Road asphalt substitute materials based on recycled oil and their applications

Abstract

The invention discloses a road asphalt substitute material based on recycled oil and its application. The road asphalt substitute material of the invention comprises, by mass, 100 parts of waste grease, 18 to 45 parts of petroleum coke, 18 to 39 parts of waste rubber powder and 6 to 14 parts of pretreated waste plastic. The pretreated waste plastic is prepared by heating polypropylene wax to a molten state, adding dibenzoyl peroxide, methacrylic acid and styrene, stirring for 1 to 2 hours, and then adding the waste plastic in batches and stirring until the waste plastic is completely dissolved. The mass ratio of the polypropylene wax, dibenzoyl peroxide, methacrylic acid, styrene and waste plastic is 1:0.02 to 0.03:0.3 to 0.5:0.2 to 0.4:5 to 6. The invention recycles waste materials from waste plastic, waste grease and waste rubber powder, adds petroleum coke and treats the waste plastic using a pretreatment process to prepare a road asphalt substitute material having properties similar to those of SBS modified asphalt in the prior art. The road asphalt substitute material can replace the asphalt in the prior art for paving the middle layer of the road.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering materials and relates to road asphalt substitute materials based on recycled oil and their applications. Background Art

[0002] Waste oil refers to various low-quality oils found in daily life, such as recycled cooking oil and reused frying oil. It is a type of extremely poor-quality, unsanitary, non-edible oil. Recycling waste oil can yield recycled oil. The emergence of large amounts of waste oil not only pollutes the environment but also increases food safety risks when waste oil returns to the table. While waste oil is extremely harmful to society, it is also a resource-recyclable waste, so the best solution is recycling it and turning waste into treasure.

[0003] In recent years, there have been research reports on the application of waste oil and fat in the field of asphalt at home and abroad. A US patent mentions the use of an environmentally friendly asphalt regeneration agent to regenerate aged asphalt or soften original asphalt. This regeneration agent is derived from oil extracted from plants. Scholars from Washington State University in the United States have prepared a "bio-asphalt", which is produced by composite production of waste cooking oil and fly ash. Malaysian scholars have studied the feasibility of using waste oil and fat as a regeneration agent for the regeneration of aged asphalt. Domestic patents mention the use of waste oil and fat to regenerate or soften asphalt. Chen Meizhu, Wu Shaopeng and others from Wuhan University of Technology added a certain amount of regeneration agent, waste oil and fat and cottonseed oil to waste asphalt, and compared their respective high-temperature rheological properties. Although these reports have laid a theoretical foundation for the research of the present invention, the existing technology requires a certain proportion of asphalt or old asphalt as the matrix, and there are few reports on the use of recycled oil as the matrix without the addition of asphalt.

[0004] Furthermore, as the consumption of plastic products continues to grow, the amount of plastic waste generated in my country is also increasing annually. This waste plastic primarily comes from plastic film, plastic yarn and woven fabrics, foam plastics, plastic packaging and containers, household plastic products, plastic bags, and agricultural mulch. It is diverse and complex in composition, including polyethylene, polypropylene, and polyvinyl chloride. Therefore, the recycling and reuse of waste plastics has become a key focus of sustainable development in recent years.

[0005] Regarding the research on the application of plastics in the field of asphalt, there is a patent in China that utilizes multiple components such as petroleum resin, rubber oil, thermoplastic elastomer, rubber-like modifier, high-density polyethylene, thermoplastic resin, high viscosity agent, warm mix agent, polyamide to prepare colored asphalt binder. This colored asphalt is not only complex in components and expensive, but more importantly, it has poor cohesion with the mixture, has the shortcomings of high temperature resistance, durability and strength, and is generally only used as a road surface material. In addition, due to the complex composition of waste plastics, when applied to the field of asphalt, problems such as immiscible materials and serious segregation will easily occur. Therefore, in the prior art, most of the research is directed to single high-density polyethylene, and existing processes can not realize the comprehensive reuse of waste plastics.

