Polyurethane modified asphalt for drainage asphalt pavement as well as preparation method and application of polyurethane modified asphalt

Abstract

The invention discloses polyurethane modified asphalt for a drainage asphalt pavement as well as a preparation method and application thereof, and belongs to the technical field of asphalt modification, the polyurethane modified asphalt for the drainage asphalt pavement comprises the following raw materials: matrix asphalt, a thermosetting polyurethane prepolymer, a catalyst and a compatilizer; based on 100 wt% of the addition amount of the matrix asphalt, the addition amount of the thermosetting polyurethane prepolymer is 33.3-66.7 wt%, the addition amount of the catalyst is 0.5-1 wt%, and the addition amount of the compatilizer is 0.5-1 wt%; the problems that in an existing drainage asphalt pavement technology, due to insufficient adhesion, aggregate falls off, water damage is caused by rainwater in the interior, the service life cannot be met due to insufficient structural strength, and due to the fact that in an existing polyurethane modified asphalt technology, polyurethane curing is fast, construction operability is insufficient are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt modification, and in particular relates to a polyurethane modified asphalt for drainage asphalt pavement, and a preparation method and application thereof. Background Art

[0002] Asphalt is a dark brown complex mixture of hydrocarbons of different molecular weights and their non-metallic derivatives. It is a kind of high-viscosity organic liquid. Asphalt is an organic gelling material that is waterproof, moisture-proof and anti-corrosive. The survey results of rainy day accidents on my country's highways show that the accident rate on rainy days is about 8 times that on sunny days, and serious accidents such as chain rear-end collisions and hydroplaning are more frequent. In addition, the rolling noise between the road surface and the tires during high-speed driving seriously affects the living environment of residents along the route. In this context, drainage asphalt pavement has become the only choice to solve the frequent rainy day accidents in China with its outstanding advantages such as excellent anti-skid performance, low noise, suppression of water mist, prevention of hydroplaning and reduction of glare.

[0003] The mixture gradation currently used is PAC-13 (i.e., drainage asphalt mixture). Drainage asphalt pavement has problems such as aggregate shedding due to insufficient adhesion caused by its large void structure, water damage caused by rainwater inside, and insufficient structural strength that cannot meet the service life. There is room for further improvement. Ordinary road petroleum asphalt is limited by its own chemical composition and structure, which seriously affects its use as a mixture binder. In addition, the current construction temperature of modified asphalt mixtures is generally above 175°C, and the preparation time of modified asphalt is relatively long, usually 1.5 hours, resulting in a lot of energy consumption and environmental problems.

[0004] Therefore, it is necessary to modify asphalt to improve its road performance and make it more suitable for drainage asphalt pavement. Polyurethane is a kind of high-performance polymer material with oil resistance, wear resistance, aging resistance, high adhesion, high impact strength and excellent low-temperature resistance. Polyurethane improves the intermolecular force of modified petroleum asphalt by hydrogen bonds produced by chemical reaction with colloid in petroleum asphalt, and then improves the mechanical performance index of modified asphalt by adjusting the molecular weight of polyurethane elastomer. The modified asphalt obtained by using polyurethane as asphalt modifier is stronger than the modified asphalt obtained by traditional polymer modifier in terms of durability and elastic recovery. This is mainly because the addition of polyurethane modifier can greatly improve the elastic properties of matrix asphalt, and the increase of this property can make the asphalt pavement have a strong resistance to plastic deformation under factors such as vehicle load and environmental load. This will greatly extend the service life of asphalt pavement and can effectively improve the quality of road use. However, polyurethane modified asphalt has the problem of rapid curing of polyurethane during the application process, which leads to insufficient operability of asphalt pavement construction and seriously affects the performance of polyurethane asphalt pavement, which also inhibits the promotion of polyurethane modified asphalt. Summary of the invention

[0005] In order to solve the problems existing in the prior art, such as aggregate shedding due to insufficient adhesion, water damage caused by rainwater inside, insufficient structural strength to meet the service life, and insufficient construction operability due to fast curing of polyurethane, the present invention proposes a polyurethane modified asphalt for drainage asphalt pavement and a preparation method and application thereof, which reduces the construction temperature of the drainage asphalt pavement.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A polyurethane modified asphalt (TPUA) for drainage asphalt pavement, the raw materials comprising base asphalt, thermosetting polyurethane prepolymer (PU), catalyst and compatibilizer;

[0009] Based on the addition amount of the base asphalt being 100wt%, the addition amount of the thermosetting polyurethane prepolymer is 33.3-66.7wt%, the addition amount of the catalyst is 0.5-1wt%, and the addition amount of the compatibilizer is 0.5-1wt%.

