Warm-mixed rubber powder composite modified asphalt for roads and preparation method of warm-mixed rubber powder composite modified asphalt

Abstract

The invention relates to the technical field of functional asphalt pavement materials, in particular to warm-mixing rubber powder composite modified asphalt for roads and a preparation method thereof, and the method comprises the following steps: heating an unaged asphalt cementing material to a flowing state; preliminarily stirring and mixing the rubber powder and the raw asphalt in the asphalt cement; carrying out shearing treatment on the rubber powder and the asphalt cement; stirring and mixing the rubber powder and the asphalt cementing material asphalt again to obtain hot rubber powder modified asphalt; and adding the wax-based warm-mixing additive into the hot rubber powder modified asphalt, and uniformly stirring to obtain the warm-mixing rubber powder composite modified asphalt. Compared with the prior art, the method has the advantages that the dispersibility and compatibility of the rubber powder in the asphalt are improved, so that the storage stability and uniformity of the asphalt are improved, and the like.

Description

Technical Field

[0001] This invention relates to the field of functional asphalt pavement materials, and in particular to a warm-mix rubber powder composite modified asphalt for roads and its preparation method. Background Technology

[0002] Compared to polymer-modified asphalt (PMA), traditional asphalt binders often fall short in terms of resistance to rutting, water, thermal cracking, fuel residues, loosening, and aging, making it difficult to meet the ever-increasing demands of transportation. Meanwhile, the disposal of waste tires also presents serious environmental and resource challenges. Adding rumb rubber (CR) from waste tires to asphalt can not only improve its rheological and mechanical properties but also provide an effective strategy for large-scale tire recycling. Therefore, rumb rubber-modified bitumen (CRMB) is considered a sustainable material that combines environmental remediation and advanced pavement engineering. However, its large-scale application is still subject to many limitations, including issues such as storage stability, processing uniformity, and long-term performance consistency, as well as environmental drawbacks such as higher mixing temperatures, higher energy consumption, and additional gas emissions.

[0003] In recent years, the application of rubber and warm mix additives (WMA) in warm rubberized bitumen (WRB) to improve the resilience of road infrastructure has received increasing attention, which can further enhance the environmental performance of WRB. This is because warm mix technology can reduce the construction temperature of asphalt pavement by 20°C-30°C, thereby reducing carbon emissions during asphalt pavement construction by more than 30%, thus improving the working conditions of asphalt pavement. Furthermore, previous research results have shown that the combination of rubber powder and wax-based warm mix additives can have a positive synergistic effect on the rheological properties of asphalt. Therefore, warm mix rubberized bitumen can promote the development of environmentally friendly asphalt pavements.

[0004] Currently, rubber powder modified asphalt generally suffers from insufficient stability during high-temperature storage and transportation. Due to the limited compatibility between rubber powder and base asphalt, rubber powder particles are prone to uneven swelling, agglomeration, or sedimentation, leading to phase separation under static conditions. This manifests as an increased difference in softening point and uneven performance distribution. This insufficient storage stability restricts the centralized production and large-scale application of rubber powder modified asphalt and also adversely affects engineering quality control.

[0005] A search revealed several Chinese invention patent applications. CN117272580A discloses a polar-enhanced recycled rubber-plastic asphalt modifier based on shear desulfurization-surface oxidation and its preparation method. It employs a twin-screw anisotropic shear extrusion process and immersion in hydrogen peroxide solution to improve the compatibility, stability, and road performance of the modified asphalt. CN116254006A proposes a high-temperature pyrolysis high-content rubber powder-rock asphalt composite modified asphalt and its preparation method, involving rubber powder premixing, high-temperature pyrolysis shearing, thermomechanical stirring of the modifier, and heat preservation. The modified asphalt exhibits good storage stability and durability. CN114685846A discloses a supercritical decrosslinking pretreated rubber powder and rubber powder modified asphalt and its preparation method. The rubber powder, decrosslinking agent, and dry ice are mixed evenly and placed in a sealed high-pressure reactor. Electric heating raises the temperature and pressure of carbon dioxide within the reactor, reaching a supercritical state, thereby improving the storage stability, workability, and environmental friendliness of the rubber powder modified asphalt. However, existing patent applications require expensive testing equipment and specialized, toxic chemical reagents. Therefore, the universality and engineering applicability of current rubber powder compatibility improvement solutions are limited.

