Rock asphalt-interfacial activated rubber powder composite modified asphalt material and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, in particular to a rock asphalt-interfacial activated rubber powder composite modified asphalt material and a preparation method thereof. The rock asphalt-interfacial activated rubber powder composite modified asphalt material is prepared from the following raw materials in percentage by mass: 4 to 6 percent of natural rock asphalt, 15 to 20 percent of rubber powder, 0.1 to 0.2 percent of silane coupling agent, 2 to 5 percent of light aromatic hydrocarbon oil, 0.1 to 3 percent of stabilizer and the balance of matrix asphalt. The material is prepared by co-doping raw material powder into matrix asphalt according to the mass fraction and adopting a step-by-step high-temperature high-shear process, and the composite modified asphalt with good compatibility and network structure stability is formed. The composite modified asphalt has the effects of high-temperature stability, low-temperature flexibility and uniform microstructure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road engineering materials, and particularly relates to a rock asphalt-interfacial activated rubber powder composite modified asphalt material and a preparation method thereof. BACKGROUND

[0002] With the continuous increase of traffic volume and the increasingly harsh service conditions of roads, the performance requirements of road asphalt materials are constantly improving. Especially in high-temperature, heavy-load and cold regions, traditional base asphalt has been difficult to meet the current demand for durability and structural performance of road engineering due to its strong viscosity-temperature sensitivity, easy permanent deformation at high temperature and easy cracking at low temperature. Therefore, the development of high-performance modified asphalt materials has become a hot spot in material research in recent years.

[0003] As a natural asphalt, rock asphalt has high softening point, high aromatic content and complex colloid-asphaltene structure, which gives it good high-temperature stability and aging resistance. It has been widely used in high-grade roads, heavy-load traffic and airport runways, etc. However, the rigid structure of rock asphalt also brings the problem of low-temperature brittleness, and its dosage is not easy to control. Once the proportion is too high, it is easy to cause the asphalt mixture to crack or early damage under low-temperature conditions, which seriously restricts its popularization and application.

[0004] In order to make up for the rigidity defect of rock asphalt, researchers try to use elastomers such as SBS (styrene-butadiene-styrene block copolymer) or waste rubber powder (Crumb Rubber, CR) in combination with rock asphalt. As an elastic reinforcing component, rubber powder has good tensile recovery capacity, strain adaptability and tackifying effect, and it can significantly improve the elasticity and fatigue resistance of the asphalt system after absorbing part of the light components. However, the current common RA / CR composite system still has the following deficiencies: 1. The proportion of the composite is highly empirical: most studies use equal proportions or fixed proportions, and there is a lack of systematic optimization of the proportion and macro-micro coordination verification; 2. Insufficient structural compatibility: different sources of rock asphalt and rubber powder have poor interface compatibility, and are prone to "phase separation" problems, and the waste tire vulcanized rubber powder commonly crushed at room temperature is easy to cause the rock asphalt-rubber powder composite system to have high viscosity and poor compatibility, resulting in deterioration of the material performance; 3. Lack of understanding of micro-mechanism: current researches mostly focus on macro-rheological properties or short-term mechanical performance, and there are relatively few studies on the modification mechanism, functional group changes and aging evolution path at the micro level; 4. One-sided evaluation of aging performance: the conventional DSR and BBR evaluation methods cannot fully reflect the aging stability and functional structure retention ability of the composite material. SUMMARY

[0005] The present application aims to provide a rock asphalt-interfacial activated rubber powder composite modified asphalt material and a preparation method thereof, overcome the defects of existing rock asphalt or rubber powder single modified asphalt material, such as unbalanced high-temperature or low-temperature performance, poor aging stability, too high viscosity, poor storage stability, etc., and provide a rock asphalt-interfacial activated rubber powder composite modified asphalt material and a preparation method thereof, which are widely applicable to heavy traffic, high-temperature or cold area road construction.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The present application provides a rock asphalt-interfacial activated rubber powder composite modified asphalt material, which is composed of the following raw materials in mass fraction: natural rock asphalt 4-6%, rubber powder 15-20%, silane coupling agent 0.1-0.2%, light aromatic oil 2-5%, stabilizer 0.1-3%, and the rest is base asphalt.

