Road asphalt substitute material taking recovered oil as matrix and application

Abstract

The invention discloses a road asphalt substitute material taking recovered oil as a matrix and application, the road asphalt substitute material comprises the following components in parts by mass: 100 parts of waste oil, 18-45 parts of petroleum coke, 18-39 parts of waste rubber powder and 6-14 parts of pretreated waste plastic; the preparation process of the pretreated waste plastic comprises the following steps: heating polypropylene wax to a molten state, adding dibenzoyl peroxide, methacrylic acid and styrene, stirring for 1-2 hours, adding the waste plastic in batches, and stirring until the waste plastic is completely dissolved; the mass ratio of the polypropylene wax to the dibenzoyl peroxide to the methacrylic acid to the styrene to the waste plastics is 1: (0.02-0.03): (0.3-0.5): (0.2-0.4): (5-6); according to the invention, waste plastic, waste grease and waste rubber powder are recycled, petroleum coke is added, and the waste plastic is treated by a pretreatment process, so that the road asphalt substitute material with properties similar to those of SBS modified asphalt in the prior art is prepared, and the road asphalt substitute material can replace asphalt in the prior art to be used for paving a road middle-layer surface.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials for road engineering, and relates to a road asphalt substitute material based on recycled oils and its application. Background Art

[0002] Waste oils generally refer to various inferior oils existing in life, such as recycled edible oils, repeatedly used frying oils, etc. They are non-edible oils with extremely poor quality and extremely unhygienic. Recycling waste oils can obtain recycled oils. The emergence of a large amount of waste oils not only pollutes the environment but also increases the potential food safety hazard of waste oils flowing back to the dining table. Waste oils are extremely harmful to society, but at the same time, waste oils are also a kind of waste that can be resourcefully utilized. Therefore, the best solution is to recycle them to turn waste into treasure.

[0003] In recent years, there have been research reports on the application of waste oils in the field of asphalt at home and abroad. There is a patent in the United States that mentions using an environmentally friendly asphalt rejuvenator to rejuvenate aged asphalt or soften virgin asphalt, and this rejuvenator is derived from plant-extracted oils. Scholars at Washington State University in the United States prepared a kind of "bio-asphalt", which is produced by compounding waste cooking oil and fly ash, etc. Malaysian scholars studied the feasibility of using waste oils as rejuvenators for aged asphalt rejuvenation. There is a patent in China that mentions using waste oils to rejuvenate or soften asphalt. Chen Meizhu, Wu Shaopeng, etc. at Wuhan University of Technology incorporated a certain amount of rejuvenator, waste oil, and cottonseed oil into waste asphalt respectively, and comparatively studied their respective high-temperature rheological properties. Although these reports have laid a theoretical foundation for the research of the present invention, in the prior art, a certain proportion of asphalt or old asphalt is required as the matrix, and there are few reports on those based on recycled oils without adding asphalt.

[0004] In addition, with the continuous increase in the consumption of plastic products, the amount of waste plastics generated in China every year is also increasing. Waste plastics mainly come from plastic films, plastic filaments and woven products, foam plastics, plastic packaging boxes and containers, daily-use plastic products, plastic bags, and agricultural films, etc. They are diverse in type and complex in composition, including polyethylene, polypropylene, polyvinyl chloride, etc. Therefore, the recycling and reuse of waste plastics in recent years have also been one of the key concerns of sustainable development.

[0005] Regarding the research on the application of plastics in the asphalt field, there are domestic patents that use various components such as petroleum resin, rubber oil, thermoplastic elastomer, rubber-based modifier, high-density polyethylene, thermoplastic resin, high-viscosity agent, warm mix agent, and polyamide to prepare colored asphalt binder. This kind of colored asphalt not only has complex components and relatively high prices, but more importantly, its adhesion to the mixture is poor, and it has the disadvantages of insufficient high-temperature performance, durability, and strength. Generally, it is only used as a pavement material. In addition, due to the complex composition of waste plastics, problems such as immiscibility and severe segregation between materials are likely to occur when applied to the asphalt field. Therefore, in the existing technology, most of the research is focused on single high-density polyethylene, and the existing process cannot achieve the comprehensive recycling 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 a "bitumen-like" material without adding asphalt and meeting the requirements for paving the middle layer of expressways and urban roads is studied.

