Multi-element modifier for improving construction workability of rubber asphalt mixture as well as preparation method and application of multi-element modifier

Abstract

The invention discloses a multi-element modifier for improving the construction workability of a rubber asphalt mixture. The multi-element modifier comprises the following components in parts by weight: 49-66 parts of a rubber body material, 2-13 parts of a thermoplastic elastomer, 20-40 parts of a plasticizer, 5-13 parts of a viscosity modifier and 1-3 parts of a coupling agent. The preparation method comprises the following steps: (1) putting the rubber body material, the thermoplastic elastomer and the plasticizer into a high-pressure reaction kettle in proportion for reaction to obtain a premix A, (2) proportioning the premix A, the viscosity modifier and the coupling agent in proportion and putting into a closed mixer to obtain a rubber compound B, and (3) shearing, granulating and screening the rubber compound B to obtain the multi-element modifier. The multi-element modifier disclosed by the invention not only can reduce the high-temperature viscosity of a rubber asphalt mixture and reduce the construction temperature, but also can enable an asphalt mixing process to be carried out in a simple and continuous manner, so that the energy consumption is effectively reduced, and the construction quality is stabilized.

Description

Technical Field

[0001] The invention relates to the technical field of modified materials for road asphalt mixtures, and in particular to a multi-component modifier for improving the construction and workability of rubber asphalt mixtures, and a preparation method and application thereof. Background Art

[0002] With the development of the national economy, the traffic volume on my country's roads has increased rapidly, the number of heavy vehicles has gradually increased, a large number of roads are overloaded, and the performance of the road surface has been greatly reduced. Therefore, improving the technical performance of asphalt and extending the service life of asphalt pavement have become objective problems faced by people.

[0003] At present, the research on using tire rubber powder as an admixture for rubber asphalt is quite extensive. The road surface paved with rubber powder modified asphalt has high thermal stability, is not easy to soften in summer, and reduces the occurrence of rutting diseases; has good low-temperature crack resistance, and is not easy to crack in winter; has good adhesion to stone, is not easy to produce pockmarks and peeling; has good durability, and the service life of the asphalt pavement can be extended by 0.5~1.0 times.

[0004] However, due to the swelling of rubber powder in rubber asphalt and the absorption of light components in asphalt, rubber asphalt has excellent road performance, but also exhibits extremely high high-temperature viscosity. The overly viscous asphalt makes the mixing temperature of traditional rubber asphalt higher than 180°C, the temperature of factory-made rubber asphalt as high as 200°C, and the paving temperature of the mixture above 185°C. On the one hand, it will cause short-term rapid aging of rubber asphalt, and on the other hand, it will make the road surface difficult to compact and the quality difficult to control. In addition to consuming more energy in the production process, more importantly, the high temperature produces a large amount of smoke, CO2 and harmful gases (such as CO, NO X , SO2, benzene solubles, etc.), these harmful substances pose a huge threat to human health.

[0005] In addition, rubber asphalt is mostly produced in factories or processed next to mixing plants. Rubber powder and other additives are first added to asphalt for modification, and then sprayed into heated graded crushed stone for mixing. This production and use method is easily affected by the construction progress. If the rubber asphalt cannot be used and consumed in time after production, the continuous high temperature conditions will destroy the structure of the rubber powder, which will lead to the deterioration of the performance of the modified asphalt.

[0006] It can be seen that the quality problems, energy consumption and environmental pollution caused by traditional rubber asphalt production cannot be ignored and can no longer meet the current national environmental protection requirements. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a multi-component modifier for improving the construction and workability of rubber asphalt mixture, which comprises the following components in parts by weight: 49 to 66 parts of rubber base material, 2 to 13 parts of thermoplastic elastomer, 20 to 40 parts of plasticizer, 5 to 13 parts of viscosity regulator, and 1 to 3 parts of coupling agent.

[0008] The rubber bulk material is one or more of automobile tire powder, solution polymerized styrene butadiene rubber powder, and medium vinyl butadiene rubber powder, and the rubber powder mesh number of the rubber bulk material is 60-120 meshes.

[0009] The thermoplastic elastomer is one or both of styrene-isoprene block copolymer and EVA.

[0010] The plasticizer is one or more of aromatic hydrocarbon oil, furfural oil and epoxidized soybean oil.

[0011] The viscosity regulator is one or more of terpene resin, APAO and Sasol wax.

