A low-carbon high-performance modified asphalt and asphalt concrete and preparation method thereof

Abstract

The present invention discloses a low-carbon high-performance modified asphalt and asphalt concrete and a preparation method thereof, and relates to the technical field of asphalt preparation for road engineering. The low-carbon high-performance modified asphalt uses camellia shell powder prepared from waste camellia shells as a raw material as an asphalt modifier, and the addition amount of the camellia shell powder is 4 to 16wt% of the base asphalt. The modified asphalt modified with camellia shell powder has excellent high temperature performance and creep resistance. The asphalt modification method of the present invention has a simple preparation process, low energy consumption, and low application cost. The present invention can not only realize the comprehensive resource utilization of waste camellia shells, turn waste into treasure, increase the added value of waste camellia shells, and solve the environmental problems caused by the incineration of waste camellia shells, but also greatly improve the comprehensive performance of ordinary petroleum asphalt.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt materials for road engineering, and specifically to a modified asphalt and asphalt concrete and a preparation method thereof, and in particular to a low-carbon and high-performance modified asphalt and asphalt concrete using waste camellia oleifera shells as a modifier and a preparation method thereof. Background Art

[0002] Most of the existing highway pavements in my country are asphalt pavements. However, with the continuous development of the transportation industry, the traffic volume has increased rapidly, and the performance of traditional matrix asphalt has been unable to meet the needs of the growing traffic volume. In addition, traditional matrix asphalt pavements are also unable to meet the needs of current heavy-load traffic, and the damage caused to asphalt pavements by severe climates such as freezing rain and snow, extreme high and low temperature differences, has greatly shortened the service life of traditional matrix asphalt pavements. The resulting maintenance and renewal of asphalt pavements has led to huge losses of resources and energy and a significant increase in costs, which has also hindered the development of highways. In addition, traditional matrix asphalt is mostly petroleum asphalt, which is a non-renewable resource, further hindering the sustainable development of road engineering.

[0003] In order to improve the pavement performance of traditional base asphalt, the most important way to obtain high-performance asphalt is to modify the base asphalt with modifiers. For example, SBS modifier is a commonly used asphalt modifier, but the production of SBS modifier involves petrochemical raw materials, which is unsustainable and costly.

[0004] Then people found that modifying traditional petroleum asphalt by biomass or biowaste can improve the material properties of traditional base asphalt. For example:

[0005] Chinese patent document CN110511574A discloses a lignin asphalt modifier, whose formula is composed of soluble lignin, insoluble lignin, residual oil and / or vegetable oil mixed in a mass ratio of 5-30:10-57:40-13. It uses biomass as raw material, and obtains high-purity soluble lignin and insoluble lignin after acid treatment, enzyme hydrolysis, saccharification and fermentation, and biodegradation treatment of the biomass, and mixes the soluble lignin and insoluble lignin with residual oil and / or vegetable oil under heating conditions. Adding 5-15% to the base asphalt can improve the ductility and softening point of the asphalt and reduce the advantages of asphalt penetration. However, the preparation process of the lignin modifier in this scheme is complicated, and the energy consumption and cost are high, which also limits the application of the modifier.

[0006] Chinese patent document CN109957257A discloses a biomass asphalt modifier and its preparation method and application. The scheme uses rice straw as raw material, and reacts with a mixture of polyethylene glycol 400, propylene glycol and p-hydroxyphenylethanol under acid catalysis under high temperature and high pressure to obtain a biomass modifier with good thermoplasticity; the biomass modifier is used to modify road base asphalt, and the obtained modified asphalt can significantly improve the low-temperature deformation ability of the base asphalt without changing the high-temperature performance of the base asphalt. The biomass modifier of this scheme includes biomass rice straw raw materials and some chemical substances, and the composition is relatively complex, and the cost is correspondingly increased.

