CN111847973B - Compound double modified asphalt mixture additive - Google Patents

Abstract

The invention provides a compound double-modified asphalt mixture additive, which takes natural rock asphalt as a main raw material, is assisted by organic high-molecular polymer, water-soluble chitosan, nano diatomite and other raw materials, and achieves the purposes of improving the high-temperature deformation resistance, the water damage resistance and the low-temperature crack resistance of a road modified asphalt composite material through the molecular crosslinking, condensation, association and complexing coordination of the organic high-molecular polymer, the rock asphalt, the chitosan and the nano diatomite.

Description

Compound double modified asphalt mixture additive

technical field

The invention relates to the technical field of engineering materials, in particular to a compounded double-modified asphalt mixture additive.

Background technique

The composition and structure of ordinary petroleum asphalt determines its poor high and low temperature stability, easy flow at high temperature, brittle cracking at low temperature, insufficient elasticity and aging resistance, and ordinary petroleum asphalt cannot meet the requirements of high-grade road use. Modification of ordinary petroleum asphalt is a practical demand for road petroleum asphalt pavement materials. The promotion and application of modified asphalt composite materials for green and environment-friendly roads has become an inevitable way to build resource-saving and environment-friendly road materials.

Rock asphalt is an asphalt-like substance produced by petroleum in the crevices of rocks after hundreds of millions of years of deposition and changes under the combined effects of heat, pressure, oxidation, catalysts, and microorganisms. It is a natural solid asphalt with a large molecular weight. In August 2014, the Ministry of Transport of my country issued the "Notice on Printing and Distributing Main Technical Policies for Highway and Waterway Transportation" ([2014] No. 165 Document) to encourage the promotion and application of modified asphalt mixtures such as natural rock asphalt. Rock asphalt, as a solid asphalt substance, has stable properties, strong oxidation resistance, and strong bonding ability with aggregates. It is a natural and excellent petroleum-based asphalt modifier. It has been used in road petroleum asphalt modification and engineering practice. .

However, due to the influence of factors such as origin and source, in practice, natural rock asphalt still has shortcomings such as high-temperature deformation resistance, water damage resistance, and low-temperature crack resistance. Asphalt ductility reduction and other problems, so it is necessary to further develop new compound double-modified asphalt mixture additives.

Contents of the invention

In order to solve the problems described in the background technology, the present invention provides a compound double-modified asphalt mixture additive, which can improve the high-temperature deformation resistance, water damage resistance and low-temperature crack resistance of road-use modified asphalt composite materials .

To achieve the above object, the technical solution of the present invention is:

A compound double-modified asphalt mixture additive, prepared from the following raw materials in parts by weight: 50-85 parts of rock asphalt, 1-30 parts of organic high molecular polymer, 1-10 parts of nano diatomite, water-soluble 1-2 parts of chitosan, 1-10 parts of color masterbatch, the organic polymer is modified polyethylene or polypropylene.

Preferably, the organic polymer is modified polyethylene or polypropylene.

The organic high molecular polymer is modified polyethylene or polypropylene, and the preparation method of the organic high molecular polymer is: stirring small molecular weight polyethylene/polypropylene powder and 0.005-0.009 parts by weight of metallocene catalyst Evenly, control the reaction temperature at 160-260°C. After reacting for 3-4 hours, extrude through an extruder to form a strip-shaped mixture. After the strip-shaped mixture is cooled to room temperature, it is cut and pulverized into small particles to obtain organic polymer polymerization. thing.

Preferably, the rock asphalt has natural asphalt content > 30%, softening point > 80°C, calcium carbonate > 30wt%, flash point temperature > 250°C, heating loss < 2.0%, water content < 2%, maximum particle size <1.5 mm.

Preferably, the chitosan is water-soluble chitosan, the degree of deacetylation is >80%, and the molecular weight is >=1 million.

Preferably, the nano-diatomite has a particle size of 15-100 nm and a nano-silica content of >90%.

The present invention further provides a preparation method for the compound double-modified asphalt mixture additive described above, comprising the following steps:

S1. Weigh rock asphalt, organic high molecular polymer, nano-diatomite, chitosan, and color masterbatch by weight, crush rock asphalt, heat to 30-35°C and dry, then sieve to control the largest particle size of rock asphalt Particle size less than 1.0 mm;

S2. Spray the water-soluble chitosan on the surface of the organic polymer, mix it evenly, place it for more than 2 minutes, and then mix it with nano-diatomaceous earth and color masterbatch to obtain modified auxiliary materials;

S3. Stir the rock asphalt treated in step S1 with the modified auxiliary material obtained in step S2, and mix evenly to obtain the compound rock modified asphalt mixture additive.

