Preparation method and application of thermosetting polyurethane modified drainage asphalt mixture

Abstract

The present invention discloses a preparation method and application of a thermosetting polyurethane modified drainage asphalt mixture. The mixture comprises 4 to 8 parts by mass of thermosetting polyurethane modified asphalt and 92 to 96 parts by mass of mineral material; the thermosetting polyurethane modified asphalt is obtained by reacting 40 to 60 parts by mass of base asphalt, 40 to 60 parts by mass of polyurethane prepolymer and 10 to 20 parts by mass of chain extender; the polyurethane prepolymer is a polyether prepolymer, and its active group NCO content is 11 to 13%. The preparation process of the mixture is: after heating and stirring the base asphalt, the polyurethane prepolymer is added to carry out a grafting reaction, and then the chain extender is added and stirred to react to obtain a thermosetting polyurethane modified drainage asphalt, and then the mineral material and the remaining raw materials are added in sequence and mixed evenly to obtain. Based on the excellent performance of the mixture, it is used to prepare a double-layer drainage pavement, which effectively solves the influence of blockage on the functionality of the voids in the prior art, and while exerting the anti-blocking performance, it can maximize its drainage performance.

Description

Technical Field

[0001] The invention relates to a drainage asphalt mixture, in particular to a preparation method and application of a thermosetting polyurethane modified drainage asphalt mixture, belonging to road paving technology. Background Art

[0002] Drainage asphalt pavement has the functions of preventing water drift, suppressing water mist, anti-skid and reducing noise, and is increasingly used in highways and urban roads. Drainage asphalt pavement is paved with porous asphalt mixture, with a void ratio of 18% to 25%. The strength mainly comes from the interlocking effect of stones and the adhesion of asphalt binder to aggregates, which makes the contact time and contact surface of asphalt mixture with air, sunlight and water longer and larger, which is easy to cause aging of asphalt binder, resulting in peeling, scattering and rutting of the road surface.

[0003] Drainage asphalt mixture belongs to the open-graded skeleton structure with a large void ratio. Its road performance is greatly affected by the asphalt performance and gradation. The drainage asphalt mixture in the prior art mainly uses thermoplastic modified asphalt such as high-viscosity and high-elasticity modified asphalt and SBS modified asphalt. Although these materials can improve the performance of drainage asphalt mixture to a certain extent, as thermoplastic materials, they still cannot fundamentally solve the problem of temperature stability of asphalt materials. Secondly, special sections such as road intersections, long longitudinal slopes and bus stops still have problems such as poor durability, limited fatigue resistance and aging resistance. The prior art mostly uses the open-graded anti-skid surface layer (OGFC) mixture design method. The design result has high anti-skid ability and certain noise reduction performance, but there are still problems such as water permeability, noise reduction function attenuation and durability during use. Therefore, it is necessary to develop a new type of drainage asphalt pavement paving binder with high strength, good water stability and excellent high temperature stability, and propose a new mix design method for porous asphalt mixture so that the mixture can form a stable mineral skeleton structure and ideal porosity, effectively ensuring the performance of large-pore asphalt mixture and structural drainage needs. Summary of the invention

[0004] In view of the problems existing in the prior art, the first purpose of the present invention is to provide a method for preparing a thermosetting polyurethane modified drainage asphalt mixture, which adopts a batch feeding method and strictly controls the reaction conditions of each batch of materials to regulate the overall mechanical properties of the mixture, thereby ensuring that the resulting product ultimately exists in a three-dimensional cross-linked network structure, in which the polyurethane forms a continuous phase and the matrix asphalt forms a dispersed phase, thereby essentially solving the problem of temperature stability of asphalt materials and achieving improvements in the fatigue resistance and aging resistance of the modified asphalt.

