All-solid-waste upper layer cold recycled asphalt mixture and preparation method thereof

Abstract

The application discloses a kind of full solid waste upper layer cold regeneration asphalt mixture and preparation method thereof, the cold regeneration asphalt mixture in each material content is, asphalt pavement recycling material 48-52wt%, waste road concrete 44-48wt%, dilute asphalt 2-3wt%, cold mixing activator 1-1.8wt%, mineral powder 0.5-1wt%, dilute asphalt and cold mixing activator contain D60 de-aromatic solvent oil.The preparation method includes the following steps: preparation dilute asphalt and cold mixing activator;Asphalt pavement recycling material, waste road concrete, mineral powder are placed in oven and dried;First, asphalt pavement recycling material is placed in mixing pot and mixed, then cold mixing activator is added and mixed, then waste road concrete and dilute asphalt are added and mixed, and finally mineral powder is added and mixed, to obtain full solid waste upper layer cold regeneration asphalt mixture.The cold regeneration asphalt mixture prepared by the application has excellent comprehensive performance, can meet the performance requirements of upper layer hot mix asphalt mixture, and realizes high-level utilization.

Description

Technical Field

[0001] This invention belongs to the field of asphalt pavement materials and preparation technology, specifically relating to a cold recycled asphalt mixture for the surface layer of solid waste and its preparation method. Background Technology

[0002] Currently, my country's highway mileage has reached millions of kilometers, with over 90% of expressways being asphalt pavements. As the service life of asphalt pavements gradually increases, many asphalt pavements have reached their design lifespan, and a large number of asphalt pavements require renovation, reconstruction, and maintenance every year, resulting in a large amount of reclaimed asphalt pavement (RAP).

[0003] Recycling reclaimed asphalt pavement material (RAP) and incorporating it into new asphalt mixtures for repaving is an effective way to achieve the resource utilization of solid waste. This technology can not only effectively solve the problems of waste material stockpiling and environmental pollution, but also release the residual value of old materials, thereby reducing the demand for mining natural resources such as stone and asphalt, and simultaneously achieving carbon emission reduction benefits.

[0004] Under the combined effects of long-term traffic loads and environmental factors, asphalt pavement aggregate particles will experience fatigue damage. Furthermore, the effects of milling, crushing, and storage processes will lead to a higher proportion of fine aggregates in reclaimed asphalt pavement (RAP), resulting in a enrichment of fine aggregates. It is worth noting that due to the binding effect of aged asphalt, RAP contains a large number of fictitious particle clusters, forming a mixed aggregate of solid and fictitious particles. During the compaction of the asphalt mixture, these fictitious particle clusters will undergo structural fracture, directly altering the design gradation of the asphalt mixture.

[0005] Cold recycling technology for asphalt RAP (Rich Asphalt Pavement) significantly reduces carbon emissions and resource consumption through room temperature treatment and waste recycling, and has become the mainstream technology for highway paving, reconstruction, and maintenance. Currently, cold recycling technology is mainly divided into emulsified asphalt cold recycling and foamed asphalt cold recycling. Emulsified asphalt cold recycling disperses high-temperature asphalt with an emulsifier to form an oil-in-water emulsion. During construction, the emulsion can be mixed with aggregates at room temperature. After the water evaporates, the asphalt particles re-aggregate and demulsify, forming a continuous asphalt film that binds the aggregates. Foamed asphalt cold recycling involves injecting water into hot asphalt at 150-180℃. The water instantly vaporizes, causing the asphalt to expand in volume, forming a foam structure that mixes with the aggregates. After the foam ruptures, the asphalt encapsulates the aggregates in the form of "micro-droplets," completing the bonding. However, foamed asphalt is discontinuously distributed on the aggregate surface, exhibiting spot-welding characteristics of localized adhesion. Both of these cold recycling technologies suffer from poor integration of new and old asphalt, low application layer depth, and low recycling ratio. Therefore, there is an urgent need to develop a fully solid waste surface layer cold recycled asphalt mixture and its preparation method to solve the problems existing in current technologies.

[0006] The invention patent with publication number CN106587737A discloses an environmentally friendly recycled asphalt mixture and its preparation process. The recycled asphalt mixture includes dozens of substances such as waste asphalt, bio-asphalt, modified asphalt, waste tire powder, aggregates, mineral powder, and environmentally friendly solvent oil. The environmentally friendly solvent oil is D40, D95, or D65. In the preparation process of the recycled asphalt mixture, the waste asphalt needs to be heated to 110-125℃ and stirred for 20-60 minutes. Then, the recycling agent, environmentally friendly solvent oil, and other substances are added and stirred at 130-170℃ for 15-50 minutes. Then, waste tire powder is added and dispersed at 145℃ with high-speed shearing at 3500-5000 r / min for 30-50 minutes. Although this technical solution utilizes waste materials and the road performance of recycled asphalt mixture is relatively high, it still has the following defects: (1) The recycling ratio is low, that is, the proportion of solid waste materials such as waste asphalt and waste tire powder used is low, while the proportion of natural aggregate is still very high; (2) The preparation temperature of recycled asphalt mixture is high, that is, it is hot recycled asphalt mixture, which belongs to hot recycling technology; (3) The waste asphalt material used is waste asphalt, not asphalt pavement recycling material (RAP), because high-speed long-term shearing is aimed at asphalt rather than aggregate, while asphalt pavement recycling material belongs to the category of aggregate or is a substitute for aggregate, so it cannot be subjected to high-speed long-term shearing and mixing; (4) The performance of the prepared recycled asphalt mixture needs to be improved and it is not suitable for paving the surface layer of asphalt pavement, because the surface layer has the highest performance requirements for asphalt mixture. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a cold recycled asphalt mixture for the top layer of solid waste. The mass percentage of each substance in the cold recycled asphalt mixture is as follows: 48-52 wt% recycled asphalt pavement material, 44-48 wt% waste road concrete, 2-3 wt% diluted asphalt, 1-1.8 wt% cold mix activator, and 0.5-1 wt% mineral powder. The diluted asphalt uses D60 dearomatic solvent oil as a diluent, and the cold mix activator contains D60 dearomatic solvent oil.

[0008] Preferably, the asphalt pavement recycling material is in an oil-rich state, that is, the outer surface of the old aggregate is completely covered with old asphalt; the asphalt pavement recycling material includes two particle sizes, namely 3-5mm and 0-3mm, and the mass percentage of each particle size in the asphalt pavement recycling material is 30-50wt% for particle size 3-5mm and 50-70wt% for particle size 0-3mm.

[0009] Preferably, in any of the above embodiments, the crushing value of the waste road concrete does not exceed 30%, the inclusion content does not exceed 0.5%, the content of needle-like and flaky particles does not exceed 20%, and the adhesion rate of old mortar to the outer surface of old concrete particles does not exceed 30%; the waste road concrete includes three particle sizes, namely 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm, and the mass percentage of each particle size in the waste road concrete is as follows: 13.2-16mm accounts for 3-8wt%, 9.5-13.2mm accounts for 30-40wt%, and 4.75-9.5mm accounts for 55-62wt%.

[0010] In any of the above embodiments, it is preferred that the mass percentage of each substance in the diluted asphalt is as follows: base asphalt 78-82 wt%, antioxidant 0.8-1 wt%, anti-stripping agent 0.5-0.7 wt%, and diluent 16.5-20.5 wt%.

[0011] Preferably, in any of the above embodiments, the base asphalt is No. 70 base asphalt or No. 90 base asphalt; the antioxidant is nano zinc oxide with a particle size of 20-100 nm and a purity of not less than 90%; the anti-stripping agent is a non-amine anti-stripping agent, which is any one or more of polyphosphoric acid, phosphate ester, and nitrogen-containing complex; the diluent is D60 dearomatic solvent oil, which is obtained by fractional distillation after deep desulfurization, dearomaticization, and hydrorefining from straight-run distillate oil, hydrocracked distillate oil, or low-sulfur straight-run jet fuel, with a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03 wt%, a sulfur content of less than 0.2 mg / kg, and a saturated hydrocarbon content of greater than 99.9%.

[0012] In any of the above embodiments, it is preferred that the mass percentage of each substance in the cold-mix activator is 83.3-85.7 wt% of D60 dearomatic solvent oil and 14.3-16.7 wt% of castor oil-based bio-heavy oil.

[0013] In any of the above embodiments, it is preferred that the amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the mass percentage range of D60 dearomatic solvent oil and asphalt pavement recycled material, the amount of D60 dearomatic solvent oil added increases by 0.5-0.7 wt% for every 1 wt% increase in the amount of asphalt pavement recycled material added.

