An emulsifier-added asphalt and a method for preparing the same

Abstract

The application discloses an emulsifier-added asphalt and a preparation method thereof, and belongs to the technical field of emulsified asphalt preparation. The emulsifier-added asphalt is prepared from the following components in parts by weight: modified asphalt 55-65 parts; emulsifier aqueous solution 35-45 parts; wetting agent 0.3-0.5 parts; wherein the modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and epsilon-caprolactam. The emulsifier-added asphalt has ultralow surface tension and excellent stability, can overcome capillary resistance when being laid on the surface of a base layer, deeply penetrates into the base layer pores, does not prematurely break emulsion and block the pores during the penetration process, and is combined with the base layer through a covalent bond, thereby realizing ultrastrength bonding between the emulsifier-added asphalt and the base layer, and solving the technical problems of poor penetration performance of emulsified asphalt and unstable combination between emulsified asphalt and a road surface base layer in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of emulsified asphalt preparation, and particularly relates to an emulsifier-added asphalt and a preparation method thereof. BACKGROUND

[0002] As an important road engineering material, emulsified asphalt is essentially a water-oil or oil-water type colloidal dispersion system formed by stably dispersing high-temperature molten asphalt in the form of small particles in water phase medium under the joint action of mechanical shearing and chemical emulsifier. Compared with traditional hot-mixed asphalt technology, the core advantage of emulsified asphalt technology lies in its ability to be constructed at room temperature or low temperature, which significantly reduces energy consumption and harmful gas emissions, meeting the growing demand for energy saving and emission reduction and green environmental protection worldwide. In addition, its excellent fluidity and construction convenience make it widely used in road maintenance engineering, such as micro-surfacing, slurry seal, tack coat and primer.

[0003] However, the existing technology still faces many bottlenecks and challenges when applying emulsified asphalt to the field of primer, which has extremely high requirements for permeability and bonding performance. First of all, insufficient permeability is the primary problem when traditional emulsified asphalt is used as primer. The road base has a complex pore structure, the surface tension of traditional emulsified asphalt is relatively high, and the size distribution of asphalt particles is uneven, which causes great resistance when wetting and penetrating into the base capillary channel. More importantly, emulsified asphalt will break down prematurely during the penetration process due to water evaporation and charge interaction with the surface of aggregate, and the asphalt film formed after breaking down will quickly block the pore channel, thereby severely limiting the penetration depth and failing to form an effective "mortise and tenon" structure, resulting in insufficient locking force between the base and the asphalt surface layer. Secondly, the bonding strength and durability after solidification are not good. After the traditional emulsified asphalt breaks down to form a film, it mainly relies on physical adhesion to combine with the base material, and this physical interfacial bonding force is relatively weak. Under the long-term shearing action of traffic load and the erosion of environmental factors such as rainwater, the interface is prone to peeling and slipping, ultimately causing serious diseases such as road pushing, heaving and cracking, significantly shortening the service life of the road. In order to improve the bonding performance, researchers have tried to introduce thermosetting materials such as epoxy resin, but due to the huge polarity difference between asphalt and epoxy resin, the compatibility is extremely poor, making it difficult for epoxy resin to disperse uniformly in the asphalt phase, the addition amount is limited, the performance improvement effect is not ideal, and the storage stability of the system is also difficult to guarantee. Therefore, developing a new type of emulsified asphalt material with excellent permeability, high bonding strength and long-term durability has become a technical problem to be solved in the field.