[0010] Preferably, based on 100 wt% of the added amount of the base asphalt, the added amount of the thermosetting polyurethane prepolymer is 33.3 wt% or 66.7 wt%, more preferably 66.7 wt%.

[0011] In the present invention, the amount of thermosetting polyurethane prepolymer is greatly increased, and the maximum amount is 66.7wt%. The thermosetting polyurethane modified asphalt of the present invention is used for drainage asphalt pavement, successfully solving the problems of aggregate shedding due to insufficient adhesion of drainage asphalt pavement due to its large void structure, water damage caused by rainwater inside, insufficient structural strength and failure to meet the service life. At the same time, the construction temperature of the modified asphalt mixture can be reduced, the preparation time of the modified asphalt mixture can be shortened, and energy can be saved.

[0012] Preferably, the base asphalt is 70# petroleum asphalt.

[0013] Preferably, the thermosetting polyurethane prepolymer is a single component, with a terminal -NCO bond content of not less than 13%, a viscosity of not less than 1077 mPa·s at 25°C, a surface drying time of not less than 98 min at 30°C, a tensile strength of not less than 31.4 MPa, and an elongation at break of not less than 151.1% (tensile strength and elongation at break test standards refer to GB1040-79). -NCO in the thermosetting polyurethane prepolymer reacts with -OH bonds in asphalt to generate strength, which can improve the operability of the reaction process within the above viscosity and surface drying time, and can increase the elastic characteristics of the polyurethane modified asphalt used for drainage asphalt pavement within the above tensile strength and elongation at break.

[0014] In the present invention, the softening point of 70# petroleum asphalt is 46°C, the needle penetration at 25°C is 60-80 (0.1mm), the elongation at 10°C is 25cm, and the dynamic viscosity is 180Pa·s. The use of 70# petroleum asphalt as the matrix asphalt to prepare thermosetting polyurethane modified asphalt can significantly improve the high temperature stability of the modified asphalt. The thermosetting polyurethane prepolymer enhances the mechanical strength of the modified asphalt through chemical cross-linking reaction (such as the isocyanate component therein reacts with the active hydrogen in the asphalt to form carbamate), which helps to improve the bearing capacity and durability of the road surface. At the same time, the thermosetting polyurethane exhibits better flexibility at low temperatures, which helps to reduce cracks in the road surface in cold weather. Moreover, as the content of thermosetting polyurethane increases, the continuous phase in TPUA gradually changes from asphalt to PU. When the critical content is exceeded, the asphalt is dispersed in the PU skeleton in the form of microspheres. This structure is conducive to improving the overall performance of the modified asphalt, and has significant advantages in improving road performance, durability and reducing maintenance costs.

[0015] Preferably, the catalyst is bis(2,2-morpholinoethyl)ether, 4,4-bis-sec-butylaminodiphenylmethane or 1,4-butanediol. Preferably, the compatibilizer is maleic anhydride or maleic anhydride grafted polyethylene. The melting point of the compatibilizer is lower than 130°C, and the melting point of the above compatibilizer is lower than the preparation temperature of the modified asphalt. If the melting point of the compatibilizer is higher than the preparation temperature of the modified asphalt, the compatibilizer will not be able to melt into the modified asphalt system, which will have an adverse effect on the preparation, stability and performance of the modified asphalt.

[0016] The second technical solution of the present invention:

[0017] The present invention also provides a method for preparing the polyurethane modified asphalt for drainage asphalt pavement, comprising the following steps:

[0018] Thermosetting polyurethane prepolymer and compatibilizer are added to molten base asphalt in small amounts for multiple times, sheared and stirred at 130-140° C., catalyst is added in small amounts for multiple times, and the polyurethane modified asphalt for drainage asphalt pavement is obtained after stirring.