[0006] Therefore, in order to improve the comprehensive utilization rate of recycled oils and waste plastics, the present invention hopes to study a "bitumen-like" material without adding asphalt. Summary of the Invention

[0007] The purpose of the present invention is to improve the comprehensive utilization rate of recycled oils and waste plastics, and to study a "bitumen-like" material that does not add asphalt and has performance that meets the requirements of mid-level paving for highways and urban roads.

[0008] The technical solution adopted by the present invention is a road asphalt substitute material based on recycled oil. The key is that, by weight, the above-mentioned road asphalt substitute material includes 100 parts of waste grease, 18 to 45 parts of petroleum coke, 18 to 39 parts of waste rubber powder and 6 to 14 parts of pre-treated waste plastic;

[0009] The preparation process of the pretreated waste plastics is as follows: polypropylene wax is heated to a molten state, dibenzoyl peroxide, methacrylic acid and styrene are added, stirred for 1 to 2 hours, and then the waste plastics are added in batches and stirred until the waste plastics are completely dissolved;

[0010] The mass ratio of the polypropylene wax, dibenzoyl peroxide, methacrylic acid, styrene and waste plastic is 1:0.02-0.03:0.3-0.5:0.2-0.4:5-6.

[0011] Specifically, the above-mentioned waste grease is recycled waste grease that has been filtered and impurities removed, and the above-mentioned filtration and impurity removal includes ordinary filtration and fine filtration; the material of the above-mentioned waste plastic includes any one or combination of polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, polyamide and acrylonitrile-butadiene-styrene copolymer.

[0012] Preferably, the waste grease has a viscosity of 0.04 Pa·s to 0.06 Pa·s at 20°C and a water content of less than 0.15%.

[0013] Furthermore, the specific process of the above-mentioned road asphalt substitute material is as follows:

[0014] Add petroleum coke to waste grease, stir until fully mixed, then add waste rubber powder and pretreated waste plastic in sequence, continue stirring at 180℃~200℃ for 40min~60min, and then high-speed shear for 1min~5min.

[0015] Specifically, the high-speed shearing is performed at a rotation speed of the high-speed shearing machine of 7000 r / min to 9000 r / min.

[0016] Specifically, the above-mentioned road asphalt substitute material has a rotational viscosity of 3.0 Pa·s to 4.0 Pa·s at 180°C, an elongation greater than 10 cm, and a softening point greater than 60°C.

[0017] The key to the application of recycled oil-based road asphalt substitute materials is to mix them with the aggregate for the middle surface layer SAC-20 asphalt mixture at an oil-to-stone ratio of 4.5% to 5.5%.

[0018] Specifically, the aggregate for the above-mentioned middle surface layer SAC-20 asphalt mixture includes coarse aggregate, fine aggregate and mineral powder, and the mass ratio of the coarse aggregate, fine aggregate and mineral powder is 75-80:15-20:5.

[0019] More specifically, the mass ratio of the coarse aggregate with particle sizes ranging from 15 mm to 20 mm, 10 mm to 15 mm, 5 mm to 10 mm, and 3 mm to 5 mm in the above coarse aggregate is 21-23:23-25:22-24:7-9.

[0020] Furthermore, the specific process of the above-mentioned mixed use is: heating the road asphalt substitute material to 185° C., a bitumen film is precipitated on the surface with a granular feel, and then adding aggregate to mix and paving for use.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention utilizes recycled waste plastics, waste grease, and waste rubber powder. By adding petroleum coke and utilizing a special pretreatment process to treat the waste plastics, an environmentally friendly alternative to road asphalt is produced. This alternative exhibits properties similar to existing SBS-modified asphalt and can replace existing asphalt for paving mid-layer surfaces. The mixture produced using this invention not only meets the performance requirements of a SAC-20 mid-layer asphalt mixture, but also exhibits lower freeze-thaw splitting strength variation and improved low-temperature resistance.

[0023] During the research of the present invention, it was found that the order of adding materials is very important. The general method of mixing all materials cannot produce a material with good performance suitable for asphalt substitutes. The pretreatment method of the present invention, that is, dissolving the waste plastics before mixing, helps to make full use of the waste plastics. However, the use of existing polyethylene wax or polypropylene wax can only be used to pretreat specific types of waste plastics that are very close to their properties. When treating mixed waste plastics of various types, problems such as insolubility or shrinkage are prone to occur. The pretreatment method of the present invention can be applied to the treatment of a variety of waste plastics, and can prepare mutually soluble and non-shrinking materials for subsequent applications.