The present invention further provides the application of the compound double-modified asphalt mixture additive described above in preparing asphalt mixture.

The application described above preferably includes the following steps:

(1) Heat the finely graded aggregate to 180-190°C;

(2) Heat the base asphalt to 145-155°C;

(3) Heat the asphalt mixing container to 150-170°C;

(4) Add the aggregate heated to 180-190°C into the asphalt mixing container and dry mix for 30-120s;

(5) Add the compound double-modified asphalt mixture additive in an amount of 1-2% of the asphalt mixture mass into the asphalt mixture mixing container, and dry mix for 60-240s;

(6) Add the base asphalt heated to 145-155°C quantitatively into the asphalt mixing vessel and stir for 80-300s, and the asphalt ratio is controlled at 3.5-5%;

(7) Put the mineral powder into the asphalt mixture mixing container and stir for 80-240s, and keep the temperature at 150-170°C during the mixing process to obtain the asphalt mixture.

The compound double-modified asphalt mixture additive mentioned above is compounded with organic high molecular polymer, nano-diatomite, water-soluble chitosan and rock asphalt, and the organic high molecular polymer is polyethylene, polypropylene kind of. in:

Organic macromolecular polymers: Organic macromolecular polymers can undergo molecular cross-linking, condensation, association, and complexation coordination with rock asphalt, chitosan, and nano-diatomite, which accelerates the integration and coordination of small molecular free components in asphalt. The high molecular polymer undergoes copolymerization, cross-linking and grafting to form an interlocking interpenetrating grid continuous phase, and blends and melts polymerization to form an organic-inorganic hybrid high-polymer elastomer to achieve the purpose of double modification of aggregate and matrix asphalt. To achieve the comprehensive purpose of strengthening, toughening and anti-aging of asphalt mixture, organic high molecular polymer can fill the gap between aggregates, form a denser skeleton structure, and effectively improve the elasticity, adhesion and rigidity of asphalt mixture. Thereby significantly improving the high temperature deformation resistance, low temperature crack resistance and water damage resistance of the compound rock modified asphalt mixture.

Water-soluble chitosan: it not only plays the role of interlayer bonding of modified asphalt mixture, but also can form an oxygen barrier film to prevent the oxidation reaction of asphalt when exposed to oxygen, and can also remove active radicals in the process of autoxidative aging of asphalt mixture. The free radicals produced by the group can slow down the oxidative aging of asphalt mixture. At the same time, water-soluble chitosan can also be blended with rock asphalt and matrix asphalt to obtain high-molecular graft copolymers. To further improve the anti-oxidation ability and stability of asphalt mixture, the amino group in chitosan interacts with metal elements in asphalt mixture and nano-diatomite, so as to better improve the high-temperature deformation resistance and anti-deformation ability of asphalt mixture. Water damage ability, anti-aging, ductility and other comprehensive properties.

Nano-diatomite: nano-materials have unique surface effects, small size effects, quantum size effects and macro-quantum tunnel effects, which can be used for compound modification of asphalt, which can not only improve the road performance of asphalt, but also because rock asphalt itself contains a certain amount The natural asphalt can also reduce the asphalt ratio, save costs and save energy and reduce emissions; nano-diatomaceous earth can exert the nano-size effect, and can interact with organic polymers, color masterbatches, rock asphalt and matrix asphalt, thereby Improve the comprehensive properties of asphalt mixture such as high temperature resistance to deformation, water damage resistance, aging resistance and ductility.

Although polyethylene or polypropylene can undergo copolymerization, cross-linking and grafting with rock asphalt, nano-diatomite and asphalt, the dissolution temperature is high and the comprehensive mechanical properties are insufficient, especially some small molecular polyethylene or polypropylene, through metallocene catalysts The catalytic reaction can significantly improve the mechanical properties of modified polyethylene or polypropylene and improve impact resistance, heat resistance, and UV resistance.

The present invention uses natural rock asphalt as the main raw material, supplemented with raw materials such as organic high molecular polymer, water-soluble chitosan, nano diatomite, etc. Molecular polymers and rock asphalt, chitosan, and nano-diatomaceous earth undergo molecular cross-linking, condensation, association, and complexation coordination, which accelerates the copolymerization and cross-linking of small molecular free components in asphalt and high-molecular polymers branches, forming interlocking interpenetrating grid continuous phases, blending and melting polymerization to form organic-inorganic hybrid polymer elastomers, achieving the purpose of double modification of aggregate and matrix asphalt, and achieving the purpose of strengthening and toughening asphalt mixture , Anti-aging comprehensive purpose. The additive of the present invention also increases the adhesiveness of the aggregate surface at the same time, fills the gaps between the aggregates, forms a denser skeleton structure, effectively improves the elasticity, adhesion and rigidity of the asphalt mixture, thereby significantly improving the composite rock High temperature deformation resistance, low temperature crack resistance and water damage resistance of modified asphalt mixture.