[0006] How to reduce usage costs and achieve environmental friendliness without compromising the compatibility of rubber powder has become a key technical problem to be solved in improving the storage stability of rubber powder asphalt. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art and provide a warm-mix rubber powder composite modified asphalt for road use and its preparation method.

[0008] The objective of this invention can be achieved through the following technical solutions: According to a first aspect of the present invention, a method for preparing warm-mix rubber powder composite modified asphalt for road use is provided, the method comprising: S1. Heat the unaged asphalt binder until it reaches a fluid state; S2. Initially mix the rubber powder with the original asphalt in the asphalt binder; S3. Shear the rubber powder and asphalt binder together. S4. Mix the rubber powder and asphalt binder asphalt again to obtain hot rubber powder modified asphalt. S5. Add the wax-based warm mix additive to the hot rubber powder modified asphalt and stir evenly to obtain warm mix rubber powder composite modified asphalt.

[0009] As a preferred technical solution, the wax-based warm-stir additive is a straight-chain saturated alkane, including octadecane, tetracosane, tetracosane, and saxopide.

[0010] As a preferred technical solution, the wax-based warm-stir additive is a short-chain straight-chain saturated alkane.

[0011] As a preferred technical solution, the rubber powder includes activated rubber powder and unactivated rubber powder.

[0012] As a preferred technical solution, in step S1, the heating temperature is 160°C and the heating time is 1 hour.

[0013] As a preferred technical solution, in S2, the stirring method is mechanical, the stirring temperature is 185℃, the stirring speed is 500 rpm, and the stirring time is 30 min.

[0014] As a preferred technical solution, in S3, the shear temperature is 185℃, the stirring rate is 4500 rpm, and the stirring time is 60 min.

[0015] As a preferred technical solution, in step S4, the stirring method is mechanical, the stirring temperature is 160℃, the stirring speed is 500 rpm, and the stirring time is 5 min.

[0016] As a preferred technical solution, in step S5, the wax-based warm mix additive and the hot rubber powder modified asphalt are mixed by manual stirring at a temperature of 160°C for a time of approximately 2 minutes.

[0017] According to a second aspect of the present invention, a warm-mix rubber powder composite modified asphalt for road use is provided, comprising unaged asphalt binder, rubber powder and wax-based warm-mix additive, and prepared by the method described in any one of the first aspects above.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention achieves the preparation of warm-mix rubber powder composite modified asphalt through steps such as heating unaged asphalt binder, premixing rubber powder with virgin asphalt, shearing treatment, re-mixing, and adding wax-based warm-mix additives. This method is simple and low-cost. The introduction of wax-based warm-mix additives not only effectively reduces the construction temperature of asphalt pavement but also improves the dispersibility and compatibility of rubber powder in asphalt, thereby improving the storage stability and uniformity of asphalt. This is beneficial for achieving low-carbon, environmentally friendly, and low-harm asphalt pavement modified with rubber powder.

[0019] 2) By limiting parameters such as the proportion and type of wax-based warm mix additives, the proportion and activation state of rubber powder, the heating temperature and time of each step, and the stirring / shear rate, the preparation process of warm mix rubber powder composite modified asphalt was further optimized. Using straight-chain saturated alkanes (such as octadecane, tetracosane, tetratetradecane, and saxopride) as warm mix additives effectively improves the interfacial interaction between rubber powder and asphalt, reduces the degree of rubber powder aggregation, and ensures sufficient dispersion of rubber powder and uniform and stable asphalt system, thereby improving the overall performance and workability of warm mix rubber powder composite modified asphalt.

[0020] 3) This invention verifies through experimental data that short-chain straight-chain saturated alkanes can better disperse rubber powder and more effectively enhance the interaction between rubber powder and asphalt compared to long-chain straight-chain saturated alkanes.

