Non-stick wheel adhesive layer and preparation method thereof

Abstract

The present invention relates to new materials for road engineering, specifically a non-stick wheel adhesive layer and a preparation method thereof. The preparation method of the non-stick wheel adhesive layer provided by the present invention comprises compounding asphalt, an anti-rutting agent masterbatch, and a foaming aid to obtain a non-stick wheel mixed asphalt material, and spraying the non-stick wheel mixed asphalt material onto an asphalt pavement through mechanical foaming to obtain a non-stick wheel adhesive layer. The present invention mixes asphalt, an anti-rutting agent masterbatch, and a foaming aid, and sprays the mixture directly onto an asphalt pavement through dedicated mechanical foaming equipment. This can reduce construction steps, lower project costs, and obtain a non-stick wheel adhesive layer material with excellent high-temperature performance, achieving a non-stick wheel effect. At the same time, it improves the interlayer adhesion and shear resistance of the asphalt pavement, thereby extending the service life of the asphalt pavement.

Description

Technical Field

[0001] The invention belongs to new materials for road engineering, and particularly relates to a non-stick wheel adhesive layer and a preparation method thereof. Background Art

[0002] Since the 1990s, more and more studies have found that the quality of interlayer adhesion has a significant impact on the service life of asphalt pavements. In the construction and maintenance of asphalt pavements, more and more attention has been paid to the quality of interlayer adhesion. The structural adhesive layer of asphalt pavement is located between the various structural layers of the pavement, making the different structural layers form a whole, transmitting the stress and strain of the upper layer to the lower layer, thereby preventing the displacement and separation between layers. Asphalt pavement mainly relies on interlayer adhesion to resist horizontal shear stress. Excellent interlayer adhesion can effectively resist the impact of harsh environmental conditions on asphalt pavement, improve the durability of asphalt pavement, and extend the service life of asphalt pavement. However, when the interlayer adhesion of asphalt pavement is poor, the road surface is prone to interlayer slippage and early fatigue damage after repeated vehicle loads in high temperature environments, resulting in early diseases such as cracking, rutting, and hugging of the road surface, which reduces the service life of the asphalt pavement. Asphalt pavement tack coats include (modified) hot asphalt, (modified) emulsified asphalt, diluted asphalt, etc. according to the type of materials. Among them, emulsified asphalt tack coat is the most widely used in asphalt pavement construction and maintenance because it can be spread at room temperature, is low-carbon and environmentally friendly, and has little environmental interference, which is in line with the development concept of "green transportation".

[0003] Asphalt pavement construction typically peaks in the summer, when pavement temperatures often reach 60°C and, in extreme weather, even over 70°C. Conventional emulsified asphalt tack coats have poor high-temperature performance, leading construction vehicles to strip and remove large areas of the finished tack coat, severely damaging it and preventing it from achieving proper interlayer adhesion and water-blocking properties. This can also cause pollution to the construction site and surrounding roads. Furthermore, high summer temperatures, especially in southern China where high temperatures persist for extended periods, can soften the interlayer asphalt tack coats on existing asphalt pavements. This leads to insufficient interlayer adhesion and shear resistance, resulting in interlayer slippage and premature fatigue damage. To address these common technical issues in the asphalt pavement industry, research has developed non-stick wheel emulsified asphalt tack coats over the past decade, which have been widely adopted in actual asphalt pavement construction. To improve the high-temperature performance of non-stick wheel tack coats, hard asphalt emulsification technology is often used. The use of hard asphalt in emulsified asphalt reduces the needle penetration of the emulsified asphalt residue, increases its softening point, and thus improves its ability to withstand high temperatures. Extensive test results demonstrate that hard asphalt effectively improves the high-temperature performance of base asphalt, meeting technical specifications. When the hard asphalt addition exceeds 30%, the residual amount on the emulsified asphalt sieve increases and storage stability decreases, indicating that increasing the hard asphalt addition increases emulsification difficulty. At the same time, while maintaining the same addition level, pursuing lower-grade petroleum asphalt to achieve a higher softening point for the emulsified asphalt residue presents challenges in the preparation and storage of the emulsified asphalt. The lower the grade of the petroleum asphalt, the more difficult it is to emulsify the asphalt, requiring higher equipment requirements, and decreasing storage stability. Therefore, increasing the hard asphalt addition level and using lower-grade hard asphalt both pose significant challenges in the preparation and storage of the emulsified asphalt. Existing asphalt pavements utilize a multi-layer elastic structure, and emulsified asphalt is commonly used as a tack coat material to create a load-bearing, integrated structure. Good interlayer adhesion evenly distributes vehicle loads and improves the durability of the asphalt pavement. However, the emulsified asphalt tack coat often experiences severe wheel sticking due to construction vehicle pressure, resulting in a loss of interlayer adhesion and compromising the pavement's integrity. During operation, vehicle loads can cause significant shearing effects on the road surface, leading to rutting, cracking, slippage, and bumping. Non-stick wheel tack layers often use low-grade asphalt. However, since low-grade asphalt content exceeds 30%, it is difficult to emulsify. Reducing the content has limited impact on the high-temperature performance of the tack layer. Summary of the Invention