The compound double-modified asphalt mixture additive of the present invention is used in asphalt modification, and has achieved remarkable results in the laying of solid asphalt roads in my country, and all indicators are better than the standards of the Ministry of Communications. The high-temperature anti-rutting performance of asphalt mixture is three times higher than the standard of the Ministry of Communications (JT/T860.5-2014), and the average dynamic stability can reach 10,000 times/mm. , The freeze-thaw splitting strength can be increased by more than 20% compared with the Ministry of Communications standard JT/T860.5-2014), which is better and more significant than similar products. The compound double-modified asphalt mixture additive adopts the most advanced "external mixing direct investment" construction, which is beneficial to reduce electricity and fuel consumption and reduce the aging phenomenon of asphalt repeated heating, and the additive of the present invention does not contain wax, which improves high The quality of waxy asphalt solves the complex and high energy consumption status of traditional SBS modified asphalt production.

Since the compound double-modified asphalt mixture additive product of the present invention contains a certain amount of natural asphalt, when it is used to modify asphalt, the amount of asphalt will be reduced by 10%-15% compared with the conventional amount. The asphalt road paved by using the compound rock modified asphalt mixture modified asphalt of the present invention can all use domestic asphalt without adding anti-rutting agent products, ending my country's long-term dependence on expensive imported asphalt and anti-rutting agent products to build roads situation.

Detailed ways

The present invention will be further described below in conjunction with embodiment, but the present invention is not therefore limited among the scope of described embodiment, under the premise of not departing from the technical solution of the present invention, those skilled in the art who make the present invention Any modification or change that can be easily implemented will fall within the scope of the claims of the present invention.

Table 1 Raw material ratio of compound double modified asphalt mixture additives

For the preparation methods of the above-mentioned modified polyethylene I, modified polyethylene II, modified polyethylene III, modified polypropylene I, modified polypropylene II, and modified polypropylene III, please refer to Examples 9-10 and Example 17- 18. Examples 21-22.

Example 9

The preparation method of modified polyethylene I comprises the following steps:

The preparation method of modified polyethylene Ⅰ is as follows: mix the polyethylene powder with small molecular weight and 0.008 parts by weight of metallocene catalyst evenly, control the reaction temperature at 160-260°C, and after 3 hours of reaction, extrude through an extruder to form strips After the strip-shaped mixture is cooled to room temperature, it is cut and pulverized into small granules, and the modified polyethylene I is obtained.

Example 10

The preparation method of modified polyethylene II includes the following steps: stirring evenly the low-molecular-weight polyethylene powder and 0.005 parts by weight of metallocene catalyst, controlling the reaction temperature at 160-260°C, and extruding through an extruder after reacting for 4 hours Form a strip mixture, and after the strip mixture is cooled to room temperature, cut and pulverize into small particles to obtain modified polyethylene II.

Example 17

The preparation method of modified polyethylene III includes the following steps: stirring evenly the low-molecular-weight polyethylene powder and 0.005 parts by weight of metallocene catalyst, controlling the reaction temperature at 160-260°C, and extruding through an extruder after reacting for 4 hours Form a strip mixture, and after the strip mixture is cooled to room temperature, cut and pulverize into small particles to obtain modified polyethylene III.

Example 18

The preparation method of modified polypropylene Ⅰ includes the following steps: stirring evenly the small molecular weight polypropylene powder and 0.007 parts by weight of metallocene catalyst, controlling the reaction temperature at 160-260°C, and extruding it through an extruder after reacting for 3 hours Form a strip mixture, and after the strip mixture is cooled to room temperature, cut and pulverize into small particles to obtain modified polypropylene I.

Example 21

The preparation method of modified polypropylene II includes the following steps: mixing evenly the small molecular weight polypropylene powder and 0.006 parts by weight of the metallocene catalyst, controlling the reaction temperature at 160-260°C, and extruding it through an extruder after reacting for 3 hours Form a strip mixture, and after the strip mixture is cooled to room temperature, cut and pulverize into small particles to obtain modified polypropylene II.