[0021] 4) The warm-mix asphalt composite modified asphalt of this invention is prepared from unaged asphalt binder, rubber powder, and wax-based warm-mix additives, combining the excellent performance of rubber powder modified asphalt with the environmental advantages of warm-mix technology. This asphalt can reduce construction temperature, reduce energy consumption and harmful gas emissions. The addition of wax-based warm-mix additives makes the warm-mix rubber powder composite modified asphalt have good storage stability and uniformity, and better rubber powder dispersibility, which can effectively improve the durability and environmental friendliness of the road surface. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of a method for preparing warm-mix rubber powder composite modified asphalt for roads according to one embodiment of the present invention; Figure 2 This is a schematic flowchart of a method for preparing warm-mix rubber powder composite modified asphalt for roads, according to another embodiment of the present invention. Figure 3 This is a microscopic morphology diagram of the warm-mix rubber powder composite modified asphalt in this invention; Figure 4 The figure shows the Cole-Cole test results of warm-mix rubber powder composite modified asphalt using unactivated rubber powder in this invention. Figure 5 The figure shows the Cole-Cole test results of warm-mix rubber powder composite modified asphalt using activated rubber powder in this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] Example 1 This embodiment relates to a warm-mix rubber powder composite modified asphalt for road use and its preparation method, wherein the warm-mix rubber powder composite modified asphalt includes unaged asphalt binder, rubber powder and wax-based warm-mix additive.

[0025] Preparation method as follows Figure 1 This includes the following steps: S1. Place the unaged asphalt binder in an oven and heat it until it reaches a fluid state; S2. Use a mixing device to initially mix the unactivated / activated rubber powder with the original asphalt in the asphalt binder; S3. Use a high-shear mixer to shear the rubber powder and asphalt binder for further mixing; S4. Use a mixing device to mix the rubber powder and asphalt binder again to obtain hot rubber powder modified asphalt; S5. Add wax-based warm mix additive to hot rubber powder modified asphalt and stir manually to obtain a non-aged homogeneous mixture, i.e., warm mix rubber powder composite modified asphalt. S6. The warm-mix rubber powder composite modified asphalt was subjected to short-term and long-term aging in the laboratory to obtain warm-mix rubber powder composite modified asphalt with different aging degrees.

[0026] Step S1 includes: The oven temperature is 160℃ and the heating time is 1 hour. It should not be too long to avoid the asphalt aging due to the oven heating.

[0027] Step S2 includes: Unactivated rubber powder was prepared by activating it with KH-151 chemical reagent and was used as a material component in the comparative example. Unactivated rubber powder is referred to as activated rubber powder, and activated rubber powder is referred to as activated rubber powder. The physical and chemical properties of unactivated and activated rubber powder are shown in Table 1.

[0028] Table 1

[0029] In step S2, the rubber powder and asphalt binder are mixed mechanically at a temperature of 185°C, a speed of 500 rpm, and a time of 30 minutes.

[0030] In step S2, the proportion of rubber powder in the unaged asphalt binder is 20 wt% (by weight).

[0031] Step S3 includes: the shear temperature of the rubber powder and the unaged asphalt binder is 185°C, the stirring rate is 4500 rpm, and the stirring time is 60 min.

[0032] Step S4 includes: the rubber powder and the unaged asphalt binder are mixed mechanically, the mixing temperature is 160℃, the mixing speed is 500 rpm, and the mixing time is 5 min.

[0033] Step S5 includes: mixing the wax-based warm mix additive with the hot rubber powder modified asphalt by manual stirring at a temperature of 160°C for approximately 2 minutes. The wax-based warm mix additive is a straight-chain saturated alkane, including octadecane (C18), tetracosane (C24), tetracosane (C40), and Sasobit. The proportion of the four wax-based warm mix additives in the unaged asphalt binder does not exceed 3 wt% (by weight), ensuring the warm mix effect while avoiding the negative impact of excessive addition on asphalt performance. The added wax-based warm mix additive can be any straight-chain saturated alkane, with optimization of short-chain straight-chain saturated alkanes.

