Early-strength modified emulsified asphalt mixture and preparation method thereof

Abstract

The application discloses a kind of early-strength modified emulsified asphalt mixture and preparation method thereof, the content of each substance in the asphalt mixture is aggregate 70-80wt%, SBS modified emulsified asphalt 8-12wt%, early-strength agent 8-10wt%, mineral powder 4-8wt%, the addition amount of early-strength agent increases with the increase of the addition amount of SBS modified emulsified asphalt, when the addition amount of SBS modified emulsified asphalt increases by 1wt%, the addition amount of early-strength agent is correspondingly increased by 0.4-0.6wt%.The preparation method comprises the following steps: preparing SBS modified asphalt and keeping warm for standby;SBS modified emulsified asphalt is prepared and sealed storage; early-strength agent is prepared and stored at room temperature for standby; aggregate, early-strength agent and mineral powder are put into mixing kettle and stirred; SBS modified emulsified asphalt is added into mixing kettle and continues to stir, and early-strength modified emulsified asphalt mixture is prepared.The emulsified asphalt mixture prepared by the application has the advantages of high initial strength, fast strength growth and good road performance, and can be used for paving upper layer of high-grade pavement, and can quickly open traffic after paving.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of asphalt pavement materials and preparation, and particularly relates to an early-strength modified emulsified asphalt mixture and a preparation method thereof. BACKGROUND

[0002] At present, the total mileage of highways in China has reached several million kilometers, and more than 90% of the highways use asphalt pavement. Traditional hot-mixed asphalt mixture occupies an important position in road engineering due to its excellent road performance and wide applicability. However, hot-mixed asphalt mixture needs to be mixed, paved and compacted at high temperature, and its process limitations are more prominent: on the one hand, the material needs to be heated to a high temperature of 160-180℃ during construction, which not only leads to high energy consumption, but also causes the emission of harmful gases such as nitrogen oxides (NOx) and benzopyrene, polluting the environment and endangering personnel health; on the other hand, when the temperature of the mixture decreases, the viscosity of the asphalt increases sharply, which can easily cause uneven paving and insufficient compaction, thereby affecting the quality of the pavement.

[0003] Compared with the hot-mixing process, the construction temperature of warm-mixed asphalt mixture can be reduced by 30℃, but a large amount of energy is still consumed to heat the asphalt and aggregate during the construction process, thereby generating a large amount of smoke, waste heat and harmful gases, which not only pollutes the environment, but also further aggravates the greenhouse effect.

[0004] With the increasing emphasis on low-carbon and environmental protection, cold-mixed asphalt mixture technology has gradually become a research hotspot in the field of road engineering. Cold-mixed asphalt mixture not only has the advantages of low carbon and environmental protection, low cost and convenient construction, but also can effectively extend the construction season and provide a sustainable solution for road construction.

[0005] Cold-mixed asphalt mixture is a kind of asphalt material that can be mixed, paved and compacted at room temperature. Compared with hot-mixing process and warm-mixing process, the cold-mixing process has the following outstanding advantages: strong adaptability to construction temperature (5-40℃), no seasonal restrictions, normal construction in low-temperature environment; no need to heat the aggregate at high temperature, energy consumption reduced by 80-90%; carbon emissions and asphalt smoke emissions are greatly reduced, with low carbon and environmental protection and construction convenience. At present, cold-mixed asphalt mixture mainly realizes effective coating and bonding of aggregate through emulsified asphalt, foamed asphalt and solvent asphalt.

[0006] The cold-mixing technology represented by solvent-based asphalt cold patching material has obvious technical bottlenecks: its strength formation mainly depends on the evaporation of solvents such as kerosene and diesel to restore the viscosity of asphalt, which not only leads to low early strength of the material, but also has weak water damage resistance and insufficient anti-rutting performance, making it difficult to meet the requirements of high-grade pavement surface layer. At present, it is only suitable for temporary repair of damaged pavement such as potholes and cracks. In addition, the evaporation of diluents releases a large amount of volatile organic compounds (VOCs), which is in obvious conflict with the current green development concept.

[0007] As a road engineering material, foamed asphalt has advantages such as convenient construction, controllable cost, and old material recycling, but also has obvious technical limitations: its slow strength development leads to insufficient initial strength, and its durability is greatly affected by environmental factors, making it prone to aging, deformation, and cracking under high temperature, low temperature, and water erosion conditions. Its performance needs to be improved. In terms of construction, foamed asphalt requires strict control of process parameters, and quality control is difficult, which requires special equipment and professional operation, resulting in a significant increase in construction cost. In addition, its construction process is sensitive to weather conditions, has limited adaptability to complex road conditions, and has high raw material costs, which restricts its engineering application range.

[0008] Emulsified asphalt mixture, as the most commonly used cold-mixing technology, has received extensive attention from domestic and foreign researchers. Emulsified asphalt mixture has advantages such as simple production process, convenient storage and transportation, and environmental friendliness, which can effectively reduce energy consumption and environmental pollution and meet the requirements of green and low-carbon development. However, research has found that emulsified asphalt mixture has low initial strength and long curing period, which will cause the road to be unable to open to traffic in time after paving, and the precise control of the breaking time is still a technical difficulty. These factors not only limit the large-scale application of this technology in road engineering, but also make it mainly limited to road repair and low-grade road construction, making it difficult to meet the performance requirements of high-grade highway high-position pavement.

[0009] At present, emulsified asphalt mixture is mainly used in pavement base layer, and its application in surface layer with higher performance requirements is still in the preliminary exploration stage. The fundamental reason lies in the early strength characteristics of emulsified asphalt mixture: on the one hand, the formation of its early strength mainly depends on the breaking process of emulsified asphalt; on the other hand, its early strength as a key indicator to determine the opening time is affected by multiple factors such as temperature, humidity, and curing time.

[0010] At present, many experts and scholars improve the performance of emulsified asphalt mixture by modification and addition of external admixtures. However, existing research shows that the effect of emulsified asphalt cold mixing and cold paving technology in improving early strength is still not ideal, and there is a lack of systematic research, which leads to poor overall performance and difficulty in meeting the technical requirements of high-grade pavement surface. Therefore, in order to solve the problems of low initial strength, slow strength growth and poor water stability of emulsified asphalt mixture, it is urgent to develop an early strength modified emulsified asphalt mixture and its preparation method.

[0011] The patent for invention with publication number CN119191763A discloses an emulsified asphalt mixture and a preparation method thereof. The emulsified asphalt mixture is prepared from aggregate, early strength agent, water, mineral powder and modified emulsified asphalt. The modified emulsified asphalt is prepared from modified asphalt, water, cationic emulsifier, stabilizer and pH regulator. The modified asphalt is prepared from SBS, petroleum resin and rubber powder. The cationic emulsifier is prepared from calcium lignosulfonate, OP-10, OP-40 and OP-20. The stabilizer is polyvinyl alcohol aqueous solution. The early strength agent is prepared from double-quick cement, interfacial agent, expanding agent, retarder and carbon black. The performance indicators of the emulsified asphalt mixture in the technical solution can reach the effect of hot-mixed asphalt mixture, and it can be applied to asphalt pavement surface. However, no test data on initial strength of emulsified asphalt mixture is recorded, which shows that the technical solution focuses more on the long-term performance of emulsified asphalt mixture and ignores the initial performance. SUMMARY

[0012] To solve the problems in the prior art, the present application provides an early strength modified emulsified asphalt mixture. The mass percentage of each substance in the asphalt mixture is as follows: aggregate 70-80wt%, SBS modified emulsified asphalt 8-12wt%, early strength agent 8-10wt%, and mineral powder 4-8wt%. The sum of the contents of each substance is 100wt%. The addition amount of the early strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt. Within the mass percentage range of the early strength agent and the SBS modified emulsified asphalt, when the addition amount of the SBS modified emulsified asphalt increases by 1wt%, the addition amount of the early strength agent increases by 0.4-0.6wt% correspondingly.