[0004] To address the above technical problems, the present invention provides a non-stick wheel tack layer and a method for preparing the same. This method utilizes warm-mix technology to mechanically foam a mixture of asphalt, anti-rutting masterbatch, and a surfactant-based warm-mix additive, resulting in a non-stick wheel tack layer material with excellent high-temperature performance. This material can improve interlayer adhesion and shear resistance on asphalt pavement, extending its service life.

[0005] In a first aspect, the present invention provides a method for preparing a non-stick wheel adhesive layer, comprising compounding asphalt, an anti-rutting agent masterbatch and a foaming aid to obtain a non-stick wheel mixed asphalt material, and spraying the non-stick wheel mixed asphalt material onto an asphalt pavement by mechanical foaming to obtain a non-stick wheel adhesive layer.

[0006] In the present invention, asphalt, anti-rutting agent masterbatch and foaming aid are mixed and directly sprayed onto the asphalt pavement through special mechanical foaming equipment, which can reduce construction processes, lower project costs, and obtain a non-stick wheel adhesive layer material with excellent high-temperature performance, achieving the effect of non-stick wheels. At the same time, it improves the interlayer adhesion and shear resistance of the asphalt pavement, thereby extending the service life of the asphalt pavement.

[0007] Preferably, the method for preparing the non-stick wheel adhesive layer comprises:

[0008] 1) Mixing asphalt and anti-rutting agent masterbatch and heating them to obtain mixed asphalt;

[0009] 2) mixing the mixed asphalt with a foaming aid to obtain a non-stick wheel mixed asphalt material;

[0010] 3) The non-stick wheel mixed asphalt material is heated, and a small amount of water is added to the asphalt mix using a mechanical foaming warm mix asphalt equipment, and the mixture is sprayed onto the asphalt pavement by mechanical foaming to obtain a non-stick wheel adhesive layer.

[0011] The present invention applies warm mix technology to the development of tack coat materials, compounding asphalt, anti-rutting agent masterbatch, and foaming aid to produce a non-stick wheel mixed asphalt material, and spraying it onto the asphalt pavement through mechanical foaming warm mix technology to form a non-stick wheel tack coat. Because the mechanical foaming warm mix technology is used during the construction process to significantly reduce the viscosity of the non-stick wheel mixed asphalt material, achieving a sprayable state, and because the process of emulsification of the mixed asphalt material is reduced during the process, the cost of emulsifier is saved while avoiding the problem of insufficient storage stability of the emulsified asphalt. The non-stick wheel tack coat material proposed by the present invention significantly improves the high-temperature stability of the tack coat, the construction process is simple to operate, and the project cost is saved. The non-stick wheel effect exceeds that of the modified emulsified asphalt material, effectively ensuring the interlayer bonding effect, improving the road performance of the asphalt pavement, and extending the service life of the asphalt pavement.

