High-mixing-amount hot mix plant recycled modified asphalt mixture and preparation method thereof

Abstract

The invention discloses a high-dosage hot mix plant recycled modified asphalt mixture and a preparation method thereof. The mixture consists of the following components in parts by weight: 80-85 parts of 70 # road petroleum asphalt; 3-4 parts of an SBS restorer; 5-10 parts of swelling permeation oil; and 4-6 parts of an anti-aging agent. The new asphalt and the additive material can effectively and uniformly infiltrate the RAP surface, activate the aged asphalt coated on the RAP surface, and recover the SBS modifier in the large-dosage regenerated asphalt mixture at the same time. The problems that the activation degree of the RAP surface aged asphalt is insufficient and the recycled asphalt cannot meet the performance requirements of SBS modified asphalt under the condition of large mixing amount are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering materials, and in particular to a large-volume factory-mixed hot-regenerated modified asphalt mixture and a preparation method thereof. Background Art

[0002] In the future, bulk solid waste will continue to face severe challenges: high generation intensity, inadequate utilization, and low added value of products from comprehensive utilization. Currently, solid waste utilization remains low, occupying significant land resources and posing significant ecological and environmental safety risks.

[0003] Asphalt pavement regeneration technology has been widely used in road engineering, but the current RAP content in recycled asphalt mixtures is generally around 20-30%, which cannot fully replace new aggregates and new asphalt with RAP. Among them, the aged asphalt in RAP is difficult to fully integrate with new asphalt and regeneration agents during the production process. Due to the low RAP content in factory-mixed hot regeneration, most mixing plants are not equipped with regeneration agent spraying equipment, and the regeneration agent spraying equipment cannot act on the RAP surface comprehensively and evenly, thus failing to achieve a good regeneration effect for aged asphalt. The heating efficiency of RAP produced by large-volume factory-mixed hot recycled asphalt mixtures is insufficient, resulting in a low overall heating temperature of RAP. Usually, the method of increasing the heating temperature of the new aggregate is used to meet the overall discharge temperature of the mixture. However, due to the excessively high temperature of the new aggregate, the sprayed new asphalt and regeneration agent are very likely to age, which is not conducive to the overall performance of the recycled asphalt mixture.

[0004] Currently, the quality of regeneration agents available on the market varies greatly, with relatively low regeneration efficiency. Conventional regeneration agents are also unable to restore the SBS in SBS-modified asphalt. Therefore, developing a high-volume, factory-mixed, hot-regenerated modified asphalt mixture to improve its performance is of great social and practical significance. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention provides a high-volume, factory-mixed, hot-recycled modified asphalt mixture and its preparation method. New asphalt and additives effectively and evenly infiltrate the RAP surface, activating any aged asphalt adhered to it and restoring the modifiers in the recycled asphalt mixture. Furthermore, an anti-aging agent inhibits the aging effects of the recycled asphalt caused by contact between the excessively hot new aggregate and the recycled asphalt during mixing. These two synergistic effects enhance the overall performance of the recycled asphalt mixture.

[0006] To achieve the above object, the present invention provides a large-volume factory-mixed hot-recycled modified asphalt mixture, which is characterized by being composed of the following components in parts by weight:

[0007] 80-85 parts of 70# road petroleum asphalt;

[0008] 3-4 parts of SBS restorer;

[0009] 5-10 parts swelling penetrating oil;

[0010] 4 to 6 parts of anti-aging agent.

[0011] Furthermore, the SBS restoring agent is SBS grafted with acrylic acid and polydimethylsiloxane derivatives in steps.

[0012] Furthermore, the mass fraction of the SBS modifier in the SBS restoring agent is 85-95%, and the mass fraction of acrylic acid is 5-15%, wherein the SBS modifier has a star-shaped structure.

[0013] Furthermore, the preparation method of the SBS restoring agent comprises the following steps:

[0014] Dissolve the SBS modifier particles in toluene solvent and stir at 60°C until completely dissolved;

[0015] Add initiator and acrylic acid monomer, maintain the temperature at 80-90°C, and react for 5 hours;

[0016] Add 0.3% hydroquinone to terminate the reaction and cool to room temperature;

[0017] The reaction solution was poured into excess methanol for precipitation, filtered and dried under vacuum at 50°C for 24 h.

[0018] Furthermore, the swelling and penetrating oil is prepared by compounding the saturated oil-rich fraction and the aromatic oil-rich fraction in a ratio of 7:3.