[0004] In the prior art, CN118325352B discloses a high-permeability emulsified asphalt and a preparation method thereof. The scheme improves the compatibility of the epoxy resin with the base asphalt by pre-modifying the epoxy resin with long-chain alkylation, and then compounding a permeation aid and a curing aid, aiming to solve the problems of permeability and adhesion. Although the technical scheme improves the comprehensive performance of the emulsified asphalt to some extent, it still has inherent limitations. First, the preparation process is relatively complex, involving multiple chemical modification reactions and the compounding of multiple additives, which not only increases the control difficulty and time cost of the production process, but also puts higher requirements on the accuracy of the production equipment and process parameters, resulting in a significant increase in production cost, which is not conducive to large-scale engineering application and promotion. Second, the performance of the system is highly sensitive to environmental conditions. The curing reaction rate of the epoxy resin is closely related to the environmental temperature and humidity. Under low temperature or high humidity construction conditions, the curing reaction may not be complete or too slow, affecting the normal development of the adhesion strength, thereby narrowing the construction window period and causing inconvenience to actual engineering applications. Third, although the compatibility of the epoxy resin with the asphalt is improved by alkylation, this non-reactive physical compatibilization method may still have the risk of phase separation under long-term storage and load, thereby affecting the long-term stability of the material performance. In addition, the introduction of epoxy resin may increase the brittleness of the material to some extent, which may have a potential negative impact on the low-temperature crack resistance of the emulsified asphalt residue. SUMMARY

[0005] In view of the deficiencies of the above prior art, the present application discloses an emulsifier-added asphalt and a preparation method thereof, which prepares an emulsifier-added asphalt with good permeability, strong adhesion, and excellent durability, solving the technical problems of insufficient penetration depth and adhesion strength of the cured layer when the traditional emulsified asphalt is used as a primer in the prior art.

[0006] The present application protects an emulsifier-added asphalt, which is composed of the following components in weight parts:

[0007] Modified asphalt: 55-65 parts;

[0008] Emulsifier aqueous solution: 35-45 parts;

[0009] Wetting agent: 0.3-0.5 parts;

[0010] The modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate, and ε-caprolactam.

[0011] Preferably, the emulsifier-added asphalt is composed of the following components in weight parts:

[0012] Modified asphalt: 60 parts;

[0013] Emulsifier aqueous solution: 40 parts;

[0014] wetting agent, 0.5 parts.

[0015] Preferably, the mass ratio of the base asphalt, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, the diphenyl methane diisocyanate and the epsilon-caprolactam is 100:2~4:4~6:3~5.

[0016] Preferably, the preparation method of the modified asphalt is as follows: the base asphalt is heated to 140~150℃, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is added, and stirred and mixed uniformly, then the material is pumped into the feeding port of a double-screw extruder, the temperature of the first reaction zone is adjusted to 80~90℃, the diphenyl methane diisocyanate is added, and after 2~5min of reaction, the reaction material is moved to the second reaction zone, the temperature is adjusted to 70~80℃, the epsilon-caprolactam is added, and after 2~5min of reaction, the reaction material is extruded, and cooled to 25℃ to obtain the modified asphalt.

[0017] Preferably, the emulsifier aqueous solution is composed of deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol.

[0018] Preferably, the mass ratio of the deionized water, the polyoxyethylene-b-polyacrylic acid and the hyperbranched polyol is 30~40:1.5~2.5:2~3.

[0019] Preferably, the emulsifier aqueous solution is prepared by the following method: the hyperbranched polyol, the polyoxyethylene-b-polyacrylic acid and the deionized water are mixed at 55~65℃, and stirred uniformly to obtain the emulsifier aqueous solution.

[0020] Preferably, the base asphalt is 70# road petroleum asphalt or 90# road petroleum asphalt.

[0021] Preferably, the wetting agent is an organic silicon wetting agent.

[0022] The application also claims a preparation method of the emulsifier-added asphalt as above, comprising the following steps: the modified asphalt is heated to 135~145℃ to be in a molten state, the emulsifier aqueous solution and the wetting agent are added under a rotation speed of 3000~6000rpm for shearing emulsification, and after uniform mixing, the mixture is cooled to 25~50℃ to obtain the emulsifier-added asphalt.