[0012] Preferably, in step 3), the amount of water added is 2% to 3% of the mass of the mixed asphalt. The present invention selects the smallest amount of water possible to reduce the residual moisture in the tack layer material while meeting the foaming parameters.

[0013] Preferably, the mechanical foaming process involves introducing a small amount of water and gas into the heated non-stick wheel mixed asphalt material using a mechanical foaming warm mix asphalt equipment to form a foamed asphalt structure. This process produces a large number of small bubbles, which increases the volume of the original material and reduces its viscosity, making tack coat spraying simpler and more convenient, improving the performance of the tack coat material and construction efficiency.

[0014] According to a preferred embodiment of the present invention, the present invention first selects No. 50 base asphalt and anti-rutting asphalt masterbatch to prepare a mixed asphalt, adds a warm mix foaming agent to the mixed asphalt, heats it to a certain temperature, and simultaneously adds a small amount of water. Through a dedicated mechanical foaming device, the water turns into steam bubbles after contact with the asphalt. The rapidly expanding hot steam bubbles enter the asphalt under the action of external force, and the steam is mixed with some unvaporized droplets to form foamed asphalt. Figure 1 The picture shows the foaming of asphalt mixture. The foamed asphalt increases the volume of the original asphalt, reduces the viscosity, and makes the tack coat spraying simpler and more convenient.

[0015] Preferably, in step 1), the asphalt is heated to obtain hot asphalt, and then the anti-rutting asphalt masterbatch is mixed with the hot asphalt, stirred, and heated to obtain a mixed asphalt. The present invention improves the fluidity of the mixed asphalt by heating the low-grade asphalt and then adding the anti-rutting asphalt masterbatch and then heating it.

[0016] Preferably, in step 1) and step 3), the heating temperature is 150-170°C, such as 160, 165, or 170°C. Preferably, the asphalt is a low-grade base asphalt; preferably, the low-grade base asphalt has a grade not higher than 50, preferably 50# base asphalt, 30# base asphalt, or base asphalt with a grade lower than 30#.

[0017] More preferably, the anti-rutting agent masterbatch is an anti-rutting asphalt masterbatch; preferably, the amount of the anti-rutting agent masterbatch is 10% to 30% of the mass of the asphalt. In the present invention, the anti-rutting asphalt masterbatch is generally a processed product prepared from asphalt, a polymer such as SBS, EVA, or other modifiers, and additives.

[0018] More preferably, the foaming aid is a warm-mix foaming aid, preferably a modified silicone surfactant; preferably, the amount of the foaming aid is 0.1% to 0.15% of the mass of the mixed asphalt. In the present invention, the use of a modified silicone surfactant as a warm-mix foaming aid improves the uniformity and stability of asphalt foaming.

[0019] According to a preferred embodiment of the present invention, the present invention first selects No. 50 base asphalt and anti-rutting asphalt masterbatch to prepare a mixed asphalt, adds a warm mix foaming agent to the mixed asphalt, heats it to a certain temperature, and simultaneously adds a small amount of water. Through a dedicated mechanical foaming device, the water turns into steam bubbles after contact with the asphalt. The rapidly expanding hot steam bubbles enter the asphalt under the action of external force, and the steam is mixed with some unvaporized droplets to form foamed asphalt. Figure 1 The picture shows the foaming of asphalt mixture. The foamed asphalt increases the volume of the original asphalt, reduces the viscosity, and makes the tack coat spraying simpler and more convenient.

[0020] The preferred foaming water amount in the present invention is 2% to 3% of the mass of the mixed asphalt; the expansion ratio is 7 to 11 times, such as 8, 9, 10 times, etc.; and the half-life is 110 to 130 seconds.