[0013] Preferably, the aggregate includes nine grades of particle size, each grade of particle size accounts for 7-9wt% of the aggregate, 9.5-13.2mm accounts for 18-20wt%, 4.75-9.5mm accounts for 23-26wt%, 2.36-4.75mm accounts for 18-19wt%, 1.18-2.36mm accounts for 8-9wt%, 0.6-1.18mm accounts for 7-8wt%, 0.3-0.6mm accounts for 3-5wt%, 0.15-0.3mm accounts for 3-6wt%, 0.075-0.15mm accounts for 4-6wt%; the particle size of the mineral powder is less than 0.075mm; the aggregate and the mineral powder are both limestone.

[0014] Preferably in any of the above schemes, the mass percentage of each substance in the SBS modified emulsified asphalt is 58-60wt% of SBS modified asphalt, 6.5-7wt% of emulsifier, 1.2-1.4wt% of dilute hydrochloric acid, 32.2-34.2wt% of water, and 0.1-0.2wt% of stabilizer A.

[0015] Preferably in any of the above schemes, the mass percentage of each substance in the SBS modified asphalt is 88-90wt% of base asphalt, 6-7wt% of SBS modifier, 3-5wt% of aromatic oil, and 1-1.5wt% of stabilizer B; the base asphalt is 70# base asphalt, the SBS modifier is linear SBS modifier, and the stabilizer B is sulfur; the flash point of the aromatic oil is not less than 230℃, the density is 0.98-1.08kg / m 3 , and the kinematic viscosity at 100℃ is 15-25mm 2 / s.

[0016] Preferably in any of the above schemes, the emulsifier is a slow-fragmentation cationic SBS asphalt emulsifier, the concentration of the dilute hydrochloric acid is 0.01mol / L, and the stabilizer A is hydroxyethyl cellulose.

[0017] Preferably in any of the above schemes, the mass percentage of each substance in the early strength agent is 45-54wt% of fast-hardening sulphoaluminate cement, 18-22wt% of fly ash, 18-22wt% of silica fume, and 10-12wt% of anti-permeation agent.

[0018] Preferably in any of the above schemes, the content of silicon dioxide in the fly ash is not less than 60%, and the content of sulfur trioxide is not more than 1%; the fineness of the fly ash is not less than 94%, the water demand ratio is not more than 90%, the loss on ignition is not more than 3%, and the activity index is not less than 80%.

[0019] Preferably in any of the above schemes, the mass percentage of each substance in the anti-permeation agent is 28-32wt% of potassium aluminum sulfate, 35-40wt% of sodium silicate, 2-5wt% of glycerol stearate, 18-23wt% of polyethylene powder, and 5-8wt% of sodium polyacrylate.

[0020] The present application also provides a preparation method of the early-strength modified emulsified asphalt mixture, for preparing the early-strength modified emulsified asphalt mixture of any of the above schemes, which comprises the following steps in sequence:

[0021] Step one: prepare SBS modified asphalt according to the designed material ratio and process parameters, and store the prepared SBS modified asphalt for standby;

[0022] Step two: prepare SBS modified emulsified asphalt according to the designed material ratio and process parameters, and seal and store the prepared SBS modified emulsified asphalt;

[0023] Step three: prepare early-strength agent according to the designed material ratio, and store the prepared early-strength agent for standby at room temperature;

[0024] Step four: put aggregate, early-strength agent and mineral powder into a mixing pot according to the designed material ratio, and stir using a stirrer;

[0025] Step five: add SBS modified emulsified asphalt into the mixing pot according to the designed material ratio, and stir using a stirrer, and after the stirring is completed, the early-strength modified emulsified asphalt mixture is prepared.

[0026] Preferably, in step one, the preparation method of the SBS modified asphalt comprises the following steps in sequence: Step 1.1: weigh base asphalt, SBS modifier, aromatic oil and stabilizer B according to the designed material ratio for standby;

[0027] Step 1.2: heat the base asphalt in an electromagnetic oven, the heating temperature is 135-140℃, and the heating time is 3-5min, so that the base asphalt is kept in a flowing state, and is transferred into an oil bath pot;

[0028] Step 1.3: add aromatic oil into the oil bath pot, and stir using a stirrer, and heat at the same time, the stirring speed is 180-280r / min, when the temperature rises to 175-180℃, continue to stir for 10-15min;

[0029] Step 1.4: add SBS modifier into the oil bath pot, and stir using a stirrer, the stirring temperature is 175-180℃, the stirring speed is 180-280r / min, and the stirring time is 40-50min;

[0030] Step 1.5: Shear the mixture in the oil bath pot using a high-speed shearing instrument, the shearing temperature is 175-180℃, the shearing speed is 6500-7000r / min, and the shearing time is 80-110min;

[0031] Step 1.6: Add stabilizer B to the oil bath pot and shear using a high-speed shearing instrument, the shearing temperature is 175-180℃, the shearing speed is 6500-7000r / min, and the shearing time is 20-30min;

[0032] Step 1.7: Stir the mixture in the oil bath pot using a stirrer, the stirring temperature is 175-180℃, the stirring speed is 400-500r / min, and the stirring time is 60-90min, thereby obtaining SBS modified asphalt, and the SBS modified asphalt is kept at 175-180℃ for standby.

[0033] In any of the above schemes, preferably, in step two, the preparation method of the SBS modified emulsified asphalt comprises the following steps in order:

[0034] Step 2.1: SBS modified asphalt, emulsifier, water, dilute hydrochloric acid, and stabilizer A are weighed according to the designed material ratio for standby; Step 2.2: Heat the water to 60-80℃, then add the emulsifier into the water and stir until the emulsifier is dissolved in the water to obtain a soap solution; then add dilute hydrochloric acid into the soap solution to adjust the pH value of the soap solution to 2;

[0035] Step 2.3: Put the soap solution into the colloid mill for circulation treatment, the colloid mill speed is 1000-2000r / min, and the circulation time is 1-2min;

[0036] Step 2.4: Put the stabilizer A into the colloid mill for circulation treatment, the colloid mill speed is 1000-2000r / min, and the circulation time is 2-3min;

[0037] Step 2.5: Increase the colloid mill speed to 3500-4000r / min, then put the SBS modified asphalt kept at 175-180℃ for standby into the colloid mill for circulation treatment, the circulation time is 30-40min, and after the circulation treatment is completed, the SBS modified emulsified asphalt is prepared, pumped out, sealed and stored, and naturally cooled to room temperature for standby.

[0038] In any of the above schemes, preferably, in step three, the preparation method of the early strength agent comprises the following steps in order:

[0039] Step 3.1: Mix potassium aluminum sulfate, sodium silicate, glyceryl stearate, polyethylene powder, and sodium polyacrylate at room temperature according to the designed material ratio to prepare a permeability agent;

[0040] Step 3.2: The fast-hardening sulphoaluminate cement, fly ash, silica fume and anti-permeation agent are mixed according to the designed material ratio at normal temperature to obtain the early strength agent.

[0041] In any of the above schemes, preferably, in step four, the aggregate, early strength agent and mineral powder are put into the mixing pot for stirring, the stirring temperature is normal temperature, the stirring speed is 200-300 r / min, and the stirring time is 90-120 s.

[0042] In any of the above schemes, preferably, in step five, the SBS modified emulsified asphalt is added into the mixing pot for stirring, the stirring temperature is normal temperature, the stirring speed is 200-300 r / min, and the stirring time is 90-120 s.

