Qingchuan rock asphalt-castor oil-rice hull ash composite modified asphalt mixture and preparation method thereof

Abstract

The invention provides a Qingchuan rock asphalt-castor oil-rice hull ash composite modified asphalt mixture and a preparation method thereof, and aims to solve the technical problem of insufficient pavement performance of the asphalt mixture. The asphalt mixture is prepared from the following raw materials in parts by weight: 100 parts of mineral aggregate, 4-6 parts of asphalt, 0.5-0.75 part of Qingchuan rock asphalt, 0.4-0.6 part of castor oil, 0.45-0.7 part of rice hull ash, 0.35-2 parts of a treating agent and 0.01-0.015 part of a compatibilizer. The asphalt mixture has the advantages of excellent pavement performance, simple preparation process and non-toxic and harmless raw materials, and can enhance the high-temperature stability, low-temperature crack resistance, water stability, toughness and ductility of the asphalt pavement and prolong the service life of the asphalt pavement.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering materials, and specifically to an asphalt mixture compositely modified by Qingchuan rock asphalt-castor oil-rice husk ash and a preparation method thereof. Background Art

[0002] Among many road materials, asphalt is widely used in the field of road construction due to its advantages such as excellent bonding ability, good anti-skid performance, and strong environmental adaptability. Asphalt pavement is a flexible pavement and the most important form of pavement structure. It occupies a dominant position in my country's road transportation system. With the continuous development of high-grade highways, modern road networks have become increasingly dense, traffic volume has increased, and overloading and heavy-loading phenomena have gradually intensified. Traditional asphalt pavements have subsequently experienced road diseases and damage such as rutting, shifting, potholes, looseness, and cracks. This puts higher demands on the quality construction of asphalt pavements in the new era. Therefore, it is necessary to modify traditional asphalt pavements and develop higher-performance modified asphalt materials to enhance the strength, stability, durability, safety, and road performance of asphalt pavements to meet the increasingly stringent requirements for asphalt pavements.

[0003] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0004] The present application provides an asphalt mixture compositely modified by Qingchuan rock asphalt-castor oil-rice husk ash and a preparation method thereof, aiming to solve the technical problem of insufficient road performance (high temperature stability, low temperature crack resistance, water stability, fatigue resistance, anti-aging performance, etc.) of asphalt mixture.

[0005] According to one aspect of the present disclosure, there is provided an asphalt mixture, which is made of the following raw materials in parts by weight: 100 parts of mineral material, 4 to 6 parts of asphalt, 0.5 to 0.75 parts of Qingchuan rock asphalt, 0.4 to 0.6 parts of castor oil, 0.45 to 0.7 parts of rice husk ash, 0.35 to 2 parts of treating agent, and 0.01 to 0.015 parts of compatibilizer.

[0006] In some embodiments of the present disclosure, the asphalt mixture is made of the following raw materials in parts by weight: 100 parts of mineral material, 5.0 parts of asphalt, 0.63 parts of Qingchuan rock asphalt, 0.5 parts of castor oil, 0.58 parts of rice husk ash, 1.175 parts of treating agent, and 0.025 parts of expander.

[0007] In some embodiments of the present disclosure, the compatibilizer is maleic anhydride.

[0008] In some embodiments of the present disclosure, the asphalt is at least one of road petroleum asphalt, coal asphalt, SBS modified asphalt, PE modified asphalt, and SBR modified asphalt.

[0009] In some embodiments of the present disclosure, the modifier is 0.8-1.2 mol / L dilute hydrochloric acid and / or 0.01-0.03 mol / L manganese acetate solution.

[0010] In some embodiments of the present disclosure, the mineral material consists of coarse aggregate, fine aggregate and mineral powder.