[0007] Chinese patent document CN 110437638 A discloses an asphalt modifier, modified asphalt and asphalt modification method. The scheme uses lobster shell waste as an asphalt modifier, heats and melts the base asphalt, then adds 5-20wt% lobster shell powder, stirs manually and then stirs and shears under a high-speed shearing instrument to obtain lobster shell powder modified asphalt. The scheme can improve the stiffness of the asphalt binder and the high temperature stability and creep resistance of the base asphalt by adding waste lobster shell powder.

[0008] However, there are no related research reports on using camellia oleifera shell as a raw material as a matrix asphalt modifier. Camellia oleifera is a woody oil crop widely planted in southern my country. The total amount of camellia oleifera shell discarded each year is huge. Camellia oleifera shell is a rich biomass resource. However, camellia oleifera shell is generally considered to be agricultural waste and is discarded or burned in the camellia oil processing industry without being effectively utilized. Since camellia oleifera shell contains rich lignin, tannin and other substances, if it is not reasonably utilized, it will also pollute the environment and cause waste of resources. At present, the research on camellia oleifera shell mainly includes: extraction of functional components, materialization, fertilizerization and energyization. Camellia oleifera shell is often used to prepare activated carbon due to its special structure. However, these schemes cannot effectively realize the comprehensive resource utilization of camellia oleifera shell. The present invention intends to provide a modified asphalt using waste camellia oleifera shell as a modifier, a preparation method thereof and its application in asphalt concrete. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a low-carbon high-performance modified asphalt and asphalt concrete and a preparation method thereof. The purpose is to make full use of low-cost biomass waste camellia shells as raw materials and adopt a process with low energy consumption to achieve the modification of base asphalt to improve the high-temperature stability and creep resistance of traditional base asphalt. While realizing the comprehensive resource utilization of camellia shell waste and converting it into a high-value-added asphalt modifier product, it is applied to road engineering to realize the construction of green and long-life pavement.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a low-carbon high-performance modified asphalt, comprising an asphalt modifier and a base asphalt, wherein the asphalt modifier is camellia oleifera shell powder prepared from waste camellia oleifera shells as raw materials.

[0012] Further,

[0013] The addition amount of the camellia oleifera shell powder is 4-16wt% of the base asphalt.

[0014] Preferably, the particle size of the camellia oleifera shell powder is ≤220 mesh.

[0015] In a second aspect, the present invention provides a method for preparing the above-mentioned low-carbon high-performance modified asphalt, comprising the following steps:

[0016] S1. Preparation of camellia oleifera shell powder: washing the discarded camellia oleifera shells to remove dust and impurities on the surface and drying them; then grinding and sieving to obtain camellia oleifera shell powder with a particle size of ≤220 mesh.

[0017] S2. Heat and melt the base asphalt, then add 4-16 wt% of camellia oleifera shell powder, control the temperature at 155-165° C., and stir initially. The initial stirring is performed by low-speed stirring, such as manual stirring.

[0018] S3. After preliminary stirring, the mixed material is subjected to high-speed shearing for 40 to 50 minutes, and the temperature is controlled at 155 to 165°C;

[0019] S4. Further high-speed stirring and dispersing is performed at a rate of 400-450 rad / min, the time is controlled at 25-30 min, and the temperature is controlled at 165-170° C. to obtain the low-carbon high-performance modified asphalt.

[0020] In the above-mentioned preparation method of the present invention: the purpose of the preliminary stirring in step S2 is to preliminarily disperse the modifier, so as to avoid the modifier from floating up and separating in step S3 due to its density being lower than that of the matrix asphalt, thereby weakening the shear effect; the purpose of the high-speed shearing in step S3 is to grind the asphalt modifier, and the high-speed shearing process is generally carried out using a high-speed shearing instrument; the purpose of step S4 is to further disperse the ground asphalt modifier in the matrix asphalt, and the high-speed stirring and dispersing process is generally carried out in a high-speed agitator.

[0021] Further,

[0022] In step S1, the drying conditions of the waste camellia oleifera shells are: drying at 75°C to 90°C for 2h to 4h.

[0023] Further,

[0024] In step S2, the base asphalt is generally heated at 130-140° C. for 30-35 minutes to melt it.