[0007] Optionally, the softening point of the natural rock asphalt is 170-200℃, and the density is 1.00-1.05g / cm 3 .

[0008] Optionally, the rubber content in the rubber powder is ≥54.6%, and the volatile heating loss is ≤0.4%; the particle size of the rubber powder is ≤60 mesh.

[0009] Optionally, the silane coupling agent includes epoxy silane.

[0010] Optionally, the stabilizer is sulfur-based stabilizer.

[0011] Optionally, the base asphalt includes 80 / 100 road petroleum asphalt.

[0012] The present application also provides a preparation method of the above-mentioned rock asphalt-interfacial activated rubber powder composite modified asphalt material, which includes the following steps: After the base asphalt is preheated, the natural rock asphalt is added, and first shearing is performed to obtain a first mixture; The first mixture, rubber powder, silane coupling agent, light aromatic oil and stabilizer are subjected to second shearing to obtain the rock asphalt-interfacial activated rubber powder composite modified asphalt material.

[0013] Optionally, the preheating temperature is 170-175℃; the shearing speed of the first shearing is 2000-2500rpm, and the time is 30-35min.

[0014] Optionally, the shearing temperature of the second shearing is 165-170℃, the shearing speed is 4500-5000rpm, and the time is 30-35min.

[0015] Compared with the prior art, the present application has the following beneficial effects: The present application takes road petroleum asphalt as main material, and adds natural rock asphalt, waste tire rubber powder, silane coupling agent, light aromatic oil and stabilizer according to mass percentage, and a composite modified asphalt material with high-temperature stability, low-temperature flexibility and uniform microstructure is prepared by controlling the mixing amount of raw materials, the amount of introducing agent, the mixing order, the shearing condition and the temperature curve.

[0016] The rock asphalt of the present application provides high-temperature strength, the rubber powder compensates for low-temperature flexibility, forms a composite system of "rigidity and flexibility", and the synergistic modification effect is obvious. The microstructure of the composite components of the present application does not break down during the aging process, has good durability, and has good structural stability. The rubber powder of the present application is derived from waste tire resources, is green and environmentally friendly, has relatively low material cost, is suitable for large-scale promotion, and is economic and environmentally friendly. The material of the present application is suitable for various typical service environments, has strong adaptability, and is particularly suitable for the reconstruction and construction of rut-sensitive road sections in high-temperature areas and crack-prone roads in cold areas. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flow chart for preparing the rock asphalt-interfacial activated rubber powder composite modified asphalt material of the present application; Figure 2 Han curve graph of the 5R / 18C composite modified asphalt material prepared in Example 1 under different states. DETAILED DESCRIPTION

[0018] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0019] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within the range and any other stated value or intermediate value within the range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In case of conflict, the content of the present specification will control.

[0021] Many modifications and variations of this application of the application can be made without departing from its spirit or scope, which will be apparent to those skilled in the art. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.

[0022] As used herein, the terms "comprise", "comprising", "include", "including", "have" and "having" and the like are open-ended, that is, meaning "including but not limited to".

[0023] The raw materials used in the present application can be obtained commercially or prepared by prior art.

[0024] The present application provides a rock asphalt-interfacial activated rubber powder composite modified asphalt material, which is composed of the following raw materials in mass fraction: 4-6% of natural rock asphalt, 15-20% of rubber powder, 0.1-0.2% of silane coupling agent, 2-5% of light aromatic oil, 0.1-3% of stabilizer, and the balance of base asphalt.

[0025] Based on systematic experimental design and rheological-chemical-microscopic multi-dimensional coupling analysis, the present application proposes a composite modified asphalt system with a clear ratio of asphalt-interfacial activated rubber powder, with 5% of natural rock asphalt and 15-20% of rubber powder as the optimal ratio. Through a double-temperature and double-shear synergistic modification process, and by introducing silane coupling agent and light aromatic oil as the interfacial activator of rubber powder, the compatibility of rock asphalt and rubber powder is improved. The composite system forms a stable network structure through the synergistic effect of the two components, realizing the composite modification mechanism of "harmonious combination of rigidity and flexibility, synergistic reinforcement". The research not only verifies the excellent high and low temperature and aging resistance performance from the macroscopic performance, but also reveals the structural stability through Han curve, and confirms the physical-chemical dual modification effect through FTIR infrared spectrum, thereby providing theoretical support and practical basis for the design of composite modified asphalt system.

