An emulsified asphalt mixture and its preparation method

Abstract

The present invention belongs to the technical field of emulsified asphalt materials, and specifically relates to an emulsified asphalt mixture and a preparation method thereof. The mixture comprises 95 - 98 parts of aggregate, 3 - 5 parts of early strength agent, 0 - 2 parts of water, 0 - 3 parts of mineral powder, and 10 - 11 parts of modified emulsified asphalt. The emulsified asphalt includes modified asphalt, water, cationic emulsifier, and H regulator. The modified asphalt is obtained by compound modification of SBS, petroleum resin, and rubber powder. Through step-by-step preparation, the mixture has good emulsifying properties, can emulsify SBS and rubber powder, combines SBS, petroleum resin, and rubber powder organically, and enables the mixture to have good properties. At the same time, an early strength agent is used, and the early strength agent and the modified emulsified asphalt can play a synergistic role to further improve the properties of the mixture, making the performance indexes of the emulsified asphalt mixture in the present invention reach or even exceed those of hot mix asphalt mixture, and it can be applied to the surface layer of asphalt pavement, having strong practical application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of emulsified asphalt materials, and particularly relates to an emulsified asphalt mixture and a preparation method thereof. Background Art

[0002] At present, hot mix asphalt mixtures are mostly used on asphalt roads. The asphalt (modified asphalt) is heated to 165-170°C, and the aggregates are heated to 190-220°C, and the two are mixed in a mixing plant according to a certain ratio and gradation. After long-distance transportation of the hot mix asphalt mixture, the paving temperature is not lower than 160°C, and the compaction temperature is not lower than 150°C. It is a traditional highway asphalt pavement construction material and construction technology with high energy consumption and high carbon emissions, and it no longer meets the current needs of highway traffic. Therefore, developing a high-performance asphalt highway construction technology with energy conservation, carbon reduction, and environmental friendliness is a new problem faced by highway traffic currently.

[0003] To solve the above problems, developing the technology of "emulsified asphalt mixture" with energy conservation and carbon reduction has become an option. The "emulsified asphalt mixture" technology does not require heating the aggregates and asphalt, and construction can be carried out at normal temperature. It can be mixed, paved, and compacted on-site, and the traffic can be opened in 3-5 hours. Moreover, since the emulsified asphalt is not subjected to high-temperature hot mixing and hot paving, thermal aging is reduced, and the service life of the asphalt can be extended.

[0004] In the prior art, for example, Chinese Patent with publication number CN111099855A provides an emulsified asphalt mixture and a preparation method thereof, including aggregates, asphalt, waterborne acrylic acid, emulsifier, stabilizer, pH regulator, curing agent, and water. By adjusting the waterborne acrylic acid, stabilizer, and curing agent, the demulsification speed and forming speed of the mixture can be improved.

[0005] Another example is Chinese Patent with publication number CN105418041A, which provides an emulsified asphalt mixture and a preparation method thereof, including 4-8 parts by mass of emulsified asphalt, 2-15 parts by mass of additional water, 85-95 parts by mass of aggregates, and 0-6 parts by mass of filler. By adding fibers and plasticizers to the emulsified asphalt mixture containing cement, the purpose of improving the flexibility of the cement emulsified asphalt mixture is achieved, and at the same time, the requirement of rapid opening of traffic during construction is met. In addition, amphoteric oxides, cement, fibers, and plasticizers in the emulsified asphalt mixture can ensure rapid opening of traffic while taking into account the pavement strength, flexibility, and water damage resistance and other aspects of performance.