[0023] The application has at least the following beneficial effects:

[0024] (1) The emulsifier added asphalt of the present application has ultra-low surface tension and excellent stability, when sprayed onto the surface of the base layer, it can overcome the capillary resistance and deeply penetrate into the pores of the base layer, and will not be demulsified and clog the pores in advance during the penetration process. When the water evaporates and the emulsion is demulsified, the asphalt droplets coalesce into a film, which is in contact with the modified asphalt in the oil phase and the hyperbranched polyol in the water phase. When the upper hot asphalt mixture is laid at high temperature, the high temperature will trigger the closed system of epsilon-caprolactam capping, releasing the-NCO group and the-OH group of the hyperbranched polyol to undergo in-situ crosslinking reaction, realizing the ultra-strong chemical bonding of the emulsifier added asphalt and the base layer.

[0025] (2) In the process of preparing the emulsifier added asphalt, epsilon-caprolactam is used as a capping agent to prepare modified asphalt. During the high temperature laying of the asphalt, the continuous high temperature will trigger the closed system of epsilon-caprolactam capping, releasing the active-NCO group, so as to undergo in-situ crosslinking reaction with the-OH group of the hyperbranched polyol.

[0026] (3) In the process of preparing the emulsifier added asphalt, the flexible hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is introduced into the modified asphalt through polyurethane bond, which significantly improves the low temperature crack resistance and toughness of the final material.

[0027] (4) By adding polyoxyethylene-b-polyacrylic acid in the emulsifier aqueous solution, when mixed with the modified asphalt, the hydrophilic polyether segment forms a physical barrier with huge entropy repulsion, forming a steric hindrance layer on the surface of the asphalt droplets, effectively preventing the coalescence and demulsification of the droplets due to collision during penetration and storage, and is suitable for high penetration requirements.

[0028] (5) In the process of preparing the emulsifier added asphalt, an organic silicon wetting agent is added, which greatly reduces the surface tension of water, produces a strong Marangoni effect, and makes the asphalt droplets have extremely strong spreading speed and capacity, thereby realizing ultra-strong penetration. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0030] The hydroxyl-terminated polybutadiene acrylonitrile liquid rubber used in the embodiments of the application is from Zibo Qilong Chemical Co., Ltd., and the number average molecular weight is ≥2000; the polyoxyethylene-b-polyacrylic acid used is from Xi'an Rixi Biological Technology Co., Ltd., and the article number is 324234; the hyperbranched polyol used is from Yu'yan Huihong Plastic Factory, and the model number is MAH-9810, and the hydroxyl value is 200-300; the silicone wetting agent used is from Foshan Qianyou Chemical Co., Ltd., and the model number is AKN-1070.

[0031] One of the embodiments of the application prepares an emulsifier-added asphalt, which is composed of the following components in parts by weight:

[0032] Modified asphalt: 55-65 parts;

[0033] Emulsifier aqueous solution: 35-45 parts;

[0034] Wetting agent: 0.3-0.5 parts;

[0035] The modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and ε-caprolactam.

[0036] In one embodiment of the application, the emulsifier-added asphalt is composed of the following components in parts by weight:

[0037] Modified asphalt: 60 parts;

[0038] Emulsifier aqueous solution: 40 parts;

[0039] Wetting agent: 0.5 parts.

[0040] In one embodiment of the application, the mass ratio of the base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and ε-caprolactam is 100:2-4:4-6:3-5.

[0041] In one embodiment of the application, the preparation method of the modified asphalt is as follows: the base asphalt is heated to 140-150℃, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is added, and stirred and mixed uniformly, the material is pumped into the feeding port of a double-screw extruder, the temperature of the first reaction zone is adjusted to 80-90℃, the diphenyl methane diisocyanate is added, and after 2-5 min of reaction, the reaction material is moved to the second reaction zone, the temperature is adjusted to 70-80℃, the ε-caprolactam is added, and after 2-5 min of reaction, the reaction material is extruded, and cooled to 25℃ to obtain the modified asphalt.

