A low-temperature sensitive rubber modified asphalt mixture

Abstract

The application relates to a low-temperature-sensitive rubber modified asphalt mixture, belonging to the technical field of asphalt materials, and solves the problems of high technical cost, complex process and performance loss of rubber asphalt in reducing the viscosity of the rubber asphalt mixture. The low-temperature-sensitive rubber modified asphalt mixture comprises rubber modified asphalt, mineral materials and a solid modifier; the solid modifier is used for improving the viscosity of the mixture to reduce the construction temperature of the rubber modified asphalt mixture; the mass of the rubber modified asphalt accounts for 4.0%-5.5% of the mass of the mineral materials.

Description

Technical Field

[0001] This invention relates to the field of asphalt materials technology, and in particular to a low-temperature sensitive rubber-modified asphalt mixture. Background Technology

[0002] In 2022, China's tire production exceeded 100 million units, generating as many as 50 million waste tires annually. With the increasing number of cars on the road, the amount of waste tires generated will continue to rise significantly. How to effectively recycle and utilize these tires, avoid environmental pollution, and build a low-carbon, environmentally friendly, and resource-saving society is a new challenge we face. Processing waste tires into waste rubber powder, which can be used as a road asphalt modifier, and fully utilizing it in highway construction is one of the internationally recognized best methods for harmless and resource-efficient treatment. Using rubber-asphalt mixtures as road paving materials can scientifically reduce noise, improve wear resistance, and fully utilize waste tire conversion materials, demonstrating significant social and economic value in terms of saving social resources and protecting the environment.

[0003] Rubberized asphalt exhibits significant elasticity and elastic recovery at high temperatures, improving pavement resistance to deformation and fatigue cracking. It also demonstrates good high and low temperature performance, reducing the asphalt's temperature sensitivity. Furthermore, it boasts high viscosity, strong anti-aging and anti-oxidation capabilities. Its anti-skid properties are strong, reducing water splashing during rain, improving visibility, and lowering noise, significantly enhancing road safety and driving comfort. However, with increasing rubber powder content, the viscosity of rubberized asphalt gradually increases. This increases the difficulty of mixing, paving, and compacting asphalt mixtures. Excessive construction temperature also increases energy consumption and exacerbates the emission of harmful gases, which is detrimental to low-carbon environmental protection and the health of workers. Therefore, reducing the construction temperature of rubberized asphalt is currently a hot research topic. Warm mix additives can reduce the construction temperature of rubberized asphalt by about 20°C, but their high price hinders widespread application. CN112159597A invented a low-viscosity rubber-modified asphalt, which utilizes a combination of chemical reagents and microwave radiation to activate waste tire rubber powder, depolymerizing the vulcanized rubber on the surface of the rubber powder and improving the adhesion and compatibility between the rubber powder and the matrix. The resulting rubber asphalt has low viscosity, good thermal stability, and low odor. However, its process is too complex and not conducive to large-scale application. CN201511024254.8 invented a low-viscosity rubber asphalt that uses activated rubber powder technology to reduce the viscosity of the rubber asphalt. However, the activation of the rubber powder causes the cross-linking bonds to break, resulting in a certain loss of asphalt strength. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a composite fiber rubber modified asphalt mixture to solve the problems of high cost, complex process, and loss of rubber asphalt performance in existing technologies for reducing the viscosity of rubber asphalt mixtures.

[0005] The objective of this invention is mainly achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a low-temperature sensitive rubber-modified asphalt mixture, comprising: rubber-modified asphalt, aggregate, and solid modifier; wherein the solid modifier is used to improve the viscosity of the mixture to reduce the construction temperature of the rubber-modified asphalt mixture; wherein the mass of the rubber-modified asphalt accounts for 4.0% to 5.5% of the mass of the aggregate, and the mass of the solid modifier accounts for 0.2% to 1.5% of the mass of the aggregate.