[0011] According to another aspect of the present disclosure, there is provided a method for preparing an asphalt mixture, comprising the following steps: (1) Prepare the raw materials according to the above raw material ratios and set aside; (2) Preparation of rice husk ash modifier: rice husk and dilute hydrochloric acid are uniformly mixed in a mass ratio of 1:1.7-1.8, and then soaked for 40-50 minutes, filtered and dried at 50-70°C to obtain preliminary pretreated rice husk; the preliminary pretreated rice husk and divalent manganese ion solution are mixed in a mass ratio of 1:1.7-1.8, soaked for 55-65 minutes and stirred, and then dried at 50-70°C to obtain pretreated rice husk; the pretreated rice husk is burned at 400-600°C, and after cooling, the rice husk ash is wet-milled to obtain a rice husk ash modifier; (3) Preparation of Qingchuan rock asphalt and castor oil modifier: Dry Qingchuan rock asphalt and castor oil at 150-160°C for 30-50 min respectively for use; (4) Preparation of composite modified asphalt: The asphalt is heated and melted at a temperature of 170-190°C, and the rice husk ash modifier is first added. After shearing, Qingchuan rock asphalt and castor oil modifier are added, and a compatibilizer is added. After stirring for 50-70 minutes, the asphalt is placed in an environment of 170-180°C for swelling and development for 20-40 minutes. (5) Preparation of composite modified asphalt mixture: heat the mineral material to 170°C to 175°C, mix and stir evenly with the composite modified asphalt to obtain the mixture.

[0012] In some embodiments of the present disclosure, in the step (4), after adding rice husk ash, shearing is carried out at a shear rate of 2500-3500 r / min for 25-35 min, and then Qingchuan rock asphalt and castor oil are added in sequence and sheared at a shear rate of 5000-6000 r / min for 40-50 min.

[0013] One or more technical solutions provided in the embodiments of the present application have at least any of the following technical effects: 1. When Qingchuan rock asphalt, castor oil and rice husk ash are used in modified asphalt mixture, there is a synergistic effect: the physical and mechanical properties, road performance and durability of the asphalt mixture are jointly improved. Through reasonable ratio design, the advantages of various modifiers are further brought into play, and the adverse effects of a single modifier are avoided. Using agricultural waste such as rice husk ash as one of the modifiers can reduce the production cost of asphalt mixture and realize the recycling of resources.

[0014] 2. The polar functional groups contained in the Qingchuan rock asphalt in this application can enhance the adhesion between asphalt and aggregate, and improve the anti-stripping performance of asphalt mixture. The various organic chains contained in it can promote the cross-linking polymerization of active groups in petroleum asphalt, and can improve the arrangement and network structure of asphalt molecules, thereby enhancing the cohesion and temperature sensitivity of asphalt, especially the anti-rutting performance; castor oil helps the uniform distribution and penetration of asphalt on the surface of aggregate, enhances the bonding force between asphalt and aggregate, and thus improves the low-temperature performance and ductility of asphalt, softens asphalt and reduces its viscosity, and improves the low-temperature flexibility of asphalt; the silica contained in rice husk ash can improve the stability and durability of the mixture, and its particle structure helps to improve the water damage resistance and cracking resistance of the asphalt mixture, and its porous structure improves the storage stability and thermal stability of asphalt to a certain extent. By compounding the three materials, the high molecular structure and polar functional groups of Qingchuan rock asphalt can interact with the components in castor oil and rice husk ash to form a more stable network structure, further optimizing the rheological properties of asphalt so that it can maintain good performance at high temperatures; the polar functional groups in Qingchuan rock asphalt can enhance the adhesion between asphalt and aggregate, while castor oil improves interfacial adhesion through its oil components, and together they work to improve the overall adhesion of the mixture; castor oil can also reduce the viscosity of asphalt, increase its ductility and flexibility under low temperature conditions, thereby improving the low-temperature crack resistance of asphalt mixtures; the addition of rice husk ash can improve the internal structural stability of the mixture and further enhance its crack resistance under low temperature conditions.