[0019] Furthermore, the anti-aging agent includes a primary antioxidant and an auxiliary antioxidant, wherein:

[0020] The main antioxidant is one of butylated hydroxyanisole and butylated hydroxytoluene or a mixture of the two;

[0021] The auxiliary antioxidant is one of masterbatch and rosin resin or a mixture of the two.

[0022] The present invention also provides a method for preparing a large-volume factory-mixed hot-regenerated modified asphalt mixture, comprising the following steps:

[0023] Step (1): heat 70# road petroleum asphalt to 155°C, add swelling and penetrating oil, and stir at a speed of 800-1000 r / min for 15-20 minutes;

[0024] Step (2): adding an anti-aging agent and shearing at a speed of 2000-3000 r / min for 20-30 min to obtain regenerated blended asphalt;

[0025] Step (3): heat the RAP at 130 °C for 4 h and the new aggregate at 180 °C for 4 h;

[0026] Step (4): In a mixing pot at 175°C, first add RAP and stir for 90 seconds, then add SBS restoring agent and stir for 90 seconds, and finally add the recycled blended asphalt obtained in step (2) and stir for 90 seconds to obtain a mixture.

[0027] Furthermore, in step (4), the mass ratio of RAP to new aggregate is 6:4.

[0028] Furthermore, the performance indicators of the mixture are:

[0029] 5℃ elongation ≥33cm;

[0030] Softening point ≥78℃;

[0031] The residual penetration ratio after RTFOT aging is ≥70%.

[0032] The present invention discloses a high-volume factory-mixed hot-recycled modified asphalt mixture and a preparation method thereof, which has the following beneficial effects:

[0033] The new asphalt and additives can effectively and evenly infiltrate the RAP surface, activating the aged asphalt attached to the surface and restoring the SBS modifier in the high-volume recycled asphalt mixture. This solves the problem of insufficient activation of aged asphalt on the RAP surface at high volumes and the inability of recycled asphalt to meet the performance requirements of SBS modified asphalt.

[0034] The anti-aging agent in the recycled asphalt used in large-volume plant-mixed hot recycling technology inhibits the aging effect caused by the contact between the new aggregate and the recycled asphalt at excessively high temperatures during mixing, and the overall performance of the recycled asphalt mixture is improved through the synergistic effect of the two aspects. DETAILED DESCRIPTION

[0035] The present invention is further illustrated by examples below, but the scope of protection of the present invention is not limited to the examples. Other changes and modifications made by those skilled in the art without departing from the spirit and scope of protection of the present invention are also included in the scope of protection of the present invention.

[0036] Example 1:

[0037] The preparation process of new asphalt and additives in a large-volume factory-mixed hot recycled modified asphalt mixture is as follows:

[0038] (1) The 70# petroleum asphalt was heated to 155° C., and then 5 parts of the swelling oil were added. The stirrer was turned on at a speed of 800 r / min and stirred for 15 minutes.

[0039] (2) Replace the shearing equipment and add 4 parts of anti-aging agent to (1). The shearing machine speed is 3000r / min and the shearing is carried out for 20 minutes.

[0040] The preparation process of a large-volume factory-mixed hot recycled modified asphalt mixture is as follows:

[0041] (1) The ratio of old aggregate to new aggregate is 6:4;

[0042] (2) RAP was heated in an oven at 130°C for 4 h, and fresh aggregate was heated in an oven at 180°C for 4 h;

[0043] (3) The mixing pot temperature was set to 175°C, and RAP was added and stirred for 90 seconds;

[0044] (4) After adding 3 parts of SBS restoring agent and stirring for 90 seconds, add blended asphalt and stir for another 90 seconds to prepare a large-volume factory-mixed hot-recycled modified asphalt mixture.

[0045] The penetration of blended asphalt into aged asphalt was verified using a layered viscosity test. The test steps were as follows: 50g of aged asphalt was added to a test tube and the mixture was oven-heated to 130°C. Then, 50g of the regenerated asphalt prepared by the above method was added. The mixture was oven-heated at 130°C for 15 minutes, then refrigerated for 1 hour. The mixture was then divided into three equal sections and the Brookfield viscosity at 135°C was measured. The lower the viscosity of the lower section, the better the fusion of the new and old asphalt. The RTFOT test was used to verify the anti-aging effect of the regenerated asphalt. The performance of the regenerated asphalt with a high aged asphalt content was verified using the performance indicators of the extracted recovered asphalt. Specific indicators are shown in Table 1.