[0024] During the pretreatment of waste plastics, the present invention uses dibenzoyl peroxide in a molten state as an initiator, enabling the smooth grafting of methacrylic acid and styrene onto polypropylene wax. The use of styrene not only improves the solubility and pairing ability of polypropylene wax with styrene-based plastics, but the use of phenylacetic acid as a second monomer also prevents degradation of polypropylene wax due to free radical reactions, further facilitating the preparation of materials with more complex, three-dimensional network structures. This in turn helps improve the viscosity and other properties of the prepared asphalt substitute material. Furthermore, dibenzoyl peroxide, a vulcanizing agent, acts as a stabilizer during the asphalt preparation process, improving sample stability and long-term performance without the addition of additional stabilizers, further reducing production costs.

[0025] Furthermore, the study also found that asphalt substitute materials prepared using unrefined recycled grease are superior to refined recycled grease. This may be because the waste grease itself contains a large amount of higher fatty acid glycerides, which causes the waste grease to "gel." The recycling of conventional waste grease requires relatively complex refining processes such as alkalization and deacidification to break down the higher fatty acid glycerides. However, the research of the present invention unexpectedly discovered that the performance of road asphalt substitute materials prepared using waste grease that has only undergone physical impurity removal is actually better. This simplifies the waste grease processing process, further reduces the cost of purchasing raw materials, and improves the utilization efficiency of waste grease. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a photograph of the asphalt substitute material sample of the present invention when heated to 185°C.

[0027] Figure 2 This is a photo of the asphalt substitute material sample after mixing.

[0028] Figure 3 This is a test photo of waste plastic sample 1 that was pretreated with polypropylene wax and showed mutual solubility but shrinkage.

[0029] Figure 4This is a test photo of waste plastic sample 2 that shows mutual solubility and no shrinkage when pretreated with polypropylene wax.

[0030] Figure 5 This is a photo of the immiscible test that occurred when waste plastic sample 3 was pretreated with polyethylene wax. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] If the specific conditions are not specified in the examples, the experiments can be carried out under conventional conditions; if the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased from the market.

[0033] Example 1 to Example 6

[0034] The waste plastics were pretreated according to the following steps. The specific material ratios and parameters are shown in Table 1:

[0035] Heat 1 part of polypropylene wax to a molten state, add dibenzoyl peroxide, methacrylic acid and styrene, stir for a certain period of time, then add waste plastics in batches and stir until the waste plastics are completely dissolved;

[0036] Polypropylene wax, dibenzoyl peroxide, methacrylic acid, styrene and waste plastics are added in a certain mass ratio. The specific materials and material ratios in the waste plastics are shown in Table 2.

[0037]

[0038] Embodiment 7 to Embodiment 18

[0039] The road asphalt substitute material of the present invention is prepared according to the following steps. The specific material proportions and parameters are shown in Table 3:

[0040] By mass, petroleum coke was added to 100 parts of waste grease, stirred until fully mixed, and then waste rubber powder and pretreated waste plastic samples were added in sequence. After heating to a certain temperature and continuous stirring, the mixture was sheared at high speed for a certain time in a high-speed shearing machine.

[0041] The waste grease used in this embodiment has a viscosity of 0.04 Pa·s to 0.06 Pa·s at 20° C. and a water content of less than 0.15%. Specifically, the viscosity at 20° C. is 0.05 Pa·s and the water content is 0.14%.

[0042]

[0043] Example 19 to Example 24

[0044] The different asphalt substitute material samples were heated to 185 °C. Figure 1 There is asphalt film precipitation on the surface and a granular feel. According to a certain oil-stone ratio, add SAC-20 asphalt mixture aggregate of different particle sizes to the middle surface layer, mix and spread it for use. See the attached Figure 2 After mixing, the asphalt substitute material sample of the present invention is gray and dull in color.