[0043] In the present application, the electromagnetic oven, mixing pot, oil bath pot, stirrer, high-speed shearing instrument, colloid mill and the like used are common devices in the field, and there is no special limitation on the model, structure and the like of the devices. The aggregate includes nine grades of particle sizes, i.e. particle size 13.2-16 mm, particle size 9.5-13.2 mm, particle size 4.75-9.5 mm, particle size 2.36-4.75 mm, particle size 1.18-2.36 mm, particle size 0.6-1.18 mm, particle size 0.3-0.6 mm, particle size 0.15-0.3 mm, and particle size 0.075-0.15 mm, i.e. 13.2 mm≤particle size<16 mm, 9.5 mm≤particle size<13.2 mm, 4.75 mm≤particle size<9.5 mm, 2.36 mm≤particle size<4.75 mm, 1.18 mm≤particle size<2.36 mm, 0.6 mm≤particle size<1.18 mm, 0.3 mm≤particle size<0.6 mm, 0.15 mm≤particle size<0.3 mm, and 0.075 mm≤particle size<0.15 mm. For each grade of particle size, the material obtained after the material sequentially passes through the upper and lower two screen holes has a particle size between the upper and lower two screen holes, for example: particle size 9.5-13.2 mm (9.5 mm≤particle size<13.2 mm), i.e. the material obtained after the material sequentially passes through 13.2 mm screen holes and 9.5 mm screen holes has a particle size between 9.5-13.2 mm.

[0044] In the whole process of preparing the early strength modified emulsified asphalt mixture, the selection and ratio of each substance, the addition order of each substance, and the process parameters of each step are all very critical, especially the selection and ratio of each substance in the early strength agent. Only the synergistic effect of each formula parameter and process parameter can achieve the expected technical effect of the present application.

[0045] In the application, the early strength agent is compounded by fast hard sulphoaluminate cement, fly ash, silica ash and anti-permeation agent, wherein the content of silicon dioxide in the fly ash is not less than 60%, the content of sulfur trioxide is not more than 1%, the fineness of the fly ash is not less than 94% (namely, the passing amount of 45 mu m square hole sieve is not less than 94%, and the remaining amount is less than 6%), the water demand ratio is not more than 90%, the loss on ignition is not more than 3%, and the activity index is not less than 80%; and the anti-permeation agent is compounded by potassium aluminum sulfate, sodium silicate, glyceryl stearate, polyethylene powder and sodium polyacrylate.

[0046] The strength formation process of the emulsified asphalt mixture is mainly provided by the embedding and extruding action between aggregates and the cohesion of asphalt itself after the emulsified asphalt demulsification. The adhesion of the emulsified asphalt is mainly due to the opposite electric charges between the emulsified asphalt and the surface of the aggregate particles, and the opposite electric charges attract each other. After the emulsified asphalt demulsification, the adhesion between the asphalt and the aggregate is enhanced. The fundamental reason why the emulsified asphalt mixture cannot be used for the upper layer lies in the early strength characteristics of the emulsified asphalt mixture: on the one hand, the early strength formation mainly depends on the demulsification process of the emulsified asphalt; and on the other hand, the early strength as a key indicator to determine the opening time of traffic is affected by multiple factors such as temperature, humidity and curing time.

[0047] The rapid evaporation of water in the emulsified asphalt is beneficial to the early strength formation of the emulsified asphalt mixture. In the application, fast hard sulphoaluminate cement, silica ash, high-quality fly ash and anti-permeation agent are compounded as the early strength agent of the emulsified asphalt mixture. They not only make the emulsified asphalt demulsify rapidly by using the water in the emulsified asphalt, but also produce a high strength by the hydration products, which provides a favorable effect for the early strength of the emulsified asphalt mixture.

[0048] In the application, the early strength agent plays a key role in improving the early strength of the emulsified asphalt mixture, and the synergistic effect of each substance in the early strength agent is as follows:

[0049] (1) The fast hard sulphoaluminate cement has excellent properties such as fast setting, fast hardening, early strength, anti-permeation and corrosion resistance, and the hydration reaction of the main mineral calcium sulphoaluminate is the key to improve the early strength of the emulsified asphalt mixture. The hydration reaction is extremely fast, and a large amount of ettringite crystals can be generated within 15 minutes. The ettringite provides a stable mechanical skeleton for the mixture and is the main source of the early strength of the emulsified asphalt mixture; another product alumina gel fills the micro-pores in the mixture to improve the overall density and impermeability of the mixture. In addition, the C2S in the system slowly hydrates to generate hydrated calcium silicate and calcium hydroxide, which further fills the pores of the mixture and improves the structural density of the mixture.

[0050] (2) High-quality fly ash, which contains a large amount of glass beads, has fine particles, extremely large specific surface area, and smooth and dense surface. The mixed fly ash plays a dispersing role on the cement particles, so that the cement can be more uniformly dispersed in the mixture, at the same time, it fills the pores of the mixture and forms a lubricating layer on the surface of the aggregate, improving the fluidity of the mortar.

[0051] (3) Silica fume, which is mainly used to fill the pores of the mixture, improve the pore structure of the mixture, make the pores finer, and its high activity can accelerate the hydration reaction of sulphoaluminate cement, accelerate the demulsification of emulsified asphalt, and increase the hydration products such as hydrated calcium silicate formed by hydration reaction, thereby improving the initial strength of emulsified asphalt mixture.

[0052] (4) Anti-permeation agent, which mainly uses its film-forming property to resist external interference on the emulsified asphalt mixture, and reacts by absorbing water in the emulsified asphalt. After being exposed to water, it forms a dense waterproof, corrosion-resistant and high-temperature-resistant film on the surface of the emulsified asphalt mixture.

[0053] In the present application, the anti-permeation agent is compounded by potassium aluminum sulfate, sodium silicate, glycerol stearate, polyethylene powder and sodium polyacrylate. The synergistic effect of each substance is as follows:

[0054] When potassium aluminum sulfate is dissolved in water, Al 3+ ions and H + ions are dissociated, which leads to an acidic environment caused by H + ions. This results in a decrease in the stability of sodium silicate, which catalyzes the polycondensation reaction between Al 3+ ions and silicate ions (SiO3 2- ), forming water-insoluble, flocculent aluminum silicate gel. These gels are sticky and quickly penetrate and fill the micro-pores and small cracks inside the mixture. After solidification, the connected water-permeable channels are sealed.

[0055] Glycerol stearate and polyethylene powder are hydrophobic materials. After glycerol stearate is adsorbed in the pore wall of the material, its hydrophobic long carbon chain will face the pore wall, reducing the surface free energy of the pore wall, thereby weakening the capillary action and reducing the water brought by capillary suction. Polyethylene powder has extremely low surface energy and extremely high hydrophobicity, and the fine particles fill the internal pores of the mixture, forming a hydrophobic grid. The hydrophobic layer formed by glycerol stearate and polyethylene powder can protect the gel formed by potassium aluminum sulfate and sodium silicate from being washed away, further improving the anti-permeation effect.

[0056] Sodium polyacrylate is a high-molecular-weight, lightly cross-linked superabsorbent resin. The carboxylate ions (-COO -When sodium polyacrylate (SPA) comes into contact with water, it generates strong osmotic pressure and binds a large number of water molecules through hydrogen bonds. The molecular chains extend due to charge repulsion, causing the entire cross-linked network to absorb water and swell rapidly. This rapid increase in volume forcefully compresses and blocks the surrounding pores, cracks, and channels. The expanded sodium polyacrylate further compacts the aluminosilicate gel, enhancing its blocking ability. At the same time, the water-saturated sodium polyacrylate forms a high-viscosity hydrogel, establishing a barrier that is extremely difficult for water to pass through.