[0034] In step S6, short-term aging was carried out according to European standard EN 12607-2:2014, with an aging time of 2 hours, a temperature of 163°C, and an aged sample mass of 20g; long-term aging was carried out according to the European standard method EN 14769:2012, with an aging time of 20 hours, a temperature of 100°C, a pressure of 2.1 ± 0.1 MPa, and an aged sample mass of 50g.

[0035] This preparation method is simple, low-cost, and has good universality for compatibilizing rubber powder in asphalt. Compared with ordinary rubber powder asphalt, warm-mix rubber powder composite modified asphalt can not only reduce the construction temperature of asphalt pavement, but also has better storage stability and uniformity, which is conducive to realizing the low-carbon, environmentally friendly, and low-harm of rubber powder modified asphalt pavement.

[0036] Example 2 This embodiment also relates to a method for preparing warm-mix rubber powder composite modified asphalt for roads, such as... Figure 2 This includes the following steps: S1. Place the unaged asphalt binder in a 160℃ oven and heat for 1 hour until it reaches a fluid state. S2. Use a mixing device to initially mix 20% by mass of unactivated rubber powder with the original asphalt. The mixture is mechanically stirred at 185℃ and 500 rpm for 30 minutes. S3. Perform high-shear treatment at 185℃ and 4500 rpm for 60 minutes to promote uniform dispersion; S4. Finally, stir the mixture at 160℃ and 500 rpm for 5 minutes to ensure its homogeneity and obtain hot rubber powder modified asphalt. S5. Add 3% octadecane by mass to the hot rubber powder modified asphalt at 160℃ and stir manually for 2 minutes to obtain a non-aged and homogeneous mixture, i.e., warm-mix rubber powder composite modified asphalt. S6. The warm-mix rubber powder composite modified asphalt was subjected to short-term and long-term aging in the laboratory according to EN 12607-2:2014 and EN 14769:2012 standards, respectively, to obtain warm-mix rubber powder composite modified asphalt with different aging degrees.

[0037] Example 3 This embodiment also relates to a method for preparing warm-mix rubber powder composite modified asphalt for roads, including the following steps: S1. Place the unaged asphalt binder in a 160℃ oven and heat for 1 hour until it reaches a fluid state. S2. Use a mixing device to initially mix 20% by mass of unactivated rubber powder with the original asphalt. The mixture is mechanically stirred at 185℃ and 500 rpm for 30 minutes. S3. Perform high-shear treatment at 185℃ and 4500 rpm for 60 minutes to promote uniform dispersion; S4. Finally, stir the mixture at 160℃ and 500 rpm for 5 minutes to ensure its homogeneity and obtain hot rubber powder modified asphalt. S5. Add 3% tetracosane by mass to the hot rubber powder modified asphalt at 160℃ and stir manually for 2 minutes to obtain a non-aged and uniform mixture, i.e., warm-mix rubber powder composite modified asphalt. S6. The warm-mix rubber powder composite modified asphalt was subjected to short-term and long-term aging in the laboratory according to EN 12607-2:2014 and EN 14769:2012 standards, respectively, to obtain warm-mix rubber powder composite modified asphalt with different aging degrees.

[0038] Example 4 This embodiment also relates to a method for preparing warm-mix rubber powder composite modified asphalt for roads, including the following steps: S1. Place the unaged asphalt binder in a 160℃ oven and heat for 1 hour until it reaches a fluid state. S2. Use a mixing device to initially mix 20% by mass of unactivated rubber powder with the original asphalt. The mixture is mechanically stirred at 185℃ and 500 rpm for 30 minutes. S3. Perform high-shear treatment at 185℃ and 4500 rpm for 60 minutes to promote uniform dispersion; S4. Finally, stir the mixture at 160℃ and 500 rpm for 5 minutes to ensure its homogeneity and obtain hot rubber powder modified asphalt. S5. Add 3% by mass of tetradecane to hot rubber powder modified asphalt at 160℃ and stir manually for 2 minutes to obtain a non-aged and homogeneous mixture, i.e., warm-mix rubber powder composite modified asphalt. S6. The warm-mix rubber powder composite modified asphalt was subjected to short-term and long-term aging in the laboratory according to EN 12607-2:2014 and EN 14769:2012 standards, respectively, to obtain warm-mix rubber powder composite modified asphalt with different aging degrees.

