Cold-mixed and cold-laid modified emulsified asphalt and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, in particular to cold-mixed and cold-laid modified emulsified asphalt and a preparation method thereof.The cold-mixed and cold-laid modified emulsified asphalt is prepared from, by mass, 80%-85% of matrix asphalt, 3.8%-4.8% of an emulsifier, 6%-8% of a modifier, 0.2%-0.3% of a stabilizer, 0.5%-1.2% of a compound functional additive and the balance deionized softened water; the modifier is a compound of a polymer SBS modifier and butadiene styrene rubber, and the mass ratio of the polymer SBS modifier to the butadiene styrene rubber is 3: 1. According to the invention, by adding the modifier and optimizing the formula, the cohesiveness, the water stability and the durability are excellent, the mixture can form relatively high strength in a short time, the use requirements of roads are met, and meanwhile, in the production and construction process, asphalt and aggregate do not need to be heated, so that the energy consumption is greatly reduced, the emission of harmful gas and dust is reduced, and the environmental protection requirements are met.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials technology, specifically to a cold-mixed and cold-laid modified emulsified asphalt and its preparation method. Background Technology

[0002] In road construction and maintenance projects, traditional hot-mix asphalt mixtures require heating and mixing asphalt and aggregates at high temperatures, which not only consumes a large amount of energy but also generates a large amount of harmful gases and dust, seriously polluting the environment. At the same time, the construction of hot-mix asphalt mixtures is greatly limited by seasons and temperatures, making it difficult to construct in low temperatures or winter, and the construction period is long and the cost is high.

[0003] With technological advancements, cold-mixed asphalt mixtures can be mixed and constructed at room temperature without heating, offering advantages such as energy saving, environmental friendliness, and ease of construction, and have gradually become a research hotspot in the field of road engineering. However, existing cold-mixed emulsified asphalt generally suffers from problems such as slow strength development, poor water stability, and insufficient durability, limiting its application in high-grade roads.

[0004] Therefore, there is an urgent need for a cold-mix, cold-lay modified emulsified asphalt to solve the above problems. Summary of the Invention

[0005] To achieve the above objectives, this application employs the following technical solution: A cold-mixed and cold-laid modified emulsified asphalt, by mass percentage, comprises the following components: 80-85% base asphalt, 3.8-4.8% emulsifier, 6-8% modifier, 0.2-0.3% stabilizer, 0.5-1.2% composite functional additives, and the remainder being deionized softened water; the modifier is a compound of polymer SBS modifier and styrene-butadiene rubber, with a mass ratio of 3:1.

[0006] Furthermore, the composite functional additive is composed of nano-silica, anti-aging agent 1010 and organomontmorillonite in a mass ratio of 2:1:0.5.

[0007] A method for preparing cold-mixed and cold-laid modified emulsified asphalt includes the following steps: Step 100, preparation of emulsifier solution: add emulsifier, stabilizer and composite functional additives to deionized softened water in proportion, turn on the stirring device, heat and keep warm while stirring to obtain emulsifier solution; Step 200, modified asphalt preparation: heat the base asphalt, add the compound modifier, shear it using a high-speed shearing machine, then add the modified asphalt stabilizer, and keep it at a constant temperature of 160-170℃ for 2 hours to obtain the modified asphalt. Step 300, emulsification treatment: Slowly add the modified asphalt prepared in step 200 to the emulsifier solution obtained in step 100, control the mass ratio of modified asphalt to emulsifier solution, turn on the high-speed stirring equipment, the stirring speed is 60-80 r / min, and the stirring is carried out for 120 min. Step 400, post-processing: the emulsified asphalt is filtered through a 100-mesh filter to remove impurities and unemulsified asphalt particles, and then stored in a sealed container to obtain cold-mixed cold-lay modified emulsified asphalt.

[0008] Furthermore, in step 100, the stirring speed is 30-40 r / min, the heating temperature is 60-65℃, and the stirring time is 30-45 min.

[0009] Furthermore, in step 200, the heating temperature is 175-185℃, the shearing speed is 3000-4000 r / min, and the shearing time is 4 hours.

[0010] Further, in step 300, the mass ratio of the modified asphalt to the emulsifier solution is 1:0.8-1.2.

[0011] Compared with existing technologies, the cold-mixed and cold-laid modified emulsified asphalt and its mixture of the present invention have significant comprehensive advantages. The production and construction processes do not require heating of asphalt and aggregates, greatly reducing energy consumption and emissions of harmful gases and dust, thus meeting environmental protection requirements. Mixing, transportation, paving, and compaction operations can be completed at room temperature, unaffected by seasons or temperature, simplifying the construction process and effectively improving construction efficiency and shortening the construction cycle. Furthermore, by adding modifiers and optimizing the formula, its adhesion, water stability, and durability are excellent, enabling the mixture to achieve high strength in a short time, meeting road usage requirements. Finally, by eliminating the heating process, reducing energy consumption, and improving construction efficiency, the overall production cost is significantly reduced, resulting in good economic benefits. Attached Figure Description

[0012] Appendix Figure 1 This is a flowchart of the preparation method in this application. Detailed Implementation

[0013] The present application will be further described in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope defined by this application.

