Isocyanate activated coal gangue modified asphalt as well as preparation method and application thereof

Abstract

The invention discloses isocyanate activated coal gangue modified asphalt as well as a preparation method and application thereof and belongs to the technical field of road engineering. According to the method, isocyanate is adopted for activating coal gangue, and the activated coal gangue is used as a modifier to be mixed with matrix asphalt for modification, so that the physical performance and stability of the asphalt are improved; the method comprises the following specific steps: reacting coal gangue with isocyanate under specific conditions to increase active sites on the surface of the coal gangue, thereby enhancing the binding capacity of the coal gangue with asphalt; the activated coal gangue and matrix asphalt are mixed in proportion, and the modified asphalt is prepared through uniform stirring and specific process treatment. The modified asphalt disclosed by the invention has excellent high-temperature stability, low-temperature crack resistance and fatigue resistance, and the service life and the performance of a pavement are remarkably improved; the coal gangue is used as a modifier, so that the resource utilization of wastes is realized, the production cost of the modified asphalt is reduced, and remarkable economic and environmental benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of modified asphalt materials, and in particular to isocyanate activated gangue modified asphalt, a preparation method and application thereof. Background Art

[0002] In the field of municipal transportation construction technology, asphalt is one of the main materials for road paving, and the optimization and improvement of its performance is one of the research hotspots. Although traditional matrix asphalt can meet the needs of road construction in most cases, it still faces major problems under extreme climatic conditions, such as softening and deformation at high temperatures and brittle cracking at low temperatures.

[0003] In order to improve the high temperature stability, low temperature crack resistance and fatigue resistance of asphalt, researchers have developed a variety of modified asphalt technologies. As a common industrial waste, the large amount of coal gangue accumulated not only occupies land resources, but also may pollute the environment. In recent years, the research on the application of coal gangue in the field of building materials has gradually increased, aiming to realize the resource utilization of waste. However, directly adding coal gangue to asphalt as a modifier often leads to unsatisfactory modification effects due to its surface inertness and poor compatibility with asphalt. Summary of the invention

[0004] Technical problem to be solved: In view of the problems existing in the use of asphalt materials in the background technology, the present invention provides an isocyanate-activated coal gangue modified asphalt, a preparation method and its application. By using isocyanate to activate the coal gangue, the activity of its surface is improved, and its bonding ability with the matrix asphalt is enhanced, so as to obtain a modified asphalt material with excellent performance; this modified asphalt material not only solves the performance problems of traditional matrix asphalt at high and low temperatures, but also realizes the resource utilization of coal gangue, and has significant economic and environmental benefits.

[0005] Technical solution: The preparation method of isocyanate activated gangue modified asphalt described in the present invention comprises the following steps: Step 1: pre-treating the coal gangue to obtain coal gangue powder; Step 2: Add coal gangue powder and isocyanate into a reactor in a mass ratio of 1:(0.15-0.25), react for 1-4 hours at a reaction temperature of 120-150° C. and a stirring speed of 200-500 rpm to obtain an activated coal gangue material; Step 3: Add the activated gangue material obtained in step 1 to the base asphalt in a mass ratio of 5-15%, and stir evenly at a temperature of 150-170°C for 30-120 minutes to obtain isocyanate-activated gangue modified asphalt.

[0006] Preferably, the isocyanate in step 2 is at least one of toluene diisocyanate TDI, diphenylmethane diisocyanate MDI or isophorone diisocyanate IPDI.

[0007] Preferably, in step 1, a certain amount of coal gangue is selected, and is crushed, screened and ground to obtain coal gangue powder with a particle size of 0.1 to 100 μm.

[0008] Preferably, step 3 further includes the step of testing the high temperature stability, low temperature crack resistance and fatigue resistance of the isocyanate activated gangue modified asphalt.

[0009] The invention also discloses isocyanate activated coal gangue modified asphalt, which is prepared by adopting the preparation method.

[0010] The invention also discloses the application of isocyanate activated gangue modified asphalt in road paving. The modified asphalt is applied to the road paving of expressways, urban roads and airport runways.

[0011] Preferably, the modified asphalt and other additives including aggregates and fillers form a complete road paving material system.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses isocyanate to activate the gangue. As an active compound, isocyanate can react with functional groups such as hydroxyl and amino groups on the surface of various materials to form chemical bonds, thereby changing the surface properties and structure of the gangue material, improving its surface activity, achieving effective activation of the gangue, and enhancing its ability to bind with the matrix asphalt, thereby obtaining a modified asphalt material with excellent performance; in addition, isocyanate can also chemically react with the active groups in the asphalt, thereby improving the high-temperature deformation resistance, fatigue resistance and other properties of the asphalt material; 2. The modified asphalt prepared by this method has excellent high temperature stability, low temperature crack resistance and fatigue resistance, which can significantly improve the service life and performance of the road surface; 3. This modified asphalt material not only solves the performance problems of traditional base asphalt at high and low temperatures, but also realizes the resource utilization of coal gangue by using coal gangue, an industrial waste, as a modifier, reducing the accumulation of waste and pollution to the environment; at the same time, the cost of coal gangue is relatively low, making the modified asphalt more cost-effective and having significant economic and environmental benefits; 4. The modified asphalt of the present invention is suitable for various road construction scenarios, including highways, urban roads, airport runways, etc., and has broad application prospects.