[0039] Example 5 This embodiment also relates to a method for preparing warm-mix rubber powder composite modified asphalt for roads, including the following steps: S1. Place the unaged asphalt binder in a 160℃ oven and heat for 1 hour until it reaches a fluid state. S2. Use a mixing device to initially mix 20% by mass of unactivated rubber powder with the original asphalt. The mixture is mechanically stirred at 185℃ and 500 rpm for 30 minutes. S3. Perform high-shear treatment at 185℃ and 4500 rpm for 60 minutes to promote uniform dispersion; S4. Finally, stir the mixture at 160℃ and 500 rpm for 5 minutes to ensure its homogeneity and obtain hot rubber powder modified asphalt. S5. Add 3% by mass of Sasobid to the hot rubber powder modified asphalt at 160℃ and stir manually for 2 minutes to obtain an unaged and homogeneous mixture. S6. The warm-mix rubber powder composite modified asphalt was subjected to short-term and long-term aging in the laboratory according to EN 12607-2:2014 and EN 14769:2012 standards, respectively, to obtain warm-mix rubber powder composite modified asphalt with different aging degrees.

[0040] Example 6 This embodiment also relates to a comparative verification of a method for preparing warm-mix rubber powder composite modified asphalt for roads, including the following comparative examples: Comparative Example 1 is pure base asphalt without any wax-based warm mix additives or rubber powder.

[0041] Comparative Example 2 describes the preparation of rubber-modified asphalt by adding only unactivated rubber powder. The preparation method includes the following steps: S1. Place the unaged asphalt binder in a 160℃ oven and heat for 1 hour until it reaches a fluid state. S2. Use a mixing device to initially mix 20% by mass of unactivated rubber powder with the original asphalt. The mixture is mechanically stirred at 185℃ and 500 rpm for 30 minutes. S3. Perform high-shear treatment at 185℃ and 4500 rpm for 60 minutes to promote uniform dispersion; S4. Finally, stir the mixture at 160°C and 500 rpm for 5 minutes to ensure its homogeneity and obtain unaged hot rubber powder modified asphalt.

[0042] S5. The hot rubber powder modified asphalt was subjected to short-term and long-term aging in the laboratory according to EN 12607-2:2014 and EN 14769:2012 standards to obtain unactivated rubber powder composite modified asphalt with different aging degrees.

[0043] Comparative Example 3 is a preparation of rubber powder modified asphalt by adding only activated rubber powder. It is prepared using a method similar to S1 to S5 of Comparative Example 2, except that the unactivated rubber powder is replaced with activated rubber powder, which is derived from step S2 in Example 1.

[0044] Comparative Example 4 describes the preparation of warm-mix rubber powder composite modified asphalt by adding activated rubber powder and wax-based warm-mix additive octadecane. The preparation method is similar to that of Example 2, except that the unactivated rubber powder is replaced with activated rubber powder.

[0045] Comparative Example 5 prepared warm-mix rubber powder composite modified asphalt by adding activated rubber powder and wax-based warm-mix additive tetracosane. The preparation method was similar to that of Example 3, except that the unactivated rubber powder was replaced with activated rubber powder.

[0046] Comparative Example 6 describes the preparation of warm-mix rubber powder composite modified asphalt by adding activated rubber powder and wax-based warm-mix additive tetradecane. The preparation method of Example 4 was adopted, except that the unactivated rubber powder was replaced with activated rubber powder.

[0047] Comparative Example 7 describes the preparation of warm-mix rubber powder composite modified asphalt by adding activated rubber powder and wax-based warm-mix additive Sasobid. The preparation method is similar to that of Example 5, except that the unactivated rubber powder is replaced with activated rubber powder.

[0048] In this embodiment, an OLYMPUS BX41 fluorescence microscope was used to observe the microstructure of the warm-mix rubber powder modified asphalt from Examples 2-5 and Comparative Examples 1-7. The microstructure images are shown below. Figure 3 As shown, Figure 3 Images (c)-(f) are microscopic morphology diagrams of a warm-mix rubber powder composite modified asphalt for road use with good storage stability provided in Examples 2-5. Figure 3 (a), (b), (g), (h), (i), (j), and (k) are, in order, microscopic morphology images of asphalt in Comparative Examples 1, 2, 3, 4, 5, 6, and 7.