[0026] In the present application, the rock asphalt-interfacial activated rubber powder composite modified asphalt material comprises 4-6 wt.% of natural rock asphalt, preferably 5 wt.%.

[0027] In the present application, the rock asphalt-interfacial activated rubber powder composite modified asphalt material comprises 15-20 wt.% of rubber powder, for example, it can be 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.% or 20 wt.%.

[0028] In the present application, the rock asphalt-interfacial activated rubber powder composite modified asphalt material comprises 0.1-0.2 wt.% of silane coupling agent, preferably 0.1 wt.%.

[0029] In the present application, the rock asphalt-interfacial activated rubber powder composite modified asphalt material comprises 2-5 wt.% of light aromatic oil, preferably 3 wt.%.

[0030] In the present application, the rock asphalt-interfacial activated rubber powder composite modified asphalt material comprises 0.1-3 wt.% of stabilizer, preferably 0.3 wt.%.

[0031] In the present application, the natural rock asphalt has a softening point of 170-200℃ and a density of 1.00-1.05 g / cm 3 .

[0032] In some embodiments of the present application, the natural rock asphalt is selected from imported Iranian natural rock asphalt, which has high aromatic component and heavy component content, and can significantly improve the high-temperature modulus and heat aging resistance of the asphalt system.

[0033] In the present application, the rubber content in the rubber powder is ≥54.6%, and the volatile heating loss is ≤0.4%; the particle size of the rubber powder is ≤60 mesh.

[0034] In some embodiments of the present application, the rubber powder is obtained by crushing waste tires, and is sieved through a 60 mesh screen, has uniform particle distribution, and has a small volatile loss rate (heating weight loss is 0.34%), is suitable for blending with base asphalt under high shear conditions, can be fully expanded and adsorb light oil components under shear, and form a uniform distribution of elastic phase network structure with rock asphalt.

[0035] In the present application, the silane coupling agent comprises epoxy silane.

[0036] In the present application, there is no limitation on the type of light aromatic oil, as long as it is aromatic oil, and in the specific embodiments of the present application, the light aromatic oil is rubber oil.

[0037] In the present application, the stabilizer is preferably a sulfur-based cross-linking accelerator, and in the embodiments of the present application, it is preferably a sulfur-based stabilizer containing sulfur or some other auxiliary materials.

[0038] In the present application, the base asphalt includes 80 / 100 road petroleum asphalt, has good processability and moderate viscosity-temperature sensitivity, and is a typical road base asphalt type at home and abroad.

[0039] The present application also provides a preparation method of the above rock asphalt-interfacial activated rubber powder composite modified asphalt material, comprising the following steps: After the base asphalt is preheated, the natural rock asphalt is added, and first shearing is performed to obtain a first mixture; The first mixture, rubber powder, silane coupling agent, light aromatic oil and stabilizer are subjected to second shearing to obtain the rock asphalt-interfacial activated rubber powder composite modified asphalt material.

[0040] In the present application, after the base asphalt is preheated, the natural rock asphalt is slowly added under constant temperature conditions, and shearing is performed by a high-shear emulsification device to ensure that the rock asphalt is fully dispersed in the asphalt matrix and interacts with the light components.

[0041] In the present application, the preheating temperature is 170-175 DEG C, preferably 175 DEG C.

[0042] In the present application, the preheating temperature is 170-175 DEG C, preferably 175 DEG C.

[0043] In the present application, the preheating temperature is 170-175 DEG C, preferably 175 DEG C.

[0044] In the present application, the preheating temperature is 170-175 DEG C, preferably 175 DEG C.

[0045] The process of the present application establishes a stable "physical chimeric + chemical bonding" network system through step-by-step shearing, temperature regulation and two-component synergy, and ensures uniform material structure and stable performance.

[0046] The composite modified asphalt material of the present application can be widely applied to heavy traffic roads, high-grade highways, cold climate area roads, heavy vehicle climbing roads, airport runways, port yards and other asphalt pavement engineering with high requirements of anti-rutting, anti-cracking and durability.