[0025] Further,

[0026] The time of the initial stirring in step S2 is 10 to 20 minutes.

[0027] Further,

[0028] The high-speed shear rate in step S3 is 4500-5000 r / min.

[0029] In a third aspect, the present invention further provides an asphalt concrete, comprising the above-mentioned low-carbon high-performance modified asphalt or the low-carbon high-performance modified asphalt obtained by the above-mentioned method and mineral material; the low-carbon high-performance modified asphalt accounts for 5% to 6% of the weight of the mineral material.

[0030] Further,

[0031] The mineral material includes aggregate and mineral powder, and the void ratio of the mineral material is controlled at 3-6%.

[0032] In a fourth aspect, the present invention further provides a method for preparing the above-mentioned asphalt concrete, which specifically comprises the following steps:

[0033] (1) Weigh the low-carbon high-performance modified asphalt in proportion, and configure aggregate and mineral powder according to the mineral grading requirements.

[0034] (2) Heat the aggregate and mineral powder at 105°C ± 5°C for 4 to 6 hours;

[0035] (3) heating the low-carbon high-performance modified asphalt at 165° C. to 170° C. for 30 to 40 minutes until it melts, and heating the aggregate for 4 to 5 hours for later use;

[0036] (4) The heated aggregate and the melted low-carbon high-performance modified asphalt are placed at 165°C to 175°C and stirred for 90 to 120 seconds; then the prepared mineral powder is added and stirred for another 90 to 120 seconds at 165°C to 175°C to obtain asphalt concrete.

[0037] The present invention has the following beneficial effects:

[0038] 1. The present invention provides a low-carbon high-performance modified asphalt using camellia oleifera shell powder prepared from waste camellia oleifera shells as a modifier. The modified asphalt has excellent high-temperature performance and creep resistance.

[0039] 2. The present invention can realize the comprehensive resource utilization of waste camellia shells, turn waste into treasure, increase the added value of waste camellia shells, create new economic value, and reduce carbon emissions throughout the life cycle of the pavement. Since the components of camellia shells contain 31.35% lignin, 17.32% cellulose, and 22.00% hemicellulose, it can also replace the existing high-cost lignin.

[0040] 3. The method of the present invention uses waste camellia oleifera shells to modify base asphalt. After the waste camellia oleifera shells are cleaned and impurities are removed, the camellia oleifera shell powder obtained by drying, grinding and sieving can be directly applied to base asphalt for modification. The preparation process is simple.

[0041] Low energy consumption reduces application costs.

[0042] In summary, this application utilizes waste camellia oil shell powder to modify ordinary base asphalt, and can produce green, low-carbon, high-performance, sustainable modified asphalt and asphalt binder, which can not only solve the environmental problems caused by the incineration of waste camellia oil shells and realize the comprehensive resource utilization of camellia oil shells, but also greatly improve the comprehensive performance of ordinary petroleum asphalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a microscopic morphology image (scanning electron microscope) of the camellia oleifera shell powder asphalt modifier prepared in Example 1 of the present invention.

[0044] Figure 2 This is a microscopic morphology image (fluorescence microscopy image) of the waste camellia oleifera shell modified asphalt prepared in Example 2 of the present invention.

[0045] Figure 3 This is the thermogravimetric loss rate curve (25°C / min) of the camellia oleifera shell powder prepared in Example 1 of the present invention.

[0046] Figure 4 Viscosity-temperature curves of asphalt modified with camellia oleifera shell powder in different dosages at different temperatures provided in the embodiments of the present invention.

[0047] Figure 5 This is a schematic flow chart of the method for preparing waste tea oil shell modified asphalt according to Example 2 of the present invention. DETAILED DESCRIPTION

[0048] As used herein:

[0049] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0050] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0051] When a parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0052] In these examples, parts and percentages are by mass unless otherwise indicated.

