilizer and ammonium tetraphosphate and stir at low speed at 175 °C for 53 min to obtain environment-friendly modified asphalt, and keep it warm for standby.

[0039] S101. By mass fraction, place the aggregate and filler in an oven at 170 °C for preheating for more than 6 h respectively to obtain the preheated aggregate and preheated filler, and keep them for standby. S102. By mass fraction, when the mixing pot is heated to the mixing temperature of 165 °C, first add the preheated aggregate into the mixing pot, add polyester fiber and stir for 18 s, then add environment-friendly modified asphalt and viscosity-reducing warm mix agent and stir for 80 s, and finally add odorless and smoke-suppressing agent and preheated filler and stir for 80 s to prepare a low-emission environment-friendly odorless asphalt mixture.

[0040] Example 4 Same as Example 3, the difference is that the SBS modifier is a star-shaped SBS modifier.

[0041] Example 5 Same as Example 3, the difference is that the SBS modifier is prepared by mixing linear SBS modifier and star-shaped SBS modifier in a mass ratio of 4:1.

[0042] Comparative Example 1 Same as Example 5, the difference is that an equal amount of 70# base asphalt at 175 °C is used to replace the environment-friendly modified asphalt.

[0043] Comparative Example 2 Same as Example 5, the difference is that an equal amount of odorant 3-ethylhexanal is used to replace the odorless and smoke-suppressing agent.

[0044] Comparative Example 3 Same as Example 5, the difference is that the addition amount of the viscosity-reducing warm mix agent is 0.

[0045] Performance detection test Sample the low-emission environment-friendly odorless asphalt mixtures prepared in the above Examples 1 - 5 and Comparative Examples 1 - 3 respectively, and conduct the following tests. The results are shown in Table 2.

[0046] Freeze-thaw splitting test: The mixture is subjected to freeze-thaw cycles, and the splitting strength ratio of the test specimens before and after water damage is tested to evaluate the water stability of the mixture. The test is carried out with reference to the freeze-thaw splitting test in the "Technical Specifications for Construction of Highway Asphalt Pavements" JTG F40-2004. According to the splitting strength before freeze-thaw and after freeze-thaw, the residual strength ratio is calculated, %.

[0047] Determination of dynamic stability at 60°C: According to the rutting test of asphalt mixture T0719 in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20--2011).

[0048] Marshall test: The Marshall stability is used to test the early strength of the mixture and evaluate whether it is suitable for pavement repair with heavy traffic and short traffic opening time requirements. The initial stability of the cold patch asphalt mixture is determined with reference to the "Technical Specifications for Construction of Highway Asphalt Pavements" JTGF40-2004. The mixture is cured at room temperature for 4 h, taken out and put into the test mold, and compacted 75 times on both the front and back sides, and the initial stability is measured after demolding.

[0049] Odor intensity grade: It is judged according to the Japanese odor intensity grade, as shown in Table 1.

[0050] Table 1 Strength Index 0 Odorless 1 Slight odor perceptible 2 Weak odor but distinguishable in nature 3 Odor easily perceptible 4 Strong odor 5 Overpowering strong odor Table 2 Performance test Analyzing the data in Table 1, it can be seen that: 1) The low-emission and environmentally friendly odorless asphalt mixtures prepared in Examples 1-5 reduce the emissions and odor intensity of asphalt fumes in the asphalt mixture through technical means such as adsorption, chemical reaction, and reducing production and construction temperatures. They have the advantages of moderate construction temperature, low emissions of asphalt fumes, low concentration, and light odor. Moreover, the mixture has high dynamic stability, strong rutting resistance, good water stability, excellent road performance, and is suitable for urban road construction and tunnel construction.

[0051] 2) The performance comparison analysis of the low-emission, environmentally friendly, odorless asphalt mixtures prepared in Example 5 and Example 3-Example 4 shows that the SBS modifier is prepared by mixing a linear SBS modifier and a star-shaped SBS modifier in a mass ratio of 4:1. The synergistic effect of the linear SBS modifier and the star-shaped SBS modifier can promote physical and chemical crosslinking in the matrix asphalt, forming a more stable network structure, and further improving the comprehensive performance of the environmentally friendly modified asphalt. The high branching degree of the star-shaped SBS modifier helps to better wrap the light components in the asphalt, and works together with the linear SBS modifier to effectively inhibit the volatilization of the light components, thereby reducing the emission of asphalt smoke and reducing environmental pollution during construction.

[0052] 3) The performance comparison analysis of the low-emission, environmentally friendly, odorless asphalt mixture prepared in Example 5 and Comparative Example 1 shows that the environmentally friendly modified asphalt prepared in the present application, by adding SBS modifier, sulfur stabilizer and ammonium tetrapolyphosphate to 70# base asphalt, produces physical crosslinking, chemical crosslinking and chemical reaction, which can effectively inhibit the volatilization of light components in asphalt and reduce the emission of asphalt fume while improving the comprehensive performance of the asphalt mixture.

[0053] 4) The performance comparison analysis of the low-emission, environmentally friendly, odor-free asphalt mixture prepared in Example 5 and Comparative Example 2 shows that the addition of the odor-free smoke suppressant prepared in this application, the zinc ricinoleate in the odor-free smoke suppressant can react chemically with the harmful gases in the asphalt, converting them into harmless or low-toxic substances, thereby reducing the concentration of harmful gases in the asphalt fume. Expanded graphite and zinc oxide have an ultra-large specific surface area and a special layered structure, which can effectively adsorb harmful gases and particulate matter in asphalt fume and reduce its emissions. Expanded graphite expands rapidly when heated to form a barrier to prevent the escape of harmful gases. There is a significant synergistic effect between zinc ricinoleate, expanded graphite and zinc oxide. Zinc ricinoleate captures harmful gases through chemical reactions, while expanded graphite and zinc oxide further reduce the concentration of harmful gases through physical adsorption. This synergistic effect makes the odor-free smoke suppressant perform well in reducing asphalt fume emissions and odor levels. In summary, odorless smoke suppressants effectively reduce the emission and odor of asphalt smoke through the dual mechanisms of chemical reaction and physical adsorption. They work together with environmentally friendly modified asphalt and other additives to make asphalt mixtures more environmentally friendly and safe during construction while maintaining excellent road performance.