[0014] In any of the above embodiments, preferably, the D60 dearomatic solvent oil in the cold-mix activator is obtained by fractionation after deep desulfurization, dearomatication, and hydrocracking refining from straight-run distillate oil, hydrocracked distillate oil, or low-sulfur straight-run jet fuel, with a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%; the mass percentage of each substance in the castor oil-based bio-heavy oil is as follows: saturated hydrocarbons 0.5-0.8wt%, aromatic hydrocarbons 55-58wt%, gums 35-39wt%, and asphaltenes 4-7wt%.

[0015] In any of the above embodiments, it is preferred that the mineral powder is limestone with a particle size of less than 0.075 mm.

[0016] This invention also provides a method for preparing a cold recycled asphalt mixture with a solid waste surface layer, used to prepare the cold recycled asphalt mixture with a solid waste surface layer as described in any of the above claims, comprising the following steps in sequence:

[0017] Step 1: Prepare diluted asphalt according to the designed material ratio and process parameters, and store it at room temperature for later use;

[0018] Step 2: Mix D60 dearomatic solvent oil and castor oil-based bio-heavy oil evenly according to the designed material ratio to prepare cold-mix activator, and store it at room temperature for later use;

[0019] Step 3: Place the asphalt pavement recycling materials, waste road concrete, and mineral powder of each particle size into an oven for drying. After drying, remove the asphalt pavement recycling materials, waste road concrete, and mineral powder of each particle size from the oven and let them cool naturally to room temperature for later use.

[0020] Step 4: Put the recycled asphalt pavement materials of various particle sizes into the mixing pot and mix them with a mixer;

[0021] Step 5: Add the cold-mix activator to the mixing pot and continue mixing with a mixer;

[0022] Step 6: Add the waste road concrete and diluted asphalt of various particle sizes to the mixing pot, and continue mixing with a mixer;

[0023] Step 7: Add the mineral powder to the mixing pot and continue mixing with a mixer. After mixing is completed, the cold recycled asphalt mixture of all solid waste surface layer can be obtained.

[0024] Preferably, in step one, the method for preparing the diluted asphalt includes the following steps in sequence:

[0025] Step (1): Weigh the base asphalt, antioxidant, anti-stripping agent, and diluent according to the designed material ratio and set aside;

[0026] Step (2): Place the base asphalt into a container, and then place the container containing the base asphalt into an oven for heating at a temperature of 100-120℃ for 1-2 hours.

[0027] Step (3): After heating is complete, take out the container containing the base asphalt from the oven, add the diluent to the container, and then put the container containing the base asphalt and diluent into the oil bath. Stir with a stirrer until the base asphalt and diluent are completely mixed. The temperature of the oil bath is 60-80℃ and the stirring time is 10-15 minutes.

[0028] Step (4): Keep the temperature of the oil bath constant, continue stirring with a stirrer, and add the anti-stripping agent while stirring until the anti-stripping agent is completely mixed. The temperature of the oil bath is 60-80℃, and the stirring time is 10-15 minutes.

[0029] Step (5): Keep the temperature of the oil bath constant and continue stirring with a mixer while adding antioxidants until the antioxidants are fully mixed. The temperature of the oil bath should be 60-80℃ and the stirring time should be 10-15 minutes. After stirring is completed, diluted asphalt can be obtained.

[0030] In any of the above schemes, it is preferred that, in step three, the drying temperature of the asphalt pavement recycling material of each particle size, the waste road concrete of each particle size, and the mineral powder are all 100-110℃, and the drying time is all 1-2h.

[0031] In any of the above schemes, it is preferred that, in step four, the asphalt pavement recycled materials of various particle sizes are put into a mixing pot and stirred, with the stirring temperature at room temperature, the stirring speed at 70-100 r / min, and the stirring time at 60-90 s.

[0032] In any of the above schemes, it is preferred that, in step five, the cold-mixed activator is added to the mixing pot and stirred, with the stirring temperature at room temperature, the stirring speed at 70-100 r / min, and the stirring time at 60-90 s.

[0033] In any of the above schemes, it is preferred that, in step six, waste road concrete and diluted asphalt of various particle sizes are added to the mixing pot and stirred, with the stirring temperature at room temperature, the stirring speed at 70-100 r / min, and the stirring time at 60-90 s.

[0034] In any of the above schemes, it is preferred that in step seven, the mineral powder is added to the mixing pot and stirred, with the stirring temperature at room temperature, the stirring speed at 70-100 r / min, and the stirring time at 60-90 s.

[0035] In this invention, the recycled asphalt pavement material includes two particle size ranges: 3-5mm and 0-3mm, i.e., 3mm ≤ particle size < 5mm and 0mm < particle size < 3mm. The waste road concrete includes three particle size ranges: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm, i.e., 13.2mm ≤ particle size < 16mm, 9.5mm ≤ particle size < 13.2mm, and 4.75mm ≤ particle size < 9.5mm. For each particle size range, the material is passed through two sieves sequentially, and the resulting particle size falls between the upper and lower sieve openings. For example, a particle size of 9.5-13.2mm (9.5mm ≤ particle size < 13.2mm) means the material is passed through a 13.2mm sieve and a 9.5mm sieve sequentially, resulting in a particle size between 9.5-13.2mm.

[0036] In this invention, recycled asphalt pavement material (RAP) refers to waste mixture recovered from old asphalt pavement, obtained after milling, crushing, and screening. Its main components are old asphalt and old aggregate, with the outer surface of the old aggregate partially or completely covered by old asphalt. Recycled asphalt pavement material includes two states: oil-rich RAP and oil-lean RAP. Oil-rich RAP refers to old aggregate whose outer surface is completely covered by old asphalt, appearing entirely asphalt. Oil-lean RAP refers to old aggregate whose outer surface is not covered by old asphalt or is only partially covered, with the proportion of old asphalt not exceeding 30%. It should be noted that after milling, crushing, and screening, the exterior of the recycled asphalt pavement material is covered in dust, resembling sand in appearance. When the recycled asphalt pavement material is mixed with a cold-mix activator, the activator activates it, at which point the outer surface of the old aggregate is completely covered by old asphalt.

[0037] Waste road concrete refers to waste concrete recycled from old cement concrete pavement, which is processed by milling, crushing, screening and other methods. Its main components are old cement mortar and old aggregate, and the outer surface of the old aggregate is partially or completely covered by old cement mortar.

[0038] In this invention, D60 dearomatic solvent oil is used in both the preparation of diluted asphalt and the cold-mix activator. This is a first in cold-recycled asphalt mixture preparation technology and is also a crucial material in the preparation of cold-recycled asphalt mixtures. In the preparation of diluted asphalt, D60 dearomatic solvent oil is used as a diluent. After the base asphalt is heated to a fluid state, D60 dearomatic solvent oil, along with anti-stripping agents and antioxidants, are added to the base asphalt. The resulting diluted asphalt maintains good fluidity at room temperature after cooling. In the formulation of the cold-mix activator, D60 dearomatic solvent oil and castor oil-based bio-heavy oil are used. Here, the D60 dearomatic solvent oil activates the old asphalt in the recycled asphalt pavement material, allowing the castor oil-based bio-heavy oil to penetrate the old asphalt, filling the missing components, and also promoting the fusion between the new and old asphalt.

[0039] D60 dearomatic solvent oil is colorless, non-toxic, and has an extremely low odor. It has a narrow distillation range, strong dissolving power, good volatility, and a saturated hydrocarbon content greater than 99.9%, exhibiting excellent oxidation stability. Under room temperature and natural ventilation conditions, D60 dearomatic solvent oil can be used normally without the need for special safety and fire prevention measures, posing a very low risk of exposure. This makes the production and construction process safer and has minimal impact on the atmospheric environment and worker health. D60 dearomatic solvent oil has a moderate evaporation rate and complete evaporation, ensuring sufficient time for thorough paving and compaction at the construction site. Furthermore, D60 dearomatic solvent oil has minimal impact on the performance of cold recycled asphalt mixtures.

[0040] The cold-mix activator is a mixture of D60 dearomatic solvent oil and castor oil-based bio-heavy oil. The castor oil-based bio-heavy oil used here is a substance obtained from the residue remaining after extracting castor oil from castor seeds, through preliminary processing (only preliminary processing is required, without dehydration and deodorization). At room temperature, castor oil-based bio-heavy oil presents as a dark brown, viscous paste with a certain degree of fluidity.

