A high-performance cold mix asphalt concrete and its preparation method

Abstract

The present invention discloses a high-performance cold-mix asphalt concrete and a preparation method thereof, belonging to the technical field of asphalt concrete processing. The present invention comprises the following components by weight: 150-200 parts of pretreated aggregate, 100-120 parts of cement slurry, and 75-85 parts of composite asphalt emulsion. The modified emulsion of the present invention emulsifies and modifies the mixed asphalt to form a composite asphalt emulsion that can be stably dispersed at room temperature, and the composite asphalt emulsion is used to mix the mixed aggregate prepared from the cement slurry and the pretreated aggregate at room temperature. It can not only cold-mix and form the asphalt concrete at room temperature, improve the dispersion of asphalt in the concrete, but also effectively improve the strength, water damage resistance and water stability of the asphalt concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt concrete processing, and particularly relates to a high-performance cold mix asphalt concrete and a preparation method thereof. Background Art

[0002] With the continuous development of urban construction and the continuous improvement of infrastructure construction, the demand for asphalt concrete materials in road engineering construction gradually increases. In the traditional hot mix asphalt concrete, during the processes of production, transportation and construction, it is necessary to heat the viscous asphalt at high temperature, which has problems such as large energy consumption, serious environmental pollution and complex production process, bringing challenges to environmental protection and resource utilization;

[0003] Cold mix asphalt concrete is a pavement material prepared by mixing asphalt and aggregates in a non-thermal melting and non-steam way, so as to avoid the disadvantages of the traditional hot mix asphalt concrete that requires high-temperature heating and emits a large amount of waste gas, while maintaining good road performance. Compared with the traditional hot mix asphalt concrete, cold mix asphalt concrete has the advantages of low construction temperature, low energy consumption, small environmental pollution and short construction period.

[0004] The invention patent with the publication number of CN104724980A in the prior art discloses a cold mix type asphalt concrete mixture and a preparation method thereof. This cold mix type asphalt concrete mixture is composed of graded aggregates and two different types of asphalt binders. The specific steps are as follows:

[0005] 1) Mix the graded aggregates and petroleum asphalt evenly; 2) Add cold mix type epoxy asphalt resin and mix well;

[0006] Or: 1) Mix the graded aggregates and emulsified asphalt evenly; 2) Add cold mix type epoxy asphalt resin and mix well;

[0007] Or: 1) Mix the graded aggregates and solvent-based modified asphalt evenly; 2) Add cold mix type epoxy asphalt resin and mix well;

[0008] Or: 1) Mix the graded aggregates and solvent-based modified asphalt evenly; 2) Add cold mix type epoxy asphalt resin and mix well. The cold mix type asphalt concrete mixture prepared in this way can be stored and transported at normal temperature, can be cold mixed and constructed at normal temperature, and can reduce costs.

[0009] However, due to the high viscosity of asphalt, it is difficult for asphalt to be evenly dispersed in asphalt concrete during the processing of asphalt concrete. The bonding strength between asphalt and coarse aggregates and fine aggregates is poor, and the bearing capacity and durability of asphalt concrete roads need to be further improved. Moreover, traditional asphalt concrete often has problems such as water seepage, cracking or peeling in humid or low-temperature environments, resulting in pavement damage and increased maintenance costs. The water stability of asphalt concrete needs to be further improved.

[0010] In view of the technical deficiencies in this regard, a solution is proposed now. Summary of the Invention

[0011] The purpose of the present invention is to provide a high-performance cold-mix asphalt concrete and its preparation method to solve the technical deficiencies proposed in the background technology.

[0012] The purpose of the present invention can be achieved through the following technical solutions: A high-performance cold-mix asphalt concrete, comprising the following components by weight: 150-200 parts of pretreated aggregate, 100-120 parts of cement slurry, and 75-85 parts of composite asphalt emulsion;

[0013] The composite asphalt emulsion is composed of a modified emulsion, cellulose, and mixed asphalt in a weight ratio of 100:3-5:45-55;

[0014] The cement slurry is composed of portland cement, polycarboxylate water reducer, and drinking water in a dosage ratio of 50g:1-2g:200mL.

[0015] Further, the pretreated aggregate is obtained by the following steps:

[0016] A1. Mix coarse aggregates and fine aggregates evenly according to a weight ratio of 7:3-4 to obtain aggregate;

[0017] A2. Add the aggregate and 0.1mol / L hydrochloric acid into a reaction kettle and stir. Add KH-550 to the reaction kettle, stir at room temperature for 3-5h, and perform post-treatment to obtain the pretreated aggregate.

[0018] The synthesis reaction principle of the pretreated aggregate is:

[0019] The aggregate is cleaned by an acid solution to promote the separation of oxides, impurities or contaminants on the surface of the aggregate from the aggregate, improve the surface cleanliness and activity of the aggregate. Through the treatment with KH-550, an amino modification can be formed on the outside of the aggregate to prepare the pretreated aggregate.

[0020] Further, in step A1, the weight ratio of the coarse aggregate to the fine aggregate is 7:3-4, the particle size of the coarse aggregate is 0.5-5 cm, and the particle size of the fine aggregate is 1-5 mm; in step A2, the dosage ratio of the aggregate, 0.1 mol / L hydrochloric acid and KH-550 is 10 g:50 mL:1 g. The post-treatment includes: after the reaction is completed, standing for 10 min to skim off the upper suspended matter, washing the lower solid matter with drinking water 3 times, and then naturally drying to obtain the pretreated aggregate.