[0046] Table 1

[0047]

[0048] Example 2:

[0049] The preparation process of new asphalt and additives in a large-volume factory-mixed hot recycled modified asphalt mixture is as follows:

[0050] (1) The 70# petroleum asphalt was heated to 155° C., and then 7 parts of the swelling oil was added. The stirrer was turned on at a speed of 800 r / min and stirred for 15 minutes.

[0051] (2) Replace the shearing equipment, add 5 parts of anti-aging agent to (1), set the shearing machine speed to 3000r / min, and shear for 20min.

[0052] The preparation process of a large-volume factory-mixed hot recycled modified asphalt mixture is as follows:

[0053] (1) The ratio of old aggregate to new aggregate is 6:4;

[0054] (2) RAP was heated in an oven at 130°C for 4 h, and fresh aggregate was heated in an oven at 180°C for 4 h;

[0055] (3) The mixing pot temperature was set to 175°C, and RAP was added and stirred for 90 seconds;

[0056] (4) Add 3.5 parts of SBS restoring agent and stir for 90 seconds, then add blended asphalt and stir for another 90 seconds to prepare a large-volume factory-mixed hot-recycled modified asphalt mixture.

[0057] The penetration of blended asphalt into aged asphalt was verified using a layered viscosity test. The test steps were as follows: 50g of aged asphalt was added to a test tube and the tube was heated in an oven at 130°C. Then, 50g of the regenerated asphalt prepared by the above method was added. The tube was then heated in an oven at 130°C for 15 minutes, then refrigerated for 1 hour. The tube was then divided equally into three sections and the Brookfield viscosity at 135°C was measured. The lower the viscosity of the lower section, the better the fusion of the new and old asphalt. The RTFOT test was used to verify the anti-aging effect of the regenerated asphalt. The performance of the regenerated asphalt with a high aged asphalt content was verified using the performance indicators of the extracted recovered asphalt. Specific indicators are shown in Table 2.

[0058] Table 2

[0059]

[0060] Example 3:

[0061] The preparation process of new asphalt and additives in a large-volume factory-mixed hot recycled modified asphalt mixture is as follows:

[0062] (1) The 70# petroleum asphalt was heated to 155° C., and then 10 parts of the swelling oil was added. The stirrer was turned on at a speed of 800 r / min and stirred for 15 minutes.

[0063] (2) Replace the shearing equipment and add 6 parts of anti-aging agent to (1). The shearing machine speed is 3000r / min and the shearing is carried out for 20 minutes.

[0064] The preparation process of a large-volume factory-mixed hot recycled modified asphalt mixture is as follows:

[0065] (1) The ratio of old aggregate to new aggregate is 6:4;

[0066] (2) RAP was heated in an oven at 130°C for 4 h, and fresh aggregate was heated in an oven at 180°C for 4 h;

[0067] (3) The mixing pot temperature was set to 175°C, and RAP was added and stirred for 90 seconds;

[0068] (4) After adding 4 parts of SBS restoring agent and stirring for 90 seconds, the blended asphalt was added and stirred for another 90 seconds to prepare a large-volume factory-mixed hot-recycled modified asphalt mixture.

[0069] The penetration of blended asphalt into aged asphalt was verified using a layered viscosity test. The test steps were as follows: 50g of aged asphalt was added to a test tube and the mixture was oven-heated to 130°C. Then, 50g of the regenerated asphalt prepared by the above method was added. The mixture was oven-heated at 130°C for 15 minutes, then refrigerated for 1 hour. The mixture was then divided into three equal sections and the Brookfield viscosity at 135°C was measured. The lower the viscosity of the lower section, the better the fusion of the new and old asphalt. The RTFOT test was used to verify the anti-aging effect of the regenerated asphalt. The performance of the regenerated asphalt with a high aged asphalt content was verified using the performance indicators of the extracted recovered asphalt. Specific indicators are shown in Table 3.