[0007] Optionally, the rubber-modified asphalt comprises: base asphalt, waste rubber powder, styrene-butadiene-styrene block copolymer, liquid modifier, plasticizer, and sulfur.

[0008] Optionally, the liquid modifier includes one or more of polyisobutylene (PIB) (liquid), ethylene propylene copolymer (OCP) (liquid), polymethyl methacrylate (PMA) (liquid), poly(n-butyl ethylene ether) (BB), and chlorinated styrene-diene copolymer (HSD).

[0009] Optionally, the solid modifier includes one or more of polyisobutylene (PIB) (solid), ethylene propylene copolymer (OCP) (solid), and polymethyl methacrylate (PMA) (solid).

[0010] Optionally, the base asphalt is No. 70 or No. 90 road petroleum asphalt.

[0011] Optionally, the waste rubber powder has a mesh size of 20 to 40 mesh.

[0012] Optionally, the styrene-butadiene-styrene block copolymer has a star-shaped or linear structure.

[0013] Optionally, the plasticizer is dibutyl phthalate.

[0014] Optionally, the solid modifier is in granular or powder form.

[0015] Secondly, the present invention provides a method for preparing a low-temperature-sensitive rubber-modified asphalt mixture, for preparing the above-mentioned mixture, comprising the following steps:

[0016] Step 1: Prepare rubber-modified asphalt;

[0017] Step 2: Add the aggregate and solid modifier to the mixing pot;

[0018] Step 3: Add the rubber-modified asphalt to the mixing pot;

[0019] Step 4: Add mineral powder to the mixing pot, stir, and discharge.

[0020] Optionally, step 1 includes the following steps:

[0021] Step a: Preheat the base asphalt;

[0022] Step b: Add waste rubber powder, SBS, plasticizer and liquid modifier to the preheated base asphalt, and raise the temperature;

[0023] Step c: Add sulfur and stir to obtain rubber-modified asphalt.

[0024] Optionally, in step a, the base bitumen is preheated to 140-150°C.

[0025] Optionally, in step b, the temperature is raised to 170-180℃.

[0026] Optionally, in step 3, the rubber-modified asphalt is preheated to 155-165℃.

[0027] Optionally, in step 4, the discharge temperature is 150-160℃.

[0028] Optionally, in step c, the stirring time is 20-30 minutes.

[0029] Optionally, in step 2, the mass of the solid modifier accounts for 0.2% to 1.5% of the mass of the ore.

[0030] Optionally, in step b, the amount of liquid modifier is 0.5%-2% of the rubber-modified asphalt.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0032] (1) The low-temperature sensitive rubber-modified asphalt mixture of this application, with the help of the strong adhesion and good shear stability of the modifier, can reduce the amount of asphalt used and enhance the bonding force of the asphalt-aggregate interface of the mixture (adhesion level reaches 5); on the other hand, it can also effectively improve the fatigue resistance of the rubber-modified asphalt mixture (tensile strength up to 1.65-1.68MPa, shear strength up to 2.7-3.1MPa), reduce the shear damage caused by wheel rolling on the road surface, and reduce the probability of road surface cracking.

[0033] (2) The modifier of this invention includes both solid and liquid forms, and the timing of addition differs depending on the form. Specifically, the liquid modifier is added during the preparation of rubber-modified asphalt, while the solid modifier is added during the mixing process. The solid modifier and aggregate are thoroughly and uniformly mixed, making it easier for the aggregate to wet the asphalt, further reducing the amount of rubber-modified asphalt mixture used (the amount of rubber-modified asphalt mixture in the prior art is 4.7%-5.5%, while the amount of rubber-modified asphalt mixture in this invention is 4.0%-4.5%). Furthermore, the viscosity index modifier allows the aggregate to better bind with asphalt molecules. The mixture becomes denser, less prone to loosening and particle loss, and its stability is improved.