[0006] However, the emulsified asphalt mixture prepared in the above-mentioned existing technologies still has the following problems: 1. Compared with hot mix asphalt mixture, relevant technical indicators such as strength are still lacking, resulting in its only being able to be used in the bottom and middle layers of asphalt pavement and not being applicable to the surface layer, which restricts the popularization of the emulsified asphalt mixture technology; 2. The transportation stability is poor, and flocculation phenomena formed by demulsification are likely to occur during transportation. Summary of the Invention

[0007] In view of the problems existing in the current emulsified asphalt mixture mentioned above, the present invention provides an emulsified asphalt mixture and its preparation method. By using SBS, petroleum resin and rubber powder for compound modification and emulsifying with a cationic emulsifier, SBS, petroleum resin and rubber powder are organically combined, enabling the mixture to have good performance. At the same time, an early strength agent is used, and the early strength agent and the modified emulsified asphalt can play a synergistic role to further improve the performance of the mixture, making the performance indexes of the emulsified asphalt mixture in the present invention reach or even exceed those of the hot mix asphalt mixture and being applicable to the surface layer of asphalt pavement. The specific technical solutions are as follows:

[0008] First, the present invention provides an emulsified asphalt mixture, and the mixture comprises the following components in parts by weight: 95 - 98 parts of aggregate, 3 - 5 parts of early strength agent, 0 - 2 parts of water, 0 - 3 parts of mineral powder and 10 - 11 parts of modified emulsified asphalt; the modified emulsified asphalt comprises the following components in mass fractions: 58 - 60% of modified asphalt, 31.6 - 34.6% of water, 3 - 6% of cationic emulsifier, 2% of stabilizer and 0.4 - 1.4% of pH regulator; the modified asphalt is obtained by compound modification of SBS, petroleum resin and rubber powder, the dosage of SBS is 7 - 8% of the weight of the base asphalt, the dosage of petroleum resin is 1 - 2% of the weight of the base asphalt, and the dosage of rubber powder is 1 - 2% of the weight of the base asphalt; the cationic emulsifier comprises the following components in mass fractions: 20% of calcium lignosulfonate, 25% of OP - 10, 25% of OP - 40 and 30% of SP - 20; the stabilizer is a 10wt.% aqueous solution of polyvinyl alcohol.

[0009] Further, the early strength agent comprises the following components in mass fractions: 80% of double - quick cement, 15.5% of interfacial agent, 2% of expansion agent, 1% of retarder and 1.5% of carbon black.

[0010] Further, the emulsified asphalt mixture meets the following technical indicators: void ratio 5 - 6%, Marshall stability 25 - 30 KN, flow value 2.5 - 4 mm, freeze - thaw splitting strength ratio greater than 90%, dynamic stability 10000 - 42000 times / mm, flexural failure strain greater than 3000 με.

[0011] The present invention also provides a preparation method of the emulsified asphalt mixture, comprising the following steps:

[0012] S1 Preparation of modified asphalt: Heat the base asphalt, add a stabilizer thereto, continue stirring and heating, then add SBS, petroleum resin and rubber powder, and develop the modified asphalt after swelling and shearing;

[0013] S2 Preparation of modified emulsified asphalt: Dissolve the emulsifier in hot water, add hydrochloric acid to adjust the pH to prepare an aqueous emulsifier solution, then heat the modified asphalt, and pump it into a stirring device together with the aqueous emulsifier solution for emulsification to obtain the modified emulsified asphalt;

[0014] S3 Preparation of mixture: Heat the aggregate in a mixing device, add an early strength agent to the aggregate and mix evenly, and then add the emulsified asphalt and mix quickly and evenly to obtain the mixture.

[0015] Furthermore, in step S1, the heating temperature of the base asphalt is 140 - 145 °C, the continued heating temperature is 175 - 180 °C, the stirring time is 10 - 15 min, the swelling time is 30 - 45 min, the shearing time is 120 - 150 min, and the development time is 90 - 120 min.