[0015] 2. In this application, the surface of rice husks is pretreated with dilute hydrochloric acid and manganese acetate solution, so that the rice husk ash obtained after combustion is more active and loose and porous. This characteristic can be connected with the Qingchuan rock asphalt with a huge specific surface area inside the asphalt mixture to form a mesh connection structure, which comprehensively enhances the high-temperature deformation resistance of the asphalt pavement. Under the action of castor oil, the flexibility of the asphalt mixture is improved. On the other hand, the rice husk ash and Qingchuan rock asphalt are more fully melted into the asphalt. The three are closely combined to further enhance the mechanical strength, impact resistance and stability of the asphalt mixture. The asphalt material modified by the Qingchuan rock asphalt-castor oil-rice husk ash composite has a higher viscosity and can be evenly wrapped on the aggregate surface, which improves the interlocking force between the aggregates; at the same time, it has a stronger deformation recovery ability, which significantly improves the high and low temperature performance, water damage resistance and fatigue damage resistance of the asphalt mixture.

[0016] 3. The composite modified asphalt mixture of the present application is an environmentally friendly, non-toxic and non-corrosive composite asphalt mixture with excellent road performance. It can enhance the high-temperature stability, low-temperature crack resistance and water stability of asphalt pavement, and is of great significance to extending the service life of asphalt pavement. Its raw materials are widely available, non-toxic and harmless, the production process is pollution-free and inexpensive, the preparation process is simple, the cost is low, and it has good economic benefits. DETAILED DESCRIPTION

[0017] In order to better understand the technical solution of the present application, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0018] Unless otherwise specified, the raw materials and auxiliary raw materials involved in the following examples are all commercially available conventional raw materials; the preparation methods, detection methods and test methods involved are all conventional methods unless otherwise specified.

[0019] The composite modified asphalt mixture in the following embodiments includes the following preparation steps: Prepare the raw materials in the following weight ratios: 100 parts of mineral material, 4-6 parts of asphalt, 0.5-0.75 parts of Qingchuan rock asphalt, 0.4-0.6 parts of castor oil, 0.45-0.7 parts of rice husk ash, 0.35-2 parts of treating agent (dilute hydrochloric acid / manganese acetate solution), and 0.01-0.015 parts of bulking agent (maleic anhydride); (1) Preparation of rice husk ash modifier: First, wash the rice husk with distilled water, dry it and soak it in dilute hydrochloric acid for 45 minutes, the ratio of rice husk to dilute hydrochloric acid is 1:1.75, then rinse the rice husk with distilled water until there is no dilute hydrochloric acid in the filtrate, filter it and dry it at 60°C to obtain pretreated rice husk; then, mix the pretreated rice husk with divalent manganese ion solution in a ratio of 1:1.75 and soak it for 60 minutes with continuous stirring, and dry it at 60°C to obtain pretreated rice husk; place the pretreated rice husk in a muffle furnace for combustion, the temperature is set to 500°C, the combustion time is 2.5 hours, and after the combustion is completed, cool it to obtain rice husk ash; the cooled rice husk ash is placed in a ball mill and wet-milled for 20 minutes to obtain a rice husk ash modifier.

[0020] (2) Preparation of Qingchuan rock asphalt and castor oil modifier: Qingchuan rock asphalt and castor oil were placed in an oven at 155°C for 40 minutes for dehydration, respectively, to obtain the prepared Qingchuan rock asphalt and castor oil modifier.

[0021] (3) Preparation of composite modified asphalt: Heat the base asphalt at 180°C to melt it, add the modified rice husk ash first, stir it evenly with a high-speed shearing machine, then add Qingchuan rock asphalt and castor oil, and add maleic anhydride to increase the volume. After stirring for 60 minutes, place it in an environment of 175°C to swell and develop for 30 minutes to obtain the composite modified asphalt.

[0022] (4) Preparation of composite modified asphalt mixture: The mineral material heated to 175° C. and the composite modified asphalt obtained in step (3) are mixed and stirred uniformly according to a conventional method to obtain a composite modified asphalt mixture.