[0019] The present invention adopts the method of "multiple small amounts" to add thermosetting polyurethane prepolymer, compatibilizer and catalyst, which can ensure that they are fully dispersed and mixed in the matrix asphalt, avoid local excess or unevenness, and better control the reaction speed and degree, reduce the possibility of local overheating, avoid affecting the performance of modified asphalt, and reduce the degree of wear on equipment. For example, for thermosetting polyurethane prepolymer, it can be divided into 3-5 parts of equal mass and added to the molten matrix asphalt in 3-5 times; for compatibilizer, it can also be divided into 3-5 parts of equal mass and added to the molten matrix asphalt in 3-5 times; for catalyst, it can also be divided into 3-5 parts of equal mass and added in 3-5 times.

[0020] Preferably, in the method for preparing polyurethane modified asphalt for drainage asphalt pavement, the shear stirring time is 5-10 min, and the shear stirring rate is 1500-2000 rpm.

[0021] The third technical solution of the present invention:

[0022] The present invention also provides a polyurethane drainage asphalt mixture for drainage asphalt pavement, the raw materials of which contain the above-mentioned polyurethane modified asphalt for drainage asphalt pavement.

[0023] The fourth technical solution of the present invention:

[0024] The present invention also provides a method for preparing the polyurethane drainage asphalt mixture for drainage asphalt pavement, comprising the following steps:

[0025] The polyurethane modified asphalt for drainage asphalt pavement, mineral stone and filler are mixed and heated to obtain the polyurethane drainage asphalt mixture for drainage asphalt pavement;

[0026] The temperature of the heating and mixing is 140-150°C.

[0027] Preferably, the heating and mixing time is 2-4 minutes.

[0028] The invention uses thermosetting polyurethane modified asphalt mixed with aggregate, so that thermosetting polyurethane can be applied to drainage asphalt mixture. The invention adopts thermosetting polyurethane prepolymer with low activity and a method of mixing and using immediately, reduces the construction temperature of polyurethane drainage asphalt mixture (from the existing 175°C or above to 140-150°C), greatly shortens the preparation time of modified asphalt (from the existing 1.5h to 5-10min), and improves the overall performance of polyurethane drainage asphalt mixture.

[0029] Preferably, in the method for preparing the polyurethane drainage asphalt mixture for drainage asphalt pavement, the mineral stone is basalt or limestone; and the filler is limestone powder.

[0030] In the present invention, mineral stones and fillers are collectively referred to as aggregates, wherein the mineral stones are composed of coarse aggregates and fine aggregates, the fillers are limestone powder, the coarse aggregates account for 80-85wt% of the aggregates, and the fillers account for 2-5wt% of the aggregates.

[0031] In the present invention, the particle size of the coarse aggregate is 10-15 mm, 5-10 mm and 3-5 mm, and the particle size of the fine aggregate is 0-3 mm.

[0032] The curing method of the polyurethane drainage asphalt mixture for drainage asphalt pavement of the present invention is: the polyurethane drainage asphalt mixture is molded by using a rotary compactor, the compaction temperature is 130°C-140°C, after the temperature is lowered, the mold is removed and left to stand for 16 hours, and then it is placed in an 80°C oven for curing for 10 hours. The molding method adopted by the present invention is the rotary compaction method, which can promote the curing of polyurethane with the curing method after molding, and further optimize the performance of the polyurethane drainage asphalt mixture.

[0033] The fifth technical solution of the present invention:

[0034] The present invention also provides application of the polyurethane modified asphalt for drainage asphalt pavement in drainage asphalt pavement.

[0035] The invention improves the bonding performance and flexibility of the matrix asphalt by adding a thermosetting polyurethane prepolymer, enhances the deformation resistance of the modified asphalt pavement, greatly improves the high and low temperature performance of the modified asphalt pavement, and can reduce the energy consumption of asphalt and the emission of greenhouse gases. The construction process of the modified asphalt of the invention is simple, and the polyurethane drainage asphalt mixture can be obtained by mixing the thermosetting polyurethane modified asphalt, mineral stone and filler, and heating and mixing. In the process of pavement construction, the asphalt pavement construction temperature can be reduced, the performance and work efficiency of asphalt pavement construction are greatly improved, and carbon emissions are reduced.