[0016] Furthermore, in step S2, the hot water temperature is 55 - 60 °C, the pH value of the aqueous emulsifier solution is 1.5 - 3, and the heating temperature of the modified asphalt is 180 - 190 °C.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The present invention uses SBS, petroleum resin and rubber powder to compound-modify the base asphalt. Compared with the modified asphalt obtained by conventionally using SBS or SBS + rubber powder, petroleum resin is added and its interfacial film-forming property is utilized, which can strengthen the tensile strength between the asphalt and the stone and improve the performance of the modified asphalt. At the same time, by using three materials to compound-modify the base asphalt and utilizing the interaction between the early strength agent and them, the emulsified asphalt mixture can reach or even exceed the performance indicators of the hot mix asphalt mixture, greatly expanding the application scope and available scenarios of the emulsified asphalt mixture.

[0019] 2) The present invention uses a cationic emulsifier and a stabilizer, and defines their usage ratio. By utilizing the strong hydrophilic property of the cationic emulsifier, paving can be carried out smoothly without adding water or adding a small amount of water during the preparation of the emulsified asphalt. Adding a stabilizer can well improve the stability of the emulsified asphalt. At the same time, due to the addition of the composite modification material, the emulsification difficulty of the modified asphalt increases. Therefore, the present invention selects a specific cationic emulsifier, and by utilizing the interaction between the petroleum resin and the cationic emulsifier, the emulsification effect of the emulsified asphalt can be significantly improved, enabling the modifier and the emulsifier to be organically combined, improving the transportation and mechanical stability of the emulsified asphalt mixture, and preventing the demulsification and flocculation of the modified emulsified asphalt during transportation.

[0020] 3) The present invention uses the technology of emulsified asphalt mixture, and systematic innovations are carried out both in the preparation of modified asphalt and the preparation of the mixture. By utilizing the technical characteristics of the emulsified asphalt mixture, on the basis of ensuring the performance of the mixture, remarkable energy conservation and emission reduction are achieved. Compared with the hot mix mixture technology commonly used in the prior art, the emulsified asphalt mixture used in the present invention has a 68.95% reduction in production energy consumption and a 65.51% reduction in carbon emissions, and its energy conservation and emission reduction effect is extraordinary. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a physical diagram of an emulsified asphalt mixture in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0023] The present invention provides a method for preparing an emulsified asphalt mixture, which specifically includes the following steps:

[0024] S1 Prepare modified asphalt: Heat the base asphalt, add a stabilizer thereto, continue stirring and heating, then add SBS, petroleum resin and rubber powder, and develop the modified asphalt after swelling and shearing.

[0025] Specifically, heat the base asphalt to 140 - 145 °C, add 5% aromatic hydrocarbon oil and continue stirring and heating, raise the temperature to 175 - 180 °C and stir for 10 - 15 min. Add SBS, petroleum resin and rubber powder, after swelling for 30 - 45 min, shear at a rotational speed of 3000 - 5000 revolutions per minute for 120 - 150 min, and finally develop for 90 - 120 min under the action of a stirrer to obtain the modified asphalt. In the present invention, the dosage of SBS in the modified asphalt is 7 - 8% of the dosage of the base asphalt, the petroleum resin is 1 - 2% of the dosage of the base asphalt, and the dosage of the rubber powder is 1 - 2% of the dosage of the base asphalt. In the present invention, the base asphalt is selected from commercially available base asphalt, such as Sinopec AH-70, etc.

[0026] S2 Prepare modified emulsified asphalt: Dissolve the emulsifier in hot water, add a pH regulator to adjust the pH to make an emulsifier aqueous solution, then heat the modified asphalt, and pump the heated modified asphalt and the emulsifier aqueous solution into a stirring device together for emulsification to obtain the modified emulsified asphalt.

[0027] Specifically, the emulsifier is added to water at 55 - 60°C and stirred thoroughly until dissolved. Then, hydrochloric acid is added to adjust the pH to 1.5 - 3 to prepare an aqueous emulsifier solution. Next, the modified asphalt prepared above is heated to 180°C - 190°C and pumped into a colloid mill together with the aqueous emulsifier solution for emulsification for 1 minute to obtain modified emulsified asphalt. After its technical indicators are qualified, it is reserved for use.