[0045] The particle size of the aggregate samples used is shown in Table 4, and the specific oil-to-stone ratio and asphalt substitute material samples used are shown in Table 5.

[0046]

[0047]

[0048] Comparative Example 1

[0049] This comparative example studies the order of adding materials, using different waste plastic samples, but without pretreatment of the waste plastics. Instead, 20 parts of petroleum coke were added to 25 parts of waste grease, and stirred until fully mixed. Then, 20 parts of waste rubber powder, 3 parts of different waste plastic samples, 0.7 parts of polypropylene wax, 0.02 parts of dibenzoyl peroxide, 0.27 parts of methacrylic acid, and 0.2 parts of styrene were added in sequence. After continuous stirring at 185°C for 50 minutes, high-speed shearing was performed for 2 minutes. During the test, it was found that some test groups showed precipitation and stratification to varying degrees, resulting in some control samples not being able to be used as asphalt substitutes and not being used in subsequent test processes.

[0050] The experimental phenomena in this comparative example are briefly summarized, and the results are shown in Table 6.

[0051]

[0052] Comparative Example 2

[0053] This comparative example studies the pretreatment method of waste plastics. Polyethylene wax and polypropylene wax are used to pretreat different waste plastic samples. During the experiment, it was found that some test groups had problems such as segregation, immiscibility and shrinkage to varying degrees, resulting in some waste plastic reference samples being unsuitable for subsequent research on the preparation of asphalt substitute materials.

[0054] The experimental phenomena in this comparative example are briefly summarized, and the results are shown in Table 7.

[0055]

[0056] For the cases of mutual solubility but obvious shrinkage in Table 7, please refer to the attached Figure 3 , for mutual dissolution and no shrinkage, see the attached Figure 4 For insoluble matters, please refer to the attached Figure 5 .

[0057] Comparative Example 3

[0058] In this comparative example, the components of asphalt substitute materials were studied. Non-asphalt materials were added to 25 parts of waste grease after different treatments. After stirring until fully mixed, 20 parts of waste rubber powder and 4 parts of pretreated waste plastic sample 1 were added in sequence. The mixture was stirred at 185°C for 50 minutes and then sheared at high speed for 2 minutes to prepare an asphalt substitute material reference product. For specific material types, see Table 8.

[0059]

[0060] Note: The unrefined waste grease in Table 8 is the waste grease used in the examples of the present invention, that is, the waste grease that has been filtered by ordinary filtration and fine filtration using a semipermeable membrane to remove solid impurities; the refined waste grease is the waste grease that has been filtered by ordinary filtration and fine filtration using a semipermeable membrane to remove solid impurities, and then subjected to alkaline hydrolysis and deacidification. The resulting grease is clearer and lighter in color, and the purchase cost is also higher.

[0061] Comparative Example 4

[0062] In this comparative example, asphalt substitute material reference products 1 to 7 were mixed with aggregate sample 1 at an asphalt-to-stone ratio of 5% at a mixing temperature of 185° C. to prepare mixture reference products 1 to 7, respectively.

[0063] Comparative Example 5

[0064] In this comparative example, SBS modified asphalt was mixed with aggregate sample 1 at an oil-to-stone ratio of 5% at a mixing temperature of 185°C to prepare a mixture control product 8.

[0065] Analysis and testing

[0066] (1) Analysis of asphalt substitute material samples and reference materials

[0067] According to the test methods described in the "Asphalt Brookfield Rotational Viscosity Test" (standard number T0625), "Asphalt Penetration Test" (standard number T0604), "Asphalt Elongation Test" (standard number T0605), and "Asphalt Softening Point Test (Ring and Ball Method)" (standard number T0606), the asphalt substitute material samples and reference materials were analyzed for 180°C rotational viscosity, 25°C penetration, ductility (ring and ball method), and softening point. The results are shown in Table 9.

[0068]

[0069] As can be seen from the test results in Table 9, the asphalt substitute material sample No. prepared by the present invention has a viscosity of 3.0 Pa·s to 4.0 Pa·s, a needle penetration of 60 to 70, an elongation greater than 10 cm, and a softening point greater than 60°C, which can meet the existing asphalt property requirements for mid-level surface paving.