[0021] Further, the modified emulsion is prepared by the following steps:

[0022] B1. Add polyethylene glycol and acetone into a reaction kettle protected by nitrogen and stir. Raise the temperature of the reaction kettle to 40-50 °C, add isophorone diisocyanate into the reaction kettle, keep warm and stir for 60-90 min, add a chain extender into the reaction kettle, keep warm and stir for 2-3 h, add a capping agent into the reaction kettle, and keep warm and react for 2-3 h. After post-treatment, obtain modified polyurethane.

[0023] The synthesis reaction principle of the modified polyurethane is as follows:

[0024] The hydroxyl group on polyethylene glycol reacts with the isocyanate group on isophorone diisocyanate to form a polyurethane prepolymer. Then, the isocyanate group on the prepolymer further reacts with the active oxygen-containing group on the chain extender. After promoting the cross-linking of the prepolymer and being capped with a capping agent, the modified polyurethane is prepared.

[0025] B2. Add epoxy resin and polytetrahydrofuran into a reaction kettle protected by nitrogen and stir. Raise the temperature of the reaction kettle to 100-110 °C, keep warm and stir until the system dissolves. Add a catalyst into the reaction kettle, raise the temperature of the reaction kettle to 160-170 °C, keep warm and react for 4-6 h, and naturally cool to room temperature to obtain modified epoxy resin.

[0026] The synthesis reaction formula of the modified epoxy resin is as follows:

[0027]

[0028] In the formula,

[0029] The synthesis reaction principle of the modified epoxy resin is as follows:

[0030] Under the action of the catalyst, polytetrahydrofuran reacts with the epoxy group on the epoxy resin through nucleophilic substitution, and atoms form a ring-closure reaction product to prepare the modified epoxy resin containing a polytetrahydrofuran block.

[0031] B3. Add the modified polyurethane, modified epoxy resin, dispersion aid and purified water into a reaction kettle and mix evenly to obtain the modified emulsion.

[0032] Further, in step B1, the dosage ratio of polyethylene glycol, acetone, isophorone diisocyanate, chain extender and capping agent is 10 g: 50 mL: 5 g: 2 g: 2 g. The polyethylene glycol is polyethylene glycol 400, and the chain extender is ricinolein. The post-treatment includes: after the reaction is completed, the temperature of the reaction kettle is kept at 40-50 °C, and the solvent is removed by reduced pressure distillation to obtain modified polyurethane. In step B2, the weight ratio of epoxy resin, polytetrahydrofuran and catalyst is 10: 10: 0.1. The epoxy resin is bisphenol A epoxy resin E-44, the molecular weight of polytetrahydrofuran is 1000 ± 50, and the catalyst is potassium persulfate. In step B3, the dosage ratio of modified polyurethane, modified epoxy resin, dispersion aid and purified water is 17 g: 15 g: 5 g: 120-130 mL. The dispersion aid is composed of sodium dodecyl sulfate and polyethylene glycol 200 according to the weight ratio of 2: 1.

[0033] Further, in step B1, the preparation method of the capping agent is: add butanetetracarboxylic acid, 3-(dibutylamino) propylamine, catalyst and N, N-dimethylformamide into a reaction kettle protected by nitrogen and stir. The temperature of the reaction kettle is raised to 130-150 °C, the pressure of the reaction kettle is raised to 0.15-0.25 MPa, and keep warm and under pressure for 6-8 h, and then obtain the capping agent through post-treatment.

[0034] The synthesis reaction formula of the capping agent is:

[0035]

[0036] The synthesis reaction principle of the capping agent is:

[0037] Under the action of the catalyst potassium hydroxide, the carboxyl group in butanetetracarboxylic acid reacts with the amino group of 3-(dibutylamino) propylamine to carry out amidation reaction. By controlling the dosage ratio of butanetetracarboxylic acid and 3-(dibutylamino) propylamine, the amidated butanetetracarboxylic acid modified with carboxyl group is prepared to obtain the capping agent.

[0038] Further, the dosage ratio of butanetetracarboxylic acid and 3-(dibutylamino) propylamine is 1 mol: 3 mol, and the dosage ratio of butanetetracarboxylic acid, catalyst and N, N-dimethylformamide is 5 g: 0.2 g: 50 mL. The catalyst is potassium hydroxide. The post-treatment operation includes: after the reaction is completed, the temperature of the reaction kettle is kept at 130-150 °C, the pressure of the reaction kettle is reduced to -0.1 MPa, and the low-boiling fraction is removed by reduced pressure distillation to obtain the capping agent.

[0039] Further, the mixed asphalt is processed by the following steps:

[0040] C1. Add styrene, 1,7-octadiene, maleic anhydride, toluene and an initiator into a reaction kettle protected by nitrogen and stir. Raise the temperature of the reaction kettle to 70 - 80 °C, keep the temperature for 6 - 8 h, and conduct post-treatment to obtain the enhanced modifier.

