A fast-dissolving weakly crystalline high modulus agent, preparation method and use method thereof

Abstract

The present invention belongs to the technical field of road asphalt additives, and in particular relates to a fast-dissolving weak crystalline high modulus agent, a preparation method and a method of using the same, which are used for long-life asphalt pavements. The technical points are as follows: calculated by weight, comprising: 85 to 95 parts of reactive hard asphalt, 5 to 15 parts of reactive polyolefin, 1 to 5 parts of antioxidant, and 1 to 3 parts of stearate powder. The fast-dissolving weak crystalline high modulus agent provided by the present invention is formed by diluting reactive polyolefin with reactive hard asphalt as a matrix and then melting and granulating it. It has good quick solubility and utilizes the matrix pre-dispersion effect to improve the uniformity and stability of polyolefin in asphalt; and through the anhydride groups in the reactive hard asphalt and reactive polyolefin, chemical bonding is generated between the hard asphalt, polyolefin and matrix asphalt, thereby improving the compatibility of the three while weakening the crystallization tendency of the polyolefin, thereby achieving a high modulus of the asphalt mixture without sacrificing its low-temperature fracture resistance and medium-temperature fatigue resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of road asphalt additives, and in particular relates to a fast-dissolving weakly crystalline high modulus agent, a preparation method and a use method thereof. Background Art

[0002] One of the current technical bottlenecks hindering the longevity of asphalt pavements in my country is the permanent deformation caused by rutting in the mid-surface asphalt layer. High-modulus asphalt concrete (HMAC) boasts a dynamic modulus of up to 14,000 MPa, significantly higher than that of ordinary asphalt concrete. This demonstrates excellent rutting resistance, making it a key material for long-life asphalt pavement construction.

[0003] Currently, my country's high-performance high-modulus agents still rely primarily on imports (including from France's PRI and Germany's Rub). Domestically produced high-modulus agents differ from imported products in key performance aspects such as solubility, compressibility, crack resistance, and fatigue resistance. my country's high-modulus agents are primarily made from polyolefins, with those made from recycled polyolefins dominating the market. However, high modulus agents based on recycled polyolefins have the following problems: (1) Low melt index (190°C, 2.16kg): The melt index of polyolefin high modulus agents is generally in the range of 1-5g / 10min, while the mixing temperature of asphalt mixture is generally 160-180°C. Their solubility is insufficient, and it is impossible to ensure that they can be mixed evenly with asphalt binder during a short mixing process, which ultimately leads to unstable modification effect on asphalt mixture; (2) High melt viscosity: Polyolefin high modulus agents easily absorb light components such as saturated components and aromatic components in asphalt binder, which leads to poor compressibility of asphalt mixture and difficulty in ensuring construction quality; (3) Poor compatibility with asphalt binder: Although the direct injection process in the mixing tank has alleviated the compatibility problem between polyolefin high modulus agents and asphalt to a certain extent, polyolefin high modulus agents still exist in the asphalt binder in a non-uniform state such as strips and clusters on a microscopic scale, and the interface transition zone between the two phases is significant, which leads to poor low-temperature crack resistance and medium-temperature fatigue resistance of the asphalt mixture; (4) High crystallinity: After high-temperature mixing with stone, the polyolefin high modulus agents are distributed in an uneven state in the asphalt binder. Due to their high crystallization tendency, after the temperature of the asphalt mixture is lowered, the polyolefin high modulus agents cool and crystallize. The presence of microcrystals weakens the deformation capacity of the asphalt binder, which ultimately leads to further deterioration of the low-temperature crack resistance and medium-temperature fatigue resistance of the asphalt mixture.

[0004] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] The first purpose of the present invention is to provide a fast-dissolving weakly crystalline high modulus agent, which is directly added to the mixing tank of an asphalt mixing plant to prepare a high modulus asphalt mixture with excellent construction workability, high-temperature rutting resistance, low-temperature cracking resistance, and medium-temperature fatigue resistance, thereby solving the technical defects of existing polyolefin-based high modulus agents and meeting the urgent use needs of high modulus asphalt mixtures for low-temperature cracking resistance and medium-temperature fatigue resistance.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A fast-dissolving, weakly crystalline, high-modulus agent comprises the following components, calculated by weight: 85-95 parts of reactive hard asphalt, 5-15 parts of reactive polyolefin, 1-5 parts of antioxidant, and 1-3 parts of stearate powder. The fast-dissolving, weakly crystalline, high-modulus agent is melt-granulated at 150-190°C. By melt-granulating the fast-dissolving, weakly crystalline, high-modulus agent, the present invention ensures uniform mixing of the fast-dissolving, weakly crystalline, high-modulus agent with the base asphalt within a relatively short mixing time, thereby improving the workability of the fast-dissolving, weakly crystalline, high-modulus agent and enhancing the quality stability of the high-modulus asphalt mixture.

[0008] Furthermore, the reactive hard asphalt is produced by first oxidizing 100 parts of hard asphalt and then modifying it with 1-3 parts of unsaturated acid anhydride and 0.1-0.3 parts of initiator. Oxidation of the hard asphalt increases the asphaltene and resin content, reduces the oil content, and further raises the softening point. This, in turn, improves the modulus of the modified asphalt. Furthermore, the oxidation process of the hard asphalt enhances its compatibility with reactive polyolefins. The anhydride modification increases the polarity of the reactive hard asphalt, significantly enhancing its compatibility with olefin polymers and improving the storage stability of high-modulus asphalt.

[0009] Furthermore, the softening point of hard asphalt is 100-130°C. Hard asphalt with a high softening point can be used as a precursor raw material for a high modulus agent, which can further reduce the amount of polyolefin used.

[0010] Furthermore, the reactive polyolefin is produced by twin-screw grafting of 100 parts of a low-molecular-weight polyolefin with 3-5 parts of an unsaturated acid anhydride and 0.1-0.3 parts of an initiator. This anhydride-modified reactive polyolefin allows the anhydride groups in the molecular structure to chemically bond with both the hard asphalt and the matrix asphalt, thereby enhancing their compatibility. Furthermore, the bonding between the reactive polyolefin, the hard asphalt, and the matrix asphalt significantly reduces the reactive polyolefin's tendency to crystallize, ensuring the high-modulus binder's low-temperature resistance and fatigue resistance.

[0011] Furthermore, the molecular weight of the low-molecular-weight polyolefin is preferably between 5,000 and 15,000. A molecular weight above 5,000 ensures the polyolefin's high-modulus modification effect on asphalt. A molecular weight below 15,000 can somewhat reduce the polyolefin's tendency to crystallize, while also having a lower melting point, which helps improve the solubility of the high-modulus agent. This results in better workability and a weaker tendency to crystallize, thereby improving the modulus of the modified asphalt without sacrificing the low-temperature crack resistance and medium-temperature fatigue crack resistance of the high-modulus asphalt mixture.