[0012] The coupling agent is one or more of vinyl triethoxy silane, vinyl trimethoxy silane and vinyl tri (β-methoxyethoxy) silane.

[0013] The present invention also provides a method for preparing a multi-component modifier for improving the construction and workability of rubber asphalt mixture, which comprises the following steps: (1) Put the rubber material, thermoplastic elastomer and plasticizer into the autoclave in proportion, raise the temperature to 90~110℃ and the pressure to 10~100kg / cm 2 , stirring rate 200~500 r / min, reaction time 0.5~2 h, to obtain premix A; (2) The premix A, viscosity regulator and coupling agent are mixed in proportion and then put into a closed mixer with a rotor speed ratio of 0.9 to 1.5 and a discharge temperature of 110 to 130°C. After melt blending, plasticization and desulfurization, a mixed rubber material B is obtained; (3) The mixed rubber material B is fed into the extrusion granulator through a pipeline. The temperature of the feeding section of the extrusion granulator is 130-160 °C, the temperature of the melt desulfurization section is 150-200 °C, the temperature of the extrusion section is 130-170 °C, the screw diameter is 25 mm, and the aspect ratio is 40:1. The mixed rubber material B is heated and melted and discharged from the die. After cooling, the obtained rubber strip is sheared and granulated in the pelletizing chamber; (4) The granular rubber material is passed through a first vibrating screen with an upper mesh size of 2.36 mm and a second vibrating screen with a lower mesh size of 1.18 mm in sequence, and the rubber material with a mesh size larger than 2.36 mm and a mesh size smaller than 1.18 mm is removed to obtain a multi-element modifier.

[0014] Furthermore, in order to make full use of raw materials and achieve cost reduction and efficiency improvement, the following steps may also be included: (5) The rubber material with super particle size is input into the extrusion granulator again for granulation, and then screened by the first vibrating screen and the second vibrating screen.

[0015] The present invention also provides an application method of a multi-component modifier for improving the construction and workability of a rubber asphalt mixture, comprising the following steps: (1) Heat the crushed stone to 170-175°C, input it into the asphalt mixing plant, screen it and add it into the mixing pot according to the production mix ratio requirements; (2) Add the multi-modifier into the mixing pot through the feeder connected to the asphalt mixing plant and dry mix for 20-30 seconds; (3) After dry mixing, spray the base asphalt at 130-150 °C and stir for 30 seconds to obtain the finished rubber asphalt mixture.

[0016] The principle of improving the construction and workability of rubber asphalt mixture by the multi-component modifier of the present invention is as follows: The raw materials used in the present invention are rubber bulk materials and thermoplastic elastomers rich in high molecular polymers such as natural rubber, styrene-butadiene rubber, polystyrene-polyisoprene-polystyrene block copolymers, etc., and are heated and stirred under high pressure. The small molecular substances in the plasticizer (aromatic hydrocarbon oil, furfural oil or epoxidized soybean oil) fully plasticize and swell the rubber powder, and the cross-linked network of the polymer molecular chain is relaxed. After the mixture is put into a closed mixer, the materials are melted and blended under the action of mechanochemistry, and the vulcanized rubber powder is plasticized and degraded, and desulfurized and activated. The viscosity regulator is a low molecular weight long chain compound with a melting point of 100-130°C. When the temperature is lower than its melting point, the low molecular weight long chain compound crystallizes to improve the room temperature performance of asphalt; when the temperature is higher than its melting point, the viscosity regulator melts and disperses to reduce the high temperature viscosity of rubber asphalt. The coupling agent migrates to the interface between the stone and the asphalt to form a bonding layer of organic matrix-silane coupling agent-inorganic matrix, thereby enhancing the coating and bonding strength of rubber asphalt to the sand and gravel material.

[0017] Therefore, the multi-modifier of the present invention can not only reduce the high temperature viscosity of rubber asphalt mixture and reduce the construction temperature, but also enable the asphalt mixing process to be carried out in a simple and continuous manner, thereby effectively saving energy consumption and stabilizing the construction quality. The process flow of the invention is simple and can be operated continuously, which effectively solves the drawbacks of traditional rubber asphalt mixture and solves the problem that traditional rubber asphalt cannot be mass-produced, and meets the needs of modern green transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a preparation flow chart of the rubber asphalt mixture of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with the examples, but the protection scope of the present invention is not limited thereby. If the conditions are not specified in the examples, the conventional conditions or the manufacturer's recommendations are followed, and the reagents or instruments used are not registered manufacturers, and are all conventional products that can be purchased from the market.