[0014] A cold-mixed and cold-laid modified emulsified asphalt, by mass percentage, comprises the following components: 80-85% base asphalt, 3.8-4.8% emulsifier, 6-8% modifier, 0.2-0.3% stabilizer, 0.5-1.2% composite functional additives, and the remainder being deionized softened water.

[0015] The modifier is a compound of polymer SBS modifier and styrene-butadiene rubber in a mass ratio of 3:1. This compound resolves the contradiction between high-temperature stability and low-temperature crack resistance in single modifiers, significantly improving the overall mechanical properties of emulsified asphalt. The composite functional additive is a compound of nano-silica, anti-aging agent 1010, and organomontmorillonite in a mass ratio of 2:1:0.5. This additive effectively improves the strength, wear resistance, anti-aging properties, and water stability of emulsified asphalt, extending the service life of roads.

[0016] In some preferred embodiments of this application, the base asphalt is 70A grade road petroleum asphalt, which, due to its strong adhesion and excellent aging resistance, provides a skeleton for the emulsified asphalt. The emulsifier is a polyamine amide emulsifier, which reduces the surface tension between the base asphalt and deionized softened water, promotes uniform dispersion of base asphalt particles, and improves the stability of the emulsifier. The stabilizer is sodium carboxymethyl cellulose, and the conductivity of the deionized softened water is less than 10 μS / cm.

[0017] Combined with appendix Figure 1 A method for preparing cold-mixed and cold-laid modified emulsified asphalt includes the following steps: Step 100, Emulsifier solution preparation: Add emulsifier, stabilizer and composite functional additives to deionized softened water in proportion, turn on the stirring device, stir at 30-40 r / min, and heat to 60-65℃ at the same time, keep warm and stir for 30-45 min to ensure that all components are fully dissolved and obtain a uniform emulsifier solution. Step 200, modified asphalt preparation: The base asphalt is heated to 175-185℃ to make it flowable, a compound modifier is added, and it is sheared using a high-speed shearing machine at a shearing speed of 3000-4000 r / min for 4 hours. Then, a modified asphalt stabilizer is added, and it is kept at a constant temperature of 160-170℃ for 2 hours to obtain stable modified asphalt. Step 300, emulsification treatment: Slowly add the modified asphalt prepared in step 200 to the emulsifier solution obtained in step 100, controlling the mass ratio of modified asphalt to emulsifier solution to be 1:0.8-1.2. Turn on the high-speed stirring equipment, the stirring speed is 60-80 r / min, and the stirring time is 120 min. During storage, stir for 30 min every 120 min to ensure that the asphalt particles are uniformly dispersed in the aqueous solution. Step 400, post-processing: The emulsified asphalt is filtered through a 100-mesh filter to remove impurities and unemulsified asphalt particles, and then stored in a sealed container to obtain cold-mixed cold-lay modified emulsified asphalt.

[0018] To fully leverage the high adhesion, strong stability, and excellent durability of cold-mixed and cold-laid modified emulsified asphalt, it is scientifically compounded with graded aggregates, revitalized cement, densely filled mineral powder, and external water admixtures. By precisely controlling the mixing process, the uniform integration and synergistic effect of each component are achieved, thereby preparing a cold-mixed and cold-laid modified emulsified asphalt mixture that combines good workability, rapid strength formation, and long-term performance.

[0019] A cold-mixed, cold-laid modified emulsified asphalt mixture comprises 5.5-6.5% cold-mixed, cold-laid modified emulsified asphalt, 80-85% aggregate, 3% silicate cement, 5% mineral powder, and 2-4% added water. The cold-mixed, cold-laid modified emulsified asphalt has good adhesion, water stability, and durability, enabling the cold-mixed, cold-laid modified emulsified asphalt mixture to form high strength in a short time, meeting the requirements for road use.

[0020] The aggregates selected are hard, clean, dry, unweathered, and impurity-free crushed stone and sand. The aggregate gradation is chosen based on the road surface requirements and design standards. The aggregates include coarse and fine aggregates. Coarse aggregate constitutes 50-55% of the total mass of the mixture, and fine aggregate constitutes 30-35%. The mineral powder is obtained by grinding alkaline stones such as limestone or igneous rock, and is used to fill the voids between the aggregates, improving the density and cohesion of the mixture.