[0012] Furthermore, the reactive hard asphalt has a softening point of 120-150°C, an acid value of 10-20 mgKOH / g, an asphaltene content ≥50%, and a resin content ≥30%. The reason for preparing a reactive hard asphalt with a softening point of 120-150°C is that a softening point above 120°C enhances its reinforcing effect on the base asphalt while ensuring it does not stick to the connecting blocks at room temperature, facilitating storage, transportation, and use. A softening point below 150°C enables it to melt rapidly at pelletizing temperatures (150-190°C). Rich in asphaltene and resin, the reactive hard asphalt has a preliminary high-modulus modification effect on asphalt, which can reduce the amount of olefin polymer used to a certain extent.

[0013] Furthermore, the reactive polyolefin has a melting point of 120-160°C and an acid value of 20-60 mgKOH / g. The reason for preparing a reactive polyolefin with a softening point of 120-160°C is that a softening point above 120°C enhances its reinforcing effect on the base asphalt while ensuring that it does not stick to the connecting block at room temperature, facilitating storage, transportation, and use. A softening point below 160°C allows it to melt quickly at granulation temperatures (150-190°C).

[0014] Furthermore, the crystallization peak endothermic enthalpy of reactive polyolefin is 20.1~25.2J / g, which is much smaller than the crystallization peak endothermic enthalpy of conventional polyolefin, ensuring its weaker crystallization tendency, thereby achieving its enhancement of the matrix asphalt without sacrificing the low-temperature fracture resistance and medium-temperature fatigue resistance of the high modulus asphalt binder.

[0015] Furthermore, the unsaturated acid anhydride is one or more of maleic anhydride (MA), tetrahydrophthalic anhydride (THPA), methyltetrahydrophthalic anhydride (MeTHPA), methylnadic anhydride (MNA), and tung oil anhydride (TOA); the acid anhydride group in the unsaturated acid anhydride can undergo diene addition reaction with the double bonds on the polyolefin structure, and can also undergo diene addition reaction with hard asphalt and matrix asphalt. It is the link that produces chemical bonding between polyolefin, hard asphalt and matrix asphalt, which helps to improve the compatibility among the three.

[0016] Furthermore, the antioxidant is a mixture of a free radical segment blocker and a peroxide decomposer, and the mass ratio between the two is 1:0.5 to 1.0; the free radical segment blocker is a main antioxidant, which can delay the transmission and growth of the free radical chain during the oxidation process of the high modulus agent; the peroxide is a secondary antioxidant, which can reduce the generation of free radicals during the oxidation process of the high modulus agent; the antioxidant is a mixture of the main antioxidant and the secondary antioxidant in a certain proportion, which can significantly improve the service life of the high modulus agent.

[0017] Furthermore, the initiator is a mixture of dibenzoyl peroxide and N,N-dimethylaniline, with a mass ratio of 1:0.5 to 1.5; the initiator generates free radicals to initiate the polymerization reaction under certain temperature conditions.

[0018] Furthermore, the stearate powder is one or more of calcium stearate, zinc stearate, and barium stearate; the stearate powder has a lubricating effect, ensuring that the high modulus agent does not stick together or clump during long-term storage, thereby meeting the needs of direct on-site injection.

[0019] The second object of the present invention is to provide a method for preparing a fast-dissolving weakly crystalline high modulus agent, which has the same technical effect.

[0020] The above technical objectives of the present invention are achieved by the following technical solutions:

[0021] <Preparation of Reactive Hard Asphalt>

[0022] A1. Put the hard asphalt into the preheating kettle and heat it to form a hard asphalt melt;

[0023] A2, continuously blowing oxygen into the medium-hard asphalt melt in A1 to deeply oxidize it to form an oxidized hard asphalt melt;

[0024] A3. Add unsaturated acid anhydride and initiator to the oxidized hard asphalt melt in A2 to anhydride it to form a reactive hard asphalt melt.

[0025] <Preparation of Reactive Polyolefin>

[0026] B1. Put low molecular weight polyolefin, unsaturated acid anhydride and initiator into a high-speed mixer in proportion and mix them evenly;

[0027] B2. The materials uniformly mixed in B1 are subjected to anhydride grafting modification through a twin-screw extruder to form a reactive polyolefin.

[0028] <Preparation of High Modulus Agent>

[0029] S1. Mix the reactive hard asphalt, free radical segment sealer, peroxide decomposer, etc. in proportion;

[0030] S2, using a twin-screw extruder to melt and mix the materials in S1 to form a reactive hard asphalt melt;

[0031] S3, adding the reactive polyolefin to the reactive hard asphalt melt in S2, and forming a fast-dissolving weakly crystalline high modulus agent melt through melting and mixing processes;

[0032] S4, the medium-soluble weak crystalline high modulus agent melt in S3 is subjected to processes such as extrusion, pelletizing, cooling, and dehydration to form uniform particles of 1 to 5 mm.

[0033] S5. 1 to 3 parts of stearate are coated on the surface of the uniform particles in S4 to form a fast-dissolving weakly crystalline high modulus agent.

[0034] As a preferred method, a method for preparing a fast-dissolving weakly crystalline high modulus agent comprises the following steps:

[0035] <Preparation of Reactive Hard Asphalt>

[0036] A1. Place 100 parts of hard asphalt into a preheated kettle and heat to 30-50°C above its softening point to form a hard asphalt melt.

[0037] A2. Pump the medium-hard asphalt melt in A1 into the oxidation kettle and continuously blow in oxygen to deeply oxidize it to form an oxidized hard asphalt melt. The oxidation temperature is 180-200°C and the oxidation time is 12-24 hours.

[0038] A3. Pump the oxidized hard asphalt melt in A2 into the anhydride reactor, and add 1 to 3 parts of unsaturated acid anhydride and 0.1 to 0.3 parts of initiator to anhydride it to form a reactive hard asphalt melt. The anhydride temperature is 150 to 170°C, and the anhydride time is 6 to 12 hours.

[0039] <Preparation of Reactive Polyolefin>

[0040] B1. Add 100 parts of low molecular weight polyolefin, 3-5 parts of unsaturated acid anhydride and 0.1-0.3 parts of initiator into a high-speed mixer in proportion and mix them evenly;

[0041] B2. The materials mixed uniformly in B1 are subjected to anhydride grafting modification through a twin-screw extruder to form a reactive polyolefin. The temperature of the twin-screw mixing section is 30 to 50° C. higher than the melting point of the low molecular weight polyolefin.