[0005] The second object of the present invention is to provide an application of a thermosetting polyurethane modified drainage asphalt mixture for preparing drainage pavement. Based on the excellent mechanical properties of the modified asphalt mixture, the drainage pavement structure is redesigned, and a double-layer structure is adopted to effectively solve the influence of blockage on the functionality of the voids in the prior art. The upper layer prevents external debris from entering the lower structure, while the lower layer mainly discharges surface water or rainwater from the pavement quickly, thereby ensuring the connectivity between the upper and lower voids and increasing the proportion of effective voids inside the pavement, which can maximize its drainage performance while exerting anti-blocking performance.

[0006] In order to achieve the above technical purpose, the present invention provides an application of a thermosetting polyurethane modified drainage asphalt mixture for preparing a drainage pavement; the structure of the drainage pavement is: a 3-5 cm upper layer of a thermosetting polyurethane modified asphalt drainage mixture, a 4-8 cm lower layer of a thermosetting polyurethane modified asphalt drainage mixture, a 2 mm waterproof adhesive layer, a 6-8 mm asphalt concrete, a 20-40 cm cement stabilized gravel base and a 15-25 cm cement stabilized gravel subbase;

[0007] The drainage asphalt mixture comprises the following raw materials in parts by weight: 4 to 8 parts by weight of thermosetting polyurethane modified asphalt and 92 to 96 parts by weight of mineral material;

[0008] The thermosetting polyurethane modified asphalt is obtained by reacting 40-60 parts by mass of base asphalt, 40-60 parts by mass of polyurethane prepolymer and 10-20 parts by mass of chain extender; the polyurethane prepolymer is a polyether prepolymer, and its active group NCO content is 11-13%.

[0009] In the technical solution provided by the present invention, the isocyanate group in the polyurethane prepolymer is firstly reacted with the hydroxyl group and the carboxyl group in the asphalt to produce the carbamate group, which is then further cross-linked to form the polyurea bonding structure, so that the system has better temperature stability and strength. At the same time, the thermoplastic asphalt in the system can improve the toughness and fatigue resistance of the thermosetting polyurethane, and can meet the use requirements of large-pore drainage pavement.

[0010] As a preferred solution, the raw materials of the asphalt mixture also include 0-1 mass parts of a coagulant.

[0011] As a preferred solution, the mineral material is at least one of basalt and limestone aggregates.

[0012] As a preferred solution, the chain extender is at least one of an aliphatic diol and an aromatic diol.

[0013] As a preferred solution, the coagulant is a tertiary amine catalyst.

[0014] As a preferred solution, the asphalt mixture has an elongation at break of 250-400% at 25°C, a tensile strength of 0.85-3.5 MPa, and a Brookfield viscosity of 1000-2750 mPa.s.

[0015] As a preferred solution, the gradation design of the mineral material adopts the aggregate embedding optimization theory to optimize the design of the upper layer and the lower layer of the drainage pavement respectively.

[0016] As a preferred solution, the maximum particle size of the upper layer of the drainage pavement is 9.5 mm, and the maximum particle size of the lower layer is 26.5 mm.

[0017] As a preferred solution, the optimization design process of the upper layer of the drainage pavement is as follows:

[0018] S1-1. The coarse aggregate proportion p is controlled to be 0, 40% and 100% in sequence, and a rotary compaction experiment is carried out to calculate the aggregate porosity e. Then, the coarse aggregate proportion and the porosity at the two points of p=0% and p=40% are combined to determine equation 1, which is: ;

[0019] S1-2. Combine the void ratio e measured when p=100% with equation 2 to calculate the coarse aggregate ratio P corresponding to when equation 2 is 0. x , the equation 2 is: ;

[0020] S1-3, calculate P from S1-2 x Substituting into equation 1, we get , and then Substituting into equation 2, we can calculate P t , take the proportion of coarse aggregate as P t ±3% two points, through two rounds of compaction, sensitivity analysis is carried out. If the requirements are met, the coarse aggregate ratio is determined to be P t If the requirements are not met, adjust the aggregate and re-optimize the design.