[0008] The technical solution adopted by the present invention is a substitute for road asphalt based on recycled oils. The key lies in that, by mass, the above-mentioned substitute for road asphalt includes 100 parts of waste grease, 18 - 45 parts of petroleum coke, 18 - 39 parts of waste rubber powder, and 6 - 14 parts of pretreated waste plastics;

[0009] The preparation process of the above-mentioned pretreated waste plastics is to heat polypropylene wax to a molten state, add benzoyl peroxide, methacrylic acid, and styrene, stir for 1 h - 2 h, and then add waste plastics in batches and stir until the waste plastics are completely dissolved;

[0010] The mass ratio of the above-mentioned polypropylene wax, benzoyl peroxide, methacrylic acid, styrene, and waste plastics 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 filtered to remove impurities, and the above-mentioned filtration to remove impurities includes ordinary filtration and fine filtration; the materials of the above-mentioned waste plastics include any one or a combination of polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, polyamide, and acrylonitrile-butadiene-styrene copolymer.

[0012] Preferably, the viscosity of the above-mentioned waste grease at 20 °C is 0.04 Pa·s - 0.06 Pa·s, and the water content is less than 0.15%.

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

[0014] Add petroleum coke to waste grease, stir until fully mixed, and then add waste rubber powder and pretreated waste plastics in sequence. Continuously stir at 180°C to 200°C for 40 min to 60 min, and then perform high-speed shearing for 1 min to 5 min.

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

[0016] Specifically, the 180°C rotational viscosity of the above road asphalt substitute is 3.0 Pa·s to 4.0 Pa·s, the ductility is greater than 10 cm, and the softening point is greater than 60 °C.

[0017] For the application of the road asphalt substitute based on recycled oils, the key lies in that it is used as an asphalt substitute and mixed with the aggregate for the middle surface layer SAC-20 asphalt mixture at an oil-stone ratio of 4.5% to 5.5%.

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

[0019] More specifically, the mass ratio of the coarse aggregates with particle sizes distributed in 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 to 23:23 to 25:22 to 24:7 to 9.

[0020] Further, the specific process of the above mixing use is: heat the road asphalt substitute to 185 °C, there is asphalt film precipitation and a granular feeling on the surface, add the aggregate and mix it before paving for use.

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

[0022] The present invention utilizes waste plastics, waste grease and waste rubber powder recycling waste materials, and prepares an environmentally friendly road asphalt substitute by adding petroleum coke and using a special pretreatment process for waste plastics. The prepared road asphalt substitute has properties similar to those of SBS modified asphalt in the prior art and can replace the asphalt in the prior art for paving the middle layer of the road. The mixture prepared by the present invention not only meets the performance requirements of the middle surface layer SAC-20 asphalt mixture, but also has a lower change in splitting strength before and after freeze-thaw and has better low-temperature resistance.

[0023] In 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 good performance asphalt substitute material. 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 multiple types of mixed waste plastics, 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 mutually soluble and non-shrinking materials can be prepared for subsequent applications.

[0024] In the pretreatment process of waste plastics, dibenzoyl peroxide can be used as an initiator in a molten state to smoothly graft methacrylic acid and styrene onto polypropylene wax. The use of styrene not only improves the solubility and pairing ability of polypropylene wax and styrene-based plastics, but also the use of phenylacetic acid as the second monomer can prevent the degradation of polypropylene wax due to free radical reaction, which is more conducive to preparing a material with a more complex and three-dimensional network structure, thereby helping to improve the viscosity and other properties of the prepared asphalt substitute material. Dibenzoyl peroxide itself is also a vulcanizing agent, which plays a role of a stabilizer in the asphalt preparation process, and can improve the stability and long-term performance of the sample without adding an additional stabilizer, thereby further reducing the production cost.

[0025] In addition, the study also found that the asphalt substitute material prepared using unrefined recycled grease is better than the refined recycled grease. This may be because there are a large number of higher fatty acid glycerides in the waste grease itself, so the waste grease will show a "gelling" phenomenon. The recycling of general waste grease requires more complicated refining processes such as alkali and deacidification to decompose the higher fatty acid glycerides. However, in the research of the present invention, it was unexpectedly found that the performance of the road asphalt substitute material prepared using waste grease that has only been physically removed is better, thereby simplifying the processing process of waste grease, further reducing the cost of purchasing raw materials, and improving 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 it is 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 4The test photos show mutual solubility and no shrinkage when the waste plastic sample 2 is pretreated with polypropylene wax.

[0030] Figure 5 The test photos show immiscibility when the waste plastic sample 3 is pretreated with polyethylene wax. Detailed implementation manners

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] For those not specified in the embodiments, they can be carried out according to conventional conditions; for the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0033] Examples 1 to 6

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

[0035] By mass, 1 part of polypropylene wax is heated to a molten state, benzoyl peroxide, methacrylic acid and styrene are added, and after stirring for a certain time, the waste plastics are added in batches and stirred until the waste plastics are completely dissolved;

[0036] The polypropylene wax, benzoyl peroxide, methacrylic acid, styrene and waste plastics are added according to a certain mass ratio. Among them, the specific materials and material ratios in the waste plastics are shown in Table 2.