[0041] The antioxidant used is nano-zinc oxide. The principle behind the improved antioxidant properties of asphalt modified with nano-zinc oxide is mainly photocatalysis and free radical scavenging. Photocatalysis involves nano-zinc oxide absorbing external light energy to generate reactive oxygen species, which can partially decompose molecules containing carbonyl functional groups produced during the use and oxidation of asphalt, thereby slowing down the oxidation rate and resisting oxidation. Free radical scavenging involves the presence of a small amount of free Zn in the asphalt colloid from nano-zinc oxide. 2+ It can combine with free radicals generated during asphalt oxidation to deactivate them, further inhibiting the chain reaction, thereby preventing free radical-induced asphalt oxidation to a certain extent.

[0042] This invention requires that the purity of nano zinc oxide be no less than 90%. Because nano zinc oxide has a very small particle size and is in the form of fine powder, it is inevitable that small impurities, dust, etc. will be mixed in, which will cause the purity to not reach 100%. This invention only requires that the purity of nano zinc oxide be no less than 90%.

[0043] In this invention, the synergistic effect between substances such as reclaimed asphalt pavement material (RAP), waste road concrete, diluent (D60), and cold mix activator (D60 + castor oil-based bio-heavy oil) enables new and old asphalt to quickly blend at room temperature, achieving physical modification, increasing the recycling ratio, and improving the road performance of cold recycled asphalt mixtures, which can be used as the surface layer of asphalt pavement.

[0044] Traditional hot recycling requires heating the recycled asphalt pavement material (RAP) to over 160°C to activate the old asphalt. In contrast, cold-mix activators, through solvent softening and component compensation regeneration, can activate old asphalt at room temperature, eliminating the heating step, reducing energy consumption and emissions, and meeting the requirements of green construction.

[0045] The recycled asphalt pavement material RAP (which can be used as fine aggregate) and waste road concrete (which can be used as coarse aggregate) form a continuous gradation of "coarse aggregate intercalation + fine aggregate filling". This reduces the amount of asphalt used while increasing the internal friction angle of the mixture, thus maximizing the proportion of solid waste recycling.

[0046] The surface of abandoned road concrete is rough and porous, containing cement hydration products, which can undergo acid-base neutralization reactions with castor oil-based bio-heavy oil and acidic components in asphalt, enhancing interfacial adhesion; diluted asphalt can more easily penetrate into the micropores of concrete, and after the viscosity is restored, it forms an "anchor" effect, significantly improving the interfacial bonding strength.

[0047] D60 dearomatic solvent oil first rapidly dissolves the old asphalt, while castor oil-based bio-heavy oil then fills in the light components to activate the old asphalt, forming a gradient synergistic effect of "dissolving first and then regenerating". This allows the RAP old asphalt to quickly regain its fluidity at room temperature, laying the foundation for subsequent fusion with new asphalt.

[0048] D60 dearomatic solvent oil simultaneously dissolves castor oil-based bio-heavy oil, old asphalt (from asphalt pavement recycled material RAP), and new asphalt (from diluted asphalt), reducing the interfacial tension among the three and promoting mutual diffusion. This solves the technical problems of the poor immiscibility between old asphalt and castor oil-based bio-heavy oil, as well as the phase separation of new and old asphalt.

[0049] In this invention, D60 dearomatic solvent oil and castor oil-based bio-heavy oil need to be mixed in advance to prepare a cold mix activator, and then the cold mix activator is first added to the asphalt pavement recycling material (RAP) and mixed.

[0050] Precise component compensation: The main defects of aged asphalt are the loss of light components (saturated and aromatic components) and the increase in asphaltenes content, leading to component imbalance and a sharp increase in viscosity. The long-chain alkanes in D60 and the long-chain aromatics in castor oil-based bio-heavy oil can replenish the saturated and aromatic components, achieving component balance.

[0051] Low-impact rapid penetration and diffusion: D60 possesses excellent fluidity and high diffusion characteristics at room temperature, allowing it to rapidly penetrate into the old asphalt of RAP, reducing its apparent viscosity and gradually transforming it from a glassy state to a viscous flow state. This creates the physical conditions for the compatibility of castor oil-based bio-heavy oil. The cold-mix activator prepared by mixing the two significantly reduces the interfacial resistance between the old asphalt and the castor oil-based bio-heavy oil, enabling the castor oil-based bio-heavy oil to disperse more evenly and rapidly in the RAP with the help of D60. This accelerates the redistribution of aged components (such as asphaltenes) and light components (oils, resins) in the old asphalt at room temperature, laying the foundation for the fusion of new and old asphalt during subsequent mixing and preventing "phase separation." After facilitating the rapid penetration of castor oil-based bio-heavy oil into the old asphalt, the short-chain alkanes in D60 can completely volatilize, having minimal impact on asphalt properties.

[0052] In the entire process of preparing cold recycled asphalt mixture, the selection and proportion of each substance, the order of addition of each substance, and the process parameters of each step are all very critical. In addition, the selection and proportion of the two substances in the cold mix activator, as well as the timing of adding the cold mix activator (adding the cold mix activator to the asphalt pavement recycling material first) are also very critical. Only by synergistically combining the various formula parameters and process parameters can the technical effect expected by this invention be achieved.

[0053] The cold recycled asphalt mixture for the top layer of solid waste and its preparation method of the present invention have the following beneficial effects:

[0054] (1) This invention uses D60 dearomatic solvent oil as a diluent and cold mix activator as a component. Starting from solving the problem of rapid compatibility between new and old asphalt at room temperature, it breaks through the technical bottlenecks of cold recycling technology in terms of layer application, recycling ratio and durability by physical modification (allowing diluted asphalt to maintain good flow at room temperature), all-solid waste formulation design (combining asphalt pavement recycling materials with waste road concrete to replace all aggregates) and process innovation (especially the pre-mixing of D60 dearomatic solvent oil with castor oil-based bio-heavy oil to prepare cold mix activator, and then allowing the cold mix activator to be mixed with asphalt pavement recycling materials first). It develops all-solid waste surface layer cold recycled asphalt mixture.

[0055] (2) This invention is the first to propose the use of D60 dearomatic solvent oil in the preparation technology of cold recycled asphalt mixture. When preparing diluted asphalt, D60 dearomatic solvent oil is used as a diluent, which can keep the diluted asphalt in a good flow state at room temperature. D60 dearomatic solvent oil is also used when preparing cold mixing activator, which can activate the old asphalt in the recycled asphalt pavement material, allowing castor oil-based bio-heavy oil to enter the interior of the old asphalt, and can also promote the rapid fusion of new and old asphalt at room temperature.

[0056] (3) The D60 dearomatic solvent oil used in this invention is a highly environmentally friendly and pollution-free excellent solvent. It is colorless, non-toxic, and has very little odor, which can provide workers with a good construction environment. At the same time, the aromatic content is less than 0.03wt%, the sulfur content is less than 0.2mg / kg, the emissions are low, and the impact on the environment is minimal.

[0057] (4) The D60 dearomatic solvent oil used in this invention has a fast dissolution rate with asphalt. It can activate the aged asphalt on the surface of the recycled asphalt pavement material at room temperature, reduce its viscosity, and promote the good integration of new and old asphalt, thereby improving the cohesion of cold recycled asphalt mixture.

[0058] (5) This invention breaks through the limitations of the recycling ratio of traditional cold recycling technology and innovatively combines asphalt pavement recycled materials with waste road concrete to replace all aggregates, realizing the recycling of all solid waste, which saves material costs and reduces energy consumption, and is conducive to the construction of "zero waste city".

[0059] (6) The cold recycled asphalt mixture prepared by the present invention has excellent comprehensive performance and can perfectly meet the performance requirements of the hot-mix asphalt mixture of the top layer (the top layer has the highest performance requirements for asphalt mixture), thus realizing high-level utilization. Attached Figure Description

[0060] Figure 1 This is a process flow diagram of a preferred embodiment of the cold recycled asphalt mixture with all solid waste top layer and its preparation method according to the present invention;

[0061] Figure 2 for Figure 1 A photograph of the actual asphalt pavement recycling material in the illustrated embodiment;

[0062] Figure 3 for Figure 1 A photograph of the actual discarded road concrete in the illustrated embodiment;

[0063] Figure 4 for Figure 1 Photographs of castor oil-based bio-heavy oil in the illustrated embodiments;

[0064] Figure 5 for Figure 1A photograph of the diluted asphalt prepared in the illustrated embodiment;

[0065] Figure 6 for Figure 1 A photograph of the cold-mix activator prepared according to the illustrated embodiment;

[0066] Figure 7 for Figure 1 The illustrated embodiment shows a photograph of the asphalt pavement recycled material mixed with the cold-mix activator.