[0021] As a preferred solution, the optimization design process of the lower layer of the drainage pavement is as follows:

[0022] S2-1, using 0~3mm aggregate, 5~10mm aggregate and 20~30mm aggregate as the aggregate design raw materials, optimize the mineral materials of coarse aggregate 5~10mm and fine aggregate 0~3mm according to steps S1-1~S1-3, and determine the ratio of coarse and fine aggregates;

[0023] S2-2. Mix aggregates of 5-10 mm and fine aggregates of 0-3 mm as fine aggregates in binary aggregates, and optimize them with aggregates of 20-30 mm according to steps S1-1 to S1-3 to determine the proportion of aggregates at each level.

[0024] As a preferred solution, the process for determining the optimal asphalt dosage of the drainage pavement is as follows: forming a Marshall specimen by double-sided compaction 50 times, curing at room temperature for 4 to 6 days, and using the porosity, Marshall stability, scattering loss rate and Kentburg scattering loss as key technical indicators to determine the optimal polyurethane dosage of the polyurethane modified asphalt of the macroporous polyurethane modified asphalt mixture;

[0025] Among them, the polyurethane modified asphalt mixture on the drainage pavement should meet the following requirements: void ratio between 16% and 20%, Marshall stability ≥ 10.0KN, flying loss rate < 0.25%, Kentburg flying loss < 18%;

[0026] Among them, the polyurethane modified asphalt mixture of the lower layer of the drainage pavement should meet the following requirements: void ratio between 20% and 28%, Marshall stability ≥ 10.0KN, scattering loss rate < 0.3%, and Fort Kent scattering loss < 20%.

[0027] As a preferred solution, the preparation process of the drainage pavement is as follows: after the base layer and the waterproof layer are laid, the lower pavement is paved according to the optimization design result of the lower layer, and 1-3 L / m 2 The curing agent is then immediately paved according to the upper layer optimization design results, and 1~2L / m 2 The health-preserving agent is available.

[0028] As a preferred solution, the health-preserving agent is a mixed aqueous solution of triethylene diamine, propylene glycol and diethylene glycol.

[0029] As a preferred solution, the preparation process of the drainage pavement is carried out in accordance with the "Technical Specifications for Design and Construction of Drained Asphalt Pavement" (JTG / T 3350-03-2020) and the "Technical Specifications for Construction of Highway Asphalt Pavement" (JTG F40-2004).

[0030] The present invention also provides a method for preparing a thermosetting polyurethane modified drainage asphalt mixture, the process of which is: after heating and stirring the base asphalt, a polyurethane prepolymer is added to carry out a grafting reaction, and then a chain extender is added and stirred to react to obtain a thermosetting polyurethane modified drainage asphalt, and then mineral material and the remaining raw materials are added in sequence and mixed evenly to obtain the mixture.

[0031] As a preferred solution, the conditions for heating and stirring the base asphalt are: shear stirring at 140-150°C for 15-30 minutes.

[0032] As a preferred solution, the grafting reaction conditions are: shear stirring at 140-150° C. for 15-30 min.

[0033] As a preferred solution, the stirring reaction conditions of the chain extender are: shear stirring at 140-150° C. for 5-10 minutes.

[0034] The present invention also provides a specific preparation process of the drainage pavement:

[0035] 1) Construction shall be carried out in accordance with the relevant provisions of the "Technical Specifications for Design and Construction of Drained Asphalt Pavement" (JTG / T 3350-03-2020) and the "Technical Specifications for Construction of Highway Asphalt Pavement" (JTG F40-2004).

[0036] 2) The heating temperature of the base asphalt is 140~150℃, the heating temperature of the polyurethane prepolymer is 60~70℃, and the chain extender is at room temperature. Stir and blend the above materials in the specified proportion for 3~5 minutes.

[0037] 3) Use an intermittent asphalt mixture mixer to produce and construct the polyurethane modified asphalt mixture for the lower layer of the drainage pavement in accordance with the provisions of the "Technical Specifications for Highway Asphalt Pavement Construction" (JTG F40-2004). The mixing temperature of the polyurethane modified asphalt mixture is 140~150℃. Use dump trucks to transport the polyurethane modified asphalt mixture, and use a paver to spread the polyurethane modified asphalt mixture.