[0053] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing the specific embodiments and are not intended to limit the present invention. In the embodiments, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0055] Example 1 (Preparation Example of Camellia oleifera Shell Powder Asphalt Modifier)

[0056] This embodiment provides a method for preparing a camellia oleifera shell powder asphalt modifier, comprising the following steps:

[0057] (1) The waste camellia oleifera shells collected from the oil mill are washed with pure water to remove surface dust and other impurities;

[0058] (2) placing the washed waste tea oil shells in an oven, adjusting the temperature to 75° C. to 90° C., and drying for 2 h to 4 h;

[0059] (3) The dried waste tea oil shells are placed in a grinder for grinding, and then sieved to obtain tea oil shell powder with a particle size of ≤220 mesh.

[0060] During the actual preparation operation, it was found that under the temperature conditions of 175°C to 185°C, a large number of bubbles would be generated during the preparation of the asphalt modified with the prepared camellia oleifera shell powder, resulting in a "bumping" phenomenon, which would cause the asphalt to be scrapped and overflow, affecting the processing and preparation of the material. At the same time, since the camellia oleifera shell powder is a biomass raw material, it contains rich substances, such as lignin, tannin (tannin), etc., which contain a variety of active groups and connecting bonds. High-temperature "bumping" may cause the main components in the camellia oleifera shell powder to be heated for a long time during the preparation process, leading to pyrolysis, causing the modification function to fail. Therefore, the present invention studies the thermogravimetric loss rate of camellia oleifera shell powder at different temperatures.

[0061] The results are as follows Figure 3 As shown, the camellia shell powder is heated at a rate of 25°C / min, and the thermogravimetric loss rate of the camellia shell powder reaches the maximum at 170°C. Combined with the melting temperature of the matrix asphalt and the fact that the temperature reaches 175°C to 185°C, "bumping" will occur, affecting its processing and preparation. The present invention determines the preparation temperature of the camellia shell powder modified asphalt to be preferably 155°C to 165°C. The preparation of the camellia shell powder modified asphalt is described below using this temperature as an example.

[0062] Furthermore, since the construction temperature will also have a certain impact on the performance of the tea shell powder modified asphalt, too high a temperature may cause excessive aging of the asphalt, thereby affecting the road performance of the tea shell powder modified asphalt. The present invention also conducted corresponding tests on the impact of the construction temperature of asphalt on the material properties. According to the "Asphalt Mixture Test Procedure" (JTG F40-2004), the mixing temperature of the asphalt mixture should be the temperature corresponding to the viscosity (0.17±0.02) Pa·s on the viscosity-temperature curve as the mixing temperature. Figure 4 The viscosity-temperature curves of the camellia shell powder modified asphalt at different temperatures are shown (the curves in the figure are from bottom to top: base asphalt, base asphalt + 4% camellia shell powder, base asphalt + 8% camellia shell powder, base asphalt + 12% camellia shell powder, base asphalt + 16% camellia shell powder). It can be seen that the preferred mixing temperature of the camellia shell powder modified asphalt provided by the present invention is preferably 165°C to 175°C. The preparation of asphalt concrete of camellia shell modified asphalt is described below using this temperature as an example.

[0063] Example 2 (Preparation Example of Modified Asphalt)

[0064] like Figure 5As shown, this embodiment provides a method for preparing waste camellia oleifera shell modified asphalt, which specifically includes the following steps:

[0065] (1) Heat 70# base asphalt at 130-140°C for 30-35 minutes to melt it;

[0066] (2) Adding a preset amount of camellia oleifera shell powder prepared in Example 1 as a modifier to the melted 70# base asphalt, controlling the temperature at 155-165° C., and manually stirring for 10-20 minutes;

[0067] (3) After preliminary stirring, the mixed material is subjected to high-speed shearing for 40 to 50 minutes, the shear rate is controlled at 4500 to 5000 r / min, and the temperature is controlled at 155 to 165°C;

[0068] (4) Further, high-speed stirring and dispersion is performed at a rate of 400 to 450 rad / min, the time is controlled at 20 to 30 minutes, and the temperature is controlled at 165 to 170° C., thereby obtaining the waste camellia shell modified asphalt.