[0020] Embodiment 1: This example provides a multi-component modifier 1 for improving the construction and workability of rubber asphalt mixture. The raw material composition is shown in Table 1: Table 1 Composition of multi-modifier The multi-component modifier 1 is obtained by the preparation method of the present invention.

[0021] The method for preparing the multi-component modifier for improving the construction and workability of rubber asphalt mixture according to the present invention specifically comprises the following steps: (1) Heavy-duty truck tire rubber powder, styrene-isoprene block copolymer and aromatic hydrocarbon oil were placed in a high-pressure reactor according to the proportions listed in Table 1, and the temperature was raised to 90 °C and the pressure was raised to 50 kg / cm 2 , stirring rate 200 r / min, stirring reaction time 1h, thereby obtaining premix A; (2) Add terpene resin and vinyl triethoxysilane to the premix A in the proportions described in Table 1, and mix in a closed mixer. Adjust the rotor speed ratio of the mixer to 0.9 and the discharge temperature to 120°C. After melt blending and plasticizing and desulfurization, obtain a mixed rubber material B. (3) The mixed rubber material B is fed into an extruder granulator (screw diameter 25 mm, aspect ratio 40:1), and the feeding section temperature is adjusted to 150°C, the melting section temperature to 180°C, and the extrusion section temperature to 150°C. The material is heated and melted and then discharged from the die. After cooling, the obtained rubber strip is sheared and granulated in the pelletizing chamber; (4) The granular rubber material is passed through a first vibrating screen with an upper mesh size of 2.36 mm and a second vibrating screen with a lower mesh size of 1.18 mm in sequence, and the rubber material with a mesh size larger than 2.36 mm and a mesh size smaller than 1.18 mm is removed to obtain a multi-element modifier 1.

[0022] The rubber materials with a size larger than 2.36 mm and smaller than 1.18 mm that have been rejected can be input into the extrusion granulator again for granulation, and screened by the first vibrating screen and the second vibrating screen to obtain qualified products, so as to make full use of the raw materials and reduce production costs.

[0023] The above multi-modifier 1 can be applied to the mixing production of rubber asphalt in the following ways, specifically including: After the best ratio of each grade of crushed stone in the mixing pot of the mixing station is determined according to the upper and lower limits of the grading, it is heated to 170-175℃, 46 kg of multi-component modifier is added, and 186 kg of base asphalt heated to 135℃ is sprayed in. After stirring and mixing for 30 seconds, the finished rubber asphalt mixture 1 is obtained.

[0024] The above-mentioned mixing station is a 4000-type asphalt mixing station, which is connected to a feeder through a pipeline, so that the feeder pipeline is connected to the mixing station admixture port. The multi-modifier described in this embodiment is poured into the feeder storage hopper. Each time the asphalt mixture is produced, the mass required for each batch of production is measured, and the multi-modifier is blown into the mixing pot of the mixing station through the air blowing system.

[0025] The finished rubber asphalt mixture 1 described in this embodiment has a low preparation temperature, low construction viscosity, is easy to mix, spread and compact, and can save road paving costs.

[0026] Embodiment 2: This example provides a multi-component modifier 2 for improving the construction and workability of rubber asphalt mixture. The raw material composition is shown in Table 2: Table 2 Composition of multi-component modifiers Among them, the ratio of heavy-duty truck rubber powder to passenger car tire rubber powder in the composite rubber powder is 1:1, the ratio of styrene-isoprene block copolymer to EVA in the thermoplastic elastomer is 1:1, the ratio of aromatic hydrocarbon oil to furfural oil to epoxidized soybean oil in the plasticizer is 1:1:1, and the ratio of terpene resin to APAO to sasol wax in the viscosity regulator is 1:1:1 (all the above are mass ratios).