[0038] 4) After the lower layer construction is completed, wait for the temperature of the lower layer to drop to room temperature and sprinkle 1~3L / m 2 After the curing agent is applied. The curing agent is a mixed aqueous solution of triethylene diamine, propylene glycol and diethylene glycol. After the curing agent is spread, the highly active tertiary amine catalyst will promote the reaction between isocyanate and polyol, and at the same time promote the curing reaction of the upper and lower layers of polyurethane modified asphalt mixture, so that the two layers are better connected into a whole, solving the problems of poor stability between layers of conventional double-layer drainage pavement and the reduction of the interconnection void ratio between the two layers by ordinary adhesive layer materials.

[0039] 5) Immediately after spreading the curing agent, the construction of the upper drainage mixture should be carried out. The construction method of the upper drainage mixture is the same as that of the lower layer. After the construction is completed, spray 1~2L / m 2 Health care agent.

[0040] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are:

[0041] 1) In the preparation method embodied in the present invention, a batch feeding method is adopted, and the reaction conditions of each batch of materials are strictly controlled to regulate the overall mechanical properties of the mixture, ensuring that the resulting product ultimately exists in a three-dimensional cross-linked network structure, in which the polyurethane forms a continuous phase and the matrix asphalt forms a dispersed phase, which essentially solves the problem of temperature stability of asphalt materials and achieves the improvement of the fatigue resistance and aging resistance of the modified asphalt.

[0042] 2) In the technical solution provided by the present invention, the modified drainage asphalt mixture is based on the synergistic effect between the various components, and a polyurea bonding structure is generated through reactions such as bonding and curing, which not only gives the system excellent temperature stability and strength, but also effectively improves the toughness and fatigue resistance of the system, thereby meeting the performance requirements of large-pore drainage pavement.

[0043] 3) In the technical solution provided by the present invention, based on the excellent mechanical properties of the modified asphalt mixture, the drainage pavement structure is redesigned, and a double-layer structure is adopted to effectively solve the influence of blockage on the functionality of the voids in the prior art. The upper layer prevents external debris from entering the lower structure, while the lower layer mainly serves to quickly discharge surface water or rainwater from the pavement, thereby ensuring the connectivity between the upper and lower layer voids and increasing the proportion of effective voids inside the pavement, while exerting anti-blocking performance and maximizing its drainage performance.

[0044] 4) In the technical solution provided by the present invention, the aggregate embedding optimization design theory is adopted to design the mineral composition of the large-pore drainage mixture, and the aggregate forms an embedding structure, thereby greatly modifying the modulus and fatigue resistance of the asphalt mixture. Furthermore, according to the curing reaction mechanism of the thermosetting polyurethane modified asphalt mixture, the present invention adopts the quick-setting agent spreading construction, which can accelerate the strength formation of the polyurethane modified asphalt mixture, reduce the pavement curing time, and at the same time, can also tightly connect the upper and lower drainage layers into a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a flow chart of aggregate extrusion in Example 1 of the present invention;

[0046] Figure 1 In the equation, F is the void ratio of fine aggregate; D is the boundary effect coefficient; C is the void ratio of coarse aggregate; and E is a constant.

[0047] Figure 2 This is a diagram of the specific process of aggregate extrusion in Example 1 of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with specific embodiments, but this is not intended to limit the present invention.

[0049] Example 1

[0050] The following is an example of a polyurethane modified asphalt drainage pavement project.

[0051] The pavement structure layers are: 4cm thermosetting polyurethane modified asphalt drainage mixture upper layer + 6cm thermosetting polyurethane modified asphalt drainage mixture lower layer + 2mm waterproof adhesive layer + 6cm asphalt concrete + 25cm cement stabilized gravel base + 20cm cement stabilized gravel subbase.

[0052] The subbase and base layers shall be constructed in accordance with the Technical Specifications for Highway Pavement Base Construction (JTG / T F20-2015), and the asphalt concrete layer and waterproof bonding layer shall be constructed in accordance with the Technical Specifications for Highway Asphalt Pavement Construction (JTG F40-2004).