[0067] Figure 8 for Figure 1 A photograph of the actual cold recycled asphalt mixture for the top layer of solid waste prepared according to the embodiment shown. Detailed Implementation

[0068] To further understand the invention, the following detailed description of the invention will be provided in conjunction with specific embodiments.

[0069] Example 1:

[0070] According to a preferred embodiment of the cold recycled asphalt mixture for the top layer of the whole solid waste according to the present invention, the mass percentage of each substance in the cold recycled asphalt mixture is as follows: 48 wt% asphalt pavement recycled material, 48 wt% waste road concrete, 2 wt% diluted asphalt, 1 wt% cold mix activator, and 1 wt% mineral powder; D60 dearomatic solvent oil is used as the diluent in the diluted asphalt, and the cold mix activator contains D60 dearomatic solvent oil.

[0071] The asphalt pavement recycling material is in an oil-rich state, meaning the outer surface of the old aggregate is completely covered with old asphalt. The asphalt pavement recycling material includes two particle sizes: 3-5 mm and 0-3 mm. The mass percentage of each particle size in the asphalt pavement recycling material is as follows: 30 wt% for 3-5 mm and 70 wt% for 0-3 mm. The mineral powder is limestone with a particle size less than 0.075 mm.

[0072] The crushing value of the waste road concrete does not exceed 30%, the inclusion content does not exceed 0.5%, the content of needle-like and flaky particles does not exceed 20%, and the adhesion rate of old mortar to the outer surface of old concrete particles does not exceed 30%. The waste road concrete includes three particle sizes: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm. The mass percentage of each particle size in the waste road concrete is as follows: 13.2-16mm accounts for 3wt%, 9.5-13.2mm accounts for 35wt%, and 4.75-9.5mm accounts for 62wt%.

[0073] The mass percentages of each substance in the diluted asphalt are as follows: base asphalt 78 wt%, antioxidant 1 wt%, anti-stripping agent 0.5 wt%, and diluent 20.5 wt%. The base asphalt is No. 70 base asphalt; the antioxidant is nano zinc oxide with a particle size of 20nm and a purity of not less than 90%; the anti-stripping agent is a non-amine anti-stripping agent, which is a nitrogen-containing complex. This nitrogen-containing complex is AR-I type anti-stripping agent produced by Shenzhen Jinlong Chemical Technology Co., Ltd., and is a solid powder; the diluent is D60 dearomatic solvent oil. The D60 dearomatic solvent oil is obtained by fractional distillation after deep desulfurization, dearomaticization, and hydrogenation refining from straight-run distillate oil, hydrocracking distillate oil, or low-sulfur straight-run jet fuel. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%. This D60 dearomatic solvent oil is produced by Jinan Yuanyang Chemical Co., Ltd.

[0074] The cold-mix activator comprises the following components by mass percentage: 83.3 wt% D60 dearomatic solvent oil and 16.7 wt% castor oil-based bio-heavy oil. The amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the range of the mass percentages of D60 dearomatic solvent oil and asphalt pavement recycled material, for every 1 wt% increase in the amount of asphalt pavement recycled material, the amount of D60 dearomatic solvent oil added increases by 0.5-0.7 wt%. In this embodiment, both the asphalt pavement recycled material and the D60 dearomatic solvent oil are added at the minimum required amounts.

[0075] In the cold-mix activator, the D60 dearomatic solvent oil is obtained by fractional distillation after deep desulfurization, dearomaticization, and hydrorefining from straight-run distillate oil, hydrocracked distillate oil, or low-sulfur straight-run jet fuel. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%. This D60 dearomatic solvent oil is produced by Jinan Yuanyang Chemical Co., Ltd. The castor oil-based bio-heavy oil contains the following mass percentages: saturated hydrocarbons 0.5 wt%, aromatic hydrocarbons 56.5 wt%, gums 39 wt%, and asphaltenes 4 wt%. This castor oil-based bio-heavy oil is produced from the residue remaining after extracting castor oil from castor seeds, through coarse processing (only coarse processing is required, without dehydration and deodorization). At room temperature, the castor oil-based bio-heavy oil is a dark brown viscous paste with a certain degree of fluidity.

[0076] like Figure 1As shown, this embodiment also provides a method for preparing a cold recycled asphalt mixture with a solid waste surface layer, which is used to prepare the above-mentioned cold recycled asphalt mixture with a solid waste surface layer, and includes the following steps in sequence:

[0077] Step 1: Prepare diluted asphalt according to the designed material ratio and process parameters, and store it at room temperature for later use;

[0078] Step 2: Mix D60 dearomatic solvent oil and castor oil-based bio-heavy oil evenly according to the designed material ratio to prepare cold-mix activator, and store it at room temperature for later use;

[0079] Step 3: Place the asphalt pavement recycling materials, waste road concrete, and mineral powder of each particle size into an oven for drying. After drying, remove the asphalt pavement recycling materials, waste road concrete, and mineral powder of each particle size from the oven and let them cool naturally to room temperature for later use.

[0080] Step 4: Put the recycled asphalt pavement materials of various particle sizes into the mixing pot and mix them with a mixer;

[0081] Step 5: Add the cold-mix activator to the mixing pot and continue mixing with a mixer;

[0082] Step 6: Add the waste road concrete and diluted asphalt of various particle sizes to the mixing pot, and continue mixing with a mixer;

[0083] Step 7: Add the mineral powder to the mixing pot and continue mixing with a mixer. After mixing is completed, the cold recycled asphalt mixture of all solid waste surface layer can be obtained.

[0084] In step one, the method for preparing diluted asphalt includes the following steps in sequence:

[0085] Step (1): Weigh the base asphalt, antioxidant, anti-stripping agent, and diluent according to the designed material ratio and set aside;

[0086] Step (2): Place the base asphalt into a container, and then place the container containing the base asphalt into an oven and heat it at 110°C for 1.5 hours.

[0087] Step (3): After heating is complete, take out the container containing the base asphalt from the oven, add the diluent to the container, and then put the container containing the base asphalt and diluent into the oil bath. Stir with a stirrer until the base asphalt and diluent are completely mixed. The temperature of the oil bath is 70°C and the stirring time is 12 minutes.

[0088] Step (4): Keep the temperature of the oil bath constant, continue stirring with a stirrer, and add the anti-stripping agent while stirring until the anti-stripping agent is completely mixed. The temperature of the oil bath is 70℃ and the stirring time is 12min.

[0089] Step (5): Keep the temperature of the oil bath constant and continue stirring with a mixer while adding antioxidants until the antioxidants are fully mixed. The temperature of the oil bath is 70°C and the stirring time is 12 minutes. After stirring is completed, diluted asphalt can be obtained.

[0090] In step three, the drying temperature for asphalt pavement recycled materials of various particle sizes, waste road concrete of various particle sizes, and mineral powder is 105℃, and the drying time is 1.5h.

[0091] In step four, asphalt pavement recycled materials of various particle sizes are placed into a mixing pot and stirred at room temperature, at a stirring speed of 85 r / min, and for a stirring time of 75 s.

[0092] In step five, the cold-mix activator is added to the mixing pot and stirred at room temperature, at a stirring speed of 85 r / min, and for 75 s.

[0093] In step six, waste road concrete and diluted asphalt of various particle sizes are added to the mixing pot and stirred at room temperature, at a stirring speed of 85 r / min, and for 75 s.

[0094] In step seven, the mineral powder is added to the mixing pot and stirred at room temperature, at a stirring speed of 85 r / min, and for 75 seconds.

[0095] In this embodiment, the asphalt pavement recycling material RAP used is as follows: Figure 2 As shown, the waste road concrete used is as follows Figure 3 As shown, the castor oil-based bio-heavy oil used is as follows: Figure 4 As shown, the prepared diluted asphalt is as follows Figure 5 As shown, the prepared cold-mix activator is as follows: Figure 6 As shown, the substance obtained by mixing asphalt pavement recycled material RAP with cold mix activator is as follows: Figure 7 As shown, the prepared all-solid-waste surface layer cold recycled asphalt mixture is as follows: Figure 8 As shown.