[0027] This example provides a method for preparing and applying a viscosity-reducing multi-component modifier for road asphalt. The specific steps are as follows: (1) Add the composite rubber powder, thermoplastic elastomer and plasticizer into the autoclave according to the proportions in Table 2, raise the temperature to 100 °C and the pressure to 80 kg / cm 2 , stirring rate 300 r / min, stirring reaction time 1 h, thereby obtaining premix A; (2) Add viscosity regulator and vinyl tri(β-methoxyethoxy)silane to the premix A in the proportions described in Table 2, and mix in a closed mixer. Adjust the rotor speed ratio of the mixer to 0.9 and the discharge temperature to 110°C. After melt blending and plasticizing and desulfurization, obtain a mixed rubber material B. (3) The mixed rubber material B was fed into an extruder granulator (screw diameter 25 mm, aspect ratio 40:1), and the feeding section temperature was adjusted to 140°C, the melting section temperature to 160°C, and the extrusion section temperature to 130°C. The material was heated and melted and then discharged from the die. After cooling, the obtained rubber strips were sheared and granulated in the pelletizing chamber. (4) passing the granular rubber material through a first vibrating screen with an upper mesh size of 2.36 mm and a second vibrating screen with a lower mesh size of 1.18 mm in sequence, and removing the rubber material with a mesh size larger than 2.36 mm and a mesh size smaller than 1.18 mm, thereby obtaining a multi-element modifier 2; The rubber materials with a size larger than 2.36 mm and smaller than 1.18 mm that have been rejected can be input into the extrusion granulator again for granulation, and screened by the first vibrating screen and the second vibrating screen to obtain qualified products, so as to make full use of the raw materials and reduce production costs.

[0028] The above multi-modifier 2 can be applied to the mixing production of rubber asphalt in the following ways, specifically including: After the best ratio of each grade of crushed stone in the mixing pot of the mixing station is determined according to the upper and lower limits of the grading, it is heated to 170-175℃, 46 kg of multi-component modifier is added, and 186 kg of base asphalt heated to 135℃ is sprayed in. After stirring and mixing for 30 seconds, the finished rubber asphalt mixture 2 is obtained.

[0029] The above-mentioned mixing station is a 4000-type asphalt mixing station, which is connected to a feeder through a pipeline, so that the feeder pipeline is connected to the mixing station admixture port. The multi-modifier described in this embodiment is poured into the feeder storage hopper. Each time the asphalt mixture is produced, the mass required for each batch of production is measured, and the multi-modifier is blown into the mixing pot of the mixing station through the air blowing system.

[0030] The finished rubber asphalt mixture 2 described in this embodiment has a low preparation temperature, low construction viscosity, is easy to mix, spread and compact, and can save road paving costs.

[0031] Comparative Example 1: This example provides a traditional modified rubber asphalt 3, the raw material composition of which is shown in Table 3: Table 3 Composition of traditional modified rubber asphalt During the preparation, truck tire rubber powder, thermoplastic elastomer and stabilizer are put into an asphalt tank according to the proportions described in Table 3, the matrix is ​​heated to 180-190°C, the stirring rate is 200 r / min, and the stirring reaction time is 2-3 h to obtain the above-mentioned traditional modified rubber asphalt 3.

[0032] The above-mentioned traditional modified rubber asphalt 3 is used to prepare asphalt mixture. The specific steps are as follows: after the optimal ratio of each grade of crushed stone in the mixing pot of the mixing station is determined according to the upper and lower limits of the grading, it is heated to 185°C, and 232 kg of traditional modified rubber asphalt 3 heated to 180-190°C is sprayed into it. After stirring and mixing for 90 s, the finished rubber asphalt mixture 3 is obtained.

[0033] The parameters of the finished rubber asphalt mixtures obtained in Examples 1 and 2 and Comparative Example 1 were compared and evaluated, as shown in Table 4.

[0034] Table 4 Comparative evaluation results of each case By comparing and analyzing the performance indicators of the above embodiments and comparative examples, it can be seen that the use of the direct-added viscosity-reducing multi-modifier described in the present invention can reduce the heating temperature of the base asphalt by more than 45°C, the heating temperature of the crushed stone by 10-20°C, and the paving and rolling temperature of the mixture by about 20°C, thereby effectively reducing the discharge temperature and construction temperature of the rubber asphalt and effectively reducing energy consumption.

[0035] Standard compaction is used to characterize the compaction characteristics of asphalt mixtures. The higher the compaction, the better the fluidity of the asphalt mixture and the lower the high-temperature viscosity under the same rolling method. Dynamic stability is used to characterize the high-temperature performance of asphalt mixtures. The higher the value, the stronger the ability of the pavement to resist softening and deformation during service. Low-temperature flexural strength and failure strain are used to characterize the low-temperature performance of asphalt mixtures. The larger the value, the better the resistance of the mixture to low-temperature cracking.