[0042] <Preparation of High Modulus Agent>

[0043] S1. Add 85-95 parts of reactive hard asphalt, 1-3 parts of free radical segment sealer, 1-3 parts of peroxide decomposer, etc. into a high-speed mixer and mix them evenly;

[0044] S2. Using a twin-screw extruder, the materials uniformly mixed in step S1 are melted and mixed to form a reactive hard asphalt melt, with the mixing section temperature being 150-170°C;

[0045] S3, setting a reactive polyolefin adding module at the end of the twin-screw mixing section, and adding 5 to 15 parts of reactive polyolefin to the reactive hard asphalt melt prepared in step S2, and melting and mixing to form a fast-dissolving weakly crystalline high modulus agent melt, and the mixing section temperature is 170 to 190° C.;

[0046] S4. The fast-dissolving weakly crystalline high modulus agent melt in S3 is subjected to processes such as extrusion, pelletizing, cooling, and dehydration to form uniform particles of 1 to 5 mm.

[0047] S5. Add 1 to 3 parts of stearate to the uniform particles in S4 and stir thoroughly to form a fast-dissolving weakly crystalline high modulus agent.

[0048] The third object of the present invention is to provide a method for using a fast-dissolving weakly crystalline high modulus agent, which has the same technical effect.

[0049] The above technical objectives of the present invention are achieved by the following technical solutions:

[0050] A method for using a fast-dissolving weakly crystalline high modulus agent comprises the following steps:

[0051] P1. Add the quick-dissolving weakly crystalline high modulus agent into the mixing tank and mix with the ore according to the mass ratio of 0.5% to 1.5% of the ore;

[0052] P2. Add asphalt binder at a mass ratio of 3.7% to 4.7% of the aggregate and mix evenly;

[0053] P3. Add mineral powder and mix evenly to form a high modulus asphalt mixture;

[0054] P4. Place the high modulus asphalt mixture mixed evenly in P3 into the material truck, simmer for 1 to 3 hours, and then spread and roll it.

[0055] Furthermore, a method for using a fast-dissolving weakly crystalline high modulus agent is specifically as follows:

[0056] P1. Add 0.5% to 1.5% of the mass ratio of the mineral material into the mixing tank of the asphalt mixing plant, and dry mix it with the hot mineral material preheated to 180-190℃ for 10-15s; make the quick-dissolving weak crystalline high modulus agent completely melt, spread and wet the surface of the hot mineral material.

[0057] P2. Spray asphalt binder preheated to 160-170℃ into the mixing cylinder of the asphalt mixing plant at a ratio of 3.7% to 4.7% of the mass of the mineral material, and continue mixing for 20-40 seconds;

[0058] P3. Add mineral powder into the mixing tank of the asphalt mixing plant according to the production mix ratio and continue stirring for 10 to 20 seconds until there is no white material and a high modulus asphalt mixture is formed;

[0059] P4. Place the high-modulus asphalt mixture prepared in P3 in a feed truck, cover with a blanket for insulation, and simmer at 160-170°C for 1-3 hours before paving and rolling. Use a double-drum roller for initial compaction, 1-2 times, with the initial compaction temperature not lower than 150°C. Use a tire roller for secondary compaction, 2-4 times, with the secondary compaction temperature not lower than 130°C. Use a double-drum roller for final compaction, 1-2 times, with the final compaction temperature not lower than 100°C.

[0060] In summary, the present invention has the following beneficial effects:

[0061] (1) This invention abandons the traditional method of directly adding olefin polymers to the mixing tank to modify the asphalt mixture. Instead, the anhydride-modified polyolefin is pre-dissolved and dispersed in the oxidized and anhydride-modified hard asphalt. Reactive hard asphalt is used as a matrix to dilute the reactive polyolefin. While significantly improving the solubility of the high modulus agent, the pre-dispersion effect of the reactive hard asphalt matrix is ​​utilized to significantly improve the distribution uniformity of the reactive polyolefin in the asphalt mixture, which only accounts for 0.03% to 0.3% of the total asphalt mixture. This ensures that the final high modulus asphalt mixture has a uniform modification effect and stable performance.

[0062] (2) The present invention uses hard asphalt with a softening point of 100-130°C as the main raw material of the high modulus agent. In order to further reduce the amount of olefin polymer used, hard asphalt rich in asphaltene and colloid is used as the precursor of the high modulus agent. The hard asphalt is subjected to an oxidative polymerization reaction using a deep oxidation process to form oxidized hard asphalt, thereby further improving the softening point and making its reinforcing effect on the matrix asphalt more significant. In addition, the diene addition reaction between the aromatic compounds in the oxidized asphalt and the double-bond anhydride is used to achieve the anhydride modification of the oxidized asphalt, thereby greatly increasing the compatibility between the oxidized hard asphalt and the olefin polymer, thereby avoiding the problems of agglomeration and large phase size of the olefin polymer in the asphalt binder due to poor compatibility.

[0063] (3) The core of the present invention is to select low molecular weight polyolefins with a molecular weight of 5000 to 15000, and to introduce anhydride groups by using the double bonds in the low molecular weight polyolefin structure through diene addition reaction. On the one hand, the anhydride groups on the molecular structure of the anhydride-modified polyolefin can form chemical bonds with hard asphalt and matrix asphalt through diene addition reaction, thereby improving the compatibility between the anhydride-modified polyolefin and hard asphalt and matrix asphalt; on the other hand, the bonding between the anhydride-modified polyolefin and the hard asphalt and matrix asphalt greatly weakens the crystallization tendency of the anhydride-modified polyolefin, which exists in the form of microcrystals in the high modulus asphalt binder, thereby achieving the goal of strengthening the matrix asphalt without sacrificing the low temperature fracture resistance and medium temperature fatigue resistance of the high modulus asphalt binder. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0065] Figure 1 Schematic diagram of the synergistic effect of reactive polyolefin, reactive hard asphalt and matrix asphalt;

[0066] Figure 2 Schematic diagram of the interaction between polyolefin, reactive hard asphalt and matrix asphalt;

[0067] Figure 3 Schematic diagram of the interaction between reactive polyolefin, hard asphalt and matrix asphalt.

[0068] Explanation of the reference numbers: 1-base asphalt; 2-hard asphalt; 3-polyolefin; 4-anhydride group; 5-reactive hard asphalt; 6-reactive polyolefin. DETAILED DESCRIPTION

[0069] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a fast-dissolving weakly crystalline high modulus agent, a preparation method and a method of use thereof proposed in accordance with the present invention, its specific implementation method, characteristics and effects are described in detail below.

[0070] Sources of raw materials used in the examples and comparative examples:

[0071] (1) Hard asphalt: DOA (softening point 100-120°C), Hebei Hankai Energy Technology Development Co., Ltd.; CLP (softening point 120-130°C), China Shenhua Coal to Liquid Chemical Co., Ltd.