[0096] The cold recycled asphalt mixture for the surface layer of this embodiment and its preparation method have the following beneficial effects: (1) Using D60 dearomatic solvent oil as a diluent and cold-mix activator, starting from solving the problem of rapid fusion of new and old asphalt at room temperature, through physical modification, all-solid-waste formulation design and process innovation, the technical bottlenecks of cold recycling technology in terms of layer application, recycling ratio and durability have been broken through, and a cold recycled asphalt mixture for the surface layer of all-solid-waste has been developed. (2) For the first time, D60 dearomatic solvent oil is used in the preparation technology of cold recycled asphalt mixture. When preparing diluted asphalt, D60 dearomatic solvent oil is used as a diluent, which can keep the diluted asphalt in a good flow state at room temperature; D60 dearomatic solvent oil is also used when preparing cold-mix activator, which can activate the old asphalt in the recycled asphalt pavement material, allowing castor oil-based bio-heavy oil to enter the interior of the old asphalt, and can also promote the rapid fusion of new and old asphalt at room temperature. (3) The D60 dearomatic solvent oil used dissolves asphalt quickly, which can activate the aged asphalt on the surface of the recycled asphalt pavement material at room temperature, reducing its viscosity, and promote the good integration of new and old asphalt, thereby improving the cohesion of the cold recycled asphalt mixture. (4) It breaks through the recycling ratio limitation of traditional cold recycling technology, combining the recycled asphalt pavement material with waste road concrete to replace all aggregates, realizing the recycling of all solid waste. (5) The cold recycled asphalt mixture has excellent comprehensive performance and can perfectly meet the performance requirements of the surface layer hot-mix asphalt mixture, realizing high-level utilization.

[0097] Example 2:

[0098] According to another preferred embodiment of the cold recycled asphalt mixture for the top layer of solid waste and its preparation method of the present invention, the material ratio, preparation process, equipment used, technical principle, and beneficial effects are basically the same as those of Embodiment 1, except that:

[0099] The mass percentages of each substance in the cold recycled asphalt mixture are as follows: 49 wt% recycled asphalt pavement material, 47 wt% waste road concrete, 2.5 wt% diluted asphalt, 1 wt% cold mix activator, and 0.5 wt% mineral powder. The diluted asphalt uses D60 dearomatic solvent oil as a diluent, and the cold mix activator contains D60 dearomatic solvent oil.

[0100] The recycled asphalt pavement material comprises two particle sizes: 3-5mm and 0-3mm. The mass percentage of each particle size in the recycled asphalt pavement material is as follows: 3-5mm accounts for 35wt%, and 0-3mm accounts for 65wt%. The waste road concrete comprises three particle sizes: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm. The mass percentage of each particle size in the waste road concrete is as follows: 13.2-16mm accounts for 5wt%, 9.5-13.2mm accounts for 40wt%, and 4.75-9.5mm accounts for 55wt%.

[0101] The mass percentages of each substance in the diluted asphalt are as follows: base asphalt 79 wt%, antioxidant 0.8 wt%, anti-stripping agent 0.7 wt%, and diluent 19.5 wt%. The base asphalt is No. 70 base asphalt; the antioxidant is nano-zinc oxide with a particle size of 40 nm and a purity of not less than 90%; the anti-stripping agent is a non-amine anti-stripping agent, specifically a nitrogen-containing complex, which is an AR-I type anti-stripping agent produced by Shenzhen Jinlong Chemical Technology Co., Ltd., and is in the form of a solid powder; the diluent is D60 dearomatic solvent oil.

[0102] The mass percentages of each substance in the cold-mix activator are as follows: 83.8 wt% D60 dearomatic solvent oil and 16.2 wt% castor oil-based bio-heavy oil. The amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the mass percentage range of D60 dearomatic solvent oil and asphalt pavement recycled material, for every 1 wt% increase in the amount of asphalt pavement recycled material added, the amount of D60 dearomatic solvent oil added increases by 0.5 wt%, ensuring it is controlled within the range of 0.5-0.7 wt%.

[0103] The castor oil-based bio-heavy oil contains the following mass percentages: saturated hydrocarbons 0.6 wt%, aromatic hydrocarbons 58 wt%, gums 35.4 wt%, and asphaltenes 6 wt%. This castor oil-based bio-heavy oil is produced from the residue remaining after extracting castor oil from castor seeds, through coarse processing (only coarse processing is required, without dehydration and deodorization). At room temperature, the castor oil-based bio-heavy oil is a dark brown viscous paste with a certain degree of fluidity.

[0104] The D60 dearomatic solvent oil used in this embodiment is obtained by fractionation of straight-run distillate oil, hydrocracking distillate oil, or low-sulfur straight-run jet fuel as raw materials, after deep desulfurization, dearomaticization, and hydrorefining. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%. This D60 dearomatic solvent oil is produced by Jinan Yuanyang Chemical Co., Ltd.

[0105] In step one, the preparation method of the diluted asphalt includes the following main process parameters: Step (2), the base asphalt is placed in an oven and heated at 100°C for 2 hours; Step (3), the diluent is added to the base asphalt and then placed in an oil bath and stirred at 60°C for 15 minutes; Step (4), an anti-stripping agent is added to the oil bath and stirred for 15 minutes; Step (5), an antioxidant is added to the oil bath and stirred for 15 minutes.

[0106] In step three, the drying temperature for the recycled asphalt pavement material, waste road concrete, and mineral powder is 100℃, and the drying time is 2 hours. In step four, the recycled asphalt pavement material is placed in a mixing pot and stirred at room temperature at a speed of 70 rpm for 90 seconds. In step five, the cold-mix activator is added to the mixing pot and stirred at room temperature at a speed of 70 rpm for 90 seconds. In step six, the waste road concrete and diluted asphalt are added to the mixing pot and stirred at room temperature at a speed of 70 rpm for 90 seconds. In step seven, the mineral powder is added to the mixing pot and stirred at room temperature at a speed of 70 rpm for 90 seconds.

[0107] Example 3:

[0108] According to another preferred embodiment of the cold recycled asphalt mixture for the top layer of solid waste and its preparation method of the present invention, the material ratio, preparation process, equipment used, technical principle, and beneficial effects are basically the same as those of Embodiment 1, except that:

[0109] The mass percentages of each substance in the cold recycled asphalt mixture are as follows: 50 wt% recycled asphalt pavement material, 45 wt% waste road concrete, 3 wt% diluted asphalt, 1.5 wt% cold mix activator, and 0.5 wt% mineral powder. The diluted asphalt uses D60 dearomatic solvent oil as a diluent, and the cold mix activator contains D60 dearomatic solvent oil.

[0110] The recycled asphalt pavement material comprises two particle sizes: 3-5mm and 0-3mm. The percentage of each particle size by mass is as follows: 3-5mm accounts for 40wt%, and 0-3mm accounts for 60wt%. The waste road concrete comprises three particle sizes: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm. The percentage of each particle size by mass is as follows: 13.2-16mm accounts for 6wt%, 9.5-13.2mm accounts for 36wt%, and 4.75-9.5mm accounts for 58wt%.

[0111] The mass percentages of each substance in the diluted asphalt are as follows: base asphalt 80 wt%, antioxidant 0.9 wt%, anti-stripping agent 0.6 wt%, and diluent 18.5 wt%. The base asphalt is No. 70 base asphalt; the antioxidant is nano-zinc oxide with a particle size of 60 nm and a purity of not less than 90%; the anti-stripping agent is a non-amine anti-stripping agent, specifically a nitrogen-containing complex, which is an AR-I type anti-stripping agent produced by Shenzhen Jinlong Chemical Technology Co., Ltd., and is in the form of a solid powder; the diluent is D60 dearomatic solvent oil.

[0112] The mass percentages of each substance in the cold-mix activator are as follows: 84.4 wt% D60 dearomatic solvent oil and 15.6 wt% castor oil-based bio-heavy oil. The amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the mass percentage range of D60 dearomatic solvent oil and asphalt pavement recycled material, for every 1 wt% increase in the amount of asphalt pavement recycled material added, the amount of D60 dearomatic solvent oil added increases by 0.6 wt%, ensuring it is controlled within the range of 0.5-0.7 wt%.

[0113] The castor oil-based bio-heavy oil contains the following mass percentages: saturated hydrocarbons 0.8 wt%, aromatic hydrocarbons 55 wt%, gums 39 wt%, and asphaltenes 5.2 wt%. This castor oil-based bio-heavy oil is produced from the residue remaining after extracting castor oil from castor seeds, through coarse processing (only coarse processing is required, without dehydration and deodorization). Under normal temperature conditions, the castor oil-based bio-heavy oil presents as a dark brown viscous paste with a certain degree of fluidity.