[0053] Thermosetting polyurethane modified asphalt mixture drainage pavement surface layer is constructed according to the following steps:

[0054] (1) Material preparation

[0055] Fine aggregate is 0~3mm basalt and limestone, with an average particle size of about 0.7mm; coarse aggregate is 5~10mm basalt and limestone, with an average particle size of 6.5mm; coarse aggregate is 5~10mm basalt and limestone, with an average particle size of 6.5mm; coarse aggregate is 20~30mm limestone, with an average particle size of 14mm. The above aggregates meet the standards of "Technical Specifications for Highway Asphalt Pavement Construction" (JTGF40-2004) and are produced by Zaozhuang Xinjinshan Intelligent Equipment Co., Ltd.

[0056] 70# matrix asphalt, Shandong Huarui Road Materials Technology Co., Ltd., in compliance with the "Technical Specifications for Highway Asphalt Pavement Construction" (JTGF40-2004) standard; polyether polyurethane prepolymer, active group NCO content is 11~13%, Wanhua Chemical Group, industrial grade; 1,14-tetradecanediol, Xiamen Juyou Chemicals Co., Ltd., industrial grade; triethylenediamine, Shandong Haoshun Chemical Co., Ltd., industrial grade; γ-aminopropyltriethoxysilane, Shandong Haoshun Chemical Co., Ltd., industrial grade.

[0057] Thermosetting polyurethane modified asphalt is prepared by mixing the following raw materials at 140° C.: 70# base asphalt, polyether polyurethane prepolymer, and 1,14-tetradecanediol in a mass ratio of 52:44:4.

[0058] (2) Composition design of thermosetting polyurethane modified asphalt mixture

[0059] The technical indicators and screening results of the two grades of thermosetting polyurethane modified asphalt mixture (PUA-10) for the upper layer of the drainage pavement of this embodiment are shown in Tables 1 and 2.

[0060]

[0061]

[0062] In the aggregate embedding theory, the average particle size is the particle size corresponding to the cumulative passing percentage of 50%, recorded as d50. If the passing percentage of each sieve hole is not 50%, the sieve hole size corresponding to the passing percentage of 50% is calculated by linear interpolation. The average particle size d of the two aggregates in Table 3-10 细集料 / d 粗集料 =0.12<0.2, which meets the average particle size control condition in the aggregate embedding theory. The mineral grading design of the skeleton embedding structure is directly carried out for these two grades of aggregate.

[0063] In order to ensure the accuracy of boundary action equation 1, p=0, 10%, and 20% were taken respectively, and three rotary compaction tests were carried out to test the void ratio of coarse and fine aggregates after rotary compaction. The results are shown in Table 3, and the aggregate embedding optimization process is shown in Figure 1 .

[0064]

[0065] Equation 1 passes through three points (0, 0.3758), (0.1, 0.3279) and (0.2, 0.3165), so the regression equation 1 is "e1=-0.2966p1+0.3698"; Equation 2 is in the form of "e=(c+1)p-1" and passes through (1.0, 0.644), so "c=0.644" can be calculated, and Equation 2 is equal to "e2=1.644p2-1"; let "e2=0", we can get "px=0.608"; let "P1=0.608", we can get "e1=0.1898", so the coordinates of point A are (0.608,0.1898). Equation 3 passes through point A and the origin, so we can get Equation 3 as "e3 =0.3122P3". Let "e2=e3", we can get "pt=0.75". Then, through two rounds of rotation compaction at "p=0.72" and "p=0.78", the void ratios obtained were higher than 0.2342, and "pt=0.75" passed the sensitivity verification, so the ratio of coarse and fine aggregates was controlled at 75:25.

[0066] According to the technical requirements of the polyurethane modified asphalt mixture that the void ratio is between 16% and 20%, the Marshall stability is ≥10.0KN, the flying loss rate is less than 0.25%, and the Kent Fort flying loss is less than 18%, the asphalt dosage of the PUA-10 mixture is determined to be 5.6%.