Example 22

The preparation method of modified polypropylene III includes the following steps: stirring evenly the small molecular weight polypropylene powder and 0.008 parts by weight of metallocene catalyst, controlling the reaction temperature at 160-260°C, and extruding through an extruder after reacting for 3 hours Form a strip mixture, and after the strip mixture is cooled to room temperature, cut and pulverize into small particles to obtain modified polypropylene III.

The preparation method of the above-mentioned compound double-modified asphalt mixture additive comprises the following steps: S1. Weigh rock asphalt, organic high molecular polymer, nano-diatomite, chitosan, color masterbatch by weight, and rock asphalt Crushed, heated to 30-35°C, dried, and then sieved to control the maximum particle size of rock asphalt particles to be less than 1.0mm; S2. Spray water-soluble chitosan on the surface of the organic polymer, mix well, place for more than 2 minutes, and then Then mix with nano-diatomite and color masterbatch to obtain modified auxiliary materials; S3. Stir the rock bitumen treated in step S1 with the modified auxiliary materials obtained in step S2, and mix evenly to obtain the compound rock modified asphalt Mixture Additives.

The above raw material composition requirements:

Rock asphalt: dark brown powder, natural bitumen content > 30%, softening point > 80°C, calcium carbonate > 30wt%, flash point temperature > 250°C, heating loss < 2.0%, water content < 2%, maximum particle size < 1.5mm. In this embodiment, rock asphalt purchased from Qingdao Meilian Energy Co., Ltd. was used.

Water-soluble chitosan: deacetylation degree > 80%, molecular weight ≥ 1 million. In this embodiment, chitosan purchased from Shanghai Luan Biotechnology Co., Ltd. was used.

Nano-diatomaceous earth: the particle size is 15-100nm, and the content of nano-silica is >90%. In this example, nanometer diatomite purchased from Lingshou County Huizi Mineral Products Co., Ltd. was used.

Color masterbatch: The maximum particle size of the particles is less than 1.0mm. This embodiment adopts the masterbatch purchased from Shenzhen Weichang Pigment Co., Ltd.

Polyethylene: The degree of polymerization is less than 3000. In this embodiment, polyethylene purchased from Shanghai Biaoda Chemical Co., Ltd. was used.

Polypropylene: The degree of polymerization is less than 4500. In this embodiment, polypropylene purchased from Shanghai Biaoda Chemical Co., Ltd. was used.

The compound double-modified asphalt mixture additives of the above-mentioned examples 1-8, 25-31 are used to modify the asphalt, which specifically includes the following steps: (1) heating the finely graded aggregate to 190°C; (2) Heat the base asphalt to 150°C; (3) Heat the asphalt mixture mixing container to 170°C; (4) Add the aggregate heated to 190°C to the asphalt mixture mixing container for 30 seconds; Add 1% compound rock modified asphalt mixture additive into the asphalt mixture mixing container, and dry mix for 90s; (6) Add base asphalt heated to 150°C quantitatively into the asphalt mixture mixing container and stir for 90s. Control at 4.2~4.5%; (7) Put mineral powder into the asphalt mixture mixing container and stir for 90s. During the mixing process, keep the temperature at 165-170°C to obtain asphalt mixture.

The compound double-modified asphalt mixture additive of the above-mentioned examples 9-24 is used to modify the asphalt, which specifically includes the following steps: (1) heating the coarse-fine graded aggregate to 180°C; (2) heating the base asphalt to 145°C; (3) Heat the asphalt mixture mixing container to 155°C; (4) Add the aggregate heated to 180°C into the asphalt mixture mixing container for 30 seconds; (5) Add 1% of the asphalt mixture mass Add the compound rock-modified asphalt mixture additive to the asphalt mixture mixing container, and dry mix for 90s; (6) Add the base asphalt heated to 145°C quantitatively into the asphalt mixture mixing container and stir for 80s, and the asphalt ratio is controlled at 3.9~ 4.3%; (7) Put the mineral powder into the asphalt mixture mixing container and stir for 90s. During the mixing process, keep the temperature at 150-155°C to obtain the asphalt mixture.

In the asphalt mixture, the weight ratio of aggregate, base asphalt and mineral powder is: 80-85 parts of aggregate, 5.5-6.5 parts of base asphalt, and 4.5-5.5 parts of mineral powder; wherein, the aggregate is natural aggregate , including gravel and river sand; the mineral powder is limestone mineral powder; the base asphalt is petroleum asphalt.