[0036] Compared with the prior art, the present invention has the following advantages and technical effects:

[0037] The invention improves the mechanical properties of the matrix asphalt by adding thermosetting polyurethane prepolymer, enhances the road surface's ability to resist low-temperature cracking, and improves the road surface's ability to resist rutting. At the same time, it reduces energy emissions during the asphalt pavement construction process. The polyurethane modified asphalt used for drainage asphalt pavement has a simple construction process, and the polyurethane drainage asphalt mixture used for drainage asphalt pavement can be obtained by simple mixing. During the pavement construction process, the construction temperature of the asphalt pavement can be reduced, and the operability and safety during the construction process can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0039] Figure 1 Graph showing the relationship between temperature and rotational viscosity of the modified asphalt prepared in Comparative Example 1 and Examples 1-2.

[0040] Figure 2 This is a relationship diagram between temperature and phase angle δ of the modified asphalt prepared in Comparative Example 1-2 and Example 1-2.

[0041] Figure 3 This is a relationship diagram between the temperature and rutting factor of the modified asphalt prepared in Comparative Example 1-2 and Example 1-2.

[0042] Figure 4 This is a relationship diagram between temperature and creep stiffness modulus of the modified asphalt prepared in Comparative Example 1-2 and Example 1-2.

[0043] Figure 5 This is a relationship diagram between temperature and creep rate of the modified asphalt prepared in Comparative Example 1-2 and Example 1-2.

[0044] Figure 6 This is a graph showing the infrared test results of the modified asphalt prepared in Comparative Example 1-2 and Example 1-2.

[0045] Figure 7 This is a fluorescence microscope comparison of the modified asphalt prepared in Examples 1-2.

[0046] Figure 8 This is the gradation curve of the drainage asphalt mixture in Example 3. DETAILED DESCRIPTION

[0047] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0048] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0049] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0050] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0051] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0052] All raw materials used in the present invention are commercially available.

[0053] Unless otherwise specified, the "parts" used in the embodiments of the present invention refer to "parts by weight". As an example, the model of the thermosetting polyurethane prepolymer is 6177, purchased from Wanhua Chemical Group Co., Ltd., with a terminal-NCO bond content of 13%, a viscosity of 1077 mPa·s at 25°C, a surface drying time of 98 min at 30°C, a tensile strength of 31.4 MPa, and an elongation at break of 151.1% (the test standards for tensile strength and elongation at break refer to GB1040-79).

[0054] In the embodiment of the present invention, maleic anhydride grafted polyethylene is purchased from Ningbo Yuntao New Materials Co., Ltd., model number is 0815, and the grafting rate is 0.8%-1%.

[0055] In an embodiment of the present invention, the limestone powder is powder that passes through a 100-mesh sieve.

[0056] The technical solution of the present invention is further illustrated by the following embodiments.

[0057] Example 1

[0058] (1) First, 120 g of thermosetting polyurethane prepolymer and 3 g of maleic anhydride were added to 360 g of 70# petroleum asphalt (the thermosetting polyurethane prepolymer and maleic anhydride were each divided into 5 equal parts and added in 5 times) (i.e., in this embodiment, the amount of thermosetting polyurethane prepolymer added was 33.3 wt % based on the amount of base asphalt added being 100 wt %), the reaction temperature was controlled at 135° C., the rotation speed was 1500 rpm, shearing and stirring were performed for 3 min, 2.5 g of bis(2,2-morpholineethyl) ether (divided into 5 equal parts and added in 5 times) was added, shearing was continued for 5 min, and the mixture was placed in a vacuum drying oven at 140° C. for 5 min to obtain a polyurethane modified asphalt for drainage asphalt pavement.

[0059] Example 2

[0060] Same as Example 1, except that the amount of thermosetting polyurethane prepolymer added is 20 g (ie, in this embodiment, based on the amount of base asphalt added being 100 wt%, the amount of thermosetting polyurethane prepolymer added is 66.7 wt%).