[0067] The mineral gradation design method of the thermosetting polyurethane modified asphalt mixture (PUA-25) for the lower layer of the drainage pavement in this embodiment is the same as that of the above-mentioned PUA-10. First, the interlocking optimization of 0~3mm limestone fine aggregate and 5~10mm limestone coarse aggregate is carried out, and then the interlocking optimization of 0~3mm and 5~10mm blended aggregate and 20~30mm limestone coarse aggregate is carried out. The mineral gradation design result is 0~3mm:5~10mm:20~30mm=5:30:65. According to the void ratio of the polyurethane modified asphalt mixture between 20% and 28%, the Marshall stability ≥10.0KN, the scattering loss rate <0.3%, and the Kentburg scattering loss <20%, the asphalt dosage of the PUA-25 mixture is determined to be 5.4%.

[0068] (3) Construction of thermosetting polyurethane modified asphalt drainage pavement

[0069] An intermittent asphalt mixing station is used for mixture production. The heating temperature of the aggregate is 150°C, the dry mixing time of the aggregate is 15s, the temperature of the polyurethane modified asphalt is 145°C, the wet mixing time of the polyurethane modified asphalt mixture is 60s, and the discharge temperature of the mixture is about 150°C.

[0070] Dump trucks are used to transport the mixture, and the transportation and waiting time of the mixture is less than 2 hours. A paver is used to spread the polyurethane modified asphalt mixture at a paving speed of 2m / min. A 12t medium-sized roller is used to statically compact the recycled mixture of the paving layer once, and vibrate and roll it once at a rolling speed of 1.5km / h to complete the initial compaction. Then a 16t heavy-duty roller is used to vibrate and statically compact it twice at a rolling speed of 2.5km / h to complete the recompacting. After curing for 4 hours, the rubber wheel is used to statically compact the surface once at a rolling speed of 1.5km / h. After the construction of the lower layer of the drainage pavement is completed and cooled to room temperature, 2L / m 2 The curing agent is a triethylene diamine aqueous solution. Immediately after spreading the curing agent, the upper drainage mixture is constructed. The construction method of the upper drainage mixture is the same as that of the lower layer. After the construction is completed, spray 1.5L / m 2 Health care agent.

[0071] After the construction of the thermosetting polyurethane modified asphalt drainage pavement was completed, it was cured for 3 days. At this time, the performance index test of the drainage pavement was carried out. The test results are shown in Table 4.

[0072]

[0073] The test results show that the thermosetting polyurethane modified asphalt drainage pavement structure of the present invention has a high bearing capacity, a small rebound deformation value under load, a high flatness, and a large water permeability coefficient, which fully meets the requirements for drainage pavement surface paving.

[0074] Example 2

[0075] The following is an example of a polyurethane modified asphalt drainage pavement project.

[0076] The pavement structure layer is: 6cm thermosetting polyurethane modified asphalt drainage mixture layer + 2mm waterproof adhesive layer + 6cm asphalt concrete + 25cm cement stabilized gravel base + 20cm cement stabilized gravel subbase.

[0077] The preparation of polyurethane modified asphalt, the production process of polyurethane modified asphalt mixture and the construction of other structural layers are the same as those in Example 1.

[0078] In this embodiment, the 6 cm thermosetting polyurethane modified asphalt drainage mixture layer (PUA-16) is used. The PUA-16 mineral grading design method is the same as the above-mentioned PUA-10. First, the interlocking optimization of 0~3 mm basalt fine aggregate and 5~10 mm basalt coarse aggregate is carried out, and then the interlocking optimization of 0~3 mm and 5~10 mm blended aggregate and 10~16 mm basalt coarse aggregate is carried out. The mineral grading design result is 0~3 mm: 5~10 mm: 10~16 mm = 8:30:62. According to the void ratio of the polyurethane modified asphalt mixture between 20% and 28%, the Marshall stability ≥10.0 KN, the scattering loss rate <0.3%, and the Kentburg scattering loss <20%, the asphalt dosage of the PUA-16 mixture is determined to be 5.6%.