[0037] Table 1: Material usage and specific parameters in the waste plastic pretreatment process

[0038]

[0039]

[0040] Table 2: Material composition and ratio of waste plastics in Examples 1 to 6

[0041]

[0042] Examples 7 to 18

[0043] The road asphalt substitute of the present invention is prepared according to the following steps. The specific material ratios and parameters are shown in Table 3:

[0044] By mass fraction, petroleum coke is added to 100 parts of waste grease. After stirring until fully mixed, waste rubber powder and pretreated waste plastic samples are added in sequence. It is heated to a certain temperature and continuously stirred, and then sheared at high speed in a high-speed shearing machine for a certain period of time.

[0045] In this example, the waste grease used 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%.

[0046] Table 3: Material dosage and specific parameters of road asphalt substitute materials

[0047]

[0048]

[0049] Examples XIX - XXIV

[0050] Heat different asphalt substitute material samples to 185 °C. See Appendix Figure 1 There is asphalt film precipitation and a granular feeling on the surface. Add aggregates of different particle sizes for the middle surface layer SAC - 20 asphalt mixture according to a certain asphalt - aggregate ratio, mix them and then spread for use. See Appendix Figure 2 After mixing with the asphalt substitute material samples of the present invention, the color is gray and not bright.

[0051] For the particle size of the aggregate samples used, see Table 4. For the specific asphalt - aggregate ratio and the asphalt substitute material samples used, see Table 5.

[0052] Table 4: Conditions of aggregate samples with different particle sizes

[0053]

[0054] Table 5: Mixing and using conditions of asphalt substitute material samples and aggregates

[0055] Example Asphalt alternative material sample number Aggregate sample number Bitumen-aggregate ratio (%) Corresponding mixture sample number Example XIX Asphalt alternative material sample number 1 Aggregate sample 1 5 Mixture sample 1 Example XX Asphalt alternative material sample number 2 Aggregate sample 2 5 Mixture sample 2 Example XXI Asphalt alternative material sample number 3 Aggregate sample 3 5.5 Mixture sample 3 Example XXII Asphalt alternative material sample number 4 Aggregate sample 4 4.5 Mixture sample 4 Example XXIII Asphalt alternative material sample number 5 Aggregate sample 1 5.2 Mixture sample 5 Example XXIV Asphalt alternative material sample number 6 Aggregate sample 2 4.8 Mixture sample 6

[0056] Comparative Example 1

[0057] In this comparative example, the feeding sequence is studied. Different waste plastic samples are used, but no pretreatment of waste plastics is carried out. Instead, 20 parts of petroleum coke are added to 25 parts of waste grease. After stirring until fully mixed, 20 parts of waste rubber powder, 3 parts of different waste plastic samples, 0.7 part of polypropylene wax, 0.02 part of dibenzoyl peroxide, 0.27 part of methacrylic acid, and 0.2 part of styrene are added in sequence. It is continuously stirred at 185 °C for 50 min and then sheared at high speed for 2 min. During the test, it is found that precipitation and stratification occur to varying degrees in some test groups, resulting in that some reference samples cannot be used as asphalt substitute materials and are not used in the subsequent test process.

[0058] The test phenomena in this comparative example are simply summarized, and the results are shown in Table 6.

[0059] Table 6: Summary Table of Test Phenomena in Comparative Example 1

[0060] Waste plastic samples used Precipitation condition Layering condition Shearing condition Name and number of the obtained reference substance Waste plastic sample 1 Yes No Normal —— Waste plastic sample 2 No No Normal Asphalt alternative material reference substance 1 Waste plastic sample 3 Yes Yes Normal —— Waste plastic sample 4 Yes Yes Normal —— Waste plastic sample 5 Yes Yes Difficult —— Waste plastic sample 6 Yes Yes Difficult ——

[0061] Comparative Example 2

[0062] In this comparative example, the waste plastic pretreatment method was studied. Polyethylene wax and polypropylene wax were used to pretreat different waste plastic samples respectively. During the test, it was found that problems such as segregation, immiscibility and shrinkage occurred to varying degrees in some test groups, resulting in that some waste plastic reference samples were not suitable for the subsequent research on the preparation of asphalt substitute materials.

[0063] The test phenomena in this comparative example are simply summarized, and the results are shown in Table 7.