[0072] (2) Polyolefins: low molecular weight polyolefins (LICOWAX PE 520, LICOWAX PE 130, LICOWAX PE190), high molecular weight polyolefins (3300F), Shanghai Kaiyin Chemical Co., Ltd.

[0073] (3) Unsaturated anhydrides: maleic anhydride (MA), tetrahydrophthalic anhydride (THPA), methyltetrahydrophthalic anhydride (MeTHPA), methylnadic anhydride (MNA), Shanghai Aladdin Biochemical Technology Co., Ltd.

[0074] (4) Initiator: dibenzoyl peroxide (BPO), N,N-dimethylaniline (DMA), Shanghai Aladdin Biochemical Technology Co., Ltd.

[0075] (5) Antioxidants: free radical segment blockers (1010, 264), peroxide decomposers (168, DLDP), Nanjing Hualiming Science and Technology Industry and Trade Co., Ltd.

[0076] (6) Stearate powder: calcium stearate, zinc stearate, barium stearate, Shanghai Kaiyin Chemical Co., Ltd.

[0077] (7) Asphalt: 70# base asphalt, Jiangsu Zhongyitong Road New Materials Co., Ltd.

[0078] The preparation method of high modulus asphalt in the examples and comparative examples is:

[0079] Refer to Appendix A of the "Technical Guide for Construction of High Modulus Surface Layer HMM-13 of Asphalt Pavement" (T / JSTERA 43-2023) to prepare high modulus asphalt. The stirring temperature is 180°C, the stirring time is 1 min, and the insulation condition is 180°C oven for 30 min.

[0080] The preparation method of the high modulus asphalt mixture (HMM-13) in the examples and comparative examples is as follows:

[0081] High modulus asphalt mixture (HMM-13) was prepared according to the "Technical Guide for the Construction of High Modulus Surface Layers of Asphalt Pavements HMM-13" (T / JSTERA 43-2023). The typical aggregate gradation is coarse aggregate (9.5-16.0 mm): coarse aggregate (4.75-9.5 mm): coarse aggregate (2.36-4.75 mm): fine aggregate (0-2.36 mm): mineral fines = 38%:19%:10%:30%:3%.

[0082] Example 1

[0083] The fast-dissolving weakly crystalline high modulus agent provided in this embodiment includes, by weight, 90 parts of reactive hard asphalt, 10 parts of reactive polyolefin, 3 parts of antioxidant, and 1 part of calcium stearate.

[0084] The preparation process of a fast-dissolving weakly crystalline high modulus agent is as follows:

[0085] <Preparation of Reactive Hard Asphalt>

[0086] A1. Place 100 parts of hard asphalt (DOA, softening point 100-120°C) into a preheated kettle and heat to 40°C above its softening point to form a hard asphalt melt;

[0087] A2. Pump the medium-hard asphalt melt in A1 into the oxidation kettle and continuously blow in oxygen to deeply oxidize it to form an oxidized hard asphalt melt. The oxidation temperature is 100°C and the oxidation time is 24 hours.

[0088] A3. Pump the oxidized hard asphalt melt in A2 into the anhydride reactor, and add 2 parts of maleic anhydride (MA) and 0.2 parts of initiator (dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) mixed in a ratio of 1:1) to anhydride it to form a reactive hard asphalt melt. The anhydride temperature is 170°C and the anhydride time is 6 hours.

[0089] <Preparation of Reactive Polyolefin>

[0090] B1. 100 parts of a low molecular weight polyolefin (LICOWAX PE 520), 4 parts of maleic anhydride (MA), and 0.2 parts of an initiator (a mixture of dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) in a ratio of 1:1) were added to a high-speed mixer and mixed uniformly;

[0091] B2. The materials mixed uniformly in B1 are subjected to anhydride grafting modification through a twin-screw extruder to form a reactive polyolefin. The temperature of the twin-screw mixing section is 50° C. higher than the melting point of the low molecular weight polyolefin.

[0092] <Preparation of High Modulus Agent>

[0093] S1. Add 90 parts of reactive hard asphalt and 3 parts of antioxidant into a high-speed mixer according to the proportion and mix them evenly;

[0094] S2. Using a twin-screw extruder, the materials uniformly mixed in step S1 are melted and mixed to form a reactive hard asphalt melt, with the mixing section temperature being 160°C;

[0095] S3, setting a reactive polyolefin adding module at the end of the twin-screw mixing section, and adding 10 parts of reactive polyolefin to the reactive hard asphalt melt prepared in step S2, and melting and mixing to form a fast-dissolving weakly crystalline high modulus agent melt, and the mixing section temperature is 180°C;

[0096] S4. The fast-dissolving weakly crystalline high modulus agent melt in S3 is subjected to processes such as extrusion, pelletizing, cooling, and dehydration to form uniform particles of 1 mm.

[0097] S5. Add 3 parts of stearate to the uniform particles in S4 and stir thoroughly to form a fast-dissolving weakly crystalline high modulus agent.

[0098] A method of using a fast-dissolving weakly crystalline high modulus agent is as follows:

[0099] P1. Add 1.0% of the mass ratio of the mineral material into the mixing tank of the asphalt mixing plant, and dry mix it with the hot mineral material preheated to 190℃ for 10 seconds; make the quick-dissolving weakly crystalline high modulus agent completely melt, spread and wet the surface of the hot mineral material.

[0100] P2. Spray 70# base asphalt preheated to 160℃ into the mixing cylinder of the asphalt mixing plant at a ratio of 4.2% of the mass of the mineral material, and continue mixing for 20 seconds;

[0101] P3. Add mineral powder into the mixing tank of the asphalt mixing plant according to the production mix ratio and continue stirring for 10 seconds until there is no white material and a high modulus asphalt mixture is formed;

[0102] P4: Place the high-modulus asphalt mixture prepared in P3 in a feed truck, cover with a blanket for insulation, and simmer at 160°C for 1 hour before paving and rolling. Use a double-drum roller for initial compaction (one pass) at 155°C; use a tire roller for secondary compaction (two passes) at 135°C; and use a double-drum roller for final compaction (two passes) at 105°C.

[0103] The performance test results of Example 1 are as follows:

[0104] Table 1 Test results of fast-dissolving weakly crystalline high modulus agent in Example 1

[0105]

[0106] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0107] Example 2

[0108] The fast-dissolving weakly crystalline high modulus agent provided in this embodiment includes, by weight, 85 parts of reactive hard asphalt, 15 parts of reactive polyolefin, 1 part of antioxidant, and 2 parts of zinc stearate.