[0036] The present invention has a simple processing technology, and the processing equipment is easily available. The product can realize continuous production. The addition of the product can reduce the high-temperature viscosity of the rubber mixture, improve the high and low temperature performance and wettability of the rubber asphalt, and improve the overall strength of the asphalt mixture. The present invention not only reduces the paving temperature of the asphalt pavement construction, saves energy consumption, and reduces the cost of engineering construction, but also effectively utilizes the recycled waste rubber products, and has a good application prospect.

[0037] The present invention describes only preferred specific embodiments. In addition, the present invention can be implemented within the upper and lower limits of each raw material, which are not listed here one by one. For those skilled in the art, various modifications and changes can be made according to the present invention. Therefore, any modifications and equivalent changes made according to the concept of the present invention should all fall within the protection scope of the present invention.

Claims

1. A multi-component modifier for improving the construction and workability of rubber asphalt mixture, characterized in that: The multi-component modifier comprises the following components in parts by weight: 49-66 parts of rubber bulk material, 2-13 parts of thermoplastic elastomer, 20-40 parts of plasticizer, 5-13 parts of viscosity regulator, and 1-3 parts of coupling agent.

2. The multi-component modifier for improving the construction and workability of rubber asphalt mixture according to claim 1, characterized in that: The rubber bulk material is one or more of automobile tire powder, solution polymerized styrene butadiene rubber powder, and medium vinyl butadiene rubber powder, and the rubber powder mesh number of the rubber bulk material is 60-120 meshes.

3. The multi-component modifier for improving the construction and workability of rubber asphalt mixture according to claim 1, characterized in that: The thermoplastic elastomer is one or both of styrene-isoprene block copolymer and EVA.

4. The multi-component modifier for improving the construction and workability of rubber asphalt mixture according to claim 1, characterized in that: The plasticizer is one or more of aromatic hydrocarbon oil, furfural oil and epoxidized soybean oil.

5. The multi-component modifier for improving the construction and workability of rubber asphalt mixture according to claim 1, characterized in that: The viscosity regulator is one or more of terpene resin, APAO and Sasol wax.

6. The multi-component modifier for improving the construction and workability of rubber asphalt mixture according to claim 1, characterized in that: The coupling agent is one or more of vinyl triethoxy silane, vinyl trimethoxy silane and vinyl tri (β-methoxyethoxy) silane.

7. A method for preparing a multi-component modifier for improving the construction and workability of rubber asphalt mixture according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Put the rubber material, thermoplastic elastomer and plasticizer into the autoclave in proportion, heat it to 90~110℃ and press it to 10~100kg / cm 2 , stirring rate 200~500 r / min, reaction time 0.5~2 h, to obtain premix A; (2) The premix A, viscosity regulator and coupling agent are mixed in proportion and then put into a closed mixer with a rotor speed ratio of 0.9 to 1.5 and a discharge temperature of 110 to 130°C. After melt blending, plasticization and desulfurization, a mixed rubber material B is obtained; (3) The mixed rubber material B is fed into the extrusion granulator through a pipeline. The temperature of the feeding section of the extrusion granulator is 130-160 °C, the temperature of the melt desulfurization section is 150-200 °C, the temperature of the extrusion section is 130-170 °C, the screw diameter is 25 mm, and the aspect ratio is 40:

1. The mixed rubber material B is heated and melted and discharged from the die. After cooling, the obtained rubber strip is sheared and granulated in the pelletizing chamber; (4) The granular rubber material is passed through a first vibrating screen with an upper mesh size of 2.36 mm and a second vibrating screen with a lower mesh size of 1.18 mm in sequence, and the rubber material with a mesh size larger than 2.36 mm and a mesh size smaller than 1.18 mm is removed to obtain a multi-element modifier.

8. The method for preparing a multi-component modifier for improving the construction and workability of rubber asphalt mixture according to claim 7, characterized in that: The following steps are also included: (5) The rubber material with super particle size is input into the extrusion granulator again for granulation, and then screened by the first vibrating screen and the second vibrating screen.

9. A method for applying the multi-component modifier for improving the construction and workability of rubber asphalt mixture according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Heat the crushed stone to 170-175℃, input it into the asphalt mixing plant, screen it and add it into the mixing pot according to the production mix ratio requirements; (2) Add the multi-modifier into the mixing pot through the feeder connected to the asphalt mixing plant and dry mix for 20-30 seconds; (3) After dry mixing, spray the base asphalt at 130-150 °C and stir for 30 seconds to obtain the finished rubber asphalt mixture.

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