[0034] (3) This invention adds a modifier during the preparation of rubber-modified asphalt mixtures, resulting in a higher viscosity index and a smoother viscosity-temperature curve, reducing the temperature sensitivity of the rubber asphalt and thus lowering the construction temperature (the construction temperature of existing rubber-modified asphalt mixtures is 175℃-185℃, while the construction temperature of the rubber-modified asphalt mixture of this invention is 155℃-165℃). When the construction temperature decreases, the viscosity increase of the asphalt slows down. Therefore, the rubber-modified asphalt mixture can still maintain good fluidity, making it easy to mix and pave, and also easy to compact, resulting in good workability. This is because the polymer coils of the modifier expand at high temperatures and contract at low temperatures. This change in coil morphology makes it have a greater thickening capacity at high temperatures and a smaller thickening capacity at low temperatures, thereby improving the viscosity-temperature properties of the fluid.

[0035] Simultaneously, the polymer coils of the modifier interact with asphalt molecules, which then interconnect to form a dense network structure. This enhances the cohesiveness of the asphalt and improves the softening point (85-90℃), ductility (28-35cm), and other indicators of the rubber-modified asphalt mixture, thus improving its high and low temperature performance. Furthermore, the dense network structure formed within the rubber asphalt positively contributes to its stability, enhancing its anti-aging properties (penetration ratio as high as 87%-90%, residual ductility as high as 16-20cm, and mass change of only 0.11%-0.25%).

[0036] (4) The preparation method of the present invention does not require additional equipment or additional procedures. The process is simple. While reducing the construction temperature, it does not increase the process cost, resulting in significant economic benefits.

[0037] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages will become apparent from the description or may be learned by practicing the invention. Detailed Implementation

[0038] In a first aspect, the present invention provides a low-temperature-sensitive rubber-modified asphalt mixture, comprising: rubber-modified asphalt, aggregate, and a solid modifier. The solid modifier is used to improve the viscosity of the mixture, thereby reducing the construction temperature of the rubber-modified asphalt mixture.

[0039] The amount of rubber-modified asphalt used accounts for 4.0% to 5.5% of the mass of the aggregate, for example, 4.0%, 4.2%, 4.4%, 4.5%, 4.7%, 4.9%, 5.0%, 5.2%, 5.3%, and 5.5%.

[0040] The amount of solid modifier used is 0.2% to 1.5% of the mineral mass, for example, 0.2%, 0.5%, 0.8%, 1.1%, 1.3%, and 1.5%.

[0041] Specifically, the solid modifier is in granular or powder form, including one or more of polyisobutylene (PIB) (solid), ethylene-propylene copolymer (OCP) (solid), and polymethyl methacrylate (PMA) (solid). By weight, its dosage is 0.2% to 1.5% of the rubber-modified asphalt mixture, for example, 0.2%, 0.5%, 0.8%, 1.1%, 1.3%, and 1.5%. Preferably, it is 0.5% to 1.2%.

[0042] It should be noted that the dosage of solid modifier is crucial for reducing the construction temperature of rubber-modified asphalt mixtures, and therefore needs to be strictly controlled. When the dosage is less than 0.2%, it will not reduce the construction temperature of rubber-modified asphalt mixtures; when the dosage is greater than 1.5%, it will not further reduce the construction temperature of rubber-modified asphalt mixtures and will also increase production costs. Therefore, this invention controls the dosage of solid modifier to be 0.5%-2% of the aggregate mass.

[0043] The composition of rubber-modified asphalt includes: base asphalt, waste rubber powder, styrene-butadiene-styrene block copolymer (SBS), liquid modifier, plasticizer, and sulfur. The softening point of rubber-modified asphalt is not less than 60℃, and the rotational viscosity at 180℃ is 1.5~4.0 Pa·s.

[0044] Specifically, the base asphalt is No. 70 or No. 90 road petroleum asphalt, preferably No. 70 asphalt. By weight, the amount of base asphalt accounts for 50%-90% of the rubber-modified asphalt, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%. Preferably, it is 60%-80%.