[0109] The preparation process of a fast-dissolving weakly crystalline high modulus agent is as follows:

[0110] <Preparation of Reactive Hard Asphalt>

[0111] A1. Place 100 parts of hard asphalt (DLC, softening point 120-130°C) into a preheated kettle and heat to 40°C above its softening point to form a hard asphalt melt;

[0112] A2. Pump the medium-hard asphalt melt in A1 into the oxidation kettle and continuously blow in oxygen to deeply oxidize it to form an oxidized hard asphalt melt. The oxidation temperature is 100°C and the oxidation time is 24 hours.

[0113] A3. Pump the oxidized hard asphalt melt in A2 into the anhydride reactor, and add 3 parts of tetrahydrophthalic anhydride (THPA) and 0.3 parts of initiator (dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) mixed in a ratio of 1:0.5) to anhydride it to form a reactive hard asphalt melt. The anhydride temperature is 170°C and the anhydride time is 6 hours.

[0114] <Preparation of Reactive Polyolefin>

[0115] B1. 100 parts of a low molecular weight polyolefin (LICOWAX PE 130), 5 parts of tetrahydrophthalic anhydride (THPA), and 0.3 parts of an initiator (a mixture of dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) at a ratio of 1:0.5) were added to a high-speed mixer and mixed uniformly;

[0116] B2. The materials mixed uniformly in B1 are subjected to anhydride grafting modification through a twin-screw extruder to form a reactive polyolefin. The temperature of the twin-screw mixing section is 50° C. higher than the melting point of the low molecular weight polyolefin.

[0117] <Preparation of High Modulus Agent>

[0118] S1. Add 85 parts of reactive hard asphalt and 1 part of antioxidant into a high-speed mixer according to the proportion and mix them evenly;

[0119] S2. Using a twin-screw extruder, the materials uniformly mixed in step S1 are melted and mixed to form a reactive hard asphalt melt, with the mixing section temperature being 160°C;

[0120] S3, setting a reactive polyolefin adding module at the end of the twin-screw mixing section, and adding 15 parts of reactive polyolefin to the reactive hard asphalt melt prepared in step S2, and melting and mixing to form a fast-dissolving weakly crystalline high modulus agent melt, and the mixing section temperature is 180°C;

[0121] S4. The fast-dissolving weakly crystalline high modulus agent melt in S3 is subjected to processes such as extrusion, pelletizing, cooling, and dehydration to form uniform particles of 1 mm.

[0122] S5. Add 2 parts of stearate to the uniform particles in S4 and stir thoroughly to form a fast-dissolving weakly crystalline high modulus agent.

[0123] A method of using a fast-dissolving weakly crystalline high modulus agent is as follows:

[0124] P1. Add 1.2% of the mass ratio of the mineral material to the mixing cylinder of the asphalt mixing plant, and dry mix it with the hot mineral material preheated to 190℃ for 10 seconds; make the quick-dissolving weakly crystalline high modulus agent completely melt, spread and wet the surface of the hot mineral material.

[0125] P2. Spray 70# base asphalt preheated to 160℃ into the mixing cylinder of the asphalt mixing plant at a ratio of 4.0% of the mass of the mineral material, and continue mixing for 20 seconds;

[0126] P3. Add mineral powder into the mixing tank of the asphalt mixing plant according to the production mix ratio and continue stirring for 10 seconds until there is no white material and a high modulus asphalt mixture is formed;

[0127] P4: Place the high-modulus asphalt mixture prepared in P3 in a feed truck, cover with a blanket for insulation, and simmer at 160°C for 1 hour before paving and rolling. Use a double-drum roller for initial compaction (one pass) at 155°C; use a tire roller for secondary compaction (two passes) at 135°C; and use a double-drum roller for final compaction (two passes) at 105°C.

[0128] The performance test results of Example 2 are as follows:

[0129] Table 2 Test results of fast-dissolving weak crystalline high modulus agent in Example 2

[0130]

[0131] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0132] Example 3

[0133] The fast-dissolving weakly crystalline high modulus agent provided in this embodiment includes, by weight, 95 parts of reactive hard asphalt, 5 parts of reactive polyolefin, 5 parts of antioxidant, and 3 parts of barium stearate.

[0134] The preparation process of a fast-dissolving weakly crystalline high modulus agent is as follows:

[0135] <Preparation of Reactive Hard Asphalt>

[0136] A1. Place 100 parts of hard asphalt (DOA, softening point 100-120°C) into a preheated kettle and heat to 40°C above its softening point to form a hard asphalt melt;

[0137] A2. Pump the medium-hard asphalt melt in A1 into the oxidation kettle and continuously blow in oxygen to deeply oxidize it to form an oxidized hard asphalt melt. The oxidation temperature is 100°C and the oxidation time is 24 hours.

[0138] A3. Pump the oxidized hard asphalt melt in A2 into the anhydride reactor, and add 1 part of methyltetrahydrophthalic anhydride (MeTHPA) and 0.1 part of initiator (dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) mixed in a ratio of 1:1.5) to anhydride it to form a reactive hard asphalt melt. The anhydride temperature is 170°C and the anhydride time is 6 hours.

[0139] <Preparation of Reactive Polyolefin>

[0140] B1. 100 parts of a low molecular weight polyolefin (LICOWAX PE 190), 3 parts of methyltetrahydrophthalic anhydride (MeTHPA), and 0.1 parts of an initiator (a mixture of dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) in a ratio of 1:1) were added to a high-speed mixer and mixed uniformly;

[0141] B2. The materials mixed uniformly in B1 are subjected to anhydride grafting modification through a twin-screw extruder to form a reactive polyolefin. The temperature of the twin-screw mixing section is 50° C. higher than the melting point of the low molecular weight polyolefin.

[0142] <Preparation of High Modulus Agent>

[0143] S1. Add 95 parts of reactive hard asphalt and 5 parts of antioxidant into a high-speed mixer according to the proportion and mix them evenly;

[0144] S2. Using a twin-screw extruder, the materials uniformly mixed in step S1 are melted and mixed to form a reactive hard asphalt melt, with the mixing section temperature being 160°C;

[0145] S3, setting a reactive polyolefin adding module at the end of the twin-screw mixing section, and adding 5 parts of reactive polyolefin to the reactive hard asphalt melt prepared in step S2, and melting and mixing to form a fast-dissolving weakly crystalline high modulus agent melt, and the mixing section temperature is 180°C;

[0146] S4. The fast-dissolving weakly crystalline high modulus agent melt in S3 is subjected to processes such as extrusion, pelletizing, cooling, and dehydration to form uniform particles of 1 mm.

[0147] S5. Add 3 parts of stearate to the uniform particles in S4 and stir thoroughly to form a fast-dissolving weakly crystalline high modulus agent.