[0028] In this example, a mixture of 20% calcium lignosulfonate, 25% OP - 10, 25% OP - 40, and 30% SP - 20 is used as the cationic emulsifier, and a 10%wt. aqueous solution of polyvinyl alcohol is used as the stabilizer. The specific ratio of the modified emulsified asphalt is shown in Table 1 below:

[0029]

[0030] S3 Prepare the mixture: Heat the aggregate in a mixing device, add mineral powder and early - strength agent to the aggregate and mix evenly, then add water and emulsified asphalt, and quickly mix evenly to obtain the mixture.

[0031] Add aggregate to the mixing device. The aggregate includes coarse aggregate and fine aggregate. Among them, the coarse aggregate should be selected as hard, rough, and angular - looking aggregate, and the technical requirements of the aggregate should meet the requirements of the "Technical Specifications for Highway Asphalt Pavement Construction". The fine aggregate should be selected as clean, dry, non - weathered, and impurity - free aggregate. It should be noted that the fine aggregate does not contain aggregate with a particle size of 0 - 2.36mm, and this part of the aggregate is replaced by the early - strength agent. This can avoid excessive fine aggregate with a particle size of 0 - 2.36mm and standardize the gradation. The gradation of the coarse aggregate and the fine aggregate follows the AC - 13 standard. Add the early - strength agent and mineral powder to the aggregate, stir and mix evenly, then pour water into it, mix evenly, and add the modified emulsified asphalt, and quickly mix to make the mixture evenly mixed. The evenly - mixed mixture is as shown in Figure 1 the figure. In the present invention, the early - strength agent selected is an early - strength agent composed of 80% double - quick cement, 15.5% interfacial agent, 2% expansion agent, 1% retarder, and 1.5% carbon black. In the present invention, the mineral powder is obtained by grinding hydrophobic stones such as limestone or strongly basic rocks in magmatic rocks.

[0032] In the emulsified asphalt mixture of the present invention, the weight parts of each component are: 95 - 98 parts of aggregate, 3 - 5 parts of early - strength agent, 0 - 2 parts of water, 0 - 3 parts of mineral powder, and 10 - 11 parts of modified emulsified asphalt.

[0033] Preparation Example 1

[0034] In this preparation example, the dosages of modifiers in the modified asphalt are 7% SBS, 1.5% petroleum resin, and 1% rubber powder respectively. The formulation of the modified emulsified asphalt is 3% cationic emulsifier, 2% stabilizer, 58% modified asphalt, 0.4% pH regulator, and 36.6% water. The preparation method is as described in the above specific implementation manner.

[0035] Preparation Example 2

[0036] The difference between this preparation example and Preparation Example 1 lies in the dosages of modifiers in the modified asphalt and the formulation of the modified emulsified asphalt. Specifically, in this preparation example, the dosages of modifiers in the modified asphalt are 8% SBS, 2% petroleum resin, and 2% rubber powder respectively. The formulation of the modified emulsified asphalt is 6% cationic emulsifier, 2% stabilizer, 60% modified asphalt, 0.4% pH regulator, and 31.6% water. The preparation method is as described in the above specific implementation manner.

[0037] Preparation Example 3

[0038] The difference between this preparation example and Preparation Example 1 lies in the dosages of modifiers in the modified asphalt and the formulation of the modified emulsified asphalt. Specifically, in this preparation example, the dosages of modifiers in the modified asphalt are 5% SBS, 1% petroleum resin, and 1% rubber powder respectively. The formulation of the modified emulsified asphalt is 2% cationic emulsifier, 2% stabilizer, 58% modified asphalt, 0.4% pH regulator, and 37.6% water. The preparation method is as described in the above specific implementation manner.