[0079] After the construction of the thermosetting polyurethane modified asphalt drainage pavement was completed, it was cured for 3 days. At this time, the performance index test of the drainage pavement was carried out. The test results are shown in Table 5.

[0080]

[0081] The test results show that the thermosetting polyurethane modified asphalt drainage pavement structure of the present invention has a high bearing capacity, a small rebound deformation value under load, a high flatness, and a large water permeability coefficient, which fully meets the requirements for drainage pavement surface paving.

[0082] Example 3

[0083] The following is an example of a polyurethane modified asphalt drainage pavement project.

[0084] The pavement structure layers are: 6cm thermosetting polyurethane modified asphalt drainage mixture upper layer + 6cm thermosetting polyurethane modified asphalt drainage mixture lower layer + 2mm waterproof adhesive layer + 2cm asphalt concrete stress absorption layer + 25cm cement stabilized gravel base layer + 20cm cement stabilized gravel subbase layer.

[0085] The upper layer is PUA-16, the lower layer is PUA-25, and the material composition design and structural layer construction are the same as in Example 1 and Example 2.

[0086] The asphalt concrete stress absorption layer shall be constructed in accordance with the Technical Specifications for Highway Asphalt Pavement Construction (JTG F40-2004).

[0087] After the construction of the thermosetting polyurethane modified asphalt drainage pavement was completed, it was cured for 3 days. At this time, the performance index test of the drainage pavement was carried out. The test results are shown in Table 6.

[0088]

[0089] Furthermore, in order to better illustrate the performance advantages of the polyurethane modified asphalt mixture used in the drainage pavement in the above embodiments, the present invention further tests the performance of the modified asphalt mixture used in Examples 1 to 3 and the OGFC drainage mixture commonly used in drainage pavements in the prior art, and the results are shown in Table 7.

[0090]

[0091] It can be seen from Table 7 that, compared with conventional OGFC, the polyurethane modified asphalt drainage mixture used in the present invention greatly improves its high temperature stability and low temperature crack resistance while ensuring that the water permeability coefficient and freeze-thaw splitting strength ratio are similar, providing a raw material basis for the redesign of the drainage pavement structure, and effectively solving the influence of blockage on the functionality of the voids in the prior art, thereby ensuring the connectivity between the upper and lower layer voids, and increasing the proportion of effective voids inside the pavement, while exerting its anti-blocking performance and maximizing its drainage performance.

Claims

1. An application of a thermosetting polyurethane modified drainage asphalt mixture, characterized in that: Used for preparing drainage pavement; the structure of the drainage pavement is: 3~5cm thermosetting polyurethane modified asphalt drainage mixture upper layer, 4~8cm thermosetting polyurethane modified asphalt drainage mixture lower layer, 2mm waterproof adhesive layer, 6~8cm asphalt concrete, 20~40cm cement stabilized gravel base and 15~25cm cement stabilized gravel subbase; The drainage asphalt mixture comprises the following raw materials in parts by weight: 4 to 8 parts by weight of thermosetting polyurethane modified asphalt and 92 to 96 parts by weight of mineral material; The thermosetting polyurethane modified asphalt is obtained by reacting 40-60 parts by mass of base asphalt, 40-60 parts by mass of polyurethane prepolymer and 10-20 parts by mass of chain extender; the polyurethane prepolymer is a polyether prepolymer, and its active group NCO content is 11-13%; The mineral material is at least one of basalt and limestone aggregate; the chain extender is at least one of aliphatic diol and aromatic diol; The drainage pavement also contains a curing agent, which is a mixed aqueous solution of triethylenediamine, propylene glycol and diethylene glycol, which simultaneously promotes the curing reaction of the upper and lower layers of polyurethane modified asphalt mixture to connect the two layers into a whole.

2. The use of a thermosetting polyurethane modified drainage asphalt mixture according to claim 1, characterized in that: The raw materials of the asphalt mixture also include 0-1 mass parts of a coagulant.