[0114] The D60 dearomatic solvent oil used in this embodiment is obtained by fractionation of straight-run distillate oil, hydrocracking distillate oil, or low-sulfur straight-run jet fuel as raw materials, after deep desulfurization, dearomaticization, and hydrorefining. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%. This D60 dearomatic solvent oil is produced by Jinan Yuanyang Chemical Co., Ltd.

[0115] In step one, the preparation method of the diluted asphalt includes the following main process parameters: Step (2), the base asphalt is placed in an oven and heated at 120°C for 1 hour; Step (3), the diluent is added to the base asphalt and then placed in an oil bath and stirred at 80°C for 10 minutes; Step (4), an anti-stripping agent is added to the oil bath and stirred for 10 minutes; Step (5), an antioxidant is added to the oil bath and stirred for 10 minutes.

[0116] In step three, the drying temperature for the recycled asphalt pavement material, waste road concrete, and mineral powder is 110℃, and the drying time is 1 hour. In step four, the recycled asphalt pavement material is placed in a mixing pot and stirred at room temperature at a speed of 100 rpm for 60 seconds. In step five, the cold-mix activator is added to the mixing pot and stirred at room temperature at a speed of 100 rpm for 60 seconds. In step six, the waste road concrete and diluted asphalt are added to the mixing pot and stirred at room temperature at a speed of 100 rpm for 60 seconds. In step seven, the mineral powder is added to the mixing pot and stirred at room temperature at a speed of 100 rpm for 60 seconds.

[0117] Example 4:

[0118] According to another preferred embodiment of the cold recycled asphalt mixture for the top layer of solid waste and its preparation method of the present invention, the material ratio, preparation process, equipment used, technical principle, and beneficial effects are basically the same as those of Embodiment 1, except that:

[0119] The mass percentages of each substance in the cold recycled asphalt mixture are as follows: 51 wt% recycled asphalt pavement material, 44 wt% waste road concrete, 2.2 wt% diluted asphalt, 1.8 wt% cold mix activator, and 1 wt% mineral powder. The diluted asphalt uses D60 dearomatic solvent oil as a diluent, and the cold mix activator contains D60 dearomatic solvent oil.

[0120] The recycled asphalt pavement material comprises two particle sizes: 3-5mm and 0-3mm. The mass percentage of each particle size in the recycled asphalt pavement material is as follows: 3-5mm accounts for 45wt%, and 0-3mm accounts for 55wt%. The waste road concrete comprises three particle sizes: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm. The mass percentage of each particle size in the waste road concrete is as follows: 13.2-16mm accounts for 7wt%, 9.5-13.2mm accounts for 33wt%, and 4.75-9.5mm accounts for 60wt%.

[0121] The mass percentages of each substance in the diluted asphalt are as follows: base asphalt 81 wt%, antioxidant 0.9 wt%, anti-stripping agent 0.6 wt%, and diluent 17.5 wt%. The base asphalt is No. 70 base asphalt; the antioxidant is nano-zinc oxide with a particle size of 80 nm and a purity of not less than 90%; the anti-stripping agent is a non-amine anti-stripping agent, specifically a nitrogen-containing complex, which is an AR-I type anti-stripping agent produced by Shenzhen Jinlong Chemical Technology Co., Ltd., and is in the form of a solid powder; the diluent is D60 dearomatic solvent oil.

[0122] The mass percentages of each substance in the cold-mix activator are as follows: 85.1 wt% D60 dearomatic solvent oil and 14.9 wt% castor oil-based bio-heavy oil. The amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the mass percentage range of D60 dearomatic solvent oil and asphalt pavement recycled material, for every 1 wt% increase in the amount of asphalt pavement recycled material added, the amount of D60 dearomatic solvent oil added increases by 0.7 wt%, ensuring that it is controlled within the range of 0.5-0.7 wt%.

[0123] The castor oil-based bio-heavy oil contains the following mass percentages: saturated hydrocarbons 0.5 wt%, aromatic hydrocarbons 55.5 wt%, gums 37 wt%, and asphaltenes 7 wt%. This castor oil-based bio-heavy oil is produced from the residue remaining after extracting castor oil from castor seeds, through coarse processing (only coarse processing is required, without dehydration and deodorization). Under normal temperature conditions, the castor oil-based bio-heavy oil presents as a dark brown viscous paste with a certain degree of fluidity.

[0124] The D60 dearomatic solvent oil used in this embodiment is obtained by fractionation of straight-run distillate oil, hydrocracking distillate oil, or low-sulfur straight-run jet fuel as raw materials, after deep desulfurization, dearomaticization, and hydrorefining. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%. This D60 dearomatic solvent oil is produced by Jinan Yuanyang Chemical Co., Ltd.

[0125] In step one, the preparation method of the diluted asphalt includes the following main process parameters: Step (2), the base asphalt is placed in an oven and heated at 105°C for 1.8 hours; Step (3), the diluent is added to the base asphalt and then placed in an oil bath and stirred at 65°C for 14 minutes; Step (4), an anti-stripping agent is added to the oil bath and stirred for 14 minutes; Step (5), an antioxidant is added to the oil bath and stirred for 14 minutes.

[0126] In step three, the drying temperature for the recycled asphalt pavement material, waste road concrete, and mineral powder is 102℃, and the drying time is 1.8 hours. In step four, the recycled asphalt pavement material is placed in a mixing pot and stirred at room temperature at a speed of 80 rpm for 80 seconds. In step five, the cold-mix activator is added to the mixing pot and stirred at room temperature at a speed of 80 rpm for 80 seconds. In step six, the waste road concrete and diluted asphalt are added to the mixing pot and stirred at room temperature at a speed of 80 rpm for 80 seconds. In step seven, the mineral powder is added to the mixing pot and stirred at room temperature at a speed of 80 rpm for 80 seconds.

[0127] Example 5:

[0128] According to another preferred embodiment of the cold recycled asphalt mixture for the top layer of solid waste and its preparation method of the present invention, the material ratio, preparation process, equipment used, technical principle, and beneficial effects are basically the same as those of Embodiment 1, except that:

[0129] The mass percentages of each substance in the cold recycled asphalt mixture are as follows: 52 wt% recycled asphalt pavement material, 44 wt% waste road concrete, 2 wt% diluted asphalt, 1.5 wt% cold mix activator, and 0.5 wt% mineral powder. The diluted asphalt uses D60 dearomatic solvent oil as a diluent, and the cold mix activator contains D60 dearomatic solvent oil.

[0130] The recycled asphalt pavement material comprises two particle sizes: 3-5mm and 0-3mm. The mass percentage of each particle size in the recycled asphalt pavement material is as follows: 3-5mm accounts for 50wt%, and 0-3mm accounts for 50wt%. The waste road concrete comprises three particle sizes: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm. The mass percentage of each particle size in the waste road concrete is as follows: 13.2-16mm accounts for 8wt%, 9.5-13.2mm accounts for 30wt%, and 4.75-9.5mm accounts for 62wt%.

[0131] The mass percentages of each substance in the diluted asphalt are as follows: base asphalt 82 wt%, antioxidant 0.9 wt%, anti-stripping agent 0.6 wt%, and diluent 16.5 wt%. The base asphalt is No. 70 base asphalt; the antioxidant is nano-zinc oxide with a particle size of 100 nm and a purity of not less than 90%; the anti-stripping agent is a non-amine anti-stripping agent, specifically a nitrogen-containing complex, which is an AR-I type anti-stripping agent produced by Shenzhen Jinlong Chemical Technology Co., Ltd., and is in the form of a solid powder; the diluent is D60 dearomatic solvent oil.

[0132] The mass percentages of each substance in the cold-mix activator are as follows: 85.7 wt% D60 dearomatic solvent oil and 14.3 wt% castor oil-based bio-heavy oil. The amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the mass percentage range of D60 dearomatic solvent oil and asphalt pavement recycled material, for every 1 wt% increase in the amount of asphalt pavement recycled material, the amount of D60 dearomatic solvent oil added increases by 0.6 wt%, ensuring it is controlled within the range of 0.5-0.7 wt%.

[0133] The castor oil-based bio-heavy oil contains the following mass percentages: saturated hydrocarbons 0.5 wt%, aromatic hydrocarbons 56 wt%, gums 37.5 wt%, and asphaltenes 6 wt%. This castor oil-based bio-heavy oil is produced from the residue remaining after extracting castor oil from castor seeds, through coarse processing (only coarse processing is required, without dehydration and deodorization). Under normal temperature conditions, the castor oil-based bio-heavy oil presents as a dark brown viscous paste with a certain degree of fluidity.