[0057] The early-strength modified emulsified asphalt mixture and its preparation method of the present invention have the following beneficial effects:

[0058] (1) This invention is the first to use fly ash and silica fume as raw materials for the preparation of early strength agent. At the same time, it innovatively develops a new type of anti-permeability agent and uses this new anti-permeability agent as a raw material for the preparation of early strength agent. By adjusting the proportion of each substance in the anti-permeability agent and the proportion of each substance in the early strength agent, the function of the early strength agent is maximized, thereby promoting the rapid formation of early strength of emulsified asphalt mixture. The early strength is very high, and the road surface can be opened to traffic quickly after paving, reducing the impact on road traffic.

[0059] (2) The emulsified asphalt mixture prepared by the present invention has high overall performance, can meet the performance requirements of hot-mix asphalt mixture, and meets the technical requirements of high-grade pavement surface layer.

[0060] (3) The emulsified asphalt mixture prepared by the present invention has excellent properties such as short molding cycle, high early strength, good stability and rapid opening to traffic. It has important practical significance for improving road construction efficiency, ensuring road performance and promoting green road construction.

[0061] (4) The emulsified asphalt mixture preparation technology of the present invention belongs to cold mixing and cold paving technology. Compared with traditional hot mixing technology and warm mixing technology, it has the advantages of low carbon and environmental protection. It is not only environmentally friendly, but also improves the working conditions of on-site construction personnel. Attached Figure Description

[0062] Figure 1 This is a process flow diagram of a preferred embodiment of the early-strength modified emulsified asphalt mixture and its preparation method according to the present invention;

[0063] Figure 2 for Figure 1 The images show actual photos of the SBS modified bitumen prepared in the embodiments shown, including: (a) overall effect, (b) stringing effect;

[0064] Figure 3 for Figure 1 Photographs of the SBS-modified emulsified asphalt prepared in the illustrated embodiment;

[0065] Figure 4 for Figure 1A physical photo of the early strength agent prepared in the embodiment shown;

[0066] Figure 5 For Figure 1 A physical photo of the early strength modified emulsified asphalt mixture prepared in the embodiment shown. DETAILED DESCRIPTION

[0067] In order to further understand the inventive content of the present application, the present application will be described in detail below in combination with specific embodiments.

[0068] Embodiment one:

[0069] According to a preferred embodiment of the early strength modified emulsified asphalt mixture of the present application, the mass percentage of each substance in the asphalt mixture is 80wt% of aggregate, 8wt% of SBS modified emulsified asphalt, 8wt% of early strength agent, and 4wt% of mineral powder, and the sum of the contents of each substance is 100wt%; the addition amount of the early strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt, and within the mass percentage range of the early strength agent and the SBS modified emulsified asphalt, when the addition amount of the SBS modified emulsified asphalt increases by 1wt%, the addition amount of the early strength agent correspondingly increases by 0.4-0.6wt%. In this embodiment, the SBS modified emulsified asphalt and the early strength agent are both the minimum addition amount.

[0070] The aggregate includes nine grades of particle size, and the mass percentage of each grade of particle size in the aggregate is 8wt% of particle size 13.2-16mm, 19wt% of particle size 9.5-13.2mm, 25wt% of particle size 4.75-9.5mm, 19wt% of particle size 2.36-4.75mm, 8wt% of particle size 1.18-2.36mm, 8wt% of particle size 0.6-1.18mm, 4wt% of particle size 0.3-0.6mm, 4wt% of particle size 0.15-0.3mm, and 5wt% of particle size 0.075-0.15mm; the particle size of the mineral powder is less than 0.075mm; and the aggregate and the mineral powder are both limestone.

[0071] The mass percentage of each substance in the SBS modified emulsified asphalt is 59wt% of SBS modified asphalt, 6.5wt% of emulsifier, 1.4wt% of dilute hydrochloric acid, 33wt% of water, and 0.1wt% of stabilizer A.

[0072] The mass percentage of each substance in the SBS modified asphalt is as follows: 89wt% of base asphalt, 6wt% of SBS modifier, 4wt% of aromatic oil, and 1wt% of stabilizer B; the base asphalt is No. 70 base asphalt, the SBS modifier is linear SBS modifier, and the stabilizer B is sulfur; the flash point of the aromatic oil is not less than 230°C, the density is 0.98-1.08 kg / m 3 , and the kinematic viscosity at 100°C is 15-25 mm 2 / s. The emulsifier is slow-fragmentation cationic SBS asphalt emulsifier, the concentration of the dilute hydrochloric acid is 0.01 mol / L, and the stabilizer A is hydroxyethyl cellulose.

[0073] The mass percentage of each substance in the early strength agent is as follows: 49wt% of fast-hardening sulphoaluminate cement, 20wt% of fly ash, 20wt% of silica fume, and 11wt% of anti-permeation agent. The content of silicon dioxide in the fly ash is not less than 60%, and the content of sulfur trioxide is not more than 1%; the fineness of the fly ash is not less than 94%, the water demand ratio is not more than 90%, the loss on ignition is not more than 3%, and the activity index is not less than 80%. The mass percentage of each substance in the anti-permeation agent is as follows: 30wt% of potassium aluminum sulfate, 38wt% of sodium silicate, 4wt% of glycerol stearate, 21wt% of polyethylene powder, and 7wt% of sodium polyacrylate.

[0074] As shown in Figure 1 , the embodiment also provides a preparation method of the early-strength modified emulsified asphalt mixture, for preparing the early-strength modified emulsified asphalt mixture, and the preparation method comprises the following steps in sequence:

[0075] Step one: preparing SBS modified asphalt according to the designed material ratio and process parameters, and storing the prepared SBS modified asphalt for standby;

[0076] Step two: preparing SBS modified emulsified asphalt according to the designed material ratio and process parameters, and sealing and storing the prepared SBS modified emulsified asphalt;

[0077] Step three: preparing early strength agent according to the designed material ratio, and storing the prepared early strength agent for standby at room temperature;

[0078] Step four: putting aggregate, early strength agent, and mineral powder into a mixing pot according to the designed material ratio, and stirring using a stirrer;

[0079] Step five: adding SBS modified emulsified asphalt into the mixing pot according to the designed material ratio, and stirring using the stirrer, and after the stirring is completed, the early-strength modified emulsified asphalt mixture is prepared.

[0080] In step one, the preparation method of the SBS modified asphalt comprises the following steps in sequence:

[0081] Step 1.1: The base asphalt, SBS modifier, aromatic oil and stabilizer B are weighed according to the designed material ratio;

[0082] Step 1.2: The base asphalt is heated in the electromagnetic oven at a temperature of 138℃ for 4 minutes to keep it in a flowing state, and then it is transferred to the oil bath pot;

[0083] Step 1.3: The aromatic oil is added to the oil bath pot and stirred by the stirrer, and the temperature is increased while stirring at a speed of 230r / min, and when the temperature reaches 178℃, the stirring is continued for 12 minutes;

[0084] Step 1.4: The SBS modifier is added to the oil bath pot and stirred by the stirrer at a temperature of 178℃ and a speed of 230r / min for 45 minutes;

[0085] Step 1.5: The mixture in the oil bath pot is sheared by the high-speed shearing instrument at a temperature of 178℃ and a speed of 6800r / min for 95 minutes;

[0086] Step 1.6: The stabilizer B is added to the oil bath pot and sheared by the high-speed shearing instrument at a temperature of 178℃ and a speed of 6800r / min for 25 minutes;

[0087] Step 1.7: The mixture in the oil bath pot is stirred by the stirrer at a temperature of 178℃ and a speed of 450r / min for 75 minutes to obtain the SBS modified asphalt, which is kept at 178℃ for standby.