[0021] In a second aspect, the present invention further provides a non-stick wheel adhesive layer prepared by a mechanical foaming method, which is prepared by the above-mentioned preparation method.

[0022] In a third aspect, the present invention further provides an asphalt pavement comprising the non-stick wheel adhesion layer prepared by the above preparation method or the above non-stick wheel adhesion layer.

[0023] The beneficial effects of the present invention are at least as follows: the present invention proposes to stir and mix asphalt, anti-rutting agent masterbatch and foaming aid, and directly spray the non-stick wheel adhesive layer material onto the asphalt pavement through mechanical foaming technology, thereby reducing the steps of preparing emulsifiers and manufacturing emulsified asphalt, simplifying the process, facilitating operation, saving project costs, and achieving a non-stick wheel effect that is better than modified emulsified asphalt, ensuring close bonding between layers, avoiding damage to the adhesive layer by construction equipment and transport vehicles, improving construction efficiency, and extending the service life of the asphalt pavement. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of asphalt foaming of the mixture according to an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of a non-stick wheel effect test according to an embodiment of the present invention.

[0027] Figure 3 The non-stick wheel effect test results provided for the embodiments and comparative examples of the present invention are shown.

[0028] Figure 4 Schematic diagram of a shear test of a non-stick wheel material according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0030] In the embodiment of the present invention, the anti-rutting asphalt masterbatch was purchased from Sinopec Luoyang Petrochemical Company, and the warm mix additive was Evonik TEGO XP32157.

[0031] Example 1 (base asphalt + 10% masterbatch)

[0032] 750g of 50# base asphalt was heated in an oven to 145°C to improve its fluidity. 75g of anti-rutting asphalt masterbatch was then added to the hot asphalt, stirred evenly, and heated to 160°C to improve the fluidity of the mixture. The mixture was then kept warm for later use. 0.825g of warm mix additive (0.1% of the mixed asphalt mass) was added to the mixture and stirred evenly. The mixture was then poured into the asphalt tank of a mechanical foaming machine, with the water volume set at 2% or 3% of the mixed asphalt mass. The non-stick wheel adhesive layer was prepared in the laboratory through mechanical foaming. Specific mechanical foaming test data is shown in Table 1. These data met the requirements for modified asphalt foaming parameters. While meeting these requirements, a lower water content of 2% was selected for foaming.

[0033]

[0034] Example 2 (base asphalt + 20% masterbatch)

[0035] 750g of 50# base asphalt was heated in an oven to 145°C to improve its fluidity. 150g of anti-rutting asphalt masterbatch was then added to the hot asphalt, stirred evenly, and heated to 165°C to improve the fluidity of the mixture. The mixture was then kept warm for later use. 0.9g of warm mix additive (0.1% of the mixed asphalt mass) was added to the mixture and stirred evenly. The mixture was then poured into the asphalt tank of the mechanical foaming equipment, with the water volume set at 2% or 3% of the mixed asphalt mass. The non-stick wheel adhesive layer was prepared in the laboratory through mechanical foaming. Specific mechanical foaming test data is shown in Table 2. These data met the requirements for the modified asphalt foaming parameters. While meeting these requirements, the 2% water content was selected for foaming, which was the lowest.

[0036]

[0037] Example 3 (base asphalt + 30% masterbatch)

[0038] 750g of 50# base asphalt was heated in an oven to 145°C to improve its fluidity. 225g of anti-rutting asphalt masterbatch was then added to the hot asphalt, stirred evenly, and heated to 170°C to improve the fluidity of the mixed asphalt. The mixture was then kept warm for later use. 0.975g of warm mix additive (0.1% of the mixed asphalt mass) was added to the mixed asphalt, stirred evenly, and poured into the asphalt tank of the mechanical foaming equipment. The water volume was set at 2% or 3% of the mixed asphalt mass. The non-stick wheel adhesive layer was prepared in the laboratory through mechanical foaming. Specific mechanical foaming test data is shown in Table 3. These data meet the requirements for modified asphalt foaming parameters. While meeting these requirements, a lower water content of 2% was selected for foaming.