[0041] The synthesis reaction formula of the enhanced modifier is:

[0042]

[0043] The synthesis reaction principle of the enhanced modifier is:

[0044] Under the action of the initiator, the unsaturated olefin double bonds on styrene, 1,7-octadiene and maleic anhydride are broken to form free radicals, and a free radical polymerization reaction occurs to prepare the enhanced modifier for olefin polymerization.

[0045] C2. Add 90# base asphalt, SBS modified asphalt and the enhanced modifier into a stirring kettle at a temperature of 120 - 150 °C and mix evenly to obtain the mixed asphalt.

[0046] Furthermore, in step C1, the molar ratio of styrene, 1,7-octadiene and maleic anhydride is 3:7:2, the dosage ratio of maleic anhydride, toluene and the initiator is 1 g:15 mL:0.05 g, and the post-treatment includes: after the reaction is completed, keep the temperature of the reaction kettle at 70 - 80 °C, distill off the solvent under reduced pressure to obtain the enhanced modifier; in step C, the weight ratio of 90# base asphalt, SBS modified asphalt and the enhanced modifier is 20:6 - 10:3 - 5.

[0047] The present invention also provides a preparation method of high-performance cold mix asphalt concrete, including the following steps:

[0048] S1. Add Portland cement, polycarboxylate water reducer and drinking water into a reaction kettle and stir for 30 - 50 min to obtain a cement slurry.

[0049] S2. Add the pretreated aggregate and the cement slurry into a stirring kettle and stir. Stir at room temperature for 15 - 20 min to obtain a mixed aggregate.

[0050] S3. Disperse the modified emulsion and cellulose in a colloid mill at a temperature of 60 - 70 °C, and slowly add the mixed asphalt at a temperature of 130 - 140 °C into the colloid mill. Keep the temperature for dispersion for 90 - 120 min. After the dispersion is completed, quickly transfer the dispersion system in the colloid mill to a cold trap at a temperature of 5 - 10 °C and rapidly cool it to room temperature to obtain a composite asphalt emulsion.

[0051] S4. Add the composite asphalt emulsion into the stirring kettle containing the mixed aggregate and stir at room temperature for 20 - 30 min to obtain asphalt concrete.

[0052] The present invention has the following beneficial effects:

[0053] 1. For the high-performance cold mix asphalt concrete of the present invention, during preparation, styrene, 1,7-octadiene, and maleic anhydride are used as raw materials, and an enhanced modifier is prepared through a free radical addition reaction to enhance and modify 90# base asphalt and SBS modified asphalt to obtain a mixed asphalt. SBS modified asphalt itself has good high-temperature resistance and low-temperature resistance. After being compounded with 90# base asphalt, it can further improve the high-temperature deformation resistance and low-temperature cracking resistance of asphalt concrete. After being modified by the enhanced modifier, the enhanced modifier has a polymer chain with a special structure, which can form a stable network structure in the asphalt, improve the high-temperature resistance of the asphalt, and at the same time, maintain a certain flexibility at low temperatures, reduce the generation of cracks, and improve the low-temperature resistance. The addition of maleic anhydride can introduce polar functional groups, and these functional groups interact with the components in the asphalt, increasing the polarity of the asphalt, improving the adhesion and elasticity of the asphalt, so that the asphalt can better absorb and disperse stress when subjected to external forces, thereby improving the elasticity and toughness of the mixed asphalt.

[0054] 2. For the high-performance cold mix asphalt concrete of the present invention, during preparation, a water-based modified polyurethane is prepared by end-capping a polyurethane prepolymer formed by the reaction of polyethylene glycol, isophorone diisocyanate, and ricinolein with a capping agent prepared by the reaction of butane tetracarboxylic acid and 3-(dibutylamino)propylamine; a water-based modified epoxy resin is prepared by embedding a polytetrahydrofuran chain segment in the molecular chain segment of bisphenol A epoxy resin; an emulsion of the modified epoxy resin and the modified polyurethane is used to emulsify and modify the mixed asphalt to obtain a composite asphalt emulsion; due to its special molecular structure and hydrophilic groups, the water-based modified polyurethane can form a stable dispersion system in the emulsion. A large number of amide bonds modified on the water-based modified polyurethane can interact with the polar components in the mixed asphalt to form strong chemical bonds or physical adsorption, effectively encapsulating the surface of the asphalt particles, reducing the surface tension between the asphalt particles, making it easier to disperse uniformly in the emulsion, improving the dispersion state of the asphalt in the emulsion, and preparing a more uniform and delicate composite asphalt emulsion. The modified epoxy resin can endow the emulsion with better flexibility and water resistance. The combined use of these two modified polymer materials can effectively prevent the emulsion from stratifying or precipitating during storage and transportation, ensuring the stability and dispersion of the emulsion, and these two modified polymer materials can also significantly enhance the adhesion between the asphalt and the aggregate, improving the water damage resistance and strength of the asphalt concrete.