[0045] Specifically, the waste rubber powder has a mesh size of 20-40 mesh, and by weight, its usage accounts for 10%-50% of the rubber-modified asphalt, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%. 20%-40% is preferred.

[0046] Specifically, the styrene-butadiene-styrene block copolymer (SBS) has a star-shaped or linear structure and, by weight, accounts for 1%-4% of the rubber-modified asphalt, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, and 4%. Preferably, it is 2%-3%.

[0047] Specifically, the liquid modifier includes one or more of polyisobutylene (PIB) (liquid), ethylene-propylene copolymer (OCP) (liquid), polymethyl methacrylate (PMA) (liquid), poly(n-butylethylene ether) (BB), and chlorinated styrene-diene copolymer (HSD). By weight, its dosage is 0.5%-2% of the rubber-modified asphalt, for example, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, and 2.0%. Preferably, it is 0.5%-1%.

[0048] It should be noted that the dosage of liquid modifier is crucial for reducing the construction temperature of rubber-modified asphalt mixtures, and therefore needs to be strictly controlled. When the dosage is less than 0.5%, it will not reduce the construction temperature of the rubber-modified asphalt mixture; when the dosage is greater than 2%, it will not further reduce the construction temperature of the rubber-modified asphalt mixture, and will also increase production costs. Therefore, this invention controls the dosage of liquid modifier to be 0.5%-2% of the rubber-modified asphalt.

[0049] Specifically, the solid modifier is in granular or powder form, including one or more of polyisobutylene (PIB) (solid), ethylene-propylene copolymer (OCP) (solid), and polymethyl methacrylate (PMA) (solid). By weight, its dosage is 0.2% to 1.5% of the rubber-modified asphalt mixture, for example, 0.2%, 0.5%, 0.8%, 1.1%, 1.3%, and 1.5%. Preferably, it is 0.5% to 1.2%.

[0050] Specifically, the plasticizer is dibutyl phthalate, which, by weight, accounts for 0-0.6% of the rubber-modified asphalt, for example, 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%. Preferably, it is 0.3%-0.6%.

[0051] Specifically, the sulfur used is elemental sulfur, and by weight, it accounts for 0-0.6% of the rubber-modified asphalt, for example, 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%. Preferably, it is 0.3%-0.6%.

[0052] Specifically, mineral materials include stone and mineral powder.

[0053] Secondly, the present invention provides a method for preparing a low-temperature-sensitive rubber-modified asphalt mixture, which includes the following steps:

[0054] Step 1: Prepare rubber-modified asphalt;

[0055] Step 2: Preheat the mixing pot, add the aggregate and solid modifier to the mixing pot, and dry mix for 60 seconds;

[0056] Step 3: Add the preheated rubber-modified asphalt to the mixing pot and stir for 90 seconds;

[0057] Step 4: Add mineral powder to the mixing pot, stir, and discharge.

[0058] In one embodiment, step 1 includes the following steps:

[0059] Step a: Preheat the base asphalt;

[0060] Step b: Heat preservation. Add waste rubber powder, SBS, plasticizer and liquid modifier to the preheated base asphalt according to the ratio, heat up and shear at high speed.

[0061] Step c: Add sulfur and stir to obtain rubber-modified asphalt.

[0062] Specifically, in step a, the base asphalt is preheated to 140-150℃, for example, 140℃, 142℃, 145℃, 148℃, or 150℃.

[0063] Specifically, in step b, the heating temperature is 170-180℃, for example, 170℃, 172℃, 175℃, 178℃, or 180℃. The high-speed shearing time is 20-30 minutes, for example, 20 minutes, 25 minutes, or 30 minutes, and the shearing speed is 5000-7000 r / min, for example, 5000 r / min, 5500 r / min, 6000 r / min, 6500 r / min, 7000 r / min, or 7500 r / min.