[0049] according to Figure 3In (b) and (g), the addition of unactivated rubber powder (hereinafter referred to as unactivated rubber powder) causes phase separation in the asphalt samples detected by fluorescence microscopy, while the degree of phase separation decreases after the rubber powder (Crumb Rubber, CR) is chemically activated. This is intuitively evident from... Figure 3 Images (c), (d), (e), and (f) show the effects of the four individual warm-mix additives on rubber-modified asphalt. C18, C24, C40, and Sasobit wax dispersed the unactivated rubber powder in the images, indicating an interaction between the wax and the unactivated rubber powder, reducing the aggregation of the rubber powder. For the activated warm-mix rubber powder composite modified asphalt system (… Figure 3 (h), (i), (j), (k)) After adding C18, C24, C40 and Sasobit, almost no phase separation occurred, which is similar to the activated rubber powder modified asphalt.

[0050] Quantitative analysis of the microstructure images of Examples 2-5 and Comparative Examples 1-7 revealed quantitative parameters of phase separation, as shown in Table 2. In Table 2, the average quantity is calculated as the area percentage divided by the average size.

[0051] Table 2

[0052] Table 2 shows that chemical activation of rubber powder can reduce the average particle size, area ratio, and average number of phases separated, thereby improving the compatibility of rubber powder. After adding C18, C24, C40, and Sasobit, the maximum changes in area ratio and average number of warm-mix rubber powder-modified asphalt systems before and after activation were 61.41% and 33.39%, and 6.14% and 17.22%, respectively. Therefore, compared with the activated CRMB sample, the morphological characteristics of the unactivated CRMB sample are more sensitive to wax-based warm-mix additives. Thus, wax-based warm-mix additives can increase the compatibility and storage stability of rubber powder in asphalt by dispersing unactivated aggregated rubber powder.

[0053] In this embodiment, a TA-HR 20 rheometer was used to conduct temperature and frequency sweep rheological experiments on Examples 2, 5, and Comparative Examples 1, 2, 3, and 7. Temperature sweep tests were performed at a constant frequency of 100 rad / s and a fixed strain of 0.01% within a temperature range of 10°C to 70°C. In the frequency sweep tests, frequencies ranging from 100 rad / s to 0.1 rad / s were applied at 10°C temperature intervals within the 10°C to 70°C range, with the strain fixed at 0.01% to maintain linear viscoelastic (LVE) conditions. The obtained Cole-Cole plot results are shown below. Figure 4 and Figure 5 As shown.

[0054] As shown in the Cole-Cole plot, the curves of the unaged asphalt samples shifted downwards and to the right after the addition of unactivated and activated rubber powders, respectively, followed by short-term and long-term aging. This indicates that oxidative aging and the elastomer properties of the unactivated and activated rubber powders themselves can improve the elasticity of asphalt. Furthermore, compared to the unactivated and activated rubber powder asphalt samples without Sasobit wax, the curves of the unactivated and activated rubber powder asphalt samples with Sasobit wax shifted significantly to the right. This suggests that adding Sasobit wax also enhances the elasticity of asphalt, which can explain the improved rutting resistance after adding Sasobit wax. In addition, according to... Figure 4 and Figure 5 The DCRMB system curve for activated rubber powder asphalt was consistently located to the left of the curve for the unactivated rubber powder asphalt sample system. Therefore, desulfurization of rubber powder can soften rubber powder asphalt and increase its viscosity.

[0055] Parameters were introduced based on polymer rheology. h This parameter is related to the molecular-level morphological defects of the polymer. Based on this, h The higher the value, the more molecular-level defects there are, and the worse the interaction between the asphalt and the rubber powder. By plotting the relationship between the storage modulus (G′) and the loss modulus (G″) on a linear scale and applying a fourth-order polynomial fit, the value can be determined according to the following formula (1). h The value is used to characterize the interaction between rubber powder and binder in warm-mix rubber powder modified asphalt samples before and after oxidative aging.