[0055] 3. When preparing the high-performance cold-mixed asphalt concrete of the present invention, the ratio of coarse aggregate to fine aggregate is optimized, and it is pretreated with dilute acid and KH-550 to prepare pretreated aggregate with a clean surface and amino modification; after fully mixing and hydrating portland cement, water reducer and drinking water, cement slurry is prepared. After mixing the pretreated aggregate with the hydrated cement slurry, it is mixed with a composite asphalt emulsion to prepare asphalt concrete; the mixing of the hydrated cement slurry and the pretreated aggregate can form a coating structure on the outside of the pretreated aggregate, and the cement slurry itself has a certain stability and can maintain stability in water for a long time without stratification or precipitation, thereby improving the water stability performance of the asphalt concrete. The amino groups modified on the surface of the pretreated aggregate can enhance the interfacial stability between the aggregate and the cement slurry, and at the same time can react with the epoxy groups in the composite asphalt emulsion to form stable chemical bonding, which can not only enhance the adhesion between the aggregate and the asphalt, reduce the peeling and loosening phenomena of the asphalt mixture under external force, improve the Marshall modulus of the asphalt concrete, but also make the interface between the asphalt and the aggregate closer, reduce the possibility of water penetration, improve the water damage resistance of the asphalt concrete, and enable it to maintain good stability and durability in a water environment. Detailed implementation mode

[0056] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0057] Example 1

[0058] This embodiment provides a preparation method for a composite emulsified asphalt for high-performance cold-mixed asphalt concrete, including the following steps:

[0059] S1. Prepare modified polyurethane

[0060] Weigh: 46.8 g of butanetetracarboxylic acid, 111.8 g of 3-(dibutylamino)propylamine, 1.87 g of potassium hydroxide and 468 mL of N,N-dimethylformamide and add them to a reaction kettle protected by nitrogen and stir. The temperature of the reaction kettle is raised to 130 °C, the pressure of the reaction kettle is raised to 0.15 MPa, and heat and pressure are maintained for 6 h. After the reaction is completed, the temperature of the reaction kettle is maintained at 130 °C, and the pressure of the reaction kettle is reduced to -0.1 MPa, and low-boiling fractions are removed by vacuum distillation to obtain a capping agent;

[0061] Weigh: 200 g of polyethylene glycol 400, 1000 mL of acetone and add them to a reaction kettle protected by nitrogen for stirring. Raise the temperature of the reaction kettle to 40 °C, add 100 g of isophorone diisocyanate to the reaction kettle, keep the temperature and stir for 60 min, add 40 g of ricinolein to the reaction kettle, keep the temperature and stir for 2 h, add 40 g of capping agent to the reaction kettle, keep the temperature and react for 2 h. After the reaction is completed, keep the temperature of the reaction kettle at 40 °C, distill off the solvent under reduced pressure to obtain the modified polyurethane.

[0062] S2. Prepare the modified epoxy resin

[0063] Weigh: 100 g of bisphenol A epoxy resin E-44 and 100 g of polytetrahydrofuran, add them to a reaction kettle protected by nitrogen for stirring. Raise the temperature of the reaction kettle to 100 °C, keep the temperature and stir until the system dissolves. Add 1 g of potassium persulfate to the reaction kettle, raise the temperature of the reaction kettle to 160 °C, keep the temperature and react for 4 h, and naturally cool to room temperature to obtain the modified epoxy resin.

[0064] S3. Prepare the modified emulsion

[0065] Mix sodium dodecyl sulfate and polyethylene glycol 200 evenly according to the weight ratio of 2:1 to obtain a dispersion aid for standby;

[0066] Weigh: 170 g of modified polyurethane, 150 g of modified epoxy resin, 50 g of dispersion aid and 1200 mL of purified water, add them to a reaction kettle and mix evenly to obtain the modified emulsion.

[0067] S4. Prepare the mixed asphalt

[0068] Add 31.2 g of styrene, 77.1 g of 1,7-octadiene, 19.6 g of maleic anhydride, 294 mL of toluene and 0.93 g of azobisisobutyronitrile to a reaction kettle protected by nitrogen for stirring. Raise the temperature of the reaction kettle to 70 °C, keep the temperature and react for 6 h. After the reaction is completed, keep the temperature of the reaction kettle at 70 °C, distill off the solvent under reduced pressure to obtain the enhanced modifier;

[0069] Weigh by weight: 20 parts of 90# base asphalt, 6 parts of SBS modified asphalt, and 3 parts of enhanced modifier, add them to a stirring kettle at 120 °C and mix evenly to obtain the mixed asphalt.

[0070] S5. Prepare the composite emulsified asphalt.

[0071] Weigh by weight: 1000 g of modified emulsion and 30 g of cellulose, add them to a colloid mill at 60 °C for dispersion, slowly add 450 g of the mixed asphalt at 130 °C to the colloid mill, keep the temperature and disperse for 90 min. After the dispersion is completed, quickly transfer the dispersion system in the colloid mill to a cold trap at 5 °C and quickly cool to room temperature to obtain the composite asphalt emulsion.

[0072] Example 2

[0073] This example provides a preparation method of a composite emulsified asphalt for high-performance cold-mix asphalt concrete, including the following steps:

[0074] S1. Prepare modified polyurethane

[0075] Weigh: 46.8 g of butanetetracarboxylic acid, 111.8 g of 3-(dibutylamino)propylamine, 1.87 g of potassium hydroxide and 468 mL of N,N-dimethylformamide and add them to a reaction kettle protected by nitrogen for stirring. The temperature of the reaction kettle is raised to 140 °C, and the pressure of the reaction kettle is raised to 0.20 MPa. After heat preservation and pressure maintenance treatment for 7 h, after the reaction is completed, the temperature of the reaction kettle is kept at 14 °C, and the pressure of the reaction kettle is reduced to -0.1 MPa. The low-boiling fractions are removed by vacuum distillation to obtain a capping agent;

[0076] Weigh: 200 g of polyethylene glycol 400 and 1000 mL of acetone and add them to a reaction kettle protected by nitrogen for stirring. The temperature of the reaction kettle is raised to 45 °C. Add 100 g of isophorone diisocyanate to the reaction kettle, keep warm and stir for 75 min. Add 40 g of ricinolein to the reaction kettle, keep warm and stir for 2.5 h. Add 40 g of the capping agent to the reaction kettle, keep warm and react for 2.5 h. After the reaction is completed, the temperature of the reaction kettle is kept at 45 °C, and the solvent is removed by vacuum distillation to obtain modified polyurethane.