[0042] In the above reaction, in the first reaction zone, the isocyanate group of diphenyl methane diisocyanate (MDI) has very high chemical reactivity, and can react with the group with active hydrogen at 80-90℃ by nucleophilic addition reaction. The substrate asphalt contains a small amount of phenolic hydroxyl group, and the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber (HTBN) contains hydroxyl groups at both ends. The reaction can be simplified as:

[0043] 〔asphalt〕-OH + OCN-MDI-NCO → 〔asphalt〕-O-CO-NH-MDI-NCO, HO-HTBN-OH + 2OCN-MDI-NCO → OCN-MDI-NH-CO-O-HTBN-O-CO-NH-MDI-NCO. After the reaction is completed, a prepolymer with asphalt or HTBN as the skeleton and -NCO groups at both ends or side chains is formed. In the second reaction zone, the N-H bond in the cyclic lactam group of ε-caprolactam has reactivity, and can react with the -NCO group at 70-80℃. The reaction can be simplified as:

[0044] 〔prepolymer〕-NCO + HN-(CH2)5-CO → 〔prepolymer〕-NH-CO-N-(CH2)5-CO. The -NCO group on the prepolymer generated in the first reaction zone is replaced by ε-caprolactam to form a closed system capped with ε-caprolactam. By introducing the flexible hydroxyl-terminated polybutadiene acrylonitrile liquid rubber into the modified asphalt through a polyurethane bond, the low-temperature crack resistance and toughness of the final material are significantly improved

[0045] In an embodiment of the present application, the emulsifier aqueous solution is composed of deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol.

[0046] In an embodiment of the present application, the mass ratio of the deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol is 30-40:1.5-2.5:2-3.

[0047] In an embodiment of the present application, the emulsifier aqueous solution is prepared by the following method: mixing the hyperbranched polyol, polyoxyethylene-b-polyacrylic acid and deionized water at 55-65℃, and stirring uniformly to obtain the emulsifier aqueous solution.

[0048] In an embodiment of the present application, the substrate asphalt is 70# road petroleum asphalt or 90# road petroleum asphalt.

[0049] In an embodiment of the present application, the wetting agent is an organic silicon wetting agent.

[0050] The application also discloses a preparation method of the emulsifier-added asphalt.

[0051] It can be understood that, by adding polyoxyethylene-b-polyacrylic acid in the emulsifier aqueous solution, when mixed with the modified asphalt, the hydrophilic polyether chain segment forms a physical barrier, and the entropy repulsion is huge, so that a steric hindrance layer is formed on the surface of the asphalt microdroplets, which effectively prevents the microdroplets from coalescing and demulsifying due to collision in the penetration and storage process, and is suitable for high penetration requirements.

[0052] In the above process, the epsilon-caprolactam-terminated closed system in the modified asphalt is basically stable at the emulsification temperature of 135-145 DEG C for a short time, and does not react significantly with the polyol in the water phase, so that the emulsification process is smoothly carried out and the storage stability of the emulsifier-added asphalt is ensured.

[0053] It can be understood that the emulsifier-added asphalt prepared in the application has ultra-low surface tension and excellent stability, can overcome the capillary resistance when sprayed on the surface of the base layer, and deeply penetrates into the pore of the base layer, and will not be demulsified and clog the pore channel in the penetration process. When the water evaporates and the emulsion is demulsified, the asphalt microdroplets coalesce into a film and are distributed between the modified asphalt in the oil phase and the hyperbranched polyol in the water phase. When the upper hot asphalt mixture is laid at high temperature, the high temperature triggers the epsilon-caprolactam-terminated closed system to release the -NCO group and the -OH group of the hyperbranched polyol to carry out in-situ crosslinking reaction, so that the emulsifier-added asphalt is bonded to the base layer.

[0054] Embodiment 1

[0055] In this embodiment, an emulsifier-added asphalt is prepared, which is composed of the following components in parts by weight:

[0056] Modified asphalt: 60 parts;

[0057] Emulsifier aqueous solution: 40 parts;

[0058] Wetting agent: 0.5 parts.

[0059] The modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and epsilon-caprolactam.