[0148] A method of using a fast-dissolving weakly crystalline high modulus agent is as follows:

[0149] P1. Add 1.5% of the mass ratio of the mineral material into the mixing tank of the asphalt mixing plant, and dry mix it with the hot mineral material preheated to 190℃ for 10 seconds; make the quick-dissolving weak crystalline high modulus agent completely melt, spread and wet the surface of the hot mineral material.

[0150] P2. Spray 70# base asphalt preheated to 160℃ into the asphalt mixing plant mixing cylinder at a ratio of 3.7% of the mass of the mineral material and continue mixing for 20 seconds;

[0151] P3. Add mineral powder into the mixing tank of the asphalt mixing plant according to the production mix ratio and continue stirring for 10 seconds until there is no white material and a high modulus asphalt mixture is formed;

[0152] P4: Place the high-modulus asphalt mixture prepared in P3 in a feed truck, cover with a blanket for insulation, and simmer at 160°C for 1 hour before paving and rolling. Use a double-drum roller for initial compaction (one pass) at 155°C; use a tire roller for secondary compaction (two passes) at 135°C; and use a double-drum roller for final compaction (two passes) at 105°C.

[0153] The performance test results of Example 3 are as follows:

[0154] Table 3 Test results of fast-dissolving weakly crystalline high modulus agent in Example 3

[0155]

[0156]

[0157] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0158] Example 4

[0159] The fast-dissolving weakly crystalline high modulus agent provided in this embodiment includes, by weight, 92 parts of reactive hard asphalt, 8 parts of reactive polyolefin, 3 parts of antioxidant, and 1 part of calcium stearate.

[0160] The preparation process of a fast-dissolving weakly crystalline high modulus agent is as follows:

[0161] <Preparation of Reactive Hard Asphalt>

[0162] A1. Place 100 parts of hard asphalt (DLC, softening point 120-130°C) into a preheated kettle and heat to 40°C above its softening point to form a hard asphalt melt;

[0163] A2. Pump the medium-hard asphalt melt in A1 into the oxidation kettle and continuously blow in oxygen to deeply oxidize it to form an oxidized hard asphalt melt. The oxidation temperature is 100°C and the oxidation time is 24 hours.

[0164] A3. Pump the oxidized hard asphalt melt in A2 into the anhydride reactor, and add 3 parts of methyl nadic anhydride (MNA) and 0.3 parts of initiator (dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) mixed in a ratio of 1:1) to anhydride it to form a reactive hard asphalt melt. The anhydride temperature is 170°C and the anhydride time is 6 hours.

[0165] <Preparation of Reactive Polyolefin>

[0166] B1. 100 parts of a low molecular weight polyolefin (LICOWAX PE 520), 5 parts of methyl nadic anhydride (MNA), and 0.3 parts of an initiator (a mixture of dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) in a ratio of 1:1) were added to a high-speed mixer and mixed uniformly;

[0167] B2. The materials mixed uniformly in B1 are subjected to anhydride grafting modification through a twin-screw extruder to form a reactive polyolefin. The temperature of the twin-screw mixing section is 50° C. higher than the melting point of the low molecular weight polyolefin.

[0168] <Preparation of High Modulus Agent>

[0169] S1. Add 92 parts of reactive hard asphalt and 3 parts of antioxidant into a high-speed mixer according to the proportion and mix them evenly;

[0170] S2. Using a twin-screw extruder, the materials uniformly mixed in step S1 are melted and mixed to form a reactive hard asphalt melt, with the mixing section temperature being 160°C;

[0171] S3, setting a reactive polyolefin adding module at the end of the twin-screw mixing section, and adding 8 parts of reactive polyolefin to the reactive hard asphalt melt prepared in step S2, and melting and mixing to form a fast-dissolving weakly crystalline high modulus agent melt, and the mixing section temperature is 180°C;

[0172] S4. The fast-dissolving weakly crystalline high modulus agent melt in S3 is subjected to processes such as extrusion, pelletizing, cooling, and dehydration to form uniform particles of 1 mm.

[0173] S5. Add 1 part of stearate to the uniform particles in S4 and stir thoroughly to form a fast-dissolving weakly crystalline high modulus agent.

[0174] A method of using a fast-dissolving weakly crystalline high modulus agent is as follows:

[0175] P1. Add 0.9% of the mass ratio of the mineral material to the mixing cylinder of the asphalt mixing plant and dry mix it with the hot mineral material preheated to 190℃ for 10 seconds; make the quick-dissolving weakly crystalline high modulus agent completely melt and spread and wet the surface of the hot mineral material.

[0176] P2. Spray 70# base asphalt preheated to 160℃ into the mixing cylinder of the asphalt mixing plant at a ratio of 4.3% of the mass of the mineral material, and continue mixing for 20 seconds;

[0177] P3. Add mineral powder into the mixing tank of the asphalt mixing plant according to the production mix ratio and continue stirring for 10 seconds until there is no white material and a high modulus asphalt mixture is formed;

[0178] P4: Place the high-modulus asphalt mixture prepared in P3 in a feed truck, cover with a blanket for insulation, and simmer at 160°C for 1 hour before paving and rolling. Use a double-drum roller for initial compaction (one pass) at 155°C; use a tire roller for secondary compaction (two passes) at 135°C; and use a double-drum roller for final compaction (two passes) at 105°C.

[0179] The performance test results of Example 4 are as follows:

[0180] Table 4 Test results of fast-dissolving weak crystalline high modulus agent in Example 4

[0181]

[0182] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0183] Comparative Example 1 (polyolefin not modified by anhydride)

[0184] The instant weakly crystalline high modulus agent provided in this comparative example comprises, by weight, 90 parts of reactive hard asphalt, 10 parts of low molecular weight polyolefin (LICOWAX PE 520), 3 parts of antioxidant, and 1 part of calcium stearate.

[0185] In this comparative example, low molecular weight polyolefin is used to replace the reactive polyolefin. The rest of the preparation process of the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0186] The method of using the low-temperature resistant and fatigue-resistant high modulus agent provided in this comparative example is the same as that in Example 1.

[0187] The performance test results of Comparative Example 1 are as follows:

[0188] Table 5 Test results of fast-dissolving weak crystalline high modulus agent in comparative example 1

[0189]

[0190] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0191] like Figure 1and Figure 2 As shown, compared with Example 1, the polyolefin in Comparative Example 1 has not been anhydrified, and is only physically soluble with the reactive hard asphalt and matrix asphalt, without chemical bonding. The compatibility between the three is poor, resulting in poor overall performance of the high modulus asphalt; at the same time, due to the lack of the above-mentioned bonding, the crystallization tendency of the polyolefin has not been weakened, resulting in poor low-temperature fracture resistance and medium-temperature fatigue performance of the high modulus asphalt binder.