[0077] S2. Prepare modified epoxy resin

[0078] Weigh: 100 g of bisphenol A epoxy resin E-44 and 100 g of polytetrahydrofuran and add them to a reaction kettle protected by nitrogen for stirring. The temperature of the reaction kettle is raised to 105 °C, and keep warm and stir until the system is dissolved. Add 1 g of potassium persulfate to the reaction kettle, raise the temperature of the reaction kettle to 165 °C, and keep warm and react for 5 h. Naturally cool to room temperature to obtain modified epoxy resin.

[0079] S3. Prepare modified emulsion

[0080] Mix sodium dodecyl sulfate and polyethylene glycol 200 evenly according to the weight ratio of 2:1 to obtain a dispersion aid for standby;

[0081] Weigh: 170 g of modified polyurethane, 150 g of modified epoxy resin, 50 g of the dispersion aid and 1250 mL of purified water and add them to a reaction kettle to mix evenly to obtain a modified emulsion.

[0082] S4. Prepare mixed asphalt

[0083] 31.2 g of styrene, 77.1 g of 1,7-octadiene, 19.6 g of maleic anhydride, 294 mL of toluene and 0.93 g of azobisisobutyronitrile were added to a reaction kettle protected by nitrogen and stirred. The temperature of the reaction kettle was raised to 75 °C and kept warm for reaction for 7 h. After the reaction was completed, the reaction kettle was kept warm at 75 °C, and the solvent was removed by distillation under reduced pressure to obtain a reinforcing modifier;

[0084] Weigh by weight: 20 parts of 90# base asphalt, 8 parts of SBS modified asphalt, and 4 parts of reinforcing modifier were added to a stirring kettle at 135 °C and mixed evenly to obtain a mixed asphalt.

[0085] S5. Prepare a composite emulsified asphalt.

[0086] Weigh by weight: 1000 g of modified emulsion and 40 g of cellulose were added to a colloid mill at 65 °C for dispersion. 500 g of the mixed asphalt at 135 °C was slowly added to the colloid mill, and dispersion was carried out while keeping warm for 105 min. After the dispersion while keeping warm was completed, the dispersion system in the colloid mill was quickly transferred to a cold trap at 7 °C, and the temperature was quickly lowered to room temperature to obtain a composite asphalt emulsion.

[0087] Example 3

[0088] This example provides a preparation method of a composite emulsified asphalt for high-performance cold-mix asphalt concrete, including the following steps:

[0089] S1. Prepare a modified polyurethane

[0090] Weigh: 46.8 g of butanetetracarboxylic acid, 111.8 g of 3-(dibutylamino)propylamine, 1.87 g of potassium hydroxide and 468 mL of N,N-dimethylformamide were added to a reaction kettle protected by nitrogen and stirred. The temperature of the reaction kettle was raised to 150 °C, and the pressure of the reaction kettle was raised to 0.25 MPa. Heat preservation and pressure preservation treatment were carried out for 8 h. After the reaction was completed, the temperature of the reaction kettle was kept at 150 °C, and the pressure of the reaction kettle was reduced to -0.1 MPa. The low-boiling fractions were removed by distillation under reduced pressure to obtain a capping agent;

[0091] Weigh: 200 g of polyethylene glycol 400, 1000 mL of acetone were added to a reaction kettle protected by nitrogen and stirred. The temperature of the reaction kettle was raised to 50 °C. 100 g of isophorone diisocyanate was added to the reaction kettle, and stirring was carried out while keeping warm for 90 min. 40 g of ricinolein was added to the reaction kettle, and stirring was carried out while keeping warm for 3 h. 40 g of capping agent was added to the reaction kettle, and reaction was carried out while keeping warm for 3 h. After the reaction was completed, the temperature of the reaction kettle was kept at 50 °C, and the solvent was removed by distillation under reduced pressure to obtain a modified polyurethane.

[0092] S2. Prepare a modified epoxy resin

[0093] Weigh: 100 g of bisphenol A epoxy resin E-44, 100 g of polytetrahydrofuran, add them to a reaction kettle under nitrogen protection and stir. Raise the temperature of the reaction kettle to 110 °C, keep stirring until the system dissolves, add 1 g of potassium persulfate to the reaction kettle, raise the temperature of the reaction kettle to 170 °C, keep the reaction for 6 h, and naturally cool to room temperature to obtain the modified epoxy resin.

