Self-healing rubber asphalt based on solid waste aggregate and preparation process thereof

Abstract

The present invention discloses a self-healing rubber asphalt based on solid waste aggregate and a preparation process thereof, belonging to the technical field of rubber asphalt. The key points of the technical solution are that the rubber asphalt comprises the following raw materials in parts by weight: 30-45 parts of base asphalt, 8-15 parts of desulfurized rubber powder, 1.5-2.6 parts of asphalt modifier, 1-2.2 parts of microcapsules, 3-7 parts of tackifying resin, 6-11 parts of nanofiller, 130-150 parts of solid waste aggregate, and 12-15 parts of mineral powder, so as to achieve the effect of improving the fatigue resistance of the rubber asphalt.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber asphalt, and in particular to a self-healing rubber asphalt based on solid waste aggregate and a preparation process thereof. Background Art

[0002] As highway mileage increases, road loads are also increasing year by year. Heavy truck traffic is increasing at a particularly rapid rate, and these extremely heavy vehicle loads are increasingly damaging the road surface, causing numerous problems for asphalt pavements. During their service life, pavement is affected by factors such as ambient temperature fluctuations and vehicle loads. Long periods of irregular and repetitive strain and stress fluctuations can cause the strength of the entire pavement structure to gradually weaken. Under the repeated effects of these loads, fatigue cracking can occur, ultimately leading to cracking, crazing, loosening, and denting. Fatigue damage cracking is a common pavement problem and a pressing issue in highway construction.

[0003] Rubber is a common modifier in base asphalt. Asphalt pavements incorporating rubber powder have excellent fatigue resistance. The rubber powder is derived from scrap tires, a hazardous industrial solid waste that is highly resistant to heat, mechanical stress, and corrosion, and is extremely difficult to degrade. While rubber asphalt pavements have greater viscosity and elastic recovery than conventional asphalt, the fatigue resistance of the mixture still does not meet the requirements of current road environments. Summary of the Invention

[0004] In order to solve the problems in the prior art, the present invention provides a self-healing rubber asphalt based on solid waste aggregate and a preparation process thereof.

[0005] The first object of the present invention is to provide a self-healing rubber asphalt based on solid waste aggregate, using the following technical solution:

[0006] A self-healing rubber asphalt based on solid waste aggregate, the rubber asphalt comprising the following raw materials in parts by weight: 30-45 parts of base asphalt, 8-15 parts of desulfurized rubber powder, 1.5-2.6 parts of asphalt modifier, 1-2.2 parts of microcapsules, 3-7 parts of tackifying resin, 6-11 parts of nanofiller, 130-150 parts of solid waste aggregate, and 12-15 parts of mineral powder.

[0007] By adopting the above-mentioned technical solution, after adding desulfurized rubber powder, asphalt modifier, microcapsules, thickening resin and nanofiller to the matrix asphalt, the present application can not only ensure the self-healing effect of rubber asphalt, but also the addition of microcapsule powder can achieve a long-term self-repair effect. Moreover, the combined use of asphalt modifier and thickening resin can effectively improve its bonding ability with solid waste aggregates, and the addition of mineral powder can fill the gaps between solid waste aggregates, thereby ensuring the density of the asphalt pavement and improving the fatigue resistance of the asphalt pavement.

[0008] In a preferred embodiment, the microcapsules are obtained by the following preparation method:

[0009] (1) adding sodium alginate into water and stirring to dissolve the alginate to form a sodium alginate solution with a concentration of 1.2-2.5 wt%;

[0010] (2) adding expanded perlite powder to the sodium alginate solution and shearing for 20-30 min at a rotation speed of 4000-5000 r / min to form a suspension, wherein the expanded perlite powder is 0.4-2.5 times the dry weight of the sodium alginate;

[0011] (3) mixing the asphalt regeneration agent and the surfactant at a temperature of 40-50° C. and stirring for 10-15 minutes to form a mixture;

[0012] (4) adding the mixture obtained in step (2) to the suspension of step (2), and shearing for 5-10 min at a temperature of 40-50° C. and a rotation speed of 14,000-15,000 r / min to obtain a mixed solution, wherein the asphalt regeneration agent is 10% of the sodium alginate solution, and the surfactant is 5% of the asphalt regeneration agent content;

[0013] (5) The mixed solution was dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 12-13 hours to form capsules. The capsules were rinsed with clean water and dried at room temperature to form microcapsules.