[0192] The data show that the segregation of the high modulus asphalt in Comparative Example 1 increased from 1.3°C to 16.8°C relative to Example 1; the low-temperature flexural failure strain of the high-modulus asphalt mixture decayed from 2897 to 1645, and the four-point bending fatigue life decreased from >1 million cycles to 78,300 cycles. This indicates that anhydride modification of low-molecular-weight polyolefins can increase their compatibility with reactive hard asphalt, thereby increasing the compatibility between the high modulus agent and 70# base asphalt, improving the storage stability of the high-modulus asphalt, and improving the low-temperature crack resistance and medium-temperature fatigue crack resistance of the high-modulus asphalt mixture.

[0193] Comparative Example 2 (high molecular weight, high crystallinity polyolefin)

[0194] The fast-dissolving weakly crystalline high modulus agent provided in this comparative example includes, by weight, 90 parts of reactive hard asphalt, 10 parts of high molecular weight polyolefin (3300F), 3 parts of antioxidant, and 1 part of calcium stearate.

[0195] In this comparative example, high molecular weight polyolefin (3300F) was used instead of low molecular weight polyolefin (LICOWAX PE 130) to prepare the reactive polyolefin. The rest of the preparation process of the fast-dissolving weakly crystalline high modulus agent provided in this comparative example was the same as that in Example 1.

[0196] The method of using the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0197] The performance test results of Comparative Example 2 are as follows:

[0198] Table 6 Test results of fast-dissolving weak crystalline high modulus agent in comparative example 2

[0199]

[0200] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0201] Compared with Example 1, Comparative Example 2 uses high molecular weight polyolefin (3300F) instead of low molecular weight polyolefin (LICOWAX PE 130) to prepare reactive polyolefin. From the data results, it can be seen that the melt index of the high modulus agent in Comparative Example 2 is decayed from 63.5 to 7.8 relative to that in Example 1, and a large amount of high modulus agent is not completely melted after dry mixing with 180°C hot mineral material for 1 minute; the crystallization peak endothermic enthalpy of the high modulus asphalt is greatly increased from 23.3J / g to 108.3J / g, and the segregation is slightly increased from 1.3°C to 5.3°C; the minimum molding temperature corresponding to 2% void ratio of the high modulus asphalt mixture is increased from 140°C to 180°C, the low-temperature bending failure strain decays from 2897 to 2248, and the four-point bending fatigue life decays from >1 million times to 215,600 times. This shows that low molecular weight polyolefin has good solubility, which can improve the solubility of high modulus agent, thus improving construction and workability, and its crystallization tendency is weak, thereby improving the modulus of 70# matrix asphalt without sacrificing the low-temperature crack resistance and medium-temperature fatigue crack resistance of high modulus asphalt mixture.

[0202] Comparative Example 3 (Oxidized hard asphalt without anhydride modification)

[0203] The instant weakly crystalline high modulus agent provided in this comparative example comprises, by weight, 90 parts of oxidized hard asphalt, 10 parts of reactive polyolefin, 3 parts of antioxidant, and 1 part of calcium stearate.

[0204] In this comparative example, oxidized hard asphalt is used to replace the reactive hard asphalt. The rest of the preparation process of the instant weakly crystalline high modulus agent G3' provided in this comparative example is the same as that in Example 1.

[0205] The method of using the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0206] The performance test results of Comparative Example 3 are as follows:

[0207] Table 7 Test results of fast-dissolving weak crystalline high modulus agent in comparative example 3

[0208]

[0209] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0210] like Figure 1 and Figure 3 As shown, compared with Example 1, the hard asphalt in Comparative Example 3 is not acid anhydride-treated, and is only physically soluble with the reactive polyolefin and matrix asphalt, without chemical bonding. The compatibility between the three is poor, resulting in poor overall performance of the high modulus asphalt.

[0211] The data show that the acid value of the high modulus agent in Comparative Example 3 decreases from 25.1 to 11.7 relative to Example 1; the segregation of high modulus asphalt increases from 1.3°C to 15.1°C; the low-temperature flexural failure strain of the high modulus asphalt mixture decreases from 2897 to 1937, and the four-point bending fatigue life decreases from >1 million times to 318,800 times. This indicates that anhydride modification of oxidized hard asphalt can increase its compatibility with reactive polyolefins, thereby increasing the compatibility between the high modulus agent and 70# base asphalt, improving the storage stability of the high modulus asphalt, and improving the low-temperature crack resistance and medium-temperature fatigue crack resistance of the high modulus asphalt mixture.

[0212] Comparative Example 4 (hard asphalt without oxidation modification)

[0213] The fast-dissolving weakly crystalline high modulus agent provided in this comparative example includes, by weight, 90 parts of unoxidized reactive hard asphalt, 10 parts of reactive polyolefin, 3 parts of antioxidant, and 1 part of calcium stearate.

[0214] In this comparative example, hard asphalt is used to replace oxidized hard asphalt to prepare reactive hard asphalt. The rest of the preparation process of the instant weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0215] The method of using the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0216] The performance test results of Comparative Example 4 are as follows:

[0217] Table 8 Test results of fast-dissolving weak crystalline high modulus agent in comparative example 4

[0218]

[0219]

[0220] Note: a- Stack 3 layers of high modulus agents in ton bags, let them stand at room temperature for 6 months, and then check whether the high modulus agents in the bottom ton bag have lumps or hardening.

[0221] Compared with Example 1, Comparative Example 4 uses hard asphalt instead of oxidized hard asphalt to prepare reactive hard asphalt, and then prepares the instant weak crystalline high modulus agent. The data results show that the acid value of the high modulus agent in Comparative Example 4 is reduced from 25.1 to 7.8 relative to Example 4; the segregation of high modulus asphalt is increased from 1.3°C to 20.3°C; the low-temperature bending failure strain of the high modulus asphalt mixture decays from 2897 to 1785, and the four-point bending fatigue life decays from >1 million times to 137,900 times. This shows that the oxidation process of hard asphalt can increase the softening point of hard asphalt, thereby having a certain effect on improving the modulus of the high modulus asphalt mixture; on the other hand, the oxidation process of hard asphalt can increase its compatibility with reactive polyolefins, thereby increasing the compatibility between the high modulus agent and 70# matrix asphalt, improving the storage stability of high modulus asphalt, and improving the low-temperature crack resistance and medium-temperature fatigue crack resistance of the high modulus asphalt mixture.