[0094] S3. Prepare the modified emulsion

[0095] Mix sodium dodecyl sulfate and polyethylene glycol 200 evenly according to the weight ratio of 2:1 to obtain a dispersion aid for standby;

[0096] Weigh: 170 g of modified polyurethane, 150 g of modified epoxy resin, 50 g of dispersion aid and 1300 mL of purified water, add them to the reaction kettle and mix evenly to obtain the modified emulsion.

[0097] S4. Prepare the mixed asphalt

[0098] Add 31.2 g of styrene, 77.1 g of 1,7-octadiene, 19.6 g of maleic anhydride, 294 mL of toluene and 0.93 g of azobisisobutyronitrile to a reaction kettle under nitrogen protection and stir. Raise the temperature of the reaction kettle to 80 °C, keep the reaction for 8 h. After the reaction is completed, keep the reaction kettle at 80 °C and distill off the solvent under reduced pressure to obtain the enhanced modifier;

[0099] Weigh by weight: 20 parts of 90# base asphalt, 10 parts of SBS modified asphalt, 5 parts of enhanced modifier, add them to a stirring kettle at 150 °C and mix evenly to obtain the mixed asphalt.

[0100] S5. Prepare the composite emulsified asphalt.

[0101] Weigh by weight: 1000 g of modified emulsion, 50 g of cellulose, add them to a colloid mill at 70 °C for dispersion, slowly add 550 g of the mixed asphalt at 140 °C to the colloid mill, keep the dispersion for 120 min. After the dispersion is completed, quickly transfer the dispersion system in the colloid mill to a cold trap at 10 °C and quickly cool to room temperature to obtain the composite asphalt emulsion.

[0102] Example 4

[0103] This example provides a preparation method of high-performance cold mix asphalt concrete, including the following steps:

[0104] Step 1. Prepare the pretreated aggregate

[0105] Mix the coarse aggregate and fine aggregate evenly according to the weight ratio of 7:3 to obtain the aggregate. Among them, the particle size of the coarse aggregate is 0.5 - 5 cm, and the particle size of the fine aggregate is 1 - 5 mm;

[0106] Weigh: Add 5 kg of aggregate and 25 L of 0.1 mol / L hydrochloric acid into the reaction kettle and stir. Add 0.5 kg of KH-550 to the reaction kettle and stir for 3 h at room temperature. After the reaction is completed, let it stand for 10 min and skim off the upper suspended matter. Wash the lower solid matter 3 times with drinking water and then air-dry it naturally to obtain the pretreated aggregate.

[0107] Step 2: Prepare the cement slurry

[0108] Weigh: Add 500 g of portland cement, 10 g of polycarboxylate superplasticizer and 2 L of drinking water into the reaction kettle and stir for 30 min to obtain the cement slurry.

[0109] Step 3: Prepare the asphalt concrete

[0110] Weigh by weight: Add 150 parts of the pretreated aggregate and 100 parts of the cement slurry into the stirring kettle and stir for 15 min at room temperature to obtain the mixed aggregate;

[0111] Add 75 parts of the composite asphalt emulsion prepared in Example 1 into the stirring kettle containing the mixed aggregate and stir for 20 min at room temperature to obtain the asphalt concrete.

[0112] Example 5

[0113] This example provides a preparation method of high-performance cold-mix asphalt concrete, including the following steps:

[0114] Step 1: Prepare the pretreated aggregate

[0115] Mix the coarse aggregate and the fine aggregate evenly according to the weight ratio of 7:3.5 to obtain the aggregate. Among them, the particle size of the coarse aggregate is 0.5 - 5 cm, and the particle size of the fine aggregate is 1 - 5 mm;

[0116] Weigh: Add 5 kg of aggregate and 25 L of 0.1 mol / L hydrochloric acid into the reaction kettle and stir. Add 0.5 kg of KH-550 to the reaction kettle and stir for 4 h at room temperature. After the reaction is completed, let it stand for 10 min and skim off the upper suspended matter. Wash the lower solid matter 3 times with drinking water and then air-dry it naturally to obtain the pretreated aggregate.

[0117] Step 2: Prepare the cement slurry

[0118] Weigh: Add 500 g of portland cement, 15 g of polycarboxylate superplasticizer and 2 L of drinking water into the reaction kettle and stir for 40 min to obtain the cement slurry.

[0119] Step 3: Prepare the asphalt concrete

[0120] Weigh by weight: Add 175 parts of the pretreated aggregate and 110 parts of the cement slurry into the stirring kettle and stir for 17 min at room temperature to obtain the mixed aggregate;

[0121] Add 80 parts of the composite asphalt emulsion prepared in Example 2 to a stirring kettle containing mixed aggregates, and stir at room temperature for 25 min to obtain asphalt concrete.

[0122] Example 6

[0123] This example provides a preparation method of high-performance cold-mix asphalt concrete, including the following steps:

[0124] Step 1: Prepare pretreated aggregates

[0125] Mix coarse aggregates and fine aggregates evenly according to a weight ratio of 7:4 to obtain aggregates. Among them, the particle size of the coarse aggregates is 0.5 - 5 cm, and the particle size of the fine aggregates is 1 - 5 mm;

[0126] Weigh: Add 5 kg of aggregates and 25 L of 0.1 mol / L hydrochloric acid to a reaction kettle and stir. Add 0.5 kg of KH-550 to the reaction kettle and stir at room temperature for 5 h. After the reaction is completed, let it stand for 10 min to skim off the upper suspended matter. Wash the lower solid matter 3 times with drinking water and then air-dry it naturally to obtain pretreated aggregates.