[0023] Wherein, in the step (3), the shearing process is: after adding rice husk ash, shearing is performed at a shear rate of 3000 r / min for 30 minutes, and then Qingchuan rock asphalt and castor oil are added in sequence and sheared at a shear rate of 5500 r / min for 45 minutes.

[0024] Example 1: A composite modified asphalt mixture is made from the following raw materials in parts by weight: 100 parts of AC-13 type mineral material, 4 parts of road petroleum asphalt, 0.5 parts of Qingchuan rock asphalt, 0.4 parts of castor oil, 0.45 parts of rice husk ash, 0.35 parts of treating agent (dilute hydrochloric acid / manganese acetate solution), and 0.01 parts of compatibilizer (maleic anhydride).

[0025] Example 2: A composite modified asphalt mixture is made from the following raw materials in parts by weight: 100 parts of AC-13 type mineral material, 4.5 parts of coal tar, 0.55 parts of Qingchuan rock asphalt, 0.45 parts of castor oil, 0.5 parts of rice husk ash, 0.76 parts of treating agent (dilute hydrochloric acid / manganese acetate solution), and 0.012 parts of compatibilizer (maleic anhydride).

[0026] Example 3: A composite modified asphalt mixture is made from the following raw materials in parts by weight: 100 parts of AC-13 type mineral material, 5 parts of SBS asphalt, 0.65 parts of Qingchuan rock asphalt, 0.5 parts of castor oil, 0.55 parts of rice husk ash, 1.18 parts of treating agent (dilute hydrochloric acid / manganese acetate solution), and 0.013 parts of compatibilizer (maleic anhydride).

[0027] Example 4: A composite modified asphalt mixture is made from the following raw materials in parts by weight: 100 parts of AC-13 mineral material, 5.5 parts of PE modified asphalt, 0.7 parts of Qingchuan rock asphalt, 0.55 parts of castor oil, 0.65 parts of rice husk ash, 1.59 parts of treating agent (dilute hydrochloric acid / manganese acetate solution), and 0.014 parts of compatibilizer (maleic anhydride).

[0028] Example 5: A composite modified asphalt mixture is made from the following raw materials in parts by weight: 100 parts of AC-13 mineral material, 6 parts of SBR modified asphalt, 0.75 parts of Qingchuan rock asphalt, 0.6 parts of castor oil, 0.7 parts of rice husk ash, 2 parts of treating agent (dilute hydrochloric acid / manganese acetate solution), and 0.015 parts of compatibilizer (maleic anhydride).

[0029] Comparative Example 1: A common asphalt mixture is made from the following raw materials in parts by weight: 100 parts of AC-13 mineral material and 3 parts of SBS asphalt.

[0030] The asphalt mixtures in Examples 1-5 and Comparative Example 1 were subjected to road performance tests, including a high temperature rutting test, a low temperature beam bending test (-10°C), a freeze-thaw splitting test, and a water immersion Marshall test, to test the road performance of the composite modified asphalt mixture of the present invention, and to compare and analyze the results with those of ordinary asphalt mixtures without adding modifiers. The test results are shown in Table 1 below.

[0031] Table 1 Comparison of main road performance indicators of various asphalt mixtures .

[0032] As can be seen from Table 1, the dynamic stability of the composite modified asphalt mixture is much greater than that of the ordinary asphalt mixture (Comparative Example 1). Therefore, the high-temperature rutting resistance of the composite modified asphalt mixture is stronger than that of the ordinary asphalt mixture; the maximum flexural strain of the composite modified asphalt mixture is much greater than that of the ordinary asphalt mixture. Therefore, the toughness and ductility of the composite modified asphalt mixture are stronger than those of the ordinary asphalt mixture; the residual stability and splitting strength of the composite modified asphalt mixture are much greater than those of the ordinary asphalt mixture. Therefore, the low-temperature crack resistance and water stability of the composite modified asphalt mixture are stronger than those of the ordinary asphalt mixture.