[0013] The present invention also has other beneficial effects which are described in the embodiments of the specification and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The present invention is a flow chart of the preparation method of isocyanate activated gangue modified asphalt; Figure 2 The softening point test results of the modified asphalt prepared in Examples 1 to 3 of the present invention and the comparative example are shown in the bar graph; Figure 3 A bar graph showing the 5°C ductility test results of the modified asphalts prepared in Examples 1 to 3 of the present invention and the comparative example; Figure 4 It is a bar chart of the time fatigue life test results of the modified asphalt prepared in Examples 1 to 3 of the present invention and the comparative example. DETAILED DESCRIPTION

[0015] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the attached Figure 1~Figure 4 The technical solutions of the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0016] like Figure 1 As shown, the present invention discloses a method for preparing isocyanate activated gangue modified asphalt, the preparation method comprising the following steps: Step 1: Select a certain amount of coal gangue, and obtain coal gangue powder with a particle size of 0.1~100μm after crushing, screening and grinding, ensuring the uniformity of coal gangue particles and good compatibility with asphalt; Step 2: Add gangue powder and isocyanate into a reactor at a mass ratio of 1:(0.15-0.25), and react for 1-4 hours at a reaction temperature of 120-150°C and a stirring speed of 200-500rpm to ensure that the isocyanate fully reacts with the functional groups on the surface of the gangue to obtain an activated gangue material; wherein the isocyanate is at least one of toluene diisocyanate TDI, diphenylmethane diisocyanate MDI or isophorone diisocyanate IPDI; in this step, the isocyanate molecules penetrate into the tiny pores of the gangue particles, react chemically with the functional groups on their surfaces, and form chemical bonds, thereby changing the surface properties and structure of the gangue material, improving its surface activity, and enhancing its ability to bind to the matrix asphalt, to obtain a modified asphalt material with excellent performance; Step 3: Add the activated gangue material obtained in step 1 to the matrix asphalt at a mass ratio of 5-15%, and stir evenly for 30-120 minutes at a temperature of 150-170°C to ensure sufficient mixing and uniform distribution of the activated gangue and the matrix asphalt to obtain isocyanate-activated gangue-modified asphalt; then, perform performance testing steps on the isocyanate-activated gangue-modified asphalt for high temperature stability, low temperature crack resistance and fatigue resistance.

[0017] The invention also discloses isocyanate activated coal gangue modified asphalt, which is prepared by adopting the preparation method.

[0018] The invention also discloses an application of isocyanate activated coal gangue modified asphalt in road paving. The modified asphalt prepared by the preparation method is applied to the road paving of expressways, urban roads and airport runways. The modified asphalt and other additives including aggregates and fillers form a complete road paving material system.

[0019] The present invention activates the coal gangue by using isocyanate. As an active compound, isocyanate can react with functional groups such as hydroxyl and amino groups on the surfaces of various materials to form chemical bonds, thereby changing the surface properties and structure of the coal gangue material and improving its surface activity, thereby achieving effective activation of the coal gangue and enhancing its bonding ability with matrix asphalt to obtain a modified asphalt material with excellent performance. In addition, isocyanate can also chemically react with active groups in asphalt, thereby improving the high-temperature deformation resistance, fatigue resistance and other properties of the asphalt material.

[0020] The following are specific embodiments of the present invention, which are used to further illustrate the technical solutions and effects of the present invention.

[0021] Example 1: The preparation method of isocyanate-activated gangue-modified asphalt of the present invention comprises the following steps: (1) pretreatment of gangue: a certain amount of gangue is selected, and gangue powder with a particle size of 50 μm is obtained by crushing, screening and grinding.

[0022] (2) Isocyanate activation treatment: Coal gangue powder and toluene diisocyanate (TDI) were added into a reactor at a mass ratio of 1:0.2, and the reaction was carried out at a reaction temperature of 120°C and a stirring speed of 300 rpm for 2 h to obtain an activated coal gangue material.

[0023] (3) Mixing modification treatment: The prepared activated coal gangue material was added to the base asphalt in a mass ratio of 15:85, and stirred evenly for 60 min at a temperature of 160 °C using a high-speed shear mixer to obtain isocyanate-activated coal gangue-modified asphalt; the isocyanate-activated coal gangue-modified asphalt was then subjected to performance tests on high temperature stability, low temperature crack resistance and fatigue resistance.

[0024] Example 2: The preparation method of isocyanate-activated gangue-modified asphalt of the present invention comprises the following steps: (1) pretreatment of gangue: a certain amount of gangue is selected, and gangue powder with a particle size of 20 μm is obtained by crushing, screening and grinding.

[0025] (2) Isocyanate activation treatment: Coal gangue powder and diphenylmethane diisocyanate (MDI) were added into a reactor at a mass ratio of 1:0.15, and the reaction was carried out at a reaction temperature of 120°C and a stirring speed of 400 rpm for 3 h to obtain an activated coal gangue material.