[0014] Because calcium alginate capsules with a single wall material have disadvantages such as poor stability and low mechanical strength, during the drying process, the capsule volume shrinks due to water volatilization, and the capsule will produce a significant sudden or explosive release of the asphalt regeneration agent, resulting in premature release or all-at-once release of the asphalt regeneration agent, thereby affecting the self-healing performance of the asphalt. By adopting the above technical solution, this application uses sodium alginate and expanded perlite powder as capsule wall materials to synergistically improve the strength and flexibility of the microcapsules. At the same time, the special structure of the expanded perlite can increase the effective adsorption of the asphalt regeneration agent in the wall material, achieving the effect of slow release of the asphalt regeneration agent and achieving a longer-term self-healing effect, thereby extending the service life of the asphalt pavement.

[0015] In a preferred embodiment, in step (5), nano-titanium dioxide is added to the mixed solution and stirred to disperse evenly, and then dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 12-13 hours to form capsules. The capsules are rinsed with clean water and dried at room temperature to form microcapsules. The amount of nano-titanium dioxide added is 1.1-1.3% by weight of the expanded perlite powder.

[0016] By adopting the above technical solution, after adding nano-titanium dioxide to the sodium alginate solution, it can have a certain sealing effect on the wall material, reduce the leakage of the asphalt regeneration agent, and improve the utilization effect of the asphalt regeneration agent. At the same time, when the addition amount of nano-titanium dioxide is limited to 1.1-1.3% of the weight of the expanded perlite powder, it can not only effectively block the micropores on the surface of the microcapsule, but also reduce its influence on the adsorption performance of the expanded perlite powder on the asphalt regeneration agent.

[0017] In a preferred embodiment, the surfactant is Tween 80.

[0018] In a preferred embodiment, the asphalt modifier is obtained by mixing 30-40 parts by weight of SBS, 18-22 parts by weight of petroleum resin, 1-2 parts by weight of antioxidant, and 0.5-1.5 parts by weight of polyamide, followed by melt extrusion and granulation.

[0019] By adopting the above technical solution, the asphalt modifier is composed of SBS, petroleum asphalt, antioxidant and polyamide, which has high solubility in the matrix asphalt and good viscoelastic properties, and can effectively improve the fatigue resistance of the asphalt pavement.

[0020] In a preferred embodiment, the nanofiller is organic montmorillonite, which is prepared by the following method:

[0021] S1. Add melamine and 2,3-epoxypropyltrimethylammonium chloride in a molar ratio of 1:6 to water, and add a catalyst at the same time, and react at 90° C. for 12 h to obtain a reaction mixture. Let the reaction mixture stand, filter, and then dry to obtain a powder;

[0022] S2. Add the powder and montmorillonite obtained in step S1 into water, ultrasonically disperse for 30 minutes, stir and react at 80±2° C. for 4 hours, let stand, filter, and dry to obtain organic montmorillonite. The amount of the powder added is 10-30% of the weight of the montmorillonite.