[0060] In this embodiment, the mass ratio of the base asphalt, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, the diphenyl methane diisocyanate and the epsilon-caprolactam is 100:3:5:4.

[0061] In this embodiment, the preparation method of the modified asphalt is as follows: the base asphalt is heated to 150℃, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is added, and stirred and mixed uniformly, the material is pumped into the feeding port of the double screw extruder, the temperature of the first reaction zone is adjusted to 80℃, the diphenyl methane diisocyanate is added, the reaction is carried out for 5 min, then the reaction material is moved to the second reaction zone, the temperature is adjusted to 80℃, the ε-caprolactam is added, the reaction is carried out for 5 min, then the reaction material is extruded, and cooled to 25℃ to obtain the modified asphalt.

[0062] In this embodiment, the emulsifier aqueous solution is composed of deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol.

[0063] In this embodiment, the mass ratio of the deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol is 40:2:2.

[0064] In this embodiment, the emulsifier aqueous solution is prepared by the following method: the hyperbranched polyol, polyoxyethylene-b-polyacrylic acid and deionized water are mixed at 60℃, and stirred uniformly to obtain the emulsifier aqueous solution.

[0065] In this embodiment, the base asphalt is 70# road petroleum asphalt.

[0066] In this embodiment, the wetting agent is an organic silicon wetting agent.

[0067] This embodiment also discloses the preparation method of the emulsifier-added asphalt, which comprises the following steps: heating the modified asphalt to 140℃ to make it in a molten state, adding the emulsifier aqueous solution and the wetting agent under a rotation speed of 5000 rpm to perform shearing emulsification, and cooling to 30℃ after uniform mixing to obtain the emulsifier-added asphalt.

[0068] Embodiment 2

[0069] This embodiment prepares an emulsifier-added asphalt, which is composed of the following components in parts by weight:

[0070] Modified asphalt: 55 parts;

[0071] Emulsifier aqueous solution: 35 parts;

[0072] Wetting agent: 0.3 parts;

[0073] The modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and ε-caprolactam.

[0074] In this embodiment, the emulsifier-added asphalt is composed of the following components in parts by weight:

[0075] Modified asphalt: 60 parts;

[0076] Emulsifier aqueous solution, 40 parts;

[0077] Wetting agent, 0.5 parts.

[0078] In this embodiment, the mass ratio of the base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenylmethane diisocyanate and ε-caprolactam is 100:4:4:5.

[0079] In this embodiment, the modified asphalt is prepared by heating the base asphalt to 140℃, adding the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, stirring and mixing uniformly, pumping into the feeding port of the double screw extruder, adjusting the temperature of the first reaction zone to 90℃, adding the diphenylmethane diisocyanate, moving the reaction material to the second reaction zone after 2 minutes of reaction, adjusting the temperature to 80℃, adding the ε-caprolactam, and extruding the reaction material after 2 minutes of reaction, and cooling to 25℃ to obtain the modified asphalt.

[0080] In this embodiment, the emulsifier aqueous solution is composed of deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol.

[0081] In this embodiment, the mass ratio of the deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol is 40:1.5:3.

[0082] In this embodiment, the emulsifier aqueous solution is prepared by mixing the hyperbranched polyol, polyoxyethylene-b-polyacrylic acid and deionized water at 65℃, and stirring uniformly to obtain the emulsifier aqueous solution.

[0083] In this embodiment, the base asphalt is 90# road petroleum asphalt.

[0084] In this embodiment, the wetting agent is a silicone wetting agent.

[0085] This embodiment also discloses a preparation method of the emulsifier-added asphalt as described above, comprising the following steps: heating the modified asphalt to 145℃ to make it in a molten state, adding the emulsifier aqueous solution and the wetting agent at a rotation speed of 3000 rpm for shearing emulsification, mixing uniformly, and cooling to 25℃ to obtain the emulsifier-added asphalt.