[0039]

[0040] Comparative Example 1 (ordinary emulsified asphalt):

[0041] Use 750g of 50# matrix asphalt to heat to 135℃ in an oven to make the mixed asphalt have better fluidity, and keep it warm for later use; add 0.4g of emulsifier to 970ml of water at 35℃, stir thoroughly until the emulsifier is completely dissolved, the amount of emulsifier used is 0.4% of the mass of the emulsified asphalt, and then use hydrochloric acid to adjust the pH of the mixed liquid to 2 to obtain the final soap solution, and keep it warm for later use; preheat the colloid mill to 70℃, and then pour 800ml of the prepared soap solution into the colloid mill for circulation, and then add the 135℃ mixed asphalt to the colloid mill, circulate for 1 minute, and the rotation speed of the colloid mill during the circulation process is 2000r / min. The obtained emulsified asphalt is cooled to 50℃ for later use.

[0042] Comparative Example 2 (Modified Emulsified Asphalt)

[0043] 750g of 50# base asphalt was heated in an oven to 145°C to improve its fluidity. 150g of anti-rutting asphalt masterbatch was then added to the hot asphalt, stirred evenly, and heated to 145°C to improve the fluidity of the mixed asphalt. The mixture was then kept warm for later use. 4g of emulsifier was added to 970ml of 35°C water and stirred thoroughly until the emulsifier was completely dissolved. The amount of emulsifier used was 0.4% of the mass of the emulsified asphalt. 30g of latex modifier was then added to the mixture and stirred thoroughly to evenly disperse it. The mixture was then acidified to a pH of 2 using hydrochloric acid to obtain the final soap solution. The solution was then kept warm for later use. A colloid mill was preheated to 70°C, and 800ml of the prepared soap solution was poured into the mill for circulation. 800g of the 145°C mixed asphalt was then added to the mill for circulation for 1 minute. The mill was rotated at 2000 rpm during the circulation process. The resulting emulsified asphalt was cooled to 50°C for later use.

[0044] Evaluation of the effect of non-stick wheels

[0045] 1) Non-stick wheel material performance test

[0046] The evaporation residue of the comparative example emulsified asphalt and the mixed asphalt before foaming of the example were tested for needle penetration and softening point with reference to JTGE20-2011 "Testing Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The results are shown in Table 4.

[0047]

[0048] 2) Test on the effect of sticky layer and non-stick wheel

[0049] The tack layer non-stick wheel effect test is a laboratory test that simulates a construction vehicle rolling over the tack layer to evaluate the non-stick wheel effect of the tack layer after it is spread and formed.

[0050] (1) Sample preparation: Prepare the non-stick wheel adhesive layer material under appropriate temperature and foaming water conditions, and 2 Apply evenly on the flat oil felt; for the comparative example, since the asphalt content in the emulsified asphalt is about 60%, 0.8kg / m 2 Use an amount of about 100g and apply it evenly on the flat oil felt. The size of the applied adhesive layer is a rectangle of 200mm*80mm. Put the sample into a 60℃ oven for curing for 1 hour to ensure that the emulsified asphalt adhesive layer material of the comparative example is fully demulsified and the residual moisture of the non-stick wheel material of the embodiment is evaporated.

[0051] (2) Non-stick wheel effect test: Place the prepared sample, a 150mm*50mm*5mm rubber strip (hardness 65HA) and unused A4 paper in a 60℃ oven for 0.5h. Then quickly take out the sample, A4 paper and rubber strip, cover the sample with the insulating A4 paper, and press the rubber strip on the sticky layer. Use a 35kg counterweight to repeatedly roll it 10 times and observe the adhesion of the A4 paper to the sticky layer. See Figure 2 The test time from taking out the sample to completing the rolling is no more than 30s. The test results of the non-stick wheel effect are shown in Figure 3 .from Figure 3 It can be seen that by comparing the hard asphalt added in different proportions, it is found that the non-stick wheel effect gradually improves with the increase of the addition amount. When the low-grade asphalt is added to 30%, it is basically non-stick. The non-stick wheel effect of the non-stick wheel adhesive layer material of the present invention is better than that of the modified emulsified asphalt adhesive layer material.