3. The use of a thermosetting polyurethane modified drainage asphalt mixture according to claim 2, characterized in that: The coagulant is a tertiary amine catalyst; the asphalt mixture has an elongation at break of 250-400% at 25°C, a tensile strength of 0.85-3.5 MPa, and a Brookfield viscosity of 1000-2750 mPa.s.

4. The use of a thermosetting polyurethane modified drainage asphalt mixture according to claim 1, characterized in that: The gradation design of the mineral material adopts the aggregate embedding optimization theory, and optimizes the upper and lower layers of the drainage pavement respectively; the maximum particle size of the upper layer of the drainage pavement is 9.5 mm, and the maximum particle size of the lower layer is 26.5 mm.

5. The use of a thermosetting polyurethane modified drainage asphalt mixture according to claim 4, characterized in that: The optimization design process of the upper layer of the drainage pavement is as follows: S1-1. The coarse aggregate proportion p is controlled to be 0, 10%, 20% and 100% in sequence, and a rotary compaction experiment is carried out to calculate the aggregate porosity e. Then, the coarse aggregate proportion and the porosity at p=10% and p=20% are combined to determine equation 1, which is: ； S1-2, the porosity ratio e measured when p=100% is combined with equation 2 to obtain equation 2: =0 corresponds to the coarse aggregate proportion P x , the equation 2 is: ; S1-3, calculate P from S1-2 x Substituting into equation 1, we get , and then Substituting into equation 2, we can calculate P t , take the proportion of coarse aggregate as P t ±3% two points, through two rounds of compaction, sensitivity analysis is carried out. If the requirements are met, the coarse aggregate ratio is determined to be P t If the requirements are not met, adjust the aggregate and re-optimize the design; In the equations 1 and 2, F is the void ratio of fine aggregate, D is the boundary effect coefficient, and c is the void ratio of coarse aggregate; The optimization design process of the lower layer of the drainage pavement is as follows: S2-1, using 0~3mm aggregate, 5~10mm aggregate and 20~30mm aggregate as the aggregate design raw materials, optimize the mineral materials of coarse aggregate 5~10mm and fine aggregate 0~3mm according to steps S1-1~S1-3, and determine the ratio of coarse and fine aggregates; S2-2. Mix aggregates of 5-10 mm and fine aggregates of 0-3 mm as fine aggregates in binary aggregates, and optimize them with aggregates of 20-30 mm according to steps S1-1 to S1-3 to determine the proportion of aggregates at each level.

6. The use of a thermosetting polyurethane modified drainage asphalt mixture according to claim 5, characterized in that: The preparation process of the drainage pavement is as follows: after the base layer and the waterproof layer are paved, the lower pavement is paved according to the optimization design result of the lower layer, and 1-3 L / m 2 The curing agent is then immediately paved according to the upper optimization design results, and 1~2L / m 2 Health-preserving agent, that is; The preparation process of the drainage pavement is carried out in accordance with the "Technical Specifications for Design and Construction of Drained Asphalt Pavement" JTG / T 3350-03-2020 and the "Technical Specifications for Construction of Highway Asphalt Pavement" JTG F40-2004.

7. The method for preparing a thermosetting polyurethane modified drainage asphalt mixture according to any one of claims 1 to 6, characterized in that: After heating and stirring the base asphalt, a polyurethane prepolymer is added to carry out a grafting reaction, and then a chain extender is added and stirred to react to obtain a thermosetting polyurethane modified drainage asphalt. Then, mineral materials and remaining raw materials are added in sequence and mixed evenly to obtain the product.

8. The method for preparing a thermosetting polyurethane modified drainage asphalt mixture according to claim 7, characterized in that: The heating and stirring conditions of the matrix asphalt are: shear stirring at 140-150°C for 15-30 minutes; the grafting reaction conditions are: shear stirring at 140-150°C for 15-30 minutes.

9. The method for preparing a thermosetting polyurethane modified drainage asphalt mixture according to claim 7, characterized in that: The stirring reaction conditions of the chain extender are: shear stirring at 140-150° C. for 5-10 minutes.

Images