[0134] The D60 dearomatic solvent oil used in this embodiment is obtained by fractionation of straight-run distillate oil, hydrocracking distillate oil, or low-sulfur straight-run jet fuel as raw materials, after deep desulfurization, dearomaticization, and hydrorefining. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%. This D60 dearomatic solvent oil is produced by Jinan Yuanyang Chemical Co., Ltd.

[0135] In step one, the preparation method of the diluted asphalt includes the following main process parameters: Step (2), the base asphalt is placed in an oven and heated at 115°C for 1.2 hours; Step (3), the diluent is added to the base asphalt and then placed in an oil bath and stirred at 75°C for 11 minutes; Step (4), an anti-stripping agent is added to the oil bath and stirred for 11 minutes; Step (5), an antioxidant is added to the oil bath and stirred for 11 minutes.

[0136] In step three, the drying temperature for the recycled asphalt pavement material, waste road concrete, and mineral powder is 108℃, and the drying time is 1.2 hours. In step four, the recycled asphalt pavement material is placed in a mixing pot and stirred at room temperature at a speed of 90 rpm for 70 seconds. In step five, the cold-mix activator is added to the mixing pot and stirred at room temperature at a speed of 90 rpm for 70 seconds. In step six, the waste road concrete and diluted asphalt are added to the mixing pot and stirred at room temperature at a speed of 90 rpm for 70 seconds. In step seven, the mineral powder is added to the mixing pot and stirred at room temperature at a speed of 90 rpm for 70 seconds.

[0137] Comparative example:

[0138] Regarding the cold-mix activator: The cold-mix activator used in the above five examples is a mixture of D60 dearomatic solvent oil and castor oil-based bio-heavy oil, wherein the D60 dearomatic solvent oil is 83.3-85.7 wt% and the castor oil-based bio-heavy oil is 14.3-16.7 wt%.

[0139] Five comparative examples were designed, with the selection and proportion of each substance in the asphalt mixture being the same as those in the five examples. The preparation method and process parameters of the asphalt mixture were also the same as those in the five examples. The difference was that the cold-mix activator was castor oil-based bio-heavy oil and did not contain D60 dearomatic solvent oil.

[0140] The cold recycled asphalt mixtures prepared in the above five examples and five comparative examples were subjected to performance tests such as molding stability, water stability and dynamic stability. The test equipment, test environment, test conditions, sample shape and size were the same. Three sets of parallel tests were performed for each performance test, and then the average value was taken.

[0141] I. Molding Stability Test

[0142] Weigh 1170g of cold recycled asphalt mixture (actual mass based on a specimen height of 63.5±1.5mm) and fill the mold. Compact both sides 50 times. Place the specimen, along with the mold, upright on its side in an oven at 105±5℃ for 48 hours. Remove and compact both sides 25 times. Then, place the specimen, along with the mold, upright at room temperature for 24 hours before demolding. Cure the specimen in a water bath at 60±1℃ for 30 minutes and determine its Marshall stability, which is the molding stability. The test results are shown in Table 1.

[0143] Table 1. Test results of molding stability of cold recycled asphalt mixtures

[0144] Example Average molding stability (KN) Example 1 10.52 Example 2 10.48 Example 3 10.35 Example 4 10.24 Example 5 10.12 Comparative Example 1 4.41 Comparative Example 2 4.85 Comparative Example 3 4.52 Comparative Example 4 4.39 Comparative Example 5 4.65

[0145] II. Water Stability Test

[0146] Weigh 1170g of cold recycled asphalt mixture (actual mass is based on controlling the specimen height to 63.5±1.5mm) and fill the mold. Compact both sides 50 times. Place the specimen and mold upright on their sides in an oven at 105±5℃ for 48h. Remove the specimen and compact both sides 25 times. Then, place the specimen and mold upright at room temperature for 24h before demolding.

[0147] The specimens were randomly divided into two groups, with no fewer than four specimens in each group. One group of specimens was kept in a 60℃ constant temperature water bath for 60 minutes and then subjected to a Marshall test. The other group of specimens was kept in a 60℃ constant temperature water bath for 48 hours and then subjected to a Marshall test. The ratio of the two groups is the residual stability ratio. The test results are shown in Table 2.

[0148] Table 2 Results of Water Immersion Residual Stability Test for Cold Recycled Asphalt Mixtures

[0149]

[0150]

[0151] The specimens were randomly divided into two groups, with no fewer than four specimens in each group. The first group of specimens was placed on a platform and stored at room temperature for later use. The second group of specimens was placed in a vacuum desiccator, the water inlet hose was closed, and the vacuum pump was turned on to achieve a vacuum level of 98.3 kPa (730 mmHg) or higher in the desiccator, which was maintained for 15 minutes. Then, the water inlet hose was opened, and cold water was introduced under negative pressure to completely immerse the specimens in the water. After immersion for 15 minutes, the pressure was restored to normal. The second group of specimens was removed and placed in a plastic bag with about 10 mL of water added. The bag was sealed tightly, and the specimens were placed in a constant temperature freezer at -18℃±2℃ for 16±1 hours. The specimens were then removed and immediately placed in a constant temperature water bath at 60±0.5℃ for 3 minutes. After soaking, the plastic bag was removed, and the specimens were kept at this temperature for another 24 hours±30 minutes. All specimens from both the first and second groups were then immersed in a constant temperature water bath at 25±0.5℃ for 2 hours±10 minutes. The test results of the first group of specimens are the splitting strength. The ratio of the splitting strength of the second group to that of the first group is the freeze-thaw splitting tensile strength ratio. The test results are shown in Table 3.

[0152] Table 3. Results of splitting tensile strength and freeze-thaw cycle splitting tensile strength tests on cold recycled asphalt mixtures.

[0153] Example Average splitting strength (MPa) Average splitting tensile strength (MPa) after freeze-thaw cycles Freeze-thaw splitting strength ratio (%) Example 1 0.57 0.56 98％ Example 2 0.54 0.53 98％ Example 3 0.53 0.51 96％ Example 4 0.51 0.48 94％ Example 5 0.50 0.44 88％ Comparative Example 1 0.41 0.22 54％ Comparative Example 2 0.43 0.23 55％ Comparative Example 3 0.41 0.22 54％ Comparative Example 4 0.42 0.24 58％ Comparative Example 5 0.41 0.22 56％

[0154] III. Dynamic Stability Test

[0155] A mold measuring 300mm long × 300mm wide × 50mm thick was used. The mixed cold recycled asphalt mixture was lightly stirred with a small shovel and then evenly poured into the mold in a circular motion from the edge to the center, ensuring the center was slightly higher than the surrounding area. Before molding, the roller was preheated to approximately 80℃. The mold containing the asphalt mixture was then placed on the platform of the roller mill. The roller was gently lowered, and the total load was adjusted to 9kN (linear load 300N / cm). The roller mill was started, and after two round trips (4 times), the load was removed, the roller was lifted, the specimen was rotated, and the same load was applied again to continue rolling until the surface of the specimen was flush with the top edge of the mold. After rolling, the specimen was quickly placed in a 60℃ electric heating drying oven to dry to constant weight.

[0156] The specimen, along with the mold, was placed in a constant-temperature chamber at 60±1℃ and kept at that temperature for 5-12 hours. The specimen and mold were then transferred to the test bench of the wheel rut testing machine, with the test wheel positioned in the center of the specimen, its direction of travel aligned with the compaction or driving direction of the specimen. The test temperature was 60℃, and the wheel pressure was 0.7MPa. The automatic rut deformation recorder was activated, and the testing machine was started. The test wheel was moved back and forth for approximately 1 hour to complete the rut test. The test results are shown in Table 4.

[0157] Table 4. Dynamic stability test results of cold recycled asphalt mixtures

[0158] Example Dynamic stability (cycles / mm) Example 1 1101 Example 2 1036 Example 3 1059 Example 4 1118 Example 5 1064 Comparative Example 1 569 Comparative Example 2 526 Comparative Example 3 610 Comparative Example 4 556 Comparative Example 5 547

[0159] As can be seen from the test results in Tables 1-4, the cold recycled asphalt mixture prepared in the above embodiments has excellent comprehensive performance and can meet the performance requirements of hot-mix asphalt mixtures. According to the requirements of the "Technical Specification for Construction of Highway Asphalt Pavement" (JTGF40-2004): the Marshall stability of hot-mix asphalt mixtures for expressways and Class I highways should not be less than 8 kN, the residual stability in the water immersion Marshall test should not be less than 80%, and the residual strength ratio in the freeze-thaw splitting test should not be less than 75%.