[0047] The rock asphalt-rubber powder composite modified asphalt material prepared by the application has excellent performance in structural uniformity, chemical stability, mechanical elasticity and service durability, and can be applied to various road construction projects as a new generation of high-performance road asphalt material.

[0048] The technical solutions provided by the application will be described in detail below in combination with examples, but they should not be understood as limiting the protection scope of the application.

[0049] In the examples of the application, the 80 / 100 road petroleum asphalt is purchased from Sinopec Zhenhai Refining and Chemical Company; the natural rock asphalt is purchased from Jiangsu Budun Leipu New Material Technology Co., Ltd., with a softening point of 170-200 ℃ and a density of about 1.02 g / cm 3 ; the rubber powder is purchased from Chengdu Sitong Rubber Plastic Co., Ltd., with a rubber content of about 54.6%, and the sulfur-based stabilizer is purchased from Tianjin Muyijing Chemical Co., Ltd.

[0050] Example 1 The rock asphalt-interfacial activated rubber powder composite modified asphalt material is prepared by weighing the natural rock asphalt, rubber powder, silane coupling agent, light aromatic oil, stabilizer and base asphalt according to the mass fraction.

[0051] According to the above mass fraction, the 80 / 100 road petroleum asphalt is preheated to 175 ℃ to ensure that it is in a molten flow state and suitable for shear dispersion, and the natural rock asphalt is slowly added under constant temperature conditions. The system is cooled to 165 ℃, and then the rubber powder, silane coupling agent, light aromatic oil and sulfur-based stabilizer are added, and the high shear mixing is continued at 5000 rpm for 30 minutes. After cooling to room temperature, the rock asphalt-interfacial activated rubber powder composite modified asphalt material is obtained, which is recorded as 5R / 18C composite modified asphalt material.

[0052] The obtained 5R / 18C composite modified asphalt material is comprehensively evaluated by standard test methods: (1) Structural stability analysis (Han curve) The Han curve of the material is drawn under the condition of temperature 64 ℃ and frequency range 0.01-100 rad / s, and the relationship between G' and G" is observed. The results are as follows Figure 2As shown, the results show that the curve slope of the composite is still close to 2 under the conditions of RTFO and PAV aging, and the relationship curve of the storage modulus and the loss modulus does not appear obvious bifurcation, which indicates that the composite structure does not occur obvious phase separation in the aging process, and indicates that the material structure is uniform, the component compatibility is good, and the material has excellent aging stability, good micro stability and component compatibility.

[0053] (2) Elasticity and anti-deformation ability (MSCR) The multi-stress creep recovery (MSCR) test is carried out at 64℃, and the residual strain (Jnr) and recovery rate (R) are tested at two stress levels of 0.1 kPa and 3.2 kPa. The results show that the Jnr of the 5R / 18C sample is lower than 1.0 kPa -1 , the R value is greater than 75%, the residual strain is minimum, the recovery rate is high, the non-recoverable creep index Jnr is significantly reduced, the elastic recovery ability is strong, the anti-fatigue performance is better than other modification systems, which indicates that the material has excellent non-linear recovery ability and deformation stability, and is suitable for high-temperature heavy-load pavement.

[0054] (3) Low-temperature crack resistance (BBR) The bending beam rheometer (BBR) is used to test the creep stiffness S and relaxation rate m values at-18℃, and the results are: S = 272 MPa, m = 0.368, which all meet the requirements of the American SHRP specification for PG 82-32 grade, which indicates that the material can effectively resist low-temperature thermal shrinkage cracks in cold environments, has excellent crack resistance, and has excellent low-temperature flexibility and strain adaptability.

[0055] (4) Dynamic shear rheometer (DSR) test The dynamic shear rheometer (DSR) test is carried out at 64℃, and the G* / sinδ value is 3.38 kPa, and the PG grade reaches 82-32, which has good high-temperature rut resistance and shear resistance.