[0070] (II) Analysis of mixed material samples and reference materials

[0071] Rutting test, low temperature bending test and freeze-thaw splitting test were carried out on the mixture samples and the reference sample to obtain the dynamic stability (60℃), low temperature bending failure strain (-10℃) and freeze-thaw splitting residual strength ratio. The results are shown in Table 10.

[0072]

[0073] From the test results in Table 10, it can be seen that the performance of the mixture sample prepared by the present invention is comparable to that of the mixture control using SBS modified asphalt. It can be seen that the asphalt substitute material prepared by the present invention can replace asphalt for paving the middle surface layer of the road.

[0074] In addition, the splitting strength change before and after freeze-thaw of the present invention is about 4%, while the splitting strength change before and after freeze-thaw of the existing SBS asphalt is 6.6%, indicating that the asphalt substitute material of the present invention has stronger low-temperature stability.

Claims

1. A road asphalt substitute material based on recycled oil, characterized in that: The road asphalt substitute material comprises, by weight, 100 parts of waste grease, 18 to 45 parts of petroleum coke, 18 to 39 parts of waste rubber powder, and 6 to 14 parts of pretreated waste plastics; The preparation process of the pretreated waste plastic is to heat polypropylene wax to a molten state, add dibenzoyl peroxide, methacrylic acid and styrene, stir for 1 to 2 hours, and then add the waste plastic in batches and stir until the waste plastic is completely dissolved; The mass ratio of the polypropylene wax, dibenzoyl peroxide, methacrylic acid, styrene and waste plastic is 1:0.02-0.03:0.3-0.5:0.2-0.4:5-6; The waste grease is recycled waste grease that has been filtered and impurities removed, and the filtering and impurity removal includes ordinary filtration and fine filtration; the material of the waste plastic includes any one or a combination of polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, polyamide and acrylonitrile-butadiene-styrene copolymer.

2. The road asphalt substitute material based on recycled oil according to claim 1, wherein the waste oil has a viscosity of 0.04 Pa·s to 0.06 Pa·s at 20°C and a water content of less than 0.15%.

3. The road asphalt substitute material based on recycled oil according to claim 1, characterized in that: The specific process of the road asphalt substitute material is as follows: Add petroleum coke to waste grease, stir until fully mixed, then add waste rubber powder and pretreated waste plastic in sequence, continue stirring at 180℃~200℃ for 40min~60min, and then high-speed shear for 1min~5min.

4. The road asphalt substitute material based on recycled oil according to claim 3, characterized in that: The high-speed shearing is performed at a rotation speed of the high-speed shearing machine of 7000 r / min to 9000 r / min.

5. The road asphalt substitute material based on recycled oil according to claim 1, characterized in that: The road asphalt substitute material has a rotational viscosity of 3.0 Pa·s to 4.0 Pa·s at 180°C, an elongation greater than 10 cm, and a softening point greater than 60°C.

6. The use of the road asphalt substitute material based on recycled oil according to any one of claims 1 to 5, characterized in that: As an asphalt substitute material, it is mixed with the aggregate of the middle surface layer SAC-20 asphalt mixture at an oil-to-stone ratio of 4.5% to 5.5%.

7. The use of the road asphalt substitute material based on recycled oil according to claim 6, characterized in that: The aggregate for the SAC-20 asphalt mixture of the middle surface layer includes coarse aggregate, fine aggregate and mineral powder, and the mass ratio of the coarse aggregate, fine aggregate and mineral powder is 75-80:15-20:

5.

8. The use of the road asphalt substitute material based on recycled oil according to claim 7, characterized in that: The mass ratio of the coarse aggregate with particle sizes distributed in the range of 15 mm to 20 mm, 10 mm to 15 mm, 5 mm to 10 mm and 3 mm to 5 mm is 21 to 23:23 to 25:22 to 24:7 to 9.

9. The use of the road asphalt substitute material based on recycled oil according to claim 8, characterized in that: The specific process of the mixed use is: heating the road asphalt substitute material to 185°C, so that an asphalt film is precipitated on the surface and a granular feel is formed, and then the aggregate is added, mixed, and then spread for use.

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