[0069] In step (2) of this embodiment, four groups of dosages of 4%, 8%, 12% and 16% of the camellia oleifera shell powder prepared in Example 1 were added as a modifier.

[0070] It is found in actual operation that when the mixing amount of camellia oleifera shell exceeds 16%, mixing is already very difficult. The mixing amount ratio of the camellia oleifera shell powder of the present invention is preferably 4-16% of the base asphalt.

[0071] Example 3 (Asphalt concrete preparation example)

[0072] The mineral materials of the embodiment of the present invention are configured with reference to the AC-13 dense graded asphalt mixture mineral material gradation table shown in Table 1 below.

[0073] Table 1 AC-13 dense graded asphalt mixture mineral aggregate gradation

[0074] Screen size (mm) 16 13.2 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Upper limit of gradation 100 100 85 68 50 38 28 20 15 8 Lower limit of gradation 100 90 68 38 24 15 10 7 5 4 Median gradation 100 95 76.5 53 37 26.5 19 13.5 10 6 Pass rate (%) 100 95 79.3 50.6 35.2 22.5 14 11 8.5 6

[0075] This embodiment provides a method for preparing asphalt concrete, comprising the following steps:

[0076] (1) Weigh the four groups of camellia shell powder (4%, 8%, 12%, 16%) of the waste camellia shell modified asphalt prepared in Example 2 in proportion, and configure the aggregate and mineral powder according to the mineral material grading requirements in Table 1, control the porosity to 3-6%, and the sieve size of the mineral powder to be less than 0.075 mm. The weight ratio of the raw materials in this example is: 5 parts of waste camellia shell modified asphalt, 96 parts of aggregate, and 4 parts of mineral powder.

[0077] (2) Heat the aggregate and mineral powder at 105°C ± 5°C for 4 to 6 hours;

[0078] (3) heating the waste camellia shell modified asphalt at 165° C. to 170° C. for 30 to 40 minutes until it melts, and heating the aggregate for 4 to 5 hours for later use;

[0079] (4) The heated aggregate and the melted waste tea oil shell modified asphalt are placed at 165°C to 175°C and stirred for 90 to 120 seconds; then the prepared mineral powder is added and stirred for another 90 to 120 seconds at 165°C to 175°C to obtain asphalt concrete.

[0080] Comparative Example 1

[0081] According to the method of Example 2, different amounts of camellia oleifera shell powder were replaced with different amounts of lignin in different mass percentages (1.25%, 2.5%, 3.76%, 5%), and the mass percentage of lignin was converted by the content of lignin in the camellia oleifera shell component of about 31.35%, to obtain lignin modified asphalt, which was recorded as Comparative Example 1.1.

[0082] According to the method of Example 3, asphalt concrete was prepared with different dosages of lignin-modified asphalt, which was recorded as Comparative Example 1.2.

[0083] Comparative Example 2

[0084] According to the method of Example 2, different amounts of camellia oleifera shell powder were replaced with different amounts of lignin and cellulose (0.7%, 1.4%, 2.1%, 2.8%) in different mass percentages (1.25%, 0.7%, 3.76%, 5%), the mass percentage of lignin was converted by the content of lignin in the camellia oleifera shell component of about 31.35%, and the mass percentage of cellulose was converted by the content of cellulose in the camellia oleifera shell component of about 17.32%, to obtain lignin and cellulose composite modified asphalt. Recorded as Comparative Example 2.1.

[0085] According to the method of Example 3, asphalt concrete was prepared with different dosages of lignin-modified asphalt, which was recorded as Comparative Example 2.2.

[0086] Comparative Example 3

[0087] According to the method of Example 3, the waste camellia oleifera shell modified asphalt was replaced with 70# base asphalt to prepare unmodified asphalt concrete, which was recorded as Comparative Example 3.