[0033] The composite modified asphalt mixture of the present application meets the relevant requirements of the Ministry of Transport's standard JTG F40-2004 "Technical Specifications for Highway Asphalt Pavement Construction". Its high temperature stability, low temperature crack resistance, water stability and other indicators are significantly higher than those of ordinary asphalt mixtures, indicating that the composite modified asphalt mixture of the present application has excellent road performance.

[0034] The present application has been described in detail above in conjunction with the embodiments; however, those skilled in the art will appreciate that, without departing from the concept of the present invention, the specific parameters in the above embodiments may be changed, or the relevant materials and method steps may be replaced by equivalents, thereby forming multiple specific embodiments, which are all within the common variation range of the present application and will not be described in detail one by one here.

Claims

1. An asphalt mixture compositely modified by Qingchuan rock asphalt-castor oil-rice husk ash, characterized in that: The invention is prepared from the following raw materials in parts by weight: 100 parts of mineral material, 4-6 parts of asphalt, 0.5-0.75 parts of Qingchuan rock asphalt, 0.4-0.6 parts of castor oil, 0.45-0.7 parts of rice husk ash, 0.35-2.00 parts of treating agent and 0.01-0.015 parts of volume extender.

2. The asphalt mixture according to claim 1, characterized in that: The invention is prepared from the following raw materials in parts by weight: 100 parts of mineral material, 5.0 parts of asphalt, 0.63 parts of Qingchuan rock asphalt, 0.5 parts of castor oil, 0.58 parts of rice husk ash, 1.175 parts of treating agent and 0.025 parts of compatibilizer.

3. The asphalt mixture according to claim 1, characterized in that: The compatibilizer is maleic anhydride.

4. The asphalt mixture according to claim 1, characterized in that: The asphalt is at least one of road petroleum asphalt, coal asphalt, SBS modified asphalt, PE modified asphalt, and SBR modified asphalt.

5. The asphalt mixture according to claim 1, characterized in that: The treatment agent is 0.8-1.2 mol / L diluted hydrochloric acid and / or 0.01-0.03 mol / L manganese acetate solution.

6. The asphalt mixture according to claim 1, characterized in that: The mineral material consists of coarse aggregate, fine aggregate and mineral powder.

7. A method for preparing an asphalt mixture according to claim 1, characterized in that: The steps include: (1) Prepare the raw materials according to the raw material ratios described in claim 1 and set aside; (2) Preparation of rice husk ash modifier: rice husk and dilute hydrochloric acid are uniformly mixed in a mass ratio of 1:1.7-1.8, and then soaked for 40-50 minutes, filtered and dried at 50-70°C to obtain preliminary pretreated rice husk; the preliminary pretreated rice husk and divalent manganese ion solution are mixed in a mass ratio of 1:1.7-1.8, soaked for 55-65 minutes and stirred, and then dried at 50-70°C to obtain pretreated rice husk; the pretreated rice husk is burned at 400-600°C, and after cooling, the rice husk ash is wet-milled to obtain a rice husk ash modifier; (3) Preparation of Qingchuan rock asphalt and castor oil modifier: Dry Qingchuan rock asphalt and castor oil at 150-160°C for 30-50 min respectively for use; (4) Preparation of composite modified asphalt: The asphalt is heated and melted at a temperature of 170-190°C, and the rice husk ash modifier is first added. After shearing, Qingchuan rock asphalt and castor oil modifier are added, and a compatibilizer is added. After stirring for 50-70 minutes, the asphalt is placed in an environment of 170-180°C for swelling and development for 20-40 minutes. (5) Preparation of composite modified asphalt mixture: heat the mineral material to 170°C to 175°C, mix and stir evenly with the composite modified asphalt to obtain the mixture.

8. The preparation method according to claim 7, characterized in that: In the step (4), after adding rice husk ash, shearing is carried out at a shear rate of 2500-3500 r / min for 25-35 minutes, and then Qingchuan rock asphalt and castor oil are added in sequence and sheared at a shear rate of 5000-6000 r / min for 40-50 minutes.