[0026] (3) Mixing modification treatment: The prepared activated coal gangue material was added to the base asphalt in a mass ratio of 10:90, and stirred evenly for 90 min at a temperature of 150 °C using a high-speed shear mixer to obtain isocyanate-activated coal gangue-modified asphalt; the isocyanate-activated coal gangue-modified asphalt was then subjected to performance tests on high temperature stability, low temperature crack resistance and fatigue resistance.

[0027] Example 3: The preparation method of isocyanate-activated coal gangue modified asphalt of the present invention comprises the following steps: (1) coal gangue pretreatment: a certain amount of coal gangue is selected, and subjected to crushing, screening and grinding treatment to obtain coal gangue powder with a particle size of 80 μm.

[0028] (2) Isocyanate activation treatment: Coal gangue powder and isophorone diisocyanate (IPDI) were added into a reactor at a mass ratio of 1:0.25, and the reaction was carried out at a reaction temperature of 140 °C and a stirring speed of 250 rpm for 1.5 h to obtain an activated coal gangue material.

[0029] (3) Mixing modification treatment: Add the activated coal gangue material obtained in step 1 to the base asphalt in a mass ratio of 5:95, and use a high-speed shear mixer to stir evenly at a temperature of 170°C for 30 minutes to obtain isocyanate-activated coal gangue-modified asphalt; then, perform performance tests on the isocyanate-activated coal gangue-modified asphalt in terms of high temperature stability, low temperature crack resistance and fatigue resistance.

[0030] Comparative example: The preparation method of gangue-modified asphalt in this embodiment includes the following steps: (1) pretreatment of gangue: a certain amount of gangue is selected, and gangue powder with a particle size of 80 μm is obtained by crushing, screening and grinding.

[0031] (2) High-temperature activation treatment: The gangue powder that has been stored for more than one year is placed in a heating furnace at 800°C and calcined for 50 min. The powder is taken out and cooled to room temperature. Then, the powder is added into a mixed solution of 35 wt% methanol solution and Tween-20 and stirred for 2 h. The powder is taken out, washed and air-dried to obtain activated gangue powder.

[0032] (3) Mixing modification treatment: Add the prepared activated coal gangue material into the base asphalt in a mass ratio of 5:95, and use a high-speed shear mixer to stir evenly at a temperature of 170°C for 30 minutes to obtain high-temperature activated coal gangue modified asphalt; then, the high-temperature activated coal gangue modified asphalt is subjected to performance tests on high-temperature stability, low-temperature crack resistance and fatigue resistance.

[0033] The modified asphalt prepared in Examples 1 to 3 and the comparative example was tested for performance according to the test standard in the "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E20-2011). The test results are as follows: Figure 2~Figure 4 shown. Figure 2~Figure 4 The test results of softening point, 5°C elongation and fatigue life of the modified asphalt prepared in Examples 1 to 3 and the comparative example respectively correspond to the high temperature stability, low temperature crack resistance and fatigue resistance of the modified asphalt. Figure 2~Figure 4 It shows that the high temperature performance, low temperature crack resistance and fatigue resistance of the isocyanate activated coal gangue modified asphalt prepared by the method of the present invention are significantly better than those of the common activated coal gangue modified asphalt.

[0034] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing isocyanate activated gangue modified asphalt, characterized in that: The preparation method comprises the following steps: Step 1: pre-treating the coal gangue to obtain coal gangue powder; Step 2: Add coal gangue powder and isocyanate into a reactor in a mass ratio of 1:(0.15-0.25), react for 1-4 hours at a reaction temperature of 120-150° C. and a stirring speed of 200-500 rpm to obtain an activated coal gangue material; Step 3: Add the activated gangue material obtained in step 1 to the base asphalt in a mass ratio of 5-15%, and stir evenly at a temperature of 150-170°C for 30-120 minutes to obtain isocyanate-activated gangue modified asphalt.

2. The method for preparing isocyanate activated gangue modified asphalt according to claim 1, characterized in that: In step 2, the isocyanate is at least one of toluene diisocyanate TDI, diphenylmethane diisocyanate MDI or isophorone diisocyanate IPDI.

3. The method for preparing isocyanate activated gangue modified asphalt according to claim 1, characterized in that: In step 1, a certain amount of coal gangue is selected, and after crushing, screening and grinding, coal gangue powder with a particle size of 0.1-100 μm is obtained.

4. The method for preparing isocyanate activated gangue modified asphalt according to claim 1, characterized in that: Step 3 is followed by a step of testing the high temperature stability, low temperature crack resistance and fatigue resistance of the isocyanate activated gangue modified asphalt.

5. An isocyanate activated coal gangue modified asphalt, characterized in that: The method is prepared by any one of claims 1 to 4.

6. Application of isocyanate activated gangue modified asphalt in road paving, wherein the modified asphalt described in claim 5 is applied to the paving of highways, urban roads and airport runways.

7. The use of the isocyanate activated gangue modified asphalt in road paving according to claim 6, characterized in that: The modified asphalt and other additives including aggregates and fillers form a complete road paving material system.

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