[0054] 5) Comparative analysis of the performance of the low-emission environmentally friendly odorless asphalt mixture prepared in Example 5 and Comparative Example 3 shows that adding a viscosity-reducing warm mix additive can significantly reduce the viscosity of the asphalt mixture at high temperatures without affecting its low-temperature viscosity. This helps to improve the workability of the mixture, making it easier to mix and compact, especially under construction conditions with lower temperatures, which can effectively improve the construction efficiency. Since the viscosity-reducing warm mix additive can reduce the high-temperature viscosity of the asphalt mixture, mixing and construction can be carried out at lower temperatures. This not only saves energy but also reduces the emissions of asphalt fumes and other harmful gases such as CO, CO2, NO x and soot, etc., thus achieving environmentally friendly construction.

[0055] The above embodiments are only used to explain the technical solutions of the present application and not to limit them. Although the above embodiments have specifically described the present application, those skilled in the art should understand that modifications or equivalent replacements can still be made to the specific implementation manners of the present application. Any modification and equivalent replacement that do not depart from the spirit and scope of the present application shall be covered by the protection scope of the present application.

Claims

1. A low-emission, environmentally friendly, odorless asphalt mixture, characterized in that: Calculated by weight, the preparation comprises the following raw materials: 3.5-7 parts of environmentally friendly modified asphalt, 0.8-1.2 parts of odorless smoke suppressant, 0.15-0.3 parts of viscosity-reducing warm mix agent, 78-87 parts of aggregate, 4-10 parts of filler and 0.2-0.5 parts of polyester fiber.

2. The low-emission, environmentally friendly, odorless asphalt mixture according to claim 1, characterized in that: The environmentally friendly modified asphalt includes the following raw materials by weight: 100 parts of 70# base asphalt, 5-8 parts of SBS modifier, 1-3 parts of diisononyl phthalate, 0.1-0.16 parts of sulfur stabilizer, and 0.1-0.3 parts of ammonium tetrapolyphosphate.

3. The low-emission, environmentally friendly, odorless asphalt mixture according to claim 2, characterized in that: The SBS modifier is at least one of a linear SBS modifier and a star-shaped SBS modifier.

4. The low-emission, environmentally friendly, odorless asphalt mixture according to claim 3, characterized in that: The SBS modifier is prepared by mixing a linear SBS modifier and a star-shaped SBS modifier in a mass ratio of 4:

1.

5. The low-emission, environmentally friendly, odorless asphalt mixture according to claim 2, characterized in that: The preparation method of the environmentally friendly modified asphalt is as follows: firstly, according to the mass fraction, heat 70# base asphalt to 155-165°C, then add diisononyl phthalate and stir for 15 minutes to obtain a mixed solution; then continue to heat the mixed solution to 170-180°C, during the heating process, evenly add SBS modifier to the mixed solution, stir and swell for 30 minutes, then shear at 170-180°C for 25-30 minutes; finally, add sulfur stabilizer and ammonium tetrapolyphosphate and stir at a low speed for 45-60 minutes at 170-180°C to obtain the environmentally friendly modified asphalt, and keep it warm for later use.

6. The low-emission, environment-friendly, odor-free asphalt mixture according to claim 1, characterized in that: The odorless smoke suppressant is prepared by mixing zinc ricinoleate, expanded graphite and zinc oxide in a mass ratio of 5:3:

2.

7. The low-emission, environment-friendly, odor-free asphalt mixture according to claim 6, characterized in that: The preparation method of the odor-free smoke suppressant is as follows: according to the mass fractions, zinc ricinoleate, expanded graphite, zinc oxide and an appropriate amount of deionized water are mixed, stirred at 60° C. for 30-40 minutes, and then dried and ground to obtain the odor-free smoke suppressant.

8. The low-emission, environment-friendly, odor-free asphalt mixture according to claim 1, characterized in that: The viscosity-reducing warm-mix agent is composed of C40-C64 alkane components and has an average molecular weight of 720.

9. The low-emission, environment-friendly, odor-free asphalt mixture according to claim 1, characterized in that: The aggregate is at least one of basalt aggregate, diabase aggregate and limestone aggregate; the filler is prepared by mixing mineral powder and steel slag powder in a mass ratio of 2:1, and the particle size of the steel slag powder is 200-300 mesh.

10. A method for preparing a low-emission, environment-friendly, odor-free asphalt mixture as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S101. Preheat the aggregate and filler in an oven at 165-175° C. for more than 6 hours according to their mass fractions, and obtain preheated aggregate and preheated filler for standby use; S102. When the mixing pot is heated to a mixing temperature of 160-170°C according to the mass fraction, first add the preheated aggregate into the mixing pot, add polyester fiber and mix for 15-20 seconds, then add environmentally friendly modified asphalt and viscosity-reducing warm mix agent and mix for 70-90 seconds, finally add odor-free smoke suppressant and preheated filler and mix for 70-90 seconds to obtain a low-emission, environmentally friendly, odor-free asphalt mixture.

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