[0064] In step b, the base asphalt is No. 70 or No. 90 road petroleum asphalt, preferably No. 70 asphalt. By weight, the amount of base asphalt accounts for 50%-90% of the rubber-modified asphalt, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%. Preferably, it is 60%-80%.

[0065] In step b, the waste rubber powder has a mesh size of 20-40 mesh, and its weight accounts for 10%-50% of the rubber-modified asphalt, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%. Preferably, it is 20%-40%.

[0066] In step b, the styrene-butadiene-styrene block copolymer (SBS) has a star-shaped or linear structure, and its weight percentage is 1%-4% of the rubber-modified asphalt, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, or 4%. Preferably, it is 2%-3%.

[0067] In step b, the liquid modifier includes one or more of polyisobutylene (PIB) (liquid), ethylene-propylene copolymer (OCP) (liquid), polymethyl methacrylate (PMA) (liquid), poly(n-butylethylene ether) (BB), and chlorinated styrene-diene copolymer (HSD). By weight, its dosage is 0.5%-2% of the rubber-modified asphalt, for example, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, or 2.0%. Preferably, it is 0.5%-1%.

[0068] Specifically, in step c, the stirring time is 20-30 minutes, for example, 20 minutes, 25 minutes, or 30 minutes.

[0069] Specifically, in step 2, the mixing pot is preheated to 160-170℃, for example, 160℃, 162℃, 165℃, 168℃, or 170℃.

[0070] Specifically, in step 3, the rubber-modified asphalt is preheated to 155-165℃, for example, 155℃, 157℃, 159℃, 160℃, 162℃, or 165℃.

[0071] Specifically, in step 4, the discharge temperature is 150-160℃, for example, 150℃, 152℃, 155℃, 158℃, or 160℃. The stirring time is 60 seconds.

[0072] Example 1

[0073] Rubber-modified asphalt includes the following raw materials, by weight: 68 parts of 70# base asphalt, 28 parts of 28-mesh rubber powder, 2 parts of styrene-butadiene-styrene block copolymer, 0.5 parts of plasticizer, 0.5 parts of sulfur, and 1 part of polyisobutylene (liquid).

[0074] The preparation steps of rubber asphalt are as follows: the base asphalt is heated to 150℃, waste rubber powder, SBS, plasticizer and EPDM copolymer are added according to the formula, the temperature is raised to 180℃, high-speed shearing is performed for 20 minutes at a shearing speed of 7000 r / min, sulfur is added, and stirring is performed for 30 minutes to obtain low temperature sensitive rubber modified asphalt.

[0075] In this embodiment, the mixture adopts an ARHM13 gradation, and the percentage of rubber-modified asphalt to aggregate by mass is 4.2%. The aggregate specifications are 11-15mm, 6-11mm, 3-6mm, 0-3mm, and mineral powder. By mass fraction, the proportions of each aggregate grade are 32 parts: 37 parts: 6 parts: 16 parts: 9 parts.

[0076] The mixture preparation steps are as follows: Heat the mixing pot to 170℃, add 0.8 parts of mineral aggregate and ethylene-propylene copolymer (solid) to the mixing pot, and dry mix for 60 seconds; heat the rubber-modified asphalt to 160℃. Add the rubber-modified asphalt to the mixing pot and stir for 90 seconds; add mineral powder to the mixing pot, maintain the discharge temperature at 160℃, stir for 60 seconds, and then discharge to obtain a low-temperature sensitive rubber-modified asphalt mixture.

[0077] The performance of the obtained low-temperature sensitive rubber-modified asphalt mixture was tested, and the results are shown in Tables 1 and 2.

[0078] Example 2

[0079] This embodiment is basically the same as Example 1, except that the amount of modifier used is 0.8 parts of polymethyl methacrylate (PMMA, liquid) and 1.0 parts of polymethyl methacrylate (PMMA, solid). The performance of the obtained low temperature sensitive rubber modified asphalt mixture was tested, and the results are shown in Table 1 and Table 2.