[0021] In preparing the above-mentioned mixture, dry mixing and wet mixing methods are used. First, aggregates, silicate cement, and mineral powder are added to a mixer in proportion and dry-mixed for 1-3 minutes to ensure uniform mixing of all components. Then, cold-mixed cold-laying modified emulsified asphalt and externally added water are added and wet-mixed for 3-5 minutes until the mixture has a uniform color and no white spots, thus obtaining the cold-mixed cold-laying modified emulsified asphalt mixture. The cold-mixed cold-laying modified emulsified asphalt mixture produced in this application can be mixed, transported, laid, and compacted at room temperature without heating the asphalt and aggregates, greatly reducing energy consumption and emissions of harmful gases and dust. Furthermore, it is not limited by season or temperature, the construction process is simple, and no complex heating equipment is required, improving construction efficiency and shortening the construction cycle. In addition, due to the reduction of heating steps and energy consumption, while improving construction efficiency, the production cost of the cold-mixed cold-laying modified emulsified asphalt and its mixture of the present invention is relatively low, resulting in good economic benefits.

[0022] During use, the prepared cold-mix asphalt mixture is transported to the paving area at the construction site and paved using a paver. The paving thickness is controlled according to design requirements. After paving, a road roller is immediately used for compaction. The compaction sequence is initial compaction, intermediate compaction, and final compaction. The number of compaction passes is determined according to the road surface compaction requirements. After compaction, the road can be opened to traffic.

[0023] Example 1 A cold-mixed and cold-laid modified emulsified asphalt, by weight percentage, comprises the following components: 82% of 70A grade road petroleum asphalt, 4.2% of polyamine amide emulsifier, 6% modifier, 0.25% sodium carboxymethyl cellulose, 0.8% composite functional additives, and the remainder being deionized softened water.

[0024] Combined with appendix Figure 1 A method for preparing cold-mixed and cold-laid modified emulsified asphalt includes the following steps: Step 100, Emulsifier solution preparation: Add emulsifier, stabilizer and composite functional additives to deionized softened water in proportion, turn on the stirring device, stir at 35 r / min, and heat to 62℃ at the same time, keep warm and stir for 40 min to ensure that all components are fully dissolved and obtain a uniform emulsifier solution. Step 200, modified asphalt preparation: The base asphalt is heated to 180℃ to make it flow, a compound modifier is added, and it is sheared using a high-speed shearing machine at a shearing speed of 3500 r / min for 4 hours. Then, a modified asphalt stabilizer is added, and it is kept at a constant temperature of 165℃ for 2 hours to obtain stable modified asphalt. Step 300, emulsification treatment: Slowly add the modified asphalt prepared in step 200 to the emulsifier solution obtained in step 100, controlling the mass ratio of modified asphalt to emulsifier solution to be 1:1. Turn on the high-speed stirring equipment, the stirring speed is 70 r / min, and the stirring time is 120 min. During storage, stir for 30 min every 120 min to ensure that the asphalt particles are uniformly dispersed in the aqueous solution. Step 400, post-processing: The emulsified asphalt is filtered through a 100-mesh filter to remove impurities and unemulsified asphalt particles, and then stored in a sealed container to obtain cold-mixed cold-lay modified emulsified asphalt.

[0025] A cold-mixed, cold-paved modified emulsified asphalt mixture comprises 6% cold-mixed, cold-paved modified emulsified asphalt, 85% aggregate, 3% silicate cement, 5% mineral powder, and 3% added water. The aggregate includes coarse aggregate and fine aggregate, with coarse aggregate accounting for 52% of the total mass of the mixture and fine aggregate accounting for 33% of the total mass of the mixture.

[0026] In preparing the above mixture, firstly, aggregates, silicate cement and mineral powder are added to a mixer in proportion and dry-mixed for 2 minutes to ensure that the components are evenly mixed. Then, cold-mixed cold-laying modified emulsified asphalt and externally added water are added and wet-mixed for 4 minutes until the mixture has a uniform color and no white spots, thus obtaining the cold-mixed cold-laying modified emulsified asphalt mixture.

[0027] Tests showed that the cold-mixed asphalt mixture prepared in this embodiment had a 4-hour compressive strength of 2.8 MPa, a water immersion residual stability of 88%, and a compaction degree of 96%. After 18 months of use, the pavement showed no cracks or loosening, demonstrating excellent performance.

[0028] Example 2 A cold-mixed and cold-laid modified emulsified asphalt, by weight percentage, comprises the following components: 83% of 70A grade road petroleum asphalt, 4% of polyamine amide emulsifier, 8% of modifier, 0.2% of sodium carboxymethyl cellulose, 0.7% of composite functional additives, and the remainder being deionized softened water.