[0070] Table 3

[0071]

[0072] Comparative Example 1:

[0073] Conventional SBS-modified asphalt was used to prepare a high-volume recycled asphalt mixture and compared with the optimal solution, Example 1. A layered viscosity test was used to verify the penetration of the blended asphalt into aged asphalt. The test steps were as follows: 50g of aged asphalt was added to a test tube, which was then heated in an oven to 130°C. Then, 50g of the recycled asphalt prepared by the above method was added. The mixture was then placed in an oven at 130°C for 15 minutes, then refrigerated for 1 hour. The mixture was then divided into three equal sections and the Brookfield viscosity at 135°C was measured. The lower the viscosity of the lower section, the better the fusion of the new and old asphalt. The RTFOT test was used to verify the anti-aging effect of the recycled asphalt. The performance of the recycled asphalt with a high aged asphalt content was verified using the performance indicators of the extracted recovered asphalt. Specific indicators are shown in Table 4.

[0074] Table 4

[0075]

[0076] Comparative Example 2:

[0077] Recycled asphalt without an anti-aging agent was used as a control group for comparison with the best solution Example 1. A layered viscosity test was used to verify the penetration of recycled asphalt into aged asphalt. The test procedure was as follows: 50g of aged asphalt was added to a test tube, which was kept in an oven at 130°C. Then, 50g of the recycle asphalt prepared by the above method was added. A control group was added with 50g of recycle asphalt without an anti-aging agent. The test tube was kept in an oven at 130°C for 15 minutes, then refrigerated for 1 hour, and then divided into three sections. The viscosity at 135°C was measured. The anti-aging effect of the recycle asphalt was verified using the RTFOT test. Specific indicators are shown in Table 5.

[0078] Table 5

[0079]

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A large-volume factory-mixed hot-recycled modified asphalt mixture, characterized in that: It is composed of the following components in parts by weight: 80-85 parts of 70# road petroleum asphalt; 3-4 parts of SBS restorer; 5-10 parts swelling penetrating oil; 4 to 6 parts of anti-aging agent.

2. The high-volume factory-mixed hot-regenerated modified asphalt mixture according to claim 1, characterized in that: The SBS restoring agent is SBS grafted with acrylic acid and polydimethylsiloxane derivatives in steps.

3. The high-volume factory-mixed hot-regenerated modified asphalt mixture according to claim 2, characterized in that: The mass fraction of the SBS modifier in the SBS restoring agent is 85-95%, and the mass fraction of acrylic acid is 5-15%, wherein the SBS modifier has a star-shaped structure.

4. The high-volume factory-mixed hot-regenerated modified asphalt mixture according to claim 2 or 3, characterized in that: The preparation method of the SBS restoring agent comprises the following steps: Dissolve the SBS modifier particles in toluene solvent and stir at 60°C until completely dissolved; Add initiator and acrylic acid monomer, maintain the temperature at 80-90°C, and react for 5 hours; Add 0.3% hydroquinone to terminate the reaction and cool to room temperature; The reaction solution was poured into excess methanol for precipitation, filtered and dried under vacuum at 50°C for 24 h.

5. The high-volume factory-mixed hot-regenerated modified asphalt mixture according to claim 1, characterized in that: The swelling and penetrating oil is prepared by compounding the saturated oil-rich fraction and the aromatic oil-rich fraction in a ratio of 7:

3.

6. The high-volume factory-mixed hot-recycled modified asphalt mixture according to claim 1, characterized in that: The anti-aging agent includes a primary antioxidant and an auxiliary antioxidant, wherein: The main antioxidant is one of butylated hydroxyanisole and butylated hydroxytoluene or a mixture of the two; The auxiliary antioxidant is one of masterbatch and rosin resin or a mixture of the two.

7. A method for preparing a high-volume factory-mixed hot-regenerated modified asphalt mixture according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step (1): heat 70# road petroleum asphalt to 155°C, add swelling and penetrating oil, and stir at a speed of 800-1000 r / min for 15-20 minutes; Step (2): adding an anti-aging agent and shearing at a speed of 2000-3000 r / min for 20-30 min to obtain regenerated blended asphalt; Step (3): heat the RAP at 130 °C for 4 h and the new aggregate at 180 °C for 4 h; Step (4): In a mixing pot at 175°C, first add RAP and stir for 90 seconds, then add SBS restoring agent and stir for 90 seconds, and finally add the recycled blended asphalt obtained in step (2) and stir for 90 seconds to obtain a mixture.

8. The preparation method according to claim 7, characterized in that The mass ratio of RAP to new aggregate in step (4) is 6:

4.

9. The preparation method according to claim 7 or 8, characterized in that The performance indicators of the mixture are: 5℃ elongation ≥33cm; Softening point ≥78℃; The residual penetration ratio after RTFOT aging is ≥70%.

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