[0052] 3) Shear strength test

[0053] The bonding layer shear strength test is to test the bonding strength between asphalt mixture layers and is used to evaluate the bonding effect between asphalt mixture layers.

[0054] (1) Sample preparation: According to the asphalt mixture specimen preparation method (wheel rolling method) in the "Highway Engineering Asphalt and Asphalt Mixture Test Procedure", the recommended gradation range of AC-16 type gradation median of the dense graded asphalt concrete mixture in the "Highway Asphalt Pavement Construction Technical Specification" was adopted. 70# base asphalt was used and the asphalt-to-stone ratio was 4.8% to form a 300mm×300mm×50mm rutting specimen by wheel rolling. After the rutting specimen was cooled to room temperature, the tack coat material was evenly spread on the rutting specimen. In the embodiment, 0.5kg / m 2 About, comparative example 0.8kg / m 2 After the specimens have cooled to room temperature, they are cut into cubes of 100mm*100mm*100mm.

[0055] (2) Shear test: Place the cube specimen in the shear test fixture and place it steadily on the test bench of the universal press (300KN). The test is applied at a speed of 5mm / min and the peak value of the test load is recorded. Figure 4 , the shear strength test results are shown in Table 5.

[0056]

[0057] The test results in Table 5 show that the interlayer bond strength of the non-stick wheel tack layer is comparable to that of the emulsified asphalt tack layer. Comparing the addition of different proportions of low-grade asphalt reveals that the interlayer shear strength increases with increasing addition proportion. This indicates that low-grade asphalt is beneficial for improving the interlayer bond performance of asphalt mixtures.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a non-stick wheel adhesive layer, characterized in that: include: 1) Mixing asphalt and anti-rutting agent masterbatch and heating them to obtain mixed asphalt; 2) mixing the mixed asphalt with a foaming aid to obtain a non-stick wheel mixed asphalt material; 3) heating the non-stick wheel mixed asphalt material, adding a small amount of water using a mechanically foamed warm mix asphalt equipment, and spraying it onto the asphalt pavement by mechanical foaming to obtain a non-stick wheel adhesive layer; In step 1), asphalt is heated to obtain hot asphalt, and then anti-rutting asphalt masterbatch is mixed with the hot asphalt, stirred and heated to obtain mixed asphalt; the asphalt has a grade of not higher than 50; the anti-rutting agent masterbatch is an anti-rutting asphalt masterbatch, and the amount of the anti-rutting agent masterbatch is 10% to 30% of the mass of the asphalt; In step 2), the foaming aid is a modified silicone surfactant, and the amount of the foaming aid is 0.1% to 0.15% of the mass of the mixed asphalt; In step 3), the amount of water added is 2% to 3% of the mass of the mixed asphalt; in step 1) and step 3), the heating temperature is 150 to 170°C.

2. The method for preparing the non-stick wheel adhesive layer according to claim 1, characterized in that: The mechanical foaming includes introducing a small amount of water and gas into the heated non-stick wheel mixed asphalt material through a mechanical foaming warm mix asphalt equipment to form a foamed asphalt structure.

3. A non-stick wheel adhesive layer prepared by mechanical foaming, characterized in that: The product is prepared by the preparation method according to claim 1 or 2.

4. An asphalt pavement, characterized in that: The invention comprises the non-stick wheel adhesive layer prepared by the preparation method according to claim 1 or 2 or the non-stick wheel adhesive layer according to claim 3.

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