[0127] Step 2: Prepare cement slurry

[0128] Weigh: Add 500 g of Portland cement, 20 g of polycarboxylate water reducer and 2 L of drinking water to a reaction kettle and stir for 50 min to obtain cement slurry.

[0129] Step 3: Prepare asphalt concrete

[0130] Weigh by weight: Add 200 parts of pretreated aggregates and 120 parts of cement slurry to a stirring kettle and stir. Stir at room temperature for 20 min to obtain mixed aggregates;

[0131] Add 85 parts of the composite asphalt emulsion prepared in Example 3 to the stirring kettle containing mixed aggregates and stir at room temperature for 30 min to obtain asphalt concrete.

[0132] Comparative Example 1

[0133] The difference between this comparative example and Example 6 is that Step 2 is cancelled, and no cement slurry is added when preparing asphalt concrete in Step 3.

[0134] Comparative Example 2

[0135] The difference between this comparative example and Example 6 is that when preparing the composite asphalt emulsion in Step 3, Step S1 is cancelled, and no modified polyurethane is added in Step S3.

[0136] Comparative Example 3

[0137] The difference between this comparative example and Example 6 is that when preparing the composite asphalt emulsion in Step 3, Step S2 is cancelled and modified epoxy resin is not added in Step S3.

[0138] Comparative Example 4

[0139] The difference between this comparative example and Example 6 is that when preparing the composite asphalt emulsion in Step 3, when preparing the mixed asphalt in Step S4, the reinforcing modifier is not added.

[0140] Performance test:

[0141] The strength and water stability of the asphalt concrete prepared in Examples 4 - 6 and Comparative Examples 1 - 4 were tested. Among them, for the strength of the asphalt concrete, the Marshall modulus of the test specimen was measured with reference to the standard JTG E20 - 2011 "Test Procedures for Bitumen and Bituminous Mixtures for Highway Engineering", and for the water stability, the freeze - thaw splitting test strength ratio and the residual stability of the immersion Marshall test of the test specimen were measured with reference to the standard GB / T 30596 - 2014 "Warm Mix Asphalt Concrete". The specific test results are shown in Table 1.

[0142] Table 1 - Data Sheet of Performance Detection of Test Specimens

[0143]

[0144] Data analysis:

[0145] By comparing and analyzing the data in Table 1 above, the Marshall modulus of the high - performance cold - mix asphalt concrete prepared by the present invention reaches 79.3 kN / mm, the residual stability of the immersion Marshall test reaches 87.2%, and the freeze - thaw splitting test strength ratio reaches 88.1%. All performance data are better than those of the comparative examples. It shows that the present invention prepares a modified emulsion by combining modified polyurethane and modified epoxy resin, and then emulsifies and modifies the mixed asphalt through the modified emulsion to form a composite asphalt emulsion that can be stably dispersed at room temperature. By mixing the mixed aggregate prepared from the cement slurry and the pretreated aggregate with the composite asphalt emulsion at room temperature, it can not only cold - mix and form the asphalt concrete at room temperature, improve the dispersion of bitumen in the concrete, but also effectively improve the strength, water damage resistance and water stability of the asphalt concrete.

[0146] The above content is only an example and explanation of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as it does not deviate from the structure of the invention or exceed the scope defined by this claim book, it shall fall within the protection scope of the present invention.

[0147] In the description of this specification, the descriptions referring to the terms "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0148] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to the specific embodiments. Obviously, according to the content of this specification, many modifications and variations can be made. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A high-performance cold mix asphalt concrete, characterized in that, It comprises the following components by weight parts: 150 - 200 parts of pretreated aggregate, 100 - 120 parts of cement slurry, and 75 - 85 parts of composite asphalt emulsion; The composite asphalt emulsion is composed of a modified emulsion, cellulose, and mixed asphalt in a weight ratio of 100:3 - 5:45 - 55; The cement slurry is composed of portland cement, polycarboxylate water reducer, and drinking water in a dosage ratio of 50g:1 - 2g:200mL; The modified emulsion is obtained by the following steps: B1. Add polyethylene glycol and acetone into a reaction kettle under nitrogen protection and stir. Raise the temperature of the reaction kettle to 40 - 50°C, add isophorone diisocyanate into the reaction kettle, keep warm and stir for 60 - 90 min, add a chain extender into the reaction kettle, keep warm and stir for 2 - 3 h, add a capping agent into the reaction kettle, keep warm and react for 2 - 3 h, and perform post-treatment to obtain modified polyurethane. Among them, the preparation method of the capping agent is: add butanetetracarboxylic acid, 3-(dibutylamino)propylamine, a catalyst, and N,N-dimethylformamide into a reaction kettle under nitrogen protection and stir. Raise the temperature of the reaction kettle to 130 - 150°C, raise the pressure of the reaction kettle to 0.15 - 0.25 MPa, perform heat and pressure preservation treatment for 6 - 8 h, and perform post-treatment to obtain the capping agent; B2. Add epoxy resin and polytetrahydrofuran into a reaction kettle under nitrogen protection and stir. Raise the temperature of the reaction kettle to 100 - 110°C, keep warm and stir until the system dissolves, add a catalyst into the reaction kettle, raise the temperature of the reaction kettle to 160 - 170°C, keep warm and react for 4 - 6 h, and naturally cool to room temperature to obtain modified epoxy resin; B3. Add the modified polyurethane, modified epoxy resin, dispersion aid, and purified water into a reaction kettle and mix evenly to obtain the modified emulsion; The mixed asphalt is obtained by the following steps: C1. Add styrene, 1,7-octadiene, maleic anhydride, toluene, and an initiator into a reaction kettle under nitrogen protection and stir. Raise the temperature of the reaction kettle to 70 - 80°C, keep warm and react for 6 - 8 h, and perform post-treatment to obtain an enhanced modifier; C2. Add 90# base asphalt, SBS modified asphalt, and the enhanced modifier into a stirring kettle at a temperature of 120 - 150°C and mix evenly to obtain the mixed asphalt.