[0056] (1) Table 3 is based on formula (1) and Figure 4 , Figure 5 The results show the effects of warm-mix rubber powder-modified asphalt before and after oxidative aging. h Values. Table 3 shows that after long-term aging, the values ​​of unactivated rubber powder asphalt (NDCRMB), unactivated rubber powder asphalt (NDCRMB) + C18, unactivated rubber powder asphalt (NDCRMB) + Sasobit, activated rubber powder asphalt (DCRMB), activated rubber powder asphalt (DCRMB) + C18, and activated rubber powder asphalt (DCRMB) + Sasobit... hThe h values ​​increased by 2.33%, 1.51%, 0.42%, 1.52%, 0.89%, and 0.88%, respectively. All samples showed varying degrees of increase in h values ​​after short-term aging (TFOT) and long-term aging (PAV), indicating that oxidative aging exacerbates the separation of rubber powder, and that aging has a greater impact on the unactivated rubber powder asphalt system. The increase in h value for activated rubber powder asphalt (DCRMB) was smaller than that for unactivated rubber powder asphalt, indicating that rubber powder activation treatment can improve the system's anti-aging ability. According to Table 3, the addition of both C18 and Sasobit wax reduced the h values ​​of both unactivated and activated rubber powder asphalt systems, with C18 wax showing a greater effect. h The h value is lower than that of the activated rubber powder asphalt system. Comparing the effects of the two waxes, the h value of the sample with C18 wax added was consistently lower than that of the sample with Sasobit wax added.

[0057] Table 3

[0058] Similarly, experiments were conducted comparing other short-chain waxes (pentadecane to teicoplanin, denoted as C15 to C25) with long-chain waxes (C40, Sasobit). The results all showed that compared with long-chain waxes, short-chain waxes can better disperse rubber powder and more effectively enhance the interaction between rubber powder and asphalt.

[0059] In summary, this embodiment, by adding a wax-based warm-mix additive to rubber powder asphalt, can reduce the phase separation of unactivated rubber powder in the asphalt and essentially achieve the aggregation level of activated rubber powder asphalt. Therefore, the warm-mix rubber powder composite modified asphalt exhibits good storage stability.

[0060] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing warm-mix rubber powder composite modified asphalt for road use, characterized in that, The method includes: S1. Heat the unaged asphalt binder until it reaches a fluid state; S2. Initially mix the rubber powder with the original asphalt in the asphalt binder; S3. Shear the rubber powder and asphalt binder together. S4. Mix the rubber powder and asphalt binder asphalt again to obtain hot rubber powder modified asphalt. S5. Add the wax-based warm mix additive to the hot rubber powder modified asphalt and stir evenly to obtain warm mix rubber powder composite modified asphalt.

2. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, The wax-based warm-mix additive is a straight-chain saturated alkane, including octadecane, tetracosane, tetracosane, and saxopide.

3. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 2, characterized in that, The wax-based warm-stir additive is a short-chain, straight-chain saturated alkane.

4. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, The rubber powder includes activated rubber powder and unactivated rubber powder.

5. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, In S1, the heating temperature is 160°C and the heating time is 1 hour.

6. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, In S2, the stirring method is mechanical, the stirring temperature is 185℃, the stirring speed is 500 rpm, and the stirring time is 30 min.

7. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, In S3, the shear temperature is 185℃, the stirring rate is 4500 rpm, and the stirring time is 60 min.

8. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, In step S4, the stirring method is mechanical, the stirring temperature is 160℃, the stirring speed is 500 rpm, and the stirring time is 5 min.

9. The method for preparing warm-mix rubber powder composite modified asphalt for road use according to claim 1, characterized in that, In step S5, the wax-based warm mix additive and the hot rubber powder modified asphalt are mixed by manual stirring at a temperature of 160°C for approximately 2 minutes.

10. A warm-mix rubber powder composite modified asphalt for road use, characterized in that, It comprises unaged asphalt binder, rubber powder, and wax-based warm mix additive, and is prepared using the method described in any one of claims 1 to 9.

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