[0061] Example 3

[0062] (1) The polyurethane modified asphalt for drainage asphalt pavement prepared in Example 1 is added to basalt crushed stone and limestone ore powder, and the gradation ratio is 10-15 mm (basalt crushed stone): 5-10 mm (basalt crushed stone): 3-5 mm (basalt crushed stone): 0-3 mm (basalt crushed stone): limestone ore powder = 40: 40: 5: 10: 5;

[0063] (2) Add the mixture of step (1) into a fully automatic asphalt mixture mixer at a mixing temperature of 145° C. for 3 min to obtain a polyurethane drainage asphalt mixture, and use a rotary compactor to form a polyurethane drainage asphalt mixture specimen at a compaction temperature of 135° C. The parameters of the rotary compactor are: pressure 600 kPa, rotation speed 30 rpm / min, rotary compaction angle 1.25°, compaction times 51 times, remove the mold after the temperature drops, and let it stand for 16 hours, and then put it into an 80° C. oven for curing for 10 hours.

[0064] Example 4

[0065] Same as Example 3, except that the polyurethane modified asphalt used for drainage asphalt pavement is prepared as in Example 2.

[0066] Comparative Example 1

[0067] Road Grade A 70# base asphalt (PG64-22).

[0068] Comparative Example 2

[0069] A high-viscosity modified asphalt for drainage asphalt pavement is composed of the following raw materials in parts by weight: 92 parts of SBS modified asphalt and 8 parts of high-viscosity HVA; the preparation method is:

[0070] (1) heating the SBS modified asphalt to 165°C until it is molten;

[0071] (2) Pour the SBS modified asphalt into a heatable container. After the temperature rises to 180°C, add the high viscosity agent into the base asphalt in 5 equal portions in 5 times. Start constant temperature and low-speed stirring at a speed of 500 rpm for 30 min. Then, at the same temperature, further perform high-speed shearing on the asphalt at a speed of 5000 rpm for 2 h. Then, place the asphalt in an oven at 185°C for 1 h to obtain a high-viscosity modified asphalt for drainage asphalt pavement.

[0072] Comparative Example 3

[0073] The high-viscosity modified asphalt of comparative example 2 was added to the fully automatic asphalt mixture mixer, and basalt crushed stone and limestone powder were added in a gradation ratio of 10-15mm (basalt crushed stone): 5-10mm (basalt crushed stone): 3-5mm (basalt crushed stone): 0-3mm (basalt crushed stone): limestone ore powder = 40:40:5:10:5. After adding the basalt crushed stone, the mixture was mixed for 90 seconds, and after adding the limestone ore powder, the mixture was mixed for another 90 seconds, and the mixing temperature was 170°C. The asphalt mixture specimen was formed by a rotary compactor, and the compaction temperature was 160°C. The parameters of the rotary compactor were: pressure 600kPa, rotation speed 30rpm / min, rotary compaction angle 1.25°, and compaction times 51 times.

[0074] Performance Testing

[0075] The modified asphalt prepared in Comparative Example 1 and Examples 1-2 was subjected to a rotational viscosity test using a Brookfield viscometer. The test standard was in accordance with the "Testing Procedures for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E20-2011). Figure 1 As shown. As the temperature rises, asphalt gradually changes from a semi-solid to a fluid, and the viscosity decreases. At the same temperature, the viscosity value is Comparative Example 1> Example 1> Example 2, which shows that the thermosetting polyurethane modified asphalt of the present invention can reduce the viscosity of asphalt, thereby reducing the paving and rolling temperature in the construction project, improving the operability of asphalt pavement construction, achieving the effect of energy saving and emission reduction, and reducing carbon emissions.

[0076] The modified asphalt prepared in Comparative Example 1-2 and Example 1-2 was tested for rheological properties. The test standard was in accordance with the Strategic Highway Research Program (AASHTO, 2010), and a temperature sweep test was performed using a TA Instruments, Model Discovery HR 10 dynamic shear rheometer (DSR). The temperature sweep test parameters were: parallel plate diameter of 25 mm, strain value of 12%, angular frequency of 10 rad / s, and parallel plate top and bottom spacing of 1 mm.