[0080] Example 3

[0081] This embodiment is basically the same as Example 1, except that the amount of modifier used is 1.0 part of poly(n-butylethylene ether) (BB, liquid) and 1.0 part of polyisobutylene (PIB, solid). The performance of the obtained low-temperature sensitive rubber-modified asphalt mixture was tested, and the results are shown in Tables 1 and 2.

[0082] Comparative Example 1

[0083] This comparative example is basically the same as Example 1, except that no liquid modifier was added when preparing the rubber-modified asphalt, and no solid modifier was added when preparing the mixture. Performance tests were performed on the obtained low-temperature sensitive rubber-modified asphalt mixture, and the results are shown in Tables 1 and 2.

[0084] Comparative Example 2

[0085] The comparative example is basically the same as Example 1, except that the solid modifier and liquid modifier are added all at once during the preparation of rubber-modified asphalt, but not during the preparation of the mixture. Performance tests were performed on the obtained low-temperature sensitive rubber-modified asphalt mixture, and the results are shown in Tables 1 and 2.

[0086] Comparative Example 3

[0087] The comparative example is basically the same as Example 1, except that the solid modifier and liquid modifier are not added during the preparation of rubber-modified asphalt, but are added all at once during the preparation of the mixture. Performance tests were performed on the obtained low-temperature sensitive rubber-modified asphalt mixture, and the results are shown in Tables 1 and 2.

[0088] Table 1 Performance of the mixtures in each embodiment and comparative example

[0089]

[0090] As can be seen from Table 1, in the embodiments of the present invention with added viscosity index modifier, compared with the comparative example, the penetration of rubber asphalt did not change significantly, but the softening point and ductility were significantly improved. The softening point reflects the high-temperature performance of asphalt, and the ductility reflects the low-temperature performance of asphalt. This shows that the addition of viscosity index modifier in the present invention has a positive effect on improving the high and low temperature performance of rubber asphalt.

[0091] Furthermore, regarding viscosity index, at 180℃, the viscosity of the embodiment of the present invention is slightly greater than that of the comparative example. This is because the viscosity index modifier has a certain thickening effect. However, at 160℃, the viscosity of the embodiment of the present invention increases slowly, while the viscosity of the comparative example at 160℃ shows a significant increase compared to that at 180℃. This indicates that the rubber asphalt modified with the viscosity index modifier of the present invention can maintain good fluidity even at lower construction temperatures, which is beneficial for mixing, paving, and compaction, and has good workability.

[0092] Penetration ratio, residual ductility, and mass change are indicators of asphalt after aging. As can be seen from Table 1, the above three indicators of the embodiments of the present invention are all better than those of the comparative example, indicating that the modified asphalt of the embodiments of the present invention does not change much in terms of indicator parameters before and after aging, and its anti-aging performance is better than that of the modified asphalt of the comparative example.

[0093] Furthermore, the porosity of the asphalt mixtures in the embodiments of the present invention is lower than that in the comparative example, and the asphalt-aggregate ratio in the embodiments is smaller than that in the comparative example, indicating that the viscosity index modifier has good adhesion ability and can achieve good compaction effect at a smaller asphalt-aggregate ratio.

[0094] The performance of the mixtures in the examples and comparative examples is shown in Table 2. As can be seen from Table 2, the dynamic stability, freeze-thaw splitting strength ratio, and maximum flexural strain of the rubber-modified asphalt mixture prepared according to the method proposed in this invention, which reflect the high and low temperature performance and water stability of the mixture, are all higher than the corresponding indicators in the comparative examples. This indicates that the performance of the rubber-modified asphalt and mixture provided by this invention is significantly improved. The low-temperature sensitive rubber-modified asphalt mixture in the examples exhibits better shear and pull-out resistance, indicating that its interlayer bond strength is higher than that of the rubber-modified asphalt mixture in the comparative examples. The addition of the viscosity index improver can effectively improve the compressive, shear, and fatigue resistance of the mixture, reducing shear damage caused by wheel-driven road surfaces.