[0088] In step two, the preparation method of the SBS modified emulsified asphalt comprises the following steps in sequence:

[0089] Step 2.1: The SBS modified asphalt, emulsifier, water, dilute hydrochloric acid and stabilizer A are weighed according to the designed material ratio for standby; Step 2.2: The water is heated to 70℃, and then the emulsifier is added to the water and stirred uniformly to dissolve the emulsifier in the water to obtain a soap solution; then the dilute hydrochloric acid is added to the soap solution to adjust the pH value of the soap solution to 2;

[0090] Step 2.3: The soap solution is put into the colloid mill for circulation treatment at a speed of 1500r / min for 1.5 minutes; Step 2.4: The stabilizer A is put into the colloid mill for circulation treatment at a speed of 1500r / min for 2.5 minutes;

[0091] Step 2.5: The rotational speed of the colloid mill is increased to 3800 r / min, and the SBS modified asphalt prepared in advance at 178℃ is poured into the colloid mill for circulation treatment, and the circulation time is 35 min. After the circulation treatment is completed, the SBS modified emulsified asphalt is prepared, and it is pumped out and stored in a sealed manner, and naturally cooled to room temperature for standby use.

[0092] In step three, the preparation method of the early strength agent comprises the following steps in order:

[0093] Step 3.1: According to the designed material ratio, the potassium aluminum sulfate, sodium silicate, glyceryl stearate, polyethylene powder and sodium polyacrylate are uniformly mixed at room temperature to prepare the impermeability agent.

[0094] Step 3.2: According to the designed material ratio, the fast-hardening sulfoaluminate cement, fly ash, silica fume and impermeability agent are uniformly mixed at room temperature to prepare the early strength agent.

[0095] In step four, the aggregate, early strength agent and mineral powder are put into the mixing pot and stirred, the stirring temperature is room temperature, the stirring speed is 250 r / min, and the stirring time is 105 s.

[0096] In step five, the SBS modified emulsified asphalt is added into the mixing pot and stirred, the stirring temperature is room temperature, the stirring speed is 250 r / min, and the stirring time is 105 s.

[0097] In this embodiment, the prepared SBS modified asphalt is as shown in Figure 2 , wherein (a) is the overall effect diagram, and (b) is the drawing effect diagram; the prepared SBS modified emulsified asphalt is as shown in Figure 3 ; the prepared early strength agent is as shown in Figure 4 ; and the prepared early strength type modified emulsified asphalt mixture is as shown in Figure 5 .

[0098] Figure 2 (b) of FIG. 1 is a drawing effect diagram of the SBS modified asphalt. Using a stick to dip the SBS modified asphalt and slowly lifting up, observing the length, continuity and fracture morphology of the formed filament (drawing), the performance effect of the SBS modified asphalt can be directly judged. As can be seen from the figure, the SBS modified asphalt prepared in this embodiment has excellent viscoelasticity (i.e., good elastic recovery ability after SBS modification), high temperature performance (the longer the filament, the better the flowability at high temperature), and modifier dispersion effect (uniformly dispersed SBS will form uniform filament).

[0099] The early-strength modified emulsified asphalt mixture and the preparation method thereof have the following beneficial effects: (1) the fly ash and silica ash are used as the preparation raw materials of the early-strength agent for the first time, a new type of anti-permeation agent is innovatively developed and used as the preparation raw material of the early-strength agent, the proportion of the substances in the anti-permeation agent and the proportion of the substances in the early-strength agent are adjusted, the function of the early-strength agent is maximized, and the emulsified asphalt mixture is promoted to quickly form early strength and has high early strength, so that the traffic can be quickly opened after the pavement is paved, and the influence on the road traffic is reduced; (2) the prepared emulsified asphalt mixture has high overall performance and can meet the performance requirements of the hot-mixed asphalt mixture and the technical requirements of the upper layer of the high-grade pavement; (3) the prepared emulsified asphalt mixture has the advantages of short molding cycle, high early strength, good stability and quick traffic opening, and has important significance for improving the road construction efficiency, guaranteeing the road performance and promoting the green road construction; and (4) the cold-mixing and cold-paving technology has the advantages of low carbon and environmental protection, is friendly to the environment and can improve the working conditions of the on-site construction personnel.

[0100] Embodiment two

[0101] According to another preferred embodiment of the early-strength modified emulsified asphalt mixture and the preparation method thereof, the selection of the substances, the preparation process, the used equipment, the technical principle and the beneficial effects are basically the same as those of the first embodiment, and the difference is that:

[0102] The mass percentage of each substance in the asphalt mixture is 78wt% of aggregate, 9wt% of SBS modified emulsified asphalt, 8.5wt% of early-strength agent and 4.5wt% of mineral powder, and the sum of the contents of the substances is 100wt%; the addition amount of the early-strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt, and within the mass percentage range of the early-strength agent and the SBS modified emulsified asphalt, when the addition amount of the SBS modified emulsified asphalt increases by 1wt%, the addition amount of the early-strength agent increases by 0.5wt% correspondingly, and the addition amount of the early-strength agent is ensured to be within the range of 0.4-0.6wt%.

[0103] The aggregate includes nine grades of particle sizes, and the mass percentage of each grade of particle size in the aggregate is 7wt% of particle size 13.2-16mm, 18wt% of particle size 9.5-13.2mm, 26wt% of particle size 4.75-9.5mm, 18wt% of particle size 2.36-4.75mm, 9wt% of particle size 1.18-2.36mm, 7wt% of particle size 0.6-1.18mm, 3wt% of particle size 0.3-0.6mm, 6wt% of particle size 0.15-0.3mm and 6wt% of particle size 0.075-0.15mm.

[0104] The mass percentage of each substance in the SBS modified emulsified asphalt is SBS modified asphalt 58wt%, emulsifier 7wt%, dilute hydrochloric acid 1.2wt%, water 33.6wt%, stabilizer A 0.2wt%.

[0105] The mass percentage of each substance in the SBS modified asphalt is base asphalt 88wt%, SBS modifier 7wt%, aromatic oil 3.5wt%, stabilizer B 1.5wt%.

[0106] The mass percentage of each substance in the early strength agent is fast hard sulphoaluminate cement 54wt%, fly ash 18wt%, silica fume 18wt%, and anti-permeation agent 10wt%. The mass percentage of each substance in the anti-permeation agent is potassium aluminum sulfate 32wt%, sodium silicate 35wt%, glycerol stearate 5wt%, polyethylene powder 20wt%, and polyacrylic acid sodium 8wt%.

[0107] In step one, the preparation method of the SBS modified asphalt comprises the following main process parameters: step 1.2, heating temperature of base asphalt 135℃, heating time 5min; step 1.3, aromatic oil is added into an oil bath pot and stirred, stirring speed 180r / min, after the temperature rises to 175℃, continue to stir for 15min; step 1.4, SBS modifier is added into the oil bath pot and stirred, stirring temperature 175℃, stirring speed 180r / min, stirring time 50min; step 1.5, the mixture in the oil bath pot is sheared, shearing temperature 175℃, shearing speed 6500r / min, shearing time 110min; step 1.6, stabilizer B is added into the oil bath pot and sheared, shearing temperature 175℃, shearing speed 6500r / min, shearing time 30min; step 1.7, the mixture in the oil bath pot is stirred, stirring temperature 175℃, stirring speed 400r / min, stirring time 90min, thereby SBS modified asphalt is prepared, and is kept at 175℃ for standby.

[0108] In step two, the preparation method of the SBS modified emulsified asphalt comprises the following main process parameters: step 2.2, water is heated to 60℃, emulsifier is added into the water and stirred to obtain a soap solution, and dilute hydrochloric acid is added to adjust the pH value of the soap solution to 2; step 2.3, the soap solution is put into a colloid mill for circulation treatment, the rotation speed of the colloid mill is 1000r / min, and the circulation time is 2min; step 2.4, stabilizer A is put into the colloid mill for circulation treatment, the rotation speed of the colloid mill is 1000r / min, and the circulation time is 3min; step 2.5, the rotation speed of the colloid mill is increased to 3500r / min, and the SBS modified asphalt kept at 175℃ for standby is put into the colloid mill for circulation treatment, and the circulation time is 40min, thereby SBS modified emulsified asphalt is prepared.