[0088] In order to verify the feasibility and effectiveness of the present invention, the following performance tests were performed on the modified asphalts and asphalt concretes prepared in the above embodiments and comparative examples:

[0089] 1. The camellia oleifera shell powder asphalt modifier prepared in Example 1 and the waste camellia oleifera shell modified asphalt prepared in Example 2 were subjected to microscopic analysis by fluorescence microscopy and electron microscopy scanning. The microscopic morphologies of the materials are as follows: Figure 1 , Figure 2 shown.

[0090] like Figure 1 As shown, under 500 times electron microscope scanning, the oil-tea camellia shell powder asphalt modifier prepared in the embodiment of the present invention is a porous granular with a rough surface. The oil-tea camellia shell powder (asphalt modifier) ​​with this microscopic morphology can absorb light components in the matrix asphalt to increase the relative content of lipids and asphaltene, thereby preliminarily improving the high-temperature stability of asphalt. At the same time, the rough porous surface can provide a place for the reaction of asphalt with tannin (tannin) in oil-tea camellia shell powder at a certain temperature and finally adsorb on the surface of the tea shell powder to form a stable three-dimensional network structure.

[0091] like Figure 2 The fluorescent microscopic image of the camellia oleifera shell powder modified asphalt further prepared in the embodiment of the present invention at 50 μm level shows that the camellia oleifera shell powder and the matrix asphalt have achieved good adhesion and formed a stable three-dimensional network structure under the effect of high-speed shear dispersion. The existence of this structure improves the high-temperature performance, low-temperature ductility and toughness of the asphalt, and ultimately plays a role in mechanical reinforcement.

[0092] 2. The modified asphalts prepared in the above embodiments and comparative examples were subjected to asphalt penetration test, ductility test and softening point test (ring and ball method) according to the "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering". The modified asphalts prepared in the above embodiments and comparative examples were also subjected to asphalt dynamic shear rheology (DSR) test and multiple stress creep recovery (MSCR) test according to the "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering". The test results are shown in Table 2 below.

[0093] 3. The asphalt concrete obtained in the above examples and comparative examples was made into asphalt mixture rutting plates. The specific method is as follows: According to the "Testing Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", asphalt mixture specimens were made (wheel rolling method) to obtain a number of asphalt mixture rutting plates. According to the "Testing Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", a 60°C rutting test of the asphalt mixture was carried out, and the test results are shown in Table 3 below.

[0094] Table 2 Performance test results of modified asphalt obtained in each embodiment and comparative example

[0095]

[0096] Table 2 Performance test results of asphalt concrete prepared in each embodiment and comparative example

[0097]

[0098] From the results of Table 2 and Table 3 above, it can be seen that the performance of asphalt improves with the increase of the amount of waste oil-tea shell powder. Within the range of the oil-tea shell powder amount of the invention (4%-16%), compared with the base asphalt, the three major indicators of the modified asphalt are improved: the modified asphalt with oil-tea shell powder amount of 4%, 8%, 12%, and 16%, the rutting factor is increased by 75.8%, 116.4%, 140.4%, and 150.2%, respectively, and the recovery rate is increased by 97.4%, 163.9%, 193.0%, and 210.8%, respectively. This shows that the use of waste oil-tea shells can improve the high-temperature performance of ordinary petroleum asphalt by increasing the deformation resistance of ordinary petroleum asphalt, and at the same time has a large degree of modification of the elastic recovery of ordinary petroleum asphalt, thereby improving its road performance.

[0099] Combined with the data of the comparative example, it can be seen that compared with the unmodified matrix asphalt concrete of comparative example 3, the high temperature and rheological properties of the asphalt material modified by lignin or lignin and cellulose are improved. This may be because lignin and cellulose absorb the light components in the matrix asphalt, thereby increasing the viscosity and viscosity of the asphalt, thereby improving the strength and durability of the asphalt. The fiber structure of lignin and cellulose can increase the toughness and crack resistance of the asphalt, thereby improving the anti-stripping and anti-cracking ability of the road surface; lignin and cellulose can also provide additional fillers, increase the volume of asphalt, and improve the stability and durability of the road surface.