2. A high-performance cold mix asphalt concrete according to claim 1, characterized in that, The pretreated aggregate is obtained by the following steps: A1. Mix coarse aggregate and fine aggregate evenly according to a weight ratio of 7:3 - 4 to obtain aggregate; A2. Add the aggregate and 0.1mol / L hydrochloric acid into a reaction kettle and stir. Add KH-550 into the reaction kettle and stir at room temperature for 3 - 5 h, and perform post-treatment to obtain the pretreated aggregate.

3. The high-performance cold mix asphalt concrete according to claim 2, wherein, In step A1, the weight ratio of the coarse aggregate to the fine aggregate is 7:3 - 4, the particle size of the coarse aggregate is 0.5 - 5 cm, and the particle size of the fine aggregate is 1 - 5 mm; in step A2, the dosage ratio of the aggregate, 0.1mol / L hydrochloric acid, and KH-550 is 10g:50mL:1g. The post-treatment includes: after the reaction is completed, let it stand for 10 min to skim off the upper suspended matter, wash the lower solid matter 3 times with drinking water, and then air dry naturally to obtain the pretreated aggregate.

4. A high-performance cold mix asphalt concrete according to claim 1, wherein, In step B1, the dosage ratio of the polyethylene glycol, acetone, isophorone diisocyanate, chain extender and end-capping agent is 10 g: 50 mL: 5 g: 2 g: 2 g. The polyethylene glycol is polyethylene glycol 400, and the chain extender is ricinolein. The post-treatment includes: after the reaction is completed, the temperature of the reaction kettle is kept at 40-50 °C, and the solvent is removed by reduced pressure distillation to obtain the modified polyurethane. In step B2, the weight ratio of the epoxy resin, polytetrahydrofuran and catalyst is 10: 10: 0.

1. The epoxy resin is bisphenol A type epoxy resin E-44, the molecular weight of the polytetrahydrofuran is 1000 ± 50, and the catalyst is potassium persulfate. In step B3, the dosage ratio of the modified polyurethane, modified epoxy resin, dispersion aid and purified water is 17 g: 15 g: 5 g: 120-130 mL. The dispersion aid is composed of sodium dodecyl sulfate and polyethylene glycol 200 according to the weight ratio of 2:

1.

5. A high-performance cold mix asphalt concrete according to claim 1, characterized in that, The dosage ratio of the butanetetracarboxylic acid and 3-(dibutylamino)propylamine is 1 mol: 3 mol. The dosage ratio of the butanetetracarboxylic acid, catalyst and N,N-dimethylformamide is 5 g: 0.2 g: 50 mL. The catalyst is potassium hydroxide. The post-treatment operation includes: after the reaction is completed, the temperature of the reaction kettle is kept at 130-150 °C, the pressure of the reaction kettle is reduced to -0.1 MPa, and the low-boiling fractions are removed by reduced pressure distillation to obtain the end-capping agent.

6. The high-performance cold-mix asphalt concrete according to claim 1, characterized in that, In step C1, the molar ratio of styrene, 1,7-octadiene and maleic anhydride is 3: 7:

2. The dosage ratio of the maleic anhydride, toluene and initiator is 1 g: 15 mL: 0.05 g. The post-treatment includes: after the reaction is completed, the reaction kettle is kept at 70-80 °C, and the solvent is removed by reduced pressure distillation to obtain the reinforcing modifier. In step C, the weight ratio of the 90# base asphalt, SBS modified asphalt and reinforcing modifier is 20: 6-10: 3-5.

7. A method for preparing a high-performance cold-mix asphalt concrete according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Add Portland cement, polycarboxylate superplasticizer and drinking water into the reaction kettle and stir for 30-50 min to obtain the cement slurry. S2. Add the pretreated aggregate and the cement slurry into the stirring kettle and stir. Stir at room temperature for 15-20 min to obtain the mixed aggregate. S3. Disperse the modified emulsion and cellulose in a colloid mill at a temperature of 60-70 °C, and slowly add the mixed asphalt at a temperature of 130-140 °C into the colloid mill. Keep the temperature for dispersion for 90-120 min. After the dispersion is completed, quickly transfer the dispersion system in the colloid mill to a cold trap at a temperature of 5-10 °C and quickly cool it to room temperature to obtain the composite asphalt emulsion. S4. Add the composite asphalt emulsion into the stirring kettle containing the mixed aggregate and stir at room temperature for 20-30 min to obtain the asphalt concrete.

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