[0039] Preparation Example 4

[0040] The difference between this preparation example and Preparation Example 1 lies in the types and dosages of modifiers in the modified asphalt. Specifically, in this preparation example, the dosages of modifiers in the modified asphalt are 8% SBS and 1.5% rubber powder respectively. The formulation of the modified emulsified asphalt is 3% cationic emulsifier, 2% stabilizer, 58% modified asphalt, 0.4% pH regulator, and 36.6% water. The preparation method is as described in the above specific implementation manner.

[0041] Preparation Example 5

[0042] The difference between this preparation example and Preparation Example 1 lies in the types and dosages of modifiers in the modified asphalt. Specifically, in this preparation example, the dosages of modifiers in the modified asphalt are 8% SBS and 1.5% petroleum resin respectively. The formulation of the modified emulsified asphalt is 3% cationic emulsifier, 2% stabilizer, 58% modified asphalt, 0.4% pH regulator, and 36.6% water. The preparation method is as described in the above specific implementation manner.

[0043] Preparation Example 6

[0044] The difference between this Preparation Example and Preparation Example 1 lies in the different types of modifiers in the modified asphalt. Specifically, in this Preparation Example, the dosages of modifiers in the modified asphalt are 10.5% SBS respectively. The proportion of the modified emulsified asphalt is 3% cationic emulsifier, 2% stabilizer, 58% modified asphalt, 0.4% pH regulator, and 36.6% water. The preparation method is as described in the above specific implementation manner.

[0045] Preparation Example 7

[0046] The difference between this Preparation Example and Preparation Example 1 lies in the different dosage ratios of the emulsifier in the modified emulsified asphalt. Specifically, in this Preparation Example, the dosages of modifiers in the modified asphalt are 7% SBS, 1.5% petroleum resin, and 1% rubber powder respectively. The proportion of the modified emulsified asphalt is 2% cationic emulsifier, 4% stabilizer, 58% modified asphalt, 0.4% pH regulator, and 35.6% water. The preparation method is as described in the above specific implementation manner.

[0047] Preparation Example 8

[0048] The difference between this Preparation Example and Preparation Example 1 lies in the different types and dosage ratios of the emulsifier in the modified emulsified asphalt. Specifically, in this Preparation Example, the dosages of modifiers in the modified asphalt are 7% SBS, 1.5% petroleum resin, and 1% rubber powder respectively. The proportion of the modified emulsified asphalt is 5% cationic emulsifier, 58% modified asphalt, 0.4% pH regulator, and 36.6% water. The preparation method is as described in the above specific implementation manner.

[0049] Example 1

[0050] In this example, the modified emulsified asphalt prepared in Preparation Example 1 is used, and the steps of preparing the mixture are the same as those in the aforementioned preparation method. The weight parts of each component of the finally prepared emulsified asphalt mixture are respectively: 95 parts of aggregate, 3 parts of early strength agent, 1 part of mineral powder, and 10 parts of modified emulsified asphalt.

[0051] Example 2

[0052] The difference between this example and Example 1 is that the modified emulsified asphalt prepared in Preparation Example 2 is used, and the steps of preparing the mixture are the same as those in Example 1. The weight parts of each component of the finally prepared emulsified asphalt mixture are respectively: 98 parts of aggregate, 5 parts of early strength agent, 1 part of water, 1 part of mineral powder, and 11 parts of modified emulsified asphalt.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 1 is that the modified emulsified asphalt prepared in Preparation Example 5 is used, and the steps of preparing the mixture are the same as those in Example 1. The weight parts of each component of the finally prepared emulsified asphalt mixture are respectively: 96 parts of aggregate, 5 parts of early strength agent, 1 part of water, 1 part of mineral powder, and 10 parts of modified emulsified asphalt.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 1 lies in that the modified emulsified asphalt prepared in Preparation Example 6 is used, and the steps for preparing the mixture are the same as those in Example 1. The weight parts of each component of the finally prepared emulsified asphalt mixture are as follows: 96 parts of aggregate, 5 parts of early strength agent, 1 part of water, 1 part of mineral powder, and 10 parts of modified emulsified asphalt.