[0109] In step four, the aggregate, early strength agent and mineral powder are put into the mixing pot and stirred, the stirring temperature is normal temperature, the stirring speed is 200 r / min, and the stirring time is 120 s.

[0110] In step five, the SBS modified emulsified asphalt is added into the mixing pot and stirred, the stirring temperature is normal temperature, the stirring speed is 200 r / min, and the stirring time is 120 s.

[0111] Example three:

[0112] According to another preferred embodiment of the early strength modified emulsified asphalt mixture and the preparation method thereof, the selection of each substance, the preparation process, the used equipment, the technical principle, the beneficial effects and the like are basically the same as those of example one, except that:

[0113] The mass percentage of each substance in the asphalt mixture is 76wt% of aggregate, 10wt% of SBS modified emulsified asphalt, 9.1wt% of early strength agent and 4.9wt% of mineral powder, and the sum of the contents of each substance is 100wt%; the addition amount of the early strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt, and within the mass percentage range of the early strength agent and the SBS modified emulsified asphalt, the addition amount of the early strength agent increases by 0.6wt% when the addition amount of the SBS modified emulsified asphalt increases by 1wt%, and it is ensured to be within the range of 0.4-0.6wt%.

[0114] The aggregate includes nine grades of particle sizes, and the mass percentage of each grade of particle size in the aggregate is 9wt% of particle size 13.2-16mm, 20wt% of particle size 9.5-13.2mm, 23wt% of particle size 4.75-9.5mm, 19wt% of particle size 2.36-4.75mm, 9wt% of particle size 1.18-2.36mm, 8wt% of particle size 0.6-1.18mm, 5wt% of particle size 0.3-0.6mm, 3wt% of particle size 0.15-0.3mm and 4wt% of particle size 0.075-0.15mm.

[0115] The mass percentage of each substance in the SBS modified emulsified asphalt is 60wt% of SBS modified asphalt, 6.5wt% of emulsifier, 1.2wt% of dilute hydrochloric acid, 32.2wt% of water and 0.1wt% of stabilizer A.

[0116] The mass percentage of each substance in the SBS modified asphalt is 90wt% of base asphalt, 6wt% of SBS modifier, 3wt% of aromatic oil and 1wt% of stabilizer B.

[0117] The mass percentage of each substance in the early strength agent is 45wt% of fast hardening sulphoaluminate cement, 21wt% of fly ash, 22wt% of silica ash, and 12wt% of anti-permeation agent. The mass percentage of each substance in the anti-permeation agent is 28wt% of potassium aluminum sulfate, 40wt% of sodium silicate, 4wt% of glyceryl stearate, 23wt% of polyethylene powder, and 5wt% of sodium polyacrylate.

[0118] In step one, the preparation method of the SBS modified asphalt comprises the following main process parameters: step 1.2, the heating temperature of the base asphalt is 140℃, and the heating time is 3min; step 1.3, the aromatic oil is added into the oil bath pot and stirred, the stirring speed is 280r / min, and after the temperature rises to 180℃, the stirring is continued for 10min; step 1.4, the SBS modifier is added into the oil bath pot and stirred, the stirring temperature is 180℃, the stirring speed is 280r / min, and the stirring time is 40min; step 1.5, the mixture in the oil bath pot is sheared, the shearing temperature is 180℃, the shearing speed is 7000r / min, and the shearing time is 80min; step 1.6, the stabilizer B is added into the oil bath pot and sheared, the shearing temperature is 180℃, the shearing speed is 7000r / min, and the shearing time is 20min; step 1.7, the mixture in the oil bath pot is stirred, the stirring temperature is 180℃, the stirring speed is 500r / min, and the stirring time is 60min, so that the SBS modified asphalt is prepared, and is kept at 180℃ for standby.

[0119] In step two, the preparation method of the SBS modified emulsified asphalt comprises the following main process parameters: step 2.2, the water is heated to 80℃, the emulsifier is added into the water and stirred to obtain a soap solution, and then dilute hydrochloric acid is added to adjust the pH value of the soap solution to 2; step 2.3, the soap solution is put into a colloid mill for circulation treatment, the rotation speed of the colloid mill is 2000r / min, and the circulation time is 1min; step 2.4, the stabilizer A is put into the colloid mill for circulation treatment, the rotation speed of the colloid mill is 2000r / min, and the circulation time is 2min; step 2.5, the rotation speed of the colloid mill is increased to 4000r / min, and then the SBS modified asphalt kept at 180℃ for standby is put into the colloid mill for circulation treatment, and the circulation time is 30min, so that the SBS modified emulsified asphalt is prepared.

[0120] In step four, the aggregate, the early strength agent and the mineral powder are put into a mixing pot and stirred, the stirring temperature is normal temperature, the stirring speed is 300r / min, and the stirring time is 90s.

[0121] In step five, the SBS modified emulsified asphalt is added into the mixing pot and stirred, the stirring temperature is normal temperature, the stirring speed is 300r / min, and the stirring time is 90s.

[0122] Example four:

[0123] According to another preferred embodiment of the early-strength modified emulsified asphalt mixture and the preparation method thereof, the selection of each substance, the preparation process, the equipment used, the technical principle, the beneficial effects, etc. are basically the same as those of Embodiment One to Embodiment Three, except that:

[0124] The mass percentage of each substance in the asphalt mixture is 74wt% of aggregate, 11wt% of SBS modified emulsified asphalt, 9.5wt% of early-strength agent, and 5.5wt% of mineral powder, and the sum of the contents of each substance is 100wt%; the addition amount of the early-strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt, and within the mass percentage range of the early-strength agent and the SBS modified emulsified asphalt, the addition amount of the early-strength agent increases by 0.4wt% when the addition amount of the SBS modified emulsified asphalt increases by 1wt%, and it is ensured to be within the range of 0.4-0.6wt%.

[0125] The aggregate includes nine grades of particle sizes, and the mass percentage of each grade of particle size in the aggregate is 8.5wt% of particle size 13.2-16mm, 19.5wt% of particle size 9.5-13.2mm, 25.5wt% of particle size 4.75-9.5mm, 18.5wt% of particle size 2.36-4.75mm, 8.5wt% of particle size 1.18-2.36mm, 7.5wt% of particle size 0.6-1.18mm, 3wt% of particle size 0.3-0.6mm, 3wt% of particle size 0.15-0.3mm, and 6wt% of particle size 0.075-0.15mm.

[0126] The mass percentage of each substance in the SBS modified emulsified asphalt is 58wt% of SBS modified asphalt, 6.8wt% of emulsifier, 1.3wt% of dilute hydrochloric acid, 33.8wt% of water, and 0.1wt% of stabilizer A.

[0127] The mass percentage of each substance in the SBS modified asphalt is 88wt% of base asphalt, 6.5wt% of SBS modifier, 4.5wt% of aromatic oil, and 1wt% of stabilizer B.

[0128] The mass percentage of each substance in the early-strength agent is 52wt% of fast-hardening sulphoaluminate cement, 19wt% of fly ash, 19wt% of silica fume, and 10wt% of anti-permeation agent. The mass percentage of each substance in the anti-permeation agent is 31wt% of potassium aluminum sulfate, 36wt% of sodium silicate, 3wt% of glycerol stearate, 22wt% of polyethylene powder, and 8wt% of sodium polyacrylate.