[0160] The ovens, mixing pots, oil baths, and agitators used in the above embodiments are all conventional equipment in the field, and there are no special requirements for the model or structure of the equipment. The AR-I type anti-stripping agent used in the above embodiments was purchased from Shenzhen Jinlong Chemical Technology Co., Ltd., the D60 dearomatic solvent oil was purchased from Jinan Yuanyang Chemical Co., Ltd., and the asphalt pavement recycled materials, waste road concrete, mineral powder, matrix asphalt, nano zinc oxide, castor oil-based bio-heavy oil, etc., were purchased from Beijing Municipal Road and Bridge Building Materials Group Co., Ltd.

[0161] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant progress of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive experimentation. For each parameter and the combinations thereof, the inventors have recorded a large amount of experimental data; however, due to space limitations, the specific experimental data is not disclosed here.

[0162] Those skilled in the art will readily understand that the all-solid-waste top-layer cold recycled asphalt mixture and its preparation method of the present invention include any combination of the inventive content and specific embodiments described in the above specification and the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combined solutions have been described. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cold recycled asphalt mixture with an all-solid waste surface layer, characterized in that, The mass percentages of each substance in the cold recycled asphalt mixture are as follows: 48-52 wt% recycled asphalt pavement material, 44-48 wt% waste road concrete, 2-3 wt% diluted asphalt, 1-1.8 wt% cold mix activator, and 0.5-1 wt% mineral powder; the diluted asphalt uses D60 dearomatic solvent oil as a diluent, and the cold mix activator contains D60 dearomatic solvent oil. The asphalt pavement recycling material is in an oil-rich state, meaning that the outer surface of the old aggregate is completely covered with old asphalt. The asphalt pavement recycling material includes two particle sizes: 3-5mm and 0-3mm. The mass percentage of each particle size in the asphalt pavement recycling material is 30-50 wt% for 3-5mm and 50-70 wt% for 0-3mm. The crushing value of the waste road concrete does not exceed 30%, the inclusion content does not exceed 0.5%, the content of needle-like and flaky particles does not exceed 20%, and the adhesion rate of old mortar to the outer surface of old concrete particles does not exceed 30%. The waste road concrete includes three particle sizes: 13.2-16mm, 9.5-13.2mm, and 4.75-9.5mm. The mass percentage of each particle size in the waste road concrete is as follows: 13.2-16mm accounts for 3-8wt%, 9.5-13.2mm accounts for 30-40wt%, and 4.75-9.5mm accounts for 55-62wt%. The diluted asphalt contains an antioxidant, which is nano zinc oxide with a particle size of 20-100 nm and a purity of not less than 90%. The mass percentages of each substance in the cold-mix activator are as follows: 83.3-85.7 wt% D60 dearomatic solvent oil and 14.3-16.7 wt% castor oil-based bio-heavy oil. The mass percentages of each substance in the castor oil-based bio-heavy oil are as follows: 0.5-0.8 wt% saturated hydrocarbons, 55-58 wt% aromatic hydrocarbons, 35-39 wt% gums, and 4-7 wt% asphaltenes. The amount of D60 dearomatic solvent oil added to the cold-mix activator increases with the amount of asphalt pavement recycled material added. Within the mass percentage range of D60 dearomatic solvent oil and asphalt pavement recycled material, for every 1 wt% increase in the amount of asphalt pavement recycled material added, the amount of D60 dearomatic solvent oil added increases by 0.5-0.7 wt%. In the process of preparing cold recycled asphalt mixture, D60 dearomatic solvent oil and castor oil-based bio-heavy oil need to be mixed in advance to prepare a cold mix activator, and then the cold mix activator is added to the asphalt pavement recycling material for mixing.

2. The all-solid-waste surface cold recycled asphalt mixture according to claim 1, characterized in that, The mass percentages of each substance in the diluted asphalt are as follows: base asphalt 78-82 wt%, antioxidant 0.8-1 wt%, anti-stripping agent 0.5-0.7 wt%, and diluent 16.5-20.5 wt%.

3. The all-solid-waste surface cold recycled asphalt mixture according to claim 2, characterized in that, The base asphalt is No. 70 or No. 90 base asphalt; the anti-stripping agent is a non-amine anti-stripping agent, which is any one or more of polyphosphoric acid, phosphate ester, and nitrogen-containing complex; the diluent is D60 dearomatic solvent oil, which is obtained by fractional distillation after deep desulfurization, dearomaticization, and hydrorefining of straight-run distillate, hydrocracking distillate, or low-sulfur straight-run jet fuel as raw materials, with a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%.

4. The all-solid-waste surface cold recycled asphalt mixture according to claim 3, characterized in that, In the cold-mix activator, the D60 dearomatic solvent oil is obtained by fractional distillation after deep desulfurization, dearomaticization, and hydrogenation refining from straight-run distillate oil, hydrocracking distillate oil, or low-sulfur straight-run jet fuel. It has a distillation range of 180-230℃, a closed-cup flash point of 60-70℃, an aromatic content of less than 0.03wt%, a sulfur content of less than 0.2mg / kg, and a saturated hydrocarbon content of greater than 99.9%.

5. A method for preparing a cold recycled asphalt mixture with an all-solid waste surface layer, characterized in that, The method for preparing the all-solid-waste surface cold recycled asphalt mixture according to any one of claims 1-4 comprises the following steps in sequence: Step 1: Prepare diluted asphalt according to the designed material ratio and process parameters, and store it at room temperature for later use; Step 2: Mix D60 dearomatic solvent oil and castor oil-based bio-heavy oil evenly according to the designed material ratio to prepare cold-mix activator, and store it at room temperature for later use; Step 3: Place the asphalt pavement recycling materials, waste road concrete, and mineral powder of each particle size into an oven for drying. After drying, remove the asphalt pavement recycling materials, waste road concrete, and mineral powder of each particle size from the oven and let them cool naturally to room temperature for later use. Step 4: Put the recycled asphalt pavement materials of various particle sizes into the mixing pot and mix them with a mixer; Step 5: Add the cold-mix activator to the mixing pot and continue mixing with a mixer; Step 6: Add the waste road concrete and diluted asphalt of various particle sizes to the mixing pot, and continue mixing with a mixer; Step 7: Add the mineral powder to the mixing pot and continue mixing with a mixer. After mixing is completed, the cold recycled asphalt mixture of all solid waste surface layer can be obtained.

6. The method for preparing cold recycled asphalt mixture with all solid waste surface layer according to claim 5, characterized in that, In step one, the method for preparing diluted asphalt includes the following steps in sequence: Step (1): Weigh the base asphalt, antioxidant, anti-stripping agent, and diluent according to the designed material ratio and set aside; Step (2): Place the base asphalt into a container, and then place the container containing the base asphalt into an oven and heat it at a temperature of 100-120℃ for 1-2 hours. Step (3): After heating is complete, take out the container containing the base asphalt from the oven, add the diluent to the container, and then put the container containing the base asphalt and diluent into the oil bath. Stir with a stirrer until the base asphalt and diluent are completely mixed. The temperature of the oil bath is 60-80℃ and the stirring time is 10-15 minutes. Step (4): Keep the temperature of the oil bath constant, continue stirring with a stirrer, and add the anti-stripping agent while stirring until the anti-stripping agent is completely mixed. The temperature of the oil bath is 60-80℃ and the stirring time is 10-15 minutes. Step (5): Keep the temperature of the oil bath constant and continue stirring with a mixer while adding antioxidants until the antioxidants are fully mixed. The temperature of the oil bath should be 60-80℃ and the stirring time should be 10-15 minutes. After stirring is completed, diluted asphalt can be obtained.

7. The method for preparing cold recycled asphalt mixture with all solid waste surface layer according to claim 6, characterized in that, In step three, the drying temperature for asphalt pavement recycled materials of various particle sizes, waste road concrete of various particle sizes, and mineral powder is 100-110℃, and the drying time is 1-2 hours. In step four, the recycled asphalt pavement materials of various particle sizes are put into the mixing pot and stirred. The stirring temperature is room temperature, the stirring speed is 70-100 r / min, and the stirring time is 60-90 s. In step five, the cold-mix activator is added to the mixing pot and stirred at room temperature, at a stirring speed of 70-100 r / min, and for a stirring time of 60-90 s. In step six, waste road concrete and diluted asphalt of various particle sizes are added to the mixing pot and stirred. The stirring temperature is room temperature, the stirring speed is 70-100 r / min, and the stirring time is 60-90 s. In step seven, the mineral powder is added to the mixing pot and stirred at room temperature, at a stirring speed of 70-100 r / min, and for a stirring time of 60-90 s.

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