[0222] Comparative Example 5 (high modulus agent without granulation)

[0223] The ratio of the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0224] The fast-dissolving weakly crystalline high modulus agent in this comparative example is not subjected to granulation treatment. The remaining preparation process of the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0225] The method of using the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0226] The performance test results of Comparative Example 5 are as follows:

[0227] Table 9 Test results of fast-dissolving weak crystalline high modulus agent in comparative example 5

[0228]

[0229] Compared with Example 1, Comparative Example 5 used an ungranulated, instant, weakly crystalline high-modulus agent to prepare high-modulus asphalt and a high-modulus asphalt mixture. The data show that as the mixing time of the high-modulus asphalt gradually increased from 1 minute to 30 minutes, the segregation of the high-modulus asphalt gradually decreased from 25.4°C to 1.1°C, and its segregation index was essentially equivalent to that of Example 1 when the mixing time reached 30 minutes. As the mixing time of the high-modulus asphalt mixture gradually increased from 1 minute to 10 minutes, the four-point bending fatigue life of the high-modulus asphalt mixture gradually increased from 136,700 cycles to >1 million cycles, and its four-point bending fatigue life was equivalent to that of Example 1 when the mixing time reached 5 minutes. The above results show that the construction and workability of the ungranulated fast-soluble weakly crystalline high modulus agent is poor. Due to the lack of the matrix dilution effect of the reactive hard asphalt on the reactive polyolefin, the ungranulated fast-soluble weakly crystalline high modulus agent cannot be mixed evenly with the matrix asphalt within a short mixing time, and thus cannot achieve uniform modification of the asphalt mixture, which ultimately affects the quality stability of the high modulus asphalt mixture.

[0230] Comparative Example 6 (no stearate powder was used for coating)

[0231] The ratio of the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0232] The fast-dissolving weakly crystalline high modulus agent in this comparative example is not subjected to stearate powder coating treatment. The remaining preparation process of the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0233] The method of using the fast-dissolving weakly crystalline high modulus agent provided in this comparative example is the same as that in Example 1.

[0234] The performance test results of Comparative Example 6 are as follows:

[0235] Table 10 Test results of fast-dissolving weak crystalline high modulus agent in comparative example 6

[0236]

[0237] Note: Stack 3 layers of high modulus agents packed in ton bags, let them stand at room temperature for 1 to 12 months, and then check whether the high modulus agents in the bottom ton bag are agglomerated or compacted.

[0238] Compared with Example 1, the instant weakly crystalline high modulus agent prepared in Comparative Example 6 was not coated with stearate powder. The data show that the instant weakly crystalline high modulus agent coated with stearate powder showed no agglomeration after 12 months of static pressure treatment. However, the instant weakly crystalline high modulus agent not coated with stearate powder showed slight agglomeration after one month of static pressure treatment and severe agglomeration after three months of treatment, failing to meet the requirements of direct on-site delivery.

[0239] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fast-dissolving weakly crystalline high modulus agent, characterized in that: Calculated by weight, it includes the following components: 85-95 parts of reactive hard asphalt, 5-15 parts of reactive polyolefin, 1-5 parts of antioxidant, and 1-3 parts of stearate powder; The reactive hard asphalt is prepared by first oxidizing 100 parts of hard asphalt and then modifying it with 1 to 3 parts of unsaturated acid anhydride and 0.1 to 0.3 parts of initiator through acid anhydride modification; the softening point of the hard asphalt is 100 to 130°C; The reactive polyolefin is obtained by grafting 100 parts of low molecular weight polyolefin with 3-5 parts of unsaturated acid anhydride and 0.1-0.3 parts of initiator through a twin-screw anhydride grafting process; the molecular weight of the low molecular weight polyolefin is 5000-15000; The instant weak crystalline high modulus agent is obtained by melt granulation at 150-190°C; The reactive hard asphalt has a softening point of 120-150°C, an acid value of 10-20 mgKOH / g, an asphaltene content of ≥50%, and a colloid content of ≥30%. The reactive polyolefin has a melting point of 120-160° C., an acid value of 20-60 mgKOH / g, and a crystallization peak endothermic enthalpy value of 20.1-25.2 J / g.

2. A fast-dissolving weakly crystalline high modulus agent according to claim 1, characterized in that The unsaturated acid anhydride is one or more of maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, and tung oil anhydride.

3. A fast-dissolving weakly crystalline high modulus agent according to claim 1, characterized in that The initiator is a mixture of dibenzoyl peroxide and N, N-dimethylaniline, and the mass ratio of the dibenzoyl peroxide to N, N-dimethylaniline is 1:0.5~1.

5.

4. A fast-dissolving weakly crystalline high modulus agent according to claim 1, characterized in that The stearate powder is one or more of calcium stearate, zinc stearate and barium stearate.

5. A fast-dissolving weakly crystalline high modulus agent according to claim 1, characterized in that, The preparation method of the reactive hard asphalt comprises the following steps: A1. heating and melting the hard asphalt to form a hard asphalt melt; A2, oxidizing the medium-hard asphalt melt in A1 to form an oxidized hard asphalt melt; A3. The oxidized hard asphalt melt in A2 is anhydrified and cooled to form reactive hard asphalt.

6. A fast-dissolving weakly crystalline high modulus agent according to claim 1, characterized in that, The preparation method of the reactive polyolefin comprises the following steps: B1. Premixing low molecular weight polyolefin, unsaturated acid anhydride and initiator in proportion; B2. The premix in B1 is modified by anhydride grafting via a twin-screw extruder to form a reactive polyolefin.

7. The method for preparing the fast-dissolving weakly crystalline high modulus agent according to any one of claims 1 to 6, wherein: The steps are as follows: S1. Premix the reactive hard asphalt and antioxidant in proportion; S2, extruding the premix in S1 through a twin-screw extruder to form a reactive hard asphalt melt; S3, adding the reactive polyolefin to the reactive hard asphalt melt in S2, and melting and mixing to form a fast-dissolving weakly crystalline high modulus agent melt; S4, extruding, pelletizing, cooling, and dehydrating the melt of the fast-dissolving weakly crystalline high modulus agent in S3 to form uniform particles; S5. Stearate powder is coated on the surface of the uniform particles in S4 to form a fast-dissolving weakly crystalline high modulus agent.

8. The method for using the fast-dissolving weakly crystalline high modulus agent according to any one of claims 1 to 6, wherein: The steps are as follows: P1. Add the instant weak crystalline high modulus agent into the mixing tank at a ratio of 0.5% to 1.5% of the mass of the ore and mix with the ore; P2. Add asphalt binder at a ratio of 3.7% to 4.7% of the mass of the aggregate and mix evenly; P3. Add mineral powder and mix evenly to form a high modulus asphalt mixture; P4. Place the high modulus asphalt mixture mixed evenly in P3 into the material truck, simmer for 1 to 3 hours, and then spread and compact it.

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