[0057] Comparative Example 3

[0058] The difference between this comparative example and Example 1 lies in that the modified emulsified asphalt prepared in Preparation Example 7 is used, and the steps for preparing the mixture are the same as those in Example 1. The weight parts of each component of the finally prepared emulsified asphalt mixture are as follows: 96 parts of aggregate, 5 parts of early strength agent, 1 part of water, 1 part of mineral powder, and 10 parts of modified emulsified asphalt.

[0059] Comparative Example 4

[0060] The difference between this comparative example and Example 1 lies in that the modified emulsified asphalt prepared in Preparation Example 8 is used, and the steps for preparing the mixture are the same as those in Example 1. The weight parts of each component of the finally prepared emulsified asphalt mixture are as follows: 96 parts of aggregate, 5 parts of early strength agent, 1 part of water, 1 part of mineral powder, and 10 parts of modified emulsified asphalt.

[0061] Comparative Example 5

[0062] The difference between this comparative example and Example 1 lies in that the dosage of the early strength agent in the modified emulsified asphalt mixture is 1 part, that is, the weight parts of each component of the mixture in this comparative example are: 98 parts of aggregate, 1 part of early strength agent, 1 part of mineral powder, and 11 parts of modified emulsified asphalt.

[0063] Experimental Example 1: Performance Detection of Modified Emulsified Asphalt

[0064] Experimental method: Detect the performance of the modified emulsified asphalt according to the test methods described in the "Specifications for Tests of Bitumen and Bituminous Mixtures for Highway Engineering" (JET E20 - 2011).

[0065] The test results are shown in Table 2 below:

[0066]

[0067] Analysis of experimental results:

[0068] In the present invention, the transportation and mechanical stability of the modified emulsified asphalt refer to the stability under mechanical impact during stirring, flowing, transporting, and pumping.

[0069] From the above experimental results, it can be seen that the modified emulsified asphalt prepared by the present invention has a qualitative improvement in terms of transportation and mechanical stability compared with the prior art. After 4 - 6 hours of transportation, the residue on the sieve is ≤ 0.05, greatly improving the stability of the modified emulsified asphalt during transportation and preventing the flocculation phenomenon caused by demulsification during transportation. Moreover, according to the different dosages of emulsifier and modifier, the softening point of the emulsified asphalt can be selectively customized to meet different usage requirements.

[0070] When the dosage of the modifier in the modified asphalt and the ratio of the modified emulsified asphalt are changed, the transportation and mechanical stability of the prepared modified emulsified asphalt deteriorate significantly, resulting in a significant increase in the residue on the sieve. The demulsification phenomenon of the modified emulsified asphalt is obvious, and obvious flocculation will occur during transportation.

[0071] Experimental Example 2: Marshall Standard Test of Modified Emulsified Asphalt Mixture in Examples and Comparative Examples

[0072] Experimental method: Making Marshall standard test specimens: (1) Weigh 1200 g of aggregate according to the grading requirements of AC - 13 and add it to the mixing basin, then add the early - strength agent and mix evenly; (2) Pour in water and mix evenly; (3) Add emulsified asphalt and mix for 1 min. (4) After mixing, the thick emulsified asphalt slurry fully adheres to the stones without flowing, and the aggregate presents a semi - loose state. (5) After the specimen is compacted, immediately use tweezers to remove the lower release paper and start demolding. After demolding, immediately use tweezers to remove the upper release paper. Take down the specimen and place the specimen indoors or outdoors. (6) According to the required placement time, the Marshall stability test of the mixture can be carried out, such as 3 hours, 4 hours, 5 hours, 22 days, etc. Before measuring the stability and flow value, measure the height of the specimen to ensure that the height meets 63.5 mm ± 1.3 mm (standard specimen); when the specimen is placed outdoors and the temperature of the specimen to be tested is higher than the indoor temperature, the specimen should be restored to room temperature before conducting the Marshall stability test. (7) If the test time is tight and relevant test conditions (such as residual stability, etc.) require natural placement for 22 days, the prepared Marshall specimens can also be placed in an oven at 60 °C and dried to a constant weight.