[0086] Example 3

[0087] This embodiment prepares an emulsifier-added asphalt, which is composed of the following ingredients in parts by weight:

[0088] Modified asphalt: 65 parts;

[0089] Emulsifier aqueous solution, 45 parts;

[0090] wetting agent, 0.5 parts;

[0091] The modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and epsilon-caprolactam.

[0092] In this embodiment, the emulsifier added asphalt is composed of the following components by weight parts:

[0093] Modified asphalt: 60 parts;

[0094] Emulsifier aqueous solution: 40 parts;

[0095] Wetting agent, 0.5 parts.

[0096] In this embodiment, the mass ratio of the base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and epsilon-caprolactam is 100:2:4:5.

[0097] In this embodiment, the preparation method of the modified asphalt is as follows: the base asphalt is heated to 140℃, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is added, stirred and mixed uniformly, pumped into the feeding port of the double screw extruder, the temperature of the first reaction zone is adjusted to 80℃, the diphenyl methane diisocyanate is added, the reaction is carried out for 4min, then the reaction material is moved to the second reaction zone, the temperature is adjusted to 80℃, the epsilon-caprolactam is added, the reaction is carried out for 4min, then the reaction material is extruded, cooled to 25℃, and the modified asphalt is obtained.

[0098] In this embodiment, the emulsifier aqueous solution is composed of deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol.

[0099] In this embodiment, the mass ratio of the deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol is 40:2.5:2.

[0100] In this embodiment, the emulsifier aqueous solution is prepared by the following method: the hyperbranched polyol, polyoxyethylene-b-polyacrylic acid and deionized water are mixed at 60℃, stirred uniformly, and the emulsifier aqueous solution is obtained.

[0101] In this embodiment, the base asphalt is 70# road petroleum asphalt.

[0102] In this embodiment, the wetting agent is an organic silicon wetting agent.

[0103] The emulsifier-added asphalt is prepared by the following steps: heating modified asphalt to 145℃ to make it in a molten state, adding an aqueous emulsifier solution and a wetting agent at a rotation speed of 3000 rpm, shearing and emulsifying, and uniformly mixing, and then cooling to 50℃.

[0104] Comparative Example 1

[0105] In the preparation of the emulsifier-added asphalt, an equal amount of 70# road petroleum asphalt is used to replace the modified asphalt, and the rest is the same as in Example 1.

[0106] Comparative Example 2

[0107] In the preparation of the emulsifier-added asphalt, no hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is added, and the rest is the same as in Example 1.

[0108] Comparative Example 3

[0109] In the preparation of the emulsifier-added asphalt, no hyperbranched polyol is added, and the rest is the same as in Example 1.

[0110] Comparative Example 4

[0111] In the preparation of the emulsifier-added asphalt, no polyoxyethylene-b-polyacrylic acid is added, and the rest is the same as in Example 1.

[0112] Performance detection, the emulsifier-added asphalt prepared in Examples 1-3 and Comparative Examples 1-4 is detected for performance.

[0113] 1. Storage stability test: according to T 0655-1993 “Emulsified Asphalt Storage Stability Test” in “Highway Engineering Asphalt and Asphalt Mixture Test Procedures” (JTG E20-2011), 250 mL of emulsifier-added asphalt is taken as a sample for each group and injected into a glass test tube, the tube opening is sealed, the test tube is vertically placed in a constant temperature environment of 25℃, and kept for 5 days, after 5 days, 50g of sample is carefully taken from the upper and lower parts of the test tube, the asphalt residue content of the upper and lower samples is determined by evaporation test, and the absolute value of the difference between the asphalt contents of the upper and lower samples is calculated, which is the storage stability (%), the smaller the difference, the better the stability, and the test results are as follows:

[0114] As can be seen from Table 1, the 5-day storage stability of Examples 1, 2 and 3 is 0.8%, 1.0% and 0.9% respectively, all of which are far less than the standard requirement of 5%, indicating that the emulsion system is very stable; the stability of Comparative Example 4 is only 12.5% due to the lack of the key emulsion stabilizing component polyoxyethylene-b-polyacrylic acid, which is far beyond the qualified standard and obvious demulsification stratification phenomenon occurs, indicating that the hydrophilic polyether segment of polyoxyethylene-b-polyacrylic acid forms an effective steric hindrance layer on the surface of the asphalt droplets, which prevents the coalescence of the droplets through entropy repulsion, thereby endowing the product with excellent storage stability; the stability of Comparative Example 1 using ordinary asphalt is also significantly worse than the examples, indicating that the modified asphalt in the application has better stability in synergistic action with the emulsion system.