[0077] The asphalt phase angle δ refers to the phase difference between the deformation of asphalt under stress and the stress. It is an important parameter that reflects the nonlinear viscoelastic properties of asphalt materials. The size of δ reflects the viscoelasticity of asphalt, that is, the relationship between the deformation speed and stress of asphalt under stress. The relationship between different asphalt temperatures and phase angle δ is shown in the figure below: Figure 2 As shown. At the same temperature, δ shows an upward trend as the temperature increases. At the same temperature, the size of the modified asphalt δ is Example 1> Example 2> Comparative Example 2. A larger δ indicates that the elasticity of the asphalt is higher than the viscosity, and the damping property is good, which can reduce road vibration and noise and improve driving comfort. This shows that the thermosetting polyurethane modified asphalt of the present invention has elastomeric characteristics and is suitable for road surface layer materials.

[0078] The rutting factor G*·sinδ reflects the ability of asphalt to resist rutting. The higher the rutting factor, the stronger the ability of asphalt to resist rutting. Figure 3 As shown. With the increase of temperature, the rutting factor of asphalt gradually decreases. At the same temperature, the order of rutting factor is Example 2>> Example 1> Comparative Example 2> Comparative Example 1. It shows that the thermosetting polyurethane modified asphalt of the present invention has good anti-rutting ability and can effectively prevent the occurrence of asphalt pavement diseases.

[0079] The modified asphalt prepared in Comparative Example 1-2 and Example 1-2 was subjected to rheological property test, and the asphalt bending creep stiffness test (BBR) was carried out using the American CANNON instrument, model TE-BBR SD to evaluate the low-temperature performance of the modified asphalt. The test temperatures were -12°C, -18°C and -24°C, and the test standards were in accordance with the "Strategic Highway Research Program" (AASHTO, 2010). The creep stiffness modulus reflects the ability of asphalt to resist load; the creep rate m value reflects the different rates of change of asphalt stiffness over time when load is applied. The bending creep stiffness modulus increases with decreasing temperature, and the creep rate decreases with decreasing temperature. The bending creep stiffness modulus and creep rate of different asphalts are shown in Figure 2. Figure 4 , Figure 5 shown.

[0080] According to the Superpave performance grade specification, the low temperature grade of asphalt is determined as follows: Example 2> Example 1> Comparative Example 2> Comparative Example 1, where Example 1 and Example 2 meet the low temperature condition of -24°C. This shows that the thermosetting polyurethane modified asphalt of the present invention has good low temperature performance, can reduce the low temperature cracking of asphalt pavement, and extend the service life of the pavement.

[0081] The modified asphalt prepared in Comparative Example 1-2 and Example 1-2 was characterized for functional groups by Fourier transform infrared spectrometer (FTIR) with a wave number range of 400-4000 cm -1 , resolution 4cm -1 The test standard is in accordance with the "General Rules for Qualitative Analysis of Near Infrared Spectroscopy" (GB / T 37969-2019). The infrared spectra of different asphalts are shown in the figure below. Figure 6 As shown, 2914.8cm -1 and 2846.9cm -1 The characteristic peaks of are due to the antisymmetric and symmetric stretching vibrations of -CH3 and -CH2, respectively. -1 There is a very obvious characteristic peak, which is the vibration absorption peak caused by the hydrogen bond reaction between the isocyanate group (-NCO) of the polyurethane and the asphalt. The peak area of ​​Example 2 is larger than that of Example 1. -1 The weak characteristic peaks that appeared were mainly caused by the vibration of C=O. It is speculated that C=O was mainly generated by the reaction of nitrogen- or oxygen-containing groups such as pyrrole, indole, and phenol in asphaltene with isocyanate. -1 The characteristic peak that appeared was the COC aliphatic ether absorption peak, indicating that a large amount of polyurethane reacted chemically with asphalt and consumed the ether bond. -1The characteristic peaks of are more obvious, further indicating the existence of chemical reaction and the disappearance of ether bond.

[0082] The modified asphalt prepared in Example 1-2 was placed under a fluorescent microscope to observe the distribution of polyurethane in the asphalt and the internal structure of the modified asphalt. The test was conducted using a Mingmei MSHOT fluorescent biological microscope MF43-M, with magnifications of 10 times, 40 times, and 100 times, respectively. The results are shown in Table 1. Figure 7 It can be seen that the modified asphalt prepared by the present invention is evenly distributed, and the polyurethane is connected with silk threads inside the asphalt to form a stable blending structure. This shows that the terminal -NCO in the system of polyurethane added to asphalt in the present invention reacts with the asphalt group to produce a cross-linked structure, which is also one of the important factors that promote its performance improvement.