[0073] Fabricating specimens for the laboratory rutting test and the bending test: (1) Weigh the aggregates according to the grading requirements of AC-13 and add them to a small mixer. Add the early-strength agent and mix evenly. (2) Pour in water and mix evenly. (3) Add the emulsified asphalt. After mixing for 1 minute, the thick emulsified asphalt slurry fully adheres to the stones without flowing, and the aggregates are in a semi-loose state. (4) Place paper at the bottom of the test mold with reference to the production method of hot mix asphalt rut specimens. (5) Observe the state of the mixture, load the mixture into the mold, and evenly load the mixture into the mold in a circular motion from the edge to the center of the test mold. Appropriately compact it once in a circular motion from the edge to the center with a small compaction hammer, with the middle slightly higher than the surrounding area. (6) After the mixture is loaded into the test mold, place separator paper above the mixture for rolling. (7) Start the rolling wheel, first roll in one direction for 2 round trips (4 times) and unload; then lift the rolling wheel, turn the specimen around; and then roll with the same load. Roll in one direction 48 times (24 round trips). (8) After compaction and forming, remove the separator paper on the surface and mark the rolling direction. (9) If the test time is too tight and the relevant test conditions require natural placement for 22 days, the prepared specimens can also be placed in an oven at 60 °C and dried to a constant weight.

[0074] The experimental results are shown in Table 3 below:

[0075]

[0076] Analysis of experimental results:

[0077] For the emulsified asphalt mixture prepared by the present invention, during the test, the Marshall stability can reach more than 25 kN, the stability reaches more than 90%, and the flow value, freeze-thaw splitting strength ratio, and bending failure strain of the small beam low-temperature anti-cracking test far exceed those of the emulsified asphalt mixture in the prior art. Each performance index also reaches or even exceeds that of the hot mix asphalt mixture, ensuring that the emulsified asphalt mixture prepared by the present invention can be used as a surface layer material. At the same time, for the emulsified asphalt mixture prepared by the present invention, the maximum dynamic stability times can reach 42,000 times, far exceeding those of the emulsified asphalt mixture and the hot mix asphalt mixture in the prior art, indicating strong transportation stability performance and compressive performance.

[0078] Experimental Example 3: Experiment on calculating the energy conservation and emission reduction effect of emulsified asphalt mixture

[0079] Experimental method: Two sections of road surfaces with different materials were selected on the mine road in Dantu District, Zhenjiang City, Jiangsu Province. One material is hot mix asphalt mixture and hot plate modified asphalt mixture (used for the upper layer), and the other is the emulsified asphalt mixture prepared in the present invention. The experimental road surface has two-way 4 lanes, a width of 22 m, a total structural thickness of 18 cm, with the lower, middle, and upper layers being 8 cm, 6 cm, and 4 cm respectively, and the road surface length is 1 km. The energy consumption and carbon emissions of the lower and middle layers were calculated according to an asphalt-aggregate ratio of 5%, and those of the upper layer were calculated according to an asphalt-aggregate ratio of 4.5%, with a modifier dosage of 5%. The experimental results are shown in Table 4:

[0080] Among them, Scheme 1 represents the road surface scheme paved with hot mix asphalt mixture and hot plate modified asphalt mixture as materials, and Scheme 2 represents the road surface scheme paved with the emulsified asphalt mixture prepared in the present invention as materials. The dosage was calculated based on the density of the compacted mixture being 2.4 t / m 3 ³. The production energy consumption includes thermal, diesel, natural gas, and electricity energy consumption, and is calculated according to the General Principles for Calculation of Comprehensive Energy Consumption GB / T 2589-2020. The carbon emissions were calculated as the energy consumption × emission factor. The emission factors of thermal, diesel, natural gas, and electricity are 2.46, 3.72, 2.87, and 0.6451 respectively. The experimental results were evaluated and recognized by the Nanjing Sub-center of China Quality Certification Center.