[0056] In summary, the composite modification ratio proposed in the application takes into account the advantages of rock asphalt in enhancing rigidity and anti-rutting at high temperatures and interface activated rubber powder in improving flexibility and inhibiting cracking at low temperatures. The 5R / 18C composite modified asphalt prepared in the application has excellent high-temperature performance in the DSR test and good low-temperature crack resistance in the BBR test, and the PG grade reaches 82-32, which is significantly better than the traditional SBS modified asphalt. Microstructure analysis shows that the material has no bifurcation trend in the Han diagram, indicating that the structure is still uniform and stable after short-term and long-term aging; in addition, the material has small non-recoverable deformation, high strain recovery rate, good elastic recovery ability and anti-fatigue performance in the MSCR test.

[0057] Comparative Example 1 The difference from Example 1 is only that the rubber powder is omitted.

[0058] Comparative Example 2 The difference from Example 1 is only that the natural rock asphalt is omitted.

[0059] Comparative Example 3 The difference from Example 1 is only that the silane coupling agent, light aromatic oil and stabilizer are omitted.

[0060] The softening point, ductility, storage stability and mass change after aging of the modified asphalt materials of Example 1 and Comparative Examples 1-3 are tested according to the standard JT / T 798-2019, and the test results are shown in Table 1.

[0061] Table 1 Test results of modified asphalt material performance of examples and comparative examples

[0062] As can be seen from Table 1, compared with Example 1, the aging performance of Comparative Example 1 decreases after omitting the rubber powder, which shows that the rubber powder has the effect of improving the anti-aging performance of the modified asphalt material; the softening point of Comparative Example 2 decreases after omitting the natural rock asphalt, which shows that the natural rock asphalt has the effect of improving the softening point of the modified asphalt material, i.e. the high-temperature anti-deformation ability; the storage stability of the modified asphalt of Comparative Example 3 is poor after omitting the silane coupling agent, light aromatic oil and stabilizer, which shows that the three auxiliary modifiers have the effects of improving the modification stability and storage stability, and compared with Example 1, the storage stability of Comparative Examples 1-3 does not meet the standard, which shows that only the synergistic effect exists between the components of the present application, which can improve the storage stability of the modified asphalt material.

[0063] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should be considered as the protection scope of the present application.

Claims

1. A rock asphalt - interfacially activated rubber powder composite modified asphalt material, characterized by, The natural rock asphalt is 4-6%, the rubber powder is 15-20%, the silane coupling agent is 0.1-0.2%, the light aromatic oil is 2-5%, the stabilizer is 0.1-3%, and the rest is the base asphalt.

2. The rock pitch - interfacially activated rubber powder complex modified pitch material of claim 1, wherein, The natural rock asphalt has a softening point of 170-200℃ and a density of 1.00-1.05 g / cm 3 .

3. The rock pitch - interfacially activated rubber powder complex modified pitch material of claim 1, wherein, The rubber content in the rubber powder is greater than or equal to 54.6%, and the volatile heat loss is less than or equal to 0.4%; the particle size of the rubber powder is less than or equal to 60 mesh.

4. The rock pitch - interfacially activated rubber powder complex modified pitch material of claim 1, wherein, The silane coupling agent comprises an epoxy silane.

5. The rock pitch - interfacially activated rubber powder complex modified pitch material of claim 1, wherein, The stabilizer is a sulfur stabilizer.

6. The rock pitch - interfacially activated rubber powder complex modified pitch material of claim 1, wherein, The base asphalt comprises 80 / 100 road petroleum asphalt.

7. A process for the preparation of rock pitch - interfacially activated rubber powder complex modified bituminous material as claimed in any one of claims 1 to 6, characterized in that, The method comprises the following steps: The base asphalt is preheated, and then the natural rock asphalt is added to perform first shearing to obtain a first mixture; The first mixture, the rubber powder, the silane coupling agent, the light aromatic oil and the stabilizer are sheared to obtain a rock asphalt-interfacial activated rubber powder composite modified asphalt material.

8. The preparation method according to claim 7, characterized in that, The preheating temperature is 170-175 DEG C; the shearing speed of the first shearing is 2000-2500 rpm, and the shearing time is 30-35 min.

9. The preparation method according to claim 7, characterized in that, The shearing temperature of the second shearing is 165-170 DEG C, the shearing speed is 4500-5000 rpm, and the shearing time is 30-35 min.

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