[0115] 2. Surface tension test: A full-automatic surface tension meter was used, and a platinum plate method was used for measurement. 50 ml of emulsifier added asphalt was taken as a sample for each group and placed in a sample cup and on a sample stage of the instrument, and the sample temperature was kept constant at 25°C. Before use, the platinum plate was burned with an alcohol lamp to ensure that its surface was clean. The instrument was started, the sample stage was automatically raised to make the liquid surface contact the platinum plate, and the instrument automatically measured the force required for the liquid to completely wet the platinum plate. The surface tension value was calculated according to the formula. Each sample was measured three times, and the average value was taken. The test results are shown in Table 2:

[0116]

[0117] As can be seen from Table 2, the surface tension of Examples 1, 2 and 3 is all at an extremely low level of 25.1-25.5 mN / m. The surface tension of Comparative Example 4 is as high as 33.4 mN / m due to the lack of polyoxyethylene-b-polyacrylic acid, proving that the composite emulsion system composed of polyoxyethylene-b-polyacrylic acid and hyperbranched polyol etc. used in the application has extremely high surface activity, which can significantly reduce the surface tension of the asphalt emulsion.

[0118] 3. Penetration depth test: A standard cement mortar test block with a size of 100 mm x 100 mm x 50 mm was prepared, the porosity was controlled at 18±1%, and the test block was dried at 105°C until the weight was constant. The test block was cooled to room temperature and placed horizontally. 50 mL of emulsifier added asphalt was taken as a sample for each group and poured evenly on the upper surface of the test block. After 24 hours of standing in an environment of 25°C and 60% humidity, the test block was split along the center line using a press. The average depth of the asphalt penetration area on the freshly split surface was measured using a vernier caliper. Each sample was tested on 3 test blocks, and the results were averaged. The test results are shown in Table 3:

[0119]

[0120] As can be seen from Table 3, the average penetration depths of Examples 1, 2 and 3 are 9.5 mm, 9.2 mm and 9.3 mm respectively, showing excellent penetration performance. In contrast, the penetration depth of Comparative Example 1 is only 5.1 mm, and the penetration depth of Comparative Example 4 is only 2.1 mm. Due to poor storage stability, the emulsion of Comparative Example 4 will quickly demulsify when it contacts the surface of the porous medium, and the asphalt particles will block the pores, thereby severely hindering further penetration. While the Examples can overcome the capillary resistance and maintain the stability of the emulsion during the penetration process due to their high stability and ultra-low surface tension, thereby achieving deep penetration.

[0121] 4. Pull-out strength test: According to the pull-out test method in JGJ 144-2019 "Technical Standard for External Wall Insulation Engineering", on the surface of a standard cement concrete slab (C30), a circular boundary die with a diameter of 50 mm was used to apply the emulsified asphalt of each group as the sample to be tested, with a thickness of 1 mm. A standard pull-out head with a diameter of 50 mm was vertically pressed onto the coating. The prepared test piece was cured at 60°C for 24 hours to evaporate the moisture and demulsify the emulsion. Subsequently, the test piece was placed in an oven at 160°C for 2 hours to simulate the high-temperature environment during the laying of the upper hot asphalt mixture. After cooling to room temperature, the pull-out strength was tested using a pull-out instrument at a loading rate of 5 mm / min until failure. The maximum pull-out strength was recorded. Five test pieces were tested for each sample, and the average value was taken. The test results are shown in Table 4:

[0122]

[0123] As can be seen from Table 4, the pull-out strengths of Examples 1, 2 and 3 are as high as 1.85 MPa, 1.78 MPa and 1.81 MPa respectively, showing super-strong interfacial bonding capacity. The pull-out strengths of Comparative Examples 1 and 3 are only 0.65 MPa and 0.71 MPa, which are significantly lower than that of Example 1. In Example 1, at high temperature, the -NCO groups in the modified asphalt, which are blocked by ε-caprolactam, are unblocked and undergo in-situ crosslinking reaction with the -OH groups of the hyperbranched polyol in the aqueous phase, forming a firm chemical bond, thereby realizing the transition from physical adhesion to chemical bonding. Comparative Example 3 lacks the polyol required for the reaction, and therefore cannot form a chemical bond, with a strength comparable to that of ordinary asphalt. The strength of Comparative Example 2 is 1.55 MPa, which is higher than that of Comparative Examples 1 and 3 but lower than that of the Examples, indicating that the addition of liquid rubber enhances the toughness of the asphalt bonding layer and improves the bonding strength.

[0124] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and any equivalent changes and improvements made within the scope of the present application should still fall within the scope of the present patent.

Claims

1. An emulsifier-added bitumen, characterized in that, Composed of the following ingredients by weight parts: Modified asphalt: 55~65 parts; Emulsifier aqueous solution, 35~45 parts; Wetting agent, 0.3~0.5 parts; The modified asphalt is composed of base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and epsilon-caprolactam, the emulsifier aqueous solution is composed of deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol, wherein the type of the hyperbranched polyol is MAH-9810, and the wetting agent is a silicone wetting agent.

2. The emulsifier-added bitumen according to claim 1, characterized in that, Composed of the following ingredients by weight parts: Modified asphalt: 60 parts; Emulsifier aqueous solution, 40 parts; Wetting agent, 0.5 parts.

3. The emulsifier-added bitumen according to claim 1, characterized in that, The mass ratio of the base asphalt, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, diphenyl methane diisocyanate and epsilon-caprolactam is 100:2~4:4~6:3~5.

4. The emulsifier-added bitumen of claim 1, wherein, The preparation method of the modified asphalt is as follows: the base asphalt is heated to 140~150℃, the hydroxyl-terminated polybutadiene acrylonitrile liquid rubber is added, stirring is performed to mix uniformly, the material is pumped into the feeding port of a double-screw extruder, the temperature of the first reaction zone is adjusted to 80~90℃, the diphenyl methane diisocyanate is added, and after 2~5 min of reaction, the reaction material is moved to the second reaction zone, the temperature is adjusted to 70~80℃, the epsilon-caprolactam is added, and after 2~5 min of reaction, the reaction material is extruded, and cooled to 25℃ to obtain the modified asphalt.

5. The emulsifier-added asphalt of claim 1, wherein, The mass ratio of the deionized water, polyoxyethylene-b-polyacrylic acid and hyperbranched polyol is 30~40:1.5~2.5:2~3.

6. The emulsifier-added asphalt of claim 1, wherein, The emulsifier aqueous solution is prepared by the following method: the hyperbranched polyol, polyoxyethylene-b-polyacrylic acid and deionized water are mixed at 55~65℃, and stirring is performed to mix uniformly to obtain the emulsifier aqueous solution.

7. The emulsifier-added asphalt of claim 1, wherein The base asphalt is 70# road petroleum asphalt or 90# road petroleum asphalt.

8. A process for the preparation of an emulsifier-extended bitumen as claimed in any one of claims 1 to 7, characterised in that, The method comprises the following steps: The modified asphalt is heated to 135~145℃ to be in a molten state, the emulsifier aqueous solution and the wetting agent are added under a rotation speed of 3000~6000 rpm to perform shearing emulsification, and after mixing uniformly, the emulsifier-added asphalt is obtained by cooling to 25~50℃.

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