The above-mixed asphalt mixture was formed into a specimen according to the compaction temperature. According to the test methods T0702-2011 and T0709-2011 in JTGE20-2011 of "Test Regulations for Asphalt and Asphalt Mixtures in Highway Engineering", the optimal asphalt ratio was used to form Marshall specimens, and the water immersion Marshall test was carried out. According to the test method T0702-2011 in JTGE20-2011 of "Test Regulations for Asphalt and Asphalt Mixtures in Highway Engineering", the Marshall test piece was compacted 50 times on both sides with the best asphalt ratio, and the freeze-thaw splitting was carried out according to the T0729-2000 method test. According to the test method T0719-2011 in JTGE20-2011 of "Test Regulations for Asphalt and Asphalt Mixtures in Highway Engineering", the rutting test was carried out at the test temperature of 60°C±1°C and the load wheel pressure of 0.7MPa±0.05MPa to check the high temperature of the mixture. stability performance. The test results are shown in Table 2.

Table 2 Test results of specimens made of modified asphalt mixtures in various examples

Claims (5)

1. The compound double-modified asphalt mixture additive is characterized by being prepared from the following raw materials in parts by weight: 50-85 parts of rock asphalt, 1-30 parts of organic high molecular polymer, 1-10 parts of nano diatomite, 1-2 parts of water-soluble chitosan and 1-10 parts of color masterbatch, wherein the organic high molecular polymer is polyethylene or polypropylene;

the organic high molecular polymer is modified polyethylene or polypropylene, and the preparation method of the organic high molecular polymer comprises the following steps: uniformly stirring a polyethylene/polypropylene powder material with a small molecular weight and 0.005-0.009 part by weight of metallocene catalyst, controlling the reaction temperature to be 160-260 ℃, reacting for 3-4h, extruding the mixture by an extruder to form a strip-shaped mixture, cooling the strip-shaped mixture to normal temperature, cutting and crushing the mixture into small particles to obtain the organic high molecular polymer;

the polyethylene: the polymerization degree is less than 3000; the polypropylene: the polymerization degree is less than 4500; the degree of deacetylation of the water-soluble chitosan is more than 80 percent, and the molecular weight of the water-soluble chitosan is more than or equal to 100 ten thousand; the particle size of the nano diatomite is 15-100nm, and the content of nano silicon dioxide is more than 90%.

2. The additive for the compound double-modified asphalt mixture according to claim 1, wherein the rock asphalt contains more than 30% of natural asphalt, has a softening point of more than 80 ℃, 30wt% of calcium carbonate, a flash point temperature of more than 250 ℃, a heating loss of less than 2.0%, a water content of less than 2%, and a maximum particle size of less than 1.5 mm.

3. The preparation method of the compound double-modified asphalt mixture additive as claimed in any one of claims 1 to 2, characterized by comprising the following steps:

s1, weighing rock asphalt, an organic high-molecular polymer, nano diatomite, water-soluble chitosan and a color master batch in parts by weight, crushing the rock asphalt, heating to 30-35 ℃, drying, and sieving to control the maximum particle size of rock asphalt particles to be less than 1.0 mm;

s2, spraying water-soluble chitosan on the surface of the organic high molecular polymer, uniformly mixing, standing for more than 2min, and then mixing with nano diatomite and a color master batch to obtain a modified auxiliary material;

and S3, stirring the rock asphalt treated in the step S1 and the modified auxiliary materials obtained in the step S2, and uniformly mixing to obtain the compound double-modified asphalt mixture additive.

4. The use of the compounded double-modified asphalt mixture additive of any one of claims 1 to 2 in the preparation of asphalt mixtures.

5. Use according to claim 4, characterized in that it comprises the following steps:

(1) Heating the coarse and fine grade aggregate to 180-190 ℃;

(2) Heating the base asphalt to 145-155 ℃;

(3) Heating an asphalt mixture mixing container to 150-170 ℃;

(4) Adding the aggregate heated to 180-190 ℃ into an asphalt mixture mixing container and dry-mixing for 30-120s;

(5) Adding the compound rock modified asphalt mixture additive with the dosage of 1-2% of the mass of the asphalt mixture into an asphalt mixture mixing container, and dry-mixing for 60-240s;

(6) Quantitatively adding the matrix asphalt heated to 145-155 ℃ into an asphalt mixture mixing container, and stirring for 80-300s, wherein the oil-stone ratio is controlled to be 3.5-5%;

(7) Adding the mineral powder into an asphalt mixture stirring container, stirring for 80-240s, and keeping the temperature at 150-170 ℃ in the stirring process to obtain the asphalt mixture.