[0100] Furthermore, the asphalt modified by the oil-tea camellia shell powder in the present invention has better performance than the asphalt material modified by lignin or lignin and cellulose. This may be because the oil-tea camellia shell powder is a composite of lignin, cellulose and other biomass. In addition to the effect of lignin and cellulose contained therein on asphalt modification, it also has a composite effect with other biomass contained in the oil-tea camellia shell. For example, the phenolic hydroxyl group in tannic acid can react with the C=O group in the biomass fiber to form a strong connection between the biomass fiber and the asphalt, forming a uniform and stable network structure.

[0101] Furthermore, the adoption of the scheme of the present invention can achieve the replacement of existing lignin asphalt modifiers, reduce the cost of lignin application, realize the comprehensive resource utilization of waste camellia oil shells, turn waste into treasure, increase the added value of waste camellia oil shells, and solve the environmental problems caused by the incineration of waste camellia oil shells. At the same time, it can also greatly improve the comprehensive performance of ordinary petroleum asphalt, especially the high temperature performance and creep resistance of asphalt materials, and increase the service life of asphalt pavement.

[0102] The above descriptions are only some preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-carbon high-performance modified asphalt, characterized in that: It comprises an asphalt modifier and a base asphalt, wherein the asphalt modifier is camellia oleifera shell powder made from waste camellia oleifera shells, and the addition amount of the camellia oleifera shell powder is 4-16wt% of the base asphalt; Specifically prepared by the following method: S1. Preparation of camellia oleifera shell powder: washing the waste camellia oleifera shells to remove dust and impurities on the surface and drying them; then grinding and sieving to obtain camellia oleifera shell powder with a particle size of ≤220 mesh; S2, heating and melting the matrix asphalt, then adding the added amount of camellia oleifera shell powder, controlling the temperature at 155-165° C., and preliminarily stirring; S3. After preliminary stirring, the mixed material is subjected to high-speed shearing for 40-50 minutes, and the temperature is controlled at 155-165°C; S4. Further high-speed stirring and dispersing is performed at a rate of 400-450 rad / min, the time is controlled at 25-30 min, and the temperature is controlled at 165-170° C. to obtain the low-carbon high-performance modified asphalt.

2. The low-carbon high-performance modified asphalt according to claim 1, characterized in that: In step S1, the drying conditions of the waste camellia oleifera shells are: drying at 75°C to 90°C for 2h to 4h.

3. The low-carbon high-performance modified asphalt according to claim 1, characterized in that: In step S2, the base asphalt is heated at 130-140° C. for 30-35 minutes to melt it.

4. The low-carbon high-performance modified asphalt according to claim 1, characterized in that: The initial stirring time in step S2 is 10 to 20 minutes.

5. The low-carbon high-performance modified asphalt according to claim 1, characterized in that: The high-speed shear rate in step S3 is 4500-5000 r / min.

6. An asphalt concrete, characterized in that: It comprises the low-carbon high-performance modified asphalt as described in any one of claims 1 to 5 and mineral material; the low-carbon high-performance modified asphalt accounts for 5% to 6% of the weight of the mineral material.

7. The asphalt concrete according to claim 6, characterized in that: The mineral material includes aggregate and mineral powder, and the void ratio of the mineral material is controlled at 3-6%.

8. A method for preparing asphalt concrete according to any one of claims 6 to 7, characterized in that: The specific steps include: (1) Weigh the low-carbon high-performance modified asphalt in proportion, and configure aggregate and mineral powder according to the mineral grading requirements; (2) Heat the aggregate and mineral powder at 105℃±5℃ for 4~6h; (3) heating the low-carbon high-performance modified asphalt at 165° C. to 170° C. for 30 to 40 minutes until it melts, and heating the aggregate for 4 to 5 hours for later use; (4) The heated aggregate and melted low-carbon high-performance modified asphalt are stirred at 165°C to 175°C for 90 to 120 seconds; then the prepared mineral powder is added and the mixture is stirred at 165°C to 175°C for another 90 to 120 seconds to obtain asphalt concrete.

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