[0083] The drainage asphalt mixture prepared by the present invention refers to the "Technical Specification for Construction and Design of Drainage Asphalt Pavement" (JTG / T335003 2020). The gradation curve of the drainage asphalt mixture in Example 3 is as follows: Figure 8 shown.

[0084] The performance test results of the polyurethane drainage asphalt mixture (mixture gradation is PAC-13) prepared in Comparative Example 3 and Examples 3-4 are shown in Table 1. The test standard is in accordance with the "Test Procedure for Asphalt and Asphalt Mixture for Highway Engineering" (JTG E20-2011).

[0085] Table 1

[0086]

[0087] The high and low temperature road performance of the polyurethane drainage asphalt mixture, Example 3 and Example 4 are both higher than that of Comparative Example 3. In the 60°C rutting test, the dynamic stability of Example 3 and Example 4 reached 19872 and 27876 times / mm respectively, which increased by more than 2 times compared with Comparative Example 3. This shows that the polyurethane drainage asphalt mixture of the present invention has good high and low temperature performance, can reduce the rutting disease of the asphalt pavement, cracks caused by low temperature cracking, and extend the service life of the pavement. In addition, the polyurethane drainage asphalt mixture of the present invention has an elastic noise reduction function, can reduce the noise generated by the pavement and tires, and improve driving comfort.

[0088] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A polyurethane modified asphalt for drainage asphalt pavement, characterized in that: The raw materials include base asphalt, thermosetting polyurethane prepolymer, catalyst and compatibilizer; Based on the addition amount of the base asphalt being 100wt%, the addition amount of the thermosetting polyurethane prepolymer is 33.3-66.7wt%, the addition amount of the catalyst is 0.5-1wt%, and the addition amount of the compatibilizer is 0.5-1wt%.

2. The polyurethane modified asphalt for drainage asphalt pavement according to claim 1, characterized in that: The thermosetting polyurethane prepolymer is a single component, has a terminal-NCO bond content of not less than 13%, a viscosity of not less than 1077 mPa·s at 25° C., a surface drying time of not less than 98 minutes at 30° C., a tensile strength of not less than 31.4 MPa, and an elongation at break of not less than 151.1%.

3. The polyurethane modified asphalt for drainage asphalt pavement according to claim 1, characterized in that: The catalyst is bis(2,2-morpholineethyl)ether, 4,4-bis-sec-butylaminodiphenylmethane or 1,4-butanediol.

4. The polyurethane modified asphalt for drainage asphalt pavement according to claim 1, characterized in that: The compatibilizer is maleic anhydride or maleic anhydride grafted polyethylene.

5. A method for preparing the polyurethane modified asphalt for drainage asphalt pavement according to any one of claims 1 to 4, characterized in that: The following steps are involved: Thermosetting polyurethane prepolymer and compatibilizer are added into molten matrix asphalt, sheared and stirred at 130-140° C., a catalyst is added, and stirred to obtain the polyurethane modified asphalt for drainage asphalt pavement.

6. The method for preparing polyurethane modified asphalt for drainage asphalt pavement according to claim 5, characterized in that: The shear stirring rate is 1500-2000 rpm, and the shear stirring time is 5-10 min.

7. A polyurethane drainage asphalt mixture for drainage asphalt pavement, characterized in that: A polyurethane modified asphalt for drainage asphalt pavement containing any one of claims 1 to 4.

8. A method for preparing a polyurethane drainage asphalt mixture for drainage asphalt pavement according to claim 7, characterized in that: The following steps are involved: The polyurethane modified asphalt for drainage asphalt pavement, mineral stone and filler are mixed and heated to obtain the polyurethane drainage asphalt mixture for drainage asphalt pavement; The temperature of the heating and mixing is 140-150°C.

9. The method for preparing a polyurethane drainage asphalt mixture for drainage asphalt pavement according to claim 8, characterized in that: The mineral stone is basalt or limestone; the filler is limestone powder.

10. Use of the polyurethane modified asphalt for drainage asphalt pavement according to any one of claims 1 to 4 in drainage asphalt pavement.

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