[0129] Embodiment Five:

[0130] According to another preferred embodiment of the early-strength modified emulsified asphalt mixture and the preparation method thereof, the selection of each substance, the preparation process, the used equipment, the technical principle, the beneficial effects and the like are basically the same as those of the first embodiment to the third embodiment, and the difference is that:

[0131] The mass percentage of each substance in the asphalt mixture is 70wt% of aggregate, 12wt% of SBS modified emulsified asphalt, 10wt% of early-strength agent and 8wt% of mineral powder, and the sum of the contents of each substance is 100wt%; the addition amount of the early-strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt, and within the mass percentage range of the early-strength agent and the SBS modified emulsified asphalt, the addition amount of the early-strength agent increases by 0.5wt% when the addition amount of the SBS modified emulsified asphalt increases by 1wt%, and it is ensured that the addition amount of the early-strength agent is within the range of 0.4-0.6wt%.

[0132] The aggregate includes nine grades of particle sizes, and the mass percentage of each grade of particle size in the aggregate is 7.5wt% of particle size 13.2-16mm, 18.5wt% of particle size 9.5-13.2mm, 24wt% of particle size 4.75-9.5mm, 19wt% of particle size 2.36-4.75mm, 8wt% of particle size 1.18-2.36mm, 7wt% of particle size 0.6-1.18mm, 4wt% of particle size 0.3-0.6mm, 6wt% of particle size 0.15-0.3mm and 6wt% of particle size 0.075-0.15mm.

[0133] The mass percentage of each substance in the SBS modified emulsified asphalt is 59wt% of SBS modified asphalt, 6.5wt% of emulsifier, 1.4wt% of dilute hydrochloric acid, 32.9wt% of water and 0.2wt% of stabilizer A.

[0134] The mass percentage of each substance in the SBS modified asphalt is 88wt% of base asphalt, 6wt% of SBS modifier, 4.8wt% of aromatic oil and 1.2wt% of stabilizer B.

[0135] The mass percentage of each substance in the early-strength agent is 47wt% of fast-hardening sulphoaluminate cement, 21wt% of fly ash, 21wt% of silica ash and 11wt% of anti-permeation agent; the mass percentage of each substance in the anti-permeation agent is 29wt% of potassium aluminum sulfate, 39wt% of sodium silicate, 2wt% of glyceryl stearate, 22wt% of polyethylene powder and 8wt% of sodium polyacrylate.

[0136] The early performance and final performance of the early strength modified emulsified asphalt mixture prepared in the above five examples are tested according to the Technical Specification for Construction of Highway Asphalt Pavement (JTG F40-2004) and the Technical Specification for Construction of Cold-mixed and Cold-laid Emulsified Asphalt Mixture Pavement (DB11 / T 2257-2024). The test equipment, test environment, test conditions, sample shape and size are the same, and three sets of parallel tests are performed for each performance test, and then the average value is taken. The test indexes of the SBS modified emulsified asphalt prepared in the above five examples all meet the specification requirements.

[0137] For the above five examples, Marshall test pieces are prepared. The test pieces are cured in a natural environment with an ambient temperature of 25-32°C and a humidity of 35±5%, without water immersion, and Marshall stability tests are directly performed. The early strength performance of the early strength modified emulsified asphalt mixture at different curing times is tested, and the test results are shown in Table 1.

[0138] Table 1 Test results of early strength performance of early strength modified emulsified asphalt mixture

[0139]

[0140] From the above test data, it can be seen that as the curing time increases, the water in the modified emulsified asphalt mixture continuously evaporates, the early strength continuously increases, the Marshall stability continuously increases, and the flow value continuously decreases. The Marshall stability of the modified emulsified asphalt mixture of the five examples after 1.5h of curing all exceeds 8KN, which has reached the requirement for opening to traffic of hot-mixed asphalt mixture. This is mainly due to the maximum function of the early strength agent, which promotes the rapid formation of early strength of the modified emulsified asphalt mixture, and the early strength is very high, which can quickly open traffic after paving the pavement, and can meet the technical requirements of the upper layer of high-grade pavement.

[0141] For the above five examples, Marshall test pieces are prepared. The curing condition is that the test pieces are dried to constant weight in an oven at 60°C (usually 48h is required); after the test pieces are cured, they are taken out of the oven and cooled to room temperature under natural conditions, and then left to stand for 24h; after the test pieces are left to stand, they are first soaked in water at 60°C for 0.5h / 48h, and then Marshall stability tests are performed, and the final performance of the early strength modified emulsified asphalt mixture is tested, and the test results are shown in Table 2.

[0142] Table 2 Test results of final performance of early strength modified emulsified asphalt mixture

[0143] Test item Example 1 Example 2 Example 3 Example 4 Example 5 Marshall stability (60°C, 0.5h) / KN 28.66 28.69 30.11 27.52 27.32 Flow value / mm 2.5 2.6 2.4 2.7 2.7 Splitting strength (15°C) / MPa 1.40 1.41 1.48 1.45 1.44 Immersion Marshall residual stability (60°C, 48h) / % 82.49 82.16 85.45 81.65 80.34 Dry-wet splitting strength ratio (15°C) / % 90.58 91.34 94.70 92.49 91.75 Freeze-thaw splitting strength ratio (15°C) / % 80.86 81.46 85.77 83.37 82.64 Splitting strength (-10°C) / MPa 4.1592 4.2317 4.5859 4.2568 4.4639 Dynamic stability (times / mm) 29036 30751 33577 24648 23917 Low-temperature beam bending failure strain / με 3193.4 3267.8 3576.8 3467.4 3263.4

[0144] From the above test data, the mechanical properties, high and low temperature performance, water stability and other indicators of the modified emulsified asphalt mixture of the five embodiments are all higher, which have reached the performance requirements of hot mix asphalt mixture and meet the technical requirements of the upper layer of high-grade pavement.

[0145] The aromatic oil (Fg107) used in the above examples was purchased from Shandong Furunada Chemical Co., Ltd., the slow crack cationic SBS asphalt emulsifier (r5520) was purchased from Xinxiang Longteng Highway Technology Co., Ltd., the aggregate, mineral powder, base asphalt, SBS modifier and the like were purchased from Beijing Municipal Road and Bridge Building Material Group Co., Ltd., the hydroxyethyl cellulose was purchased from Hubei Xiangtai Cellulose Co., Ltd., the fast hard sulphoaluminate cement, fly ash and silica fume were purchased from Zhucheng Jiuli Building Material Co., Ltd., the potassium aluminum sulfate was purchased from Langfang Qianyao Technology Co., Ltd., the sulfur, sodium silicate, glyceryl stearate, polyethylene powder, polyacrylic acid sodium, dilute hydrochloric acid and the like were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0146] It is particularly pointed out that the technical solutions of the present application involve many parameters, and the synergistic effect between each parameter needs to be considered in order to obtain the beneficial effects and significant progress of the present application. Moreover, the value range of each parameter in the technical solution is obtained through a large number of tests, and for each parameter and the mutual combination of each parameter, the inventors have recorded a large amount of test data, which is not disclosed in detail due to the limited space.

[0147] It is not difficult for those skilled in the art to understand that the present application includes any combination of the above-mentioned invention content and specific embodiment parts of the present application specification and the parts shown in the drawings, and due to the limited space and in order to make the specification concise, each scheme formed by these combinations is not described one by one. Any modification, equivalent replacement, improvement and the like made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A modified emulsified asphalt mixture of early strength, characterized by: The mass percentage of each substance in the asphalt mixture is 70-80wt% of aggregate, 8-12wt% of SBS modified emulsified asphalt, 8-10wt% of early strength agent, and 4-8wt% of mineral powder, and the sum of the content of each substance is 100wt%; the addition amount of the early strength agent increases with the increase of the addition amount of the SBS modified emulsified asphalt, and within the mass percentage range of the early strength agent and the SBS modified emulsified asphalt, the addition amount of the early strength agent increases by 0.4-0.6wt% when the addition amount of the SBS modified emulsified asphalt increases by 1wt%; The mass percentage of each substance in the early strength agent is 45-54wt% of fast-hardening sulphoaluminate cement, 18-22wt% of fly ash, 18-22wt% of silica fume, and 10-12wt% of anti-permeation agent; The mass percentage of each substance in the anti-permeation agent is 28-32wt% of potassium aluminum sulfate, 35-40wt% of sodium silicate, 2-5wt% of glyceryl stearate, 18-23wt% of polyethylene powder, and 5-8wt% of sodium polyacrylate.