[0081]

[0082] Analysis of experimental results: From the above experimental results, it can be seen that compared with the commonly used hot mix asphalt mixture in the prior art, the emulsified asphalt mixture prepared in the present invention has a 68.95% reduction in production energy consumption and a 65.51% reduction in carbon emissions, and its energy conservation and emission reduction effect is remarkable.

[0083] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. In addition, it should be understood that although this specification is described according to the implementation manners, it does not only include one technical solution. The narrative manner of this specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other implementation manners that can be understood by those skilled in the art.

Claims

1. An emulsified asphalt mixture, characterized in that: The mixture comprises the following components by weight: 95-98 parts of aggregate, 3-5 parts of early strength agent, 0-2 parts of water, 0-3 parts of mineral powder and 10-11 parts of modified emulsified asphalt; the modified emulsified asphalt comprises the following components by mass fraction: 58-60% of modified asphalt, 31.6-34.6% of water, 3-6% of cationic emulsifier, 2% of stabilizer and 0.4-1.4% of pH regulator; the modified asphalt is obtained by composite modification of SBS, petroleum resin and rubber powder, and the amount of SBS is 7-1.4% of the weight of the base asphalt. 8%, the amount of petroleum resin is 1-2% of the weight of the base asphalt, and the amount of rubber powder is 1-2% of the weight of the base asphalt; the cationic emulsifier includes the following components by mass fraction: 20% calcium lignin sulfonate, 25% OP-10, 25% OP-40 and 30% SP-20; the stabilizer is a 10wt.% polyvinyl alcohol aqueous solution; the early strength agent includes the following components by mass fraction: 80% double-fast cement, 15.5% interface agent, 2% expansion agent, 1% retarder and 1.5% carbon black.

2. The emulsified asphalt mixture according to claim 1, characterized in that: The emulsified asphalt mixture meets the following technical indicators: void ratio of 5-6%, Marshall stability of 25-30KN, flow value of 2.5-4mm, freeze-thaw splitting strength ratio greater than 90%, dynamic stability of 10000-42000 times / mm, and bending failure strain greater than 3000με.

3. A method for preparing an emulsified asphalt mixture as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: S1 Preparation of modified asphalt: After heating the base asphalt, add the stabilizer thereto, continue stirring and heating, add SBS, petroleum resin and rubber powder, and develop after swelling and shearing to obtain the modified asphalt; S2: preparing modified emulsified asphalt: dissolving an emulsifier in hot water, adding hydrochloric acid to adjust the pH to prepare an emulsifier aqueous solution, then heating the modified asphalt, and pumping the heated asphalt and the emulsifier aqueous solution into a stirring device for emulsification to obtain the modified emulsified asphalt; S3 prepares the mixture: heats the aggregate in a mixing device, adds an early strength agent to the aggregate and mixes evenly, then adds emulsified asphalt and mixes evenly to obtain the mixture.

4. The method for preparing an emulsified asphalt mixture according to claim 3, characterized in that: In step S1, the heating temperature of the matrix asphalt is 140-145° C., the continued heating temperature is 175-180° C., the stirring time is 10-15 minutes, the swelling time is 30-45 minutes, the shearing time is 120-150 minutes, and the development time is 90-120 minutes.

5. The method for preparing an emulsified asphalt mixture according to claim 3, characterized in that: In the step S2, the temperature of the hot water is 55-60°C, the pH value of the emulsifier aqueous solution is 1.5-3, and the heating temperature of the modified asphalt is 180-190°C.

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