[0029] Combined with appendix Figure 1 A method for preparing cold-mixed and cold-laid modified emulsified asphalt includes the following steps: Step 100, Emulsifier solution preparation: Add emulsifier, stabilizer and composite functional additives to deionized softened water in proportion, turn on the stirring device, stir at 32 r / min, heat to 63℃ at the same time, keep warm and stir for 35 min to ensure that all components are fully dissolved and obtain a uniform emulsifier solution. Step 200, modified asphalt preparation: The base asphalt is heated to 182°C to make it flowable, a compound modifier is added, and it is sheared using a high-speed shearing machine at a shearing speed of 3800 r / min for 4 hours. Then, a modified asphalt stabilizer is added, and it is kept at a constant temperature of 168°C for 2 hours to obtain stable modified asphalt. Step 300, emulsification treatment: Slowly add the modified asphalt prepared in step 200 to the emulsifier solution obtained in step 100, controlling the mass ratio of modified asphalt to emulsifier solution to be 1:0.9. Turn on the high-speed stirring equipment, the stirring speed is 75 r / min, and the stirring time is 120 min. During storage, stir for 30 min every 120 min to ensure that the asphalt particles are uniformly dispersed in the aqueous solution. Step 400, post-processing: The emulsified asphalt is filtered through a 100-mesh filter to remove impurities and unemulsified asphalt particles, and then stored in a sealed container to obtain cold-mixed cold-lay modified emulsified asphalt.

[0030] A cold-mixed, cold-paved modified emulsified asphalt mixture comprises 5.8% cold-mixed, cold-paved modified emulsified asphalt, 85% aggregate, 3% silicate cement, 5% mineral powder, and 2.2% added water. The aggregate includes coarse aggregate and fine aggregate, with coarse aggregate accounting for 53% of the total mass of the mixture and fine aggregate accounting for 32% of the total mass of the mixture.

[0031] In preparing the above mixture, firstly, aggregates, silicate cement and mineral powder are added to a mixer in proportion and dry-mixed for 1.5 minutes to ensure that the components are evenly mixed. Then, cold-mixed cold-laying modified emulsified asphalt and externally added water are added and wet-mixed for 3.5 minutes until the mixture has a uniform color and no white spots, thus obtaining the cold-mixed cold-laying modified emulsified asphalt mixture.

[0032] Tests showed that the cold-mixed modified emulsified asphalt mixture prepared in this embodiment had a 4-hour compressive strength of 2.6 MPa, a water immersion residual stability of 86%, and a compaction degree of 95.5%. After 15 months of use, the pavement showed no cracks or loosening, demonstrating excellent performance.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A cold-mix, cold-lay modified emulsified asphalt, characterized in that: By mass percentage, it comprises the following components: 80-85% base asphalt, 3.8-4.8% emulsifier, 6-8% modifier, 0.2-0.3% stabilizer, 0.5-1.2% composite functional additives, and the remainder is deionized softened water; the modifier is a compound of polymer SBS modifier and styrene-butadiene rubber, with a mass ratio of 3:

1.

2. The cold-mix, cold-lay modified emulsified asphalt according to claim 1, characterized in that: The composite functional additive is composed of nano-silica, anti-aging agent 1010 and organomontmorillonite in a mass ratio of 2:1:0.

5.

3. A method for preparing cold-mixed cold-laying modified emulsified asphalt as described in any one of claims 1-2, characterized in that: Includes the following steps: Step 100, preparation of emulsifier solution: add emulsifier, stabilizer and composite functional additives to deionized softened water in proportion, turn on the stirring device, heat and keep warm while stirring to obtain emulsifier solution; Step 200, modified asphalt preparation: heat the base asphalt, add the compound modifier, shear it using a high-speed shearing machine, then add the modified asphalt stabilizer, and keep it at a constant temperature of 160-170℃ for 2 hours to obtain the modified asphalt. Step 300, emulsification treatment: Slowly add the modified asphalt prepared in step 200 to the emulsifier solution obtained in step 100, control the mass ratio of modified asphalt to emulsifier solution, turn on the high-speed stirring equipment, the stirring speed is 60-80 r / min, and the stirring is carried out for 120 min. Step 400, post-processing: the emulsified asphalt is filtered through a 100-mesh filter to remove impurities and unemulsified asphalt particles, and then stored in a sealed container to obtain cold-mixed cold-lay modified emulsified asphalt.

4. The method for preparing cold-mixed and cold-laid modified emulsified asphalt according to claim 3, characterized in that: In step 100, the stirring speed is 30-40 r / min, the heating temperature is 60-65℃, and the stirring time is 30-45 min.

5. The method for preparing cold-mixed and cold-laid modified emulsified asphalt according to claim 3, characterized in that: In step 200, the heating temperature is 175-185℃, the shearing speed is 3000-4000 r / min, and the shearing time is 4 hours.

6. The method for preparing cold-mixed and cold-laid modified emulsified asphalt according to claim 3, characterized in that: In step 300, the mass ratio of the modified asphalt to the emulsifier solution is 1:0.8-1.2.

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