[0064] Table 7: Summary Table of Test Phenomena in Comparative Example 2

[0065]

[0066]

[0067] For the case of miscibility but obvious shrinkage in Table 7, see Appendix Figure 3 , for the case of miscibility and no shrinkage, see Appendix Figure 4 , for the case of immiscibility, see Appendix Figure 5 .

[0068] Comparative Example 3

[0069] In this comparative example, the components of the asphalt substitute material were studied. Non-asphalt materials were added to 25 parts of waste grease after different treatments, and after stirring until fully mixed, 20 parts of waste rubber powder and 4 parts of pretreated waste plastic sample 1 were added in sequence. After continuous stirring at 185 °C for 50 min, high-speed shearing was carried out for 2 min to prepare an asphalt substitute material reference sample. The specific types of materials are shown in Table 8.

[0070] Table 8: Types and Dosages of Materials Used in Comparative Example 3

[0071]

[0072] Note: The non-refined waste grease in Table 8 is the waste grease used in the examples of the present invention, that is, the waste grease from which solid impurities have been removed by ordinary filtration and fine filtration using a semi-permeable membrane; the refined waste grease is the waste grease after ordinary filtration and fine filtration using a semi-permeable membrane to remove solid impurities, and then through alkali hydrolysis and deacidification. The obtained grease is clearer, lighter in color, and higher in external purchase cost.

[0073] Comparative Example 4

[0074] In this comparative example, asphalt substitute reference samples 1 - 7 and aggregate sample 1 were mixed at an asphalt-aggregate ratio of 5%, and the mixing temperature was 185 °C to prepare mixture reference samples 1 - 7 respectively.

[0075] Comparative Example 5

[0076] In this comparative example, SBS modified asphalt and aggregate sample 1 were mixed at an asphalt-aggregate ratio of 5%, and the mixing temperature was 185 °C to prepare mixture reference sample 8.

[0077] Analysis and Testing

[0078] (1) Analysis of Asphalt Substitute Samples and Reference Samples

[0079] According to the test methods described in "Brookfield Rotational Viscometer Test for Asphalt" (standard number: T0625), "Penetration Test for Asphalt" (standard number: T0604), "Ductility Test for Asphalt" (standard number: T0605),

[0080] "Softening Point Test for Asphalt (Ring-and-Ball Method)" (standard number: T0606), the asphalt substitute samples and reference samples were analyzed for rotational viscosity at 180 °C, penetration at 25 °C, ductility (ring-and-ball method), and softening point. The results are shown in Table 9.

[0081] Table 9: Summary Table of Analysis Results of Asphalt Substitute Samples and Reference Samples

[0082]

[0083]

[0084] As can be seen from the test results in Table 9, the viscosity of the asphalt substitute samples prepared by the present invention is in the range of 3.0 Pa·s - 4.0 Pa·s, the penetration is 60 - 70, the ductility is greater than 10 cm, and the softening point is greater than 60 °C, which can meet the requirements of the existing asphalt properties for middle layer paving.

[0085] (2) Analysis of Mixture Samples and Reference Samples

[0086] The rutting test, low-temperature bending test, and freeze-thaw splitting test were carried out on the mixture samples and reference samples to obtain the dynamic stability at (60) °C, low-temperature bending failure strain at (-10) °C, and freeze-thaw splitting residual strength ratio. The results are shown in Table 10.

[0087] Table 10: Summary Table of Analysis Results of Mixture Samples and Reference Samples

[0088]

[0089]

[0090] As can be seen from the test results in Table 10, the performance of the mixture sample prepared by the present invention is comparable to that of the mixture control product using SBS modified asphalt. Therefore, the asphalt substitute material prepared by the present invention can replace asphalt for paving the middle surface layer of roads.

[0091] In addition, the change in splitting strength before and after freeze-thaw of the present invention is about 4%, while the change in splitting strength before and after freeze-thaw of the existing SBS asphalt is 6.6%, indicating that the low-temperature stability performance of the asphalt substitute material of the present invention is stronger.

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 plastics is to heat polypropylene wax to a molten state, add dibenzoyl peroxide, methacrylic acid and styrene, stir for 1 to 2 hours, then add the waste plastics in batches and stir until the waste plastics are 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.

2. The road asphalt substitute material based on recycled oil according to claim 1, characterized in that: 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.

3. The road asphalt substitute material based on recycled oil according to claim 1, wherein 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%.

4. 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.

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

6. 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 of more than 10 cm, and a softening point of more than 60°C.

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

8. The use of the road asphalt substitute material based on recycled oil according to claim 7, characterized in that: The aggregate for the 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.

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

10. The use of road asphalt substitute material based on recycled oil according to claim 7, 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 it has a granular feel, adding aggregates, mixing, and then paving for use.

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