[0095] Table 2 Performance of the mixtures in each example and comparative example

[0096]

[0097] Note: The tensile strength test temperature in Table 2 is 15℃, and the test method is JTJ 052-2011T0713; the dynamic stability test temperature is 60℃, and the test method is JTJ 052-2011T0719; the maximum bending tensile strain test temperature is -10℃, and the test method is JTJ 052-2011T0715.

[0098] The adhesion test results of the embodiments and comparative examples of this invention are shown in Table 2. The adhesion grade of asphalt and aggregate in Examples 1-3 reached level 5 (the asphalt film was completely preserved, and the peeling area percentage was close to 0), while the adhesion grade of asphalt and aggregate in Comparative Examples 1-3 was level 4 (a small portion of the asphalt film was moved by water, the thickness was uneven, and the peeling area percentage was less than 10%). This indicates that the adhesion between low-temperature sensitive rubber-modified asphalt and aggregate, with the addition of a viscosity index modifier, is superior to that of ordinary rubber-modified asphalt. In engineering applications, this can reduce the amount of asphalt used, enhance the bonding force at the asphalt-aggregate interface of the mixture, and reduce the probability of road surface cracking.

[0099] The rubber-modified asphalt mixture of this invention has a construction temperature of 155℃-165℃, a softening point of 85-90℃, a ductility of 28-35cm, a penetration ratio as high as 87%-90%, a residual ductility as high as 16-20cm, a mass change of only 0.11%-0.25%, a tensile strength as high as 1.65-1.68MPa, and a shear strength as high as 2.7-3.1MPa. It improves the high and low temperature performance of the rubber-modified asphalt mixture, improves its anti-aging performance, enhances its fatigue resistance, and reduces the amount of rubber-modified asphalt mixture used.

[0100] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A low temperature sensitive rubber modified asphalt mixture, characterized in that, include: Rubber-modified asphalt, mineral aggregates, and solid modifiers; The solid modifier is used to improve the viscosity of the mixture in order to reduce the construction temperature of the mixture; The rubber-modified asphalt accounts for 4.0% to 5.5% of the mass of the aggregate, and the solid modifier accounts for 0.2% to 1.5% of the mass of the aggregate. The solid modifier includes one or more of solid polyisobutylene (PIB), solid ethylene propylene copolymer (OCP), and solid polymethyl methacrylate (PMA). The rubber-modified asphalt comprises: base asphalt, waste rubber powder, styrene-butadiene-styrene block copolymer, liquid modifier, plasticizer, and sulfur; The liquid modifier includes one or more of liquid polyisobutylene (PIB), liquid ethylene propylene copolymer (OCP), liquid polymethyl methacrylate (PMA), poly(n-butyl ethylene ether) (BB), and chlorinated styrene-diene copolymer (HSD), and its amount accounts for 0.5%-2% of the rubber-modified asphalt by weight.

2. The mixture according to claim 1, characterized in that, The base asphalt is No. 70 or No. 90 road petroleum asphalt.

3. The mixture according to claim 1, characterized in that, The waste rubber powder has a mesh size of 20-40 mesh.

4. The mixture according to claim 1, characterized in that, The styrene-butadiene-styrene block copolymer has a star-shaped or linear structure.

5. The mixture of claim 1, wherein The plasticizer is dibutyl phthalate.

6. The mixture according to claim 1, characterized in that, The solid modifier is in granular or powder form.

7. A method for preparing a low-temperature-sensitive rubber-modified asphalt mixture, characterized in that, The preparation of the mixture according to any one of claims 1-6 comprises the following steps: Step 1: Prepare rubber-modified asphalt; Step 2: Add the aggregate and solid modifier to the mixing pot; Step 3: Add the rubber-modified asphalt to the mixing pot; Step 4: Add mineral powder to the mixing pot, stir, and discharge.

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