2. The early strength modified emulsified asphalt mixture according to claim 1, characterized in that: The aggregate includes nine grades of particle size, and the mass percentage of each grade of particle size in the aggregate is 7-9wt% of particle size 13.2-16mm, 18-20wt% of particle size 9.5-13.2mm, 23-26wt% of particle size 4.75-9.5mm, 18-19wt% of particle size 2.36-4.75mm, 8-9wt% of particle size 1.18-2.36mm, 7-8wt% of particle size 0.6-1.18mm, 3-5wt% of particle size 0.3-0.6mm, 3-6wt% of particle size 0.15-0.3mm, and 4-6wt% of particle size 0.075-0.15mm; the particle size of the mineral powder is less than 0.075mm; and the aggregate and the mineral powder are both limestone.

3. The early strength modified emulsified asphalt mixture according to claim 2, characterized in that: The mass percentage of each substance in the SBS modified emulsified asphalt is 58-60wt% of SBS modified asphalt, 6.5-7wt% of emulsifier, 1.2-1.4wt% of dilute hydrochloric acid, 32.2-34.2wt% of water, and 0.1-0.2wt% of stabilizer A.

4. The early strength modified emulsified asphalt mixture according to claim 3, characterized in that: The mass percentage of each substance in the SBS modified asphalt is as follows: 88-90wt% of base asphalt, 6-7wt% of SBS modifier, 3-5wt% of aromatic oil, and 1-1.5wt% of stabilizer B; the base asphalt is No. 70 base asphalt, the SBS modifier is linear SBS modifier, and the stabilizer B is sulfur; the flash point of the aromatic oil is not less than 230℃, the density is 0.98-1.08kg / m 3 , and the kinematic viscosity at 100℃ is 15-25mm 2 / s.

5. The early strength modified emulsified asphalt mixture according to claim 4, characterized in that: The emulsifier is a slow-fragmentation cationic SBS asphalt emulsifier, the concentration of the dilute hydrochloric acid is 0.01mol / L, and the stabilizer A is hydroxyethyl cellulose.

6. The early strength modified emulsified asphalt mixture according to claim 5, characterized in that: The content of silicon dioxide in the fly ash is not less than 60%, and the content of sulfur trioxide is not more than 1%; the fineness of the fly ash is not less than 94%, the water demand ratio is not more than 90%, the loss on ignition is not more than 3%, and the activity index is not less than 80%.

7. A method of producing a modified emulsified asphalt mixture of early strength, characterized by: The preparation method for preparing the early strength modified emulsified asphalt mixture of any one of claims 1-6 comprises the following steps in the order, Step one: prepare SBS modified asphalt according to the designed material ratio and process parameters, and store the prepared SBS modified asphalt for heat preservation; Step two: prepare SBS modified emulsified asphalt according to the designed material ratio and process parameters, and store the prepared SBS modified emulsified asphalt in a sealed manner; Step three: according to the design of the material ratio preparation early strength agent, and the prepared early strength agent at room temperature for standby; Step four: according to the design of the material ratio will be aggregate, early strength agent and mineral powder into the mixing pot, and using the stirrer for stirring; Step five: according to the design of the material ratio will be SBS modified emulsified asphalt into the mixing pot, and using the stirrer for stirring, after the end of stirring, namely the preparation of early strength type modified emulsified asphalt mixture.

8. The method of preparing a rapid strength modified emulsified asphalt mixture according to claim 7, characterized in that: In step one, the preparation method of SBS modified asphalt, in order of sequence, includes the following steps, Step 1.1: according to the design of the material ratio, the base asphalt, SBS modifier, aromatic oil, stabilizer B is weighed; Step 1.2: the base asphalt is put into the electromagnetic oven for heating, the heating temperature is 135-140 DEG C, the heating time is 3-5 min, the base asphalt is kept in the flowing state, and it is all transferred to the oil bath pot; Step 1.3: the aromatic oil is added into the oil bath pot, and the stirrer is used for stirring, one side stirring and one side heating, the stirring speed is 180-280 r / min, when the temperature rises to 175-180 DEG C, continue to stir for 10-15 min; Step 1.4: the SBS modifier is added into the oil bath pot, and the stirrer is used for stirring, the stirring temperature is 175-180 DEG C, the stirring speed is 180-280 r / min, and the stirring time is 40-50 min; Step 1.5: the mixture in the oil bath pot is sheared by using a high speed shearing instrument, the shearing temperature is 175-180 DEG C, the shearing speed is 6500-7000 r / min, and the shearing time is 80-110 min; Step 1.6: the stabilizer B is added into the oil bath pot, and the high speed shearing instrument is used for shearing, the shearing temperature is 175-180 DEG C, the shearing speed is 6500-7000 r / min, and the shearing time is 20-30 min; Step 1.7: the mixture in the oil bath pot is stirred by using the stirrer, the stirring temperature is 175-180 DEG C, the stirring speed is 400-500 r / min, and the stirring time is 60-90 min, the SBS modified asphalt is prepared, and is kept at 175-180 DEG C for standby; In step two, the preparation method of SBS modified emulsified asphalt, in order of sequence, includes the following steps, Step 2.1: according to the design of the material ratio, the SBS modified asphalt, emulsifier, water, dilute hydrochloric acid, stabilizer A is weighed; Step 2.2: the water is heated to 60-80 DEG C, then the emulsifier is added into the water and stirred uniformly, so that the emulsifier is dissolved in the water, and the soap solution is obtained; then the dilute hydrochloric acid is added into the soap solution, and the pH value of the soap solution is adjusted to 2; Step 2.3: the soap solution is put into the colloid mill for circulation treatment, the colloid mill rotating speed is 1000-2000 r / min, and the circulation time is 1-2 min; Step 2.4: the stabilizer A is put into the colloid mill for circulation treatment, the colloid mill rotating speed is 1000-2000 r / min, and the circulation time is 2-3 min; Step 2.5: the speed of the colloid mill is increased to 3500-4000r / min, and the SBS modified asphalt prepared at 175-180℃ is put into the colloid mill for circulation treatment, the circulation time is 30-40min, after the circulation treatment, the SBS modified emulsified asphalt is prepared, and it is pumped out and stored, and cooled to room temperature naturally for standby; In step three, the preparation method of the early strength agent comprises the following steps in sequence, Step 3.1: according to the designed material ratio, the potassium aluminum sulfate, sodium silicate, glyceryl stearate, polyethylene powder and sodium polyacrylate are uniformly mixed at room temperature to prepare the impermeability agent; Step 3.2: according to the designed material ratio, the fast hardening sulphoaluminate cement, fly ash, silica fume and impermeability agent are uniformly mixed at room temperature to prepare the early strength agent; In step four, the aggregate, early strength agent and mineral powder are put into the mixing pot and stirred, the stirring temperature is room temperature, the stirring speed is 200-300r / min, and the stirring time is 90-120s; in step five, the SBS modified emulsified asphalt is added into the mixing pot and stirred, the stirring temperature is room temperature, the stirring speed is 200-300r / min, and the stirring time is 90-120s.

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