[0023] By adopting the above technical solution, the nanofiller uses organic montmorillonite, which can effectively improve the low-temperature performance of asphalt pavement. At the same time, after the montmorillonite is modified with an intercalating agent made of melamine and 2,3-epoxypropyltrimethylammonium chloride, the interlamellar spacing of the montmorillonite is significantly increased. The increase in the interlamellar spacing can form an intercalated structure between the asphalt modifier, thickening resin, and matrix asphalt molecules, so that the asphalt modifier and thickening resin are more fully dispersed in the asphalt, thereby making the asphalt modifier, thickening resin, etc. play a better role, making the stress-bearing buffer system of the asphalt pavement more stable and the deformation recovery performance more superior. Moreover, the addition of organic montmorillonite can stabilize the role of the asphalt modifier in the asphalt and promote the asphalt modifier to better exert its low-temperature modification ability. However, when the content of organic montmorillonite exceeds a certain range, the ductility of the asphalt decreases, indicating that the excessive addition of organic montmorillonite causes particle agglomeration, weakening its effect on the low-temperature modification of asphalt.

[0024] In a preferred embodiment, the tackifying resin is composed of polystyrene maleic anhydride resin and alkylphenol-formaldehyde resin in a weight ratio of 1:1.

[0025] By adopting the above technical scheme, the addition of polystyrene maleic anhydride resin and alkylphenol formaldehyde resin can effectively bond the raw materials together, so that the obtained high-viscosity modified asphalt has good viscoelasticity. In addition, since the resin can reduce the surface free energy of the binder, the contact angle between the asphalt and the aggregate surface is reduced, and its viscosity is increased by surface diffusion and internal penetration and reaction with the asphalt, so that the adhesion between the asphalt and the aggregate surface is further increased. It can not only improve the bonding ability between the matrix asphalt and the solid waste aggregate, reduce the probability of separation of the solid waste aggregate and the asphalt after long-term use of the asphalt pavement, and improve the service life of the asphalt pavement, but also the addition of polystyrene maleic anhydride resin and alkylphenol formaldehyde resin, and its combination with desulfurized rubber powder, can effectively resist the deformation of the asphalt pavement at high temperature, improve the high-temperature stability of the asphalt, and at the same time reduce the brittleness of the asphalt at low temperature, so that the rubber asphalt has a certain low-temperature flexibility and improves the crack resistance.

[0026] In a preferred embodiment, the rubber asphalt further comprises 3-6 parts by weight of polyphosphoric acid.

[0027] By adopting the above technical solution, the combination of polyphosphoric acid and desulfurized rubber powder can effectively improve the high and low temperature performance and fatigue resistance of asphalt mixture. The reason may be that the phosphate groups in the polyphosphoric acid molecules can chemically react with the desulfurized rubber powder to form a cross-linked structure. This cross-linking can enhance the cohesion and adhesion of the rubber asphalt, thereby improving the mechanical properties and durability of the rubber asphalt. At the same time, under high temperature conditions, the polyphosphoric acid chemically reacts with the components in the asphalt to form a more stable structure, effectively improving the high and low temperature performance of the rubber asphalt and extending the service life of the rubber asphalt pavement.

[0028] The second aspect of the present invention is to provide a preparation process of the self-healing rubber asphalt based on solid waste aggregate as described above, comprising the following steps:

[0029] S1, preparatory stage, the desulfurized rubber powder is activated at 180-210℃ and then set aside;

[0030] S2. Melt the matrix asphalt at a temperature of 160-170° C., add the desulfurized rubber powder, asphalt modifier, and tackifying resin activated in step S1, and stir at a speed of 3000-4000 r / min for 20-25 minutes;

[0031] S3. Add microcapsules, nanofillers, solid waste aggregates, mineral powder and 3-6 parts by weight of polyphosphoric acid to step S2, and continue stirring at a rotation speed of 3000-4000 r / min for 30-40 minutes to obtain rubber asphalt.

[0032] In a preferred embodiment, the nanofiller is heated at 130-140° C. for 30 minutes before being added into step S3 .

[0033] By adopting the above technical solution, the present application heats the nanofiller and then adds it to the matrix asphalt, which can effectively reduce the agglomeration of the nanofiller in the matrix asphalt, so that the filler can be effectively dispersed in the matrix asphalt.

[0034] In summary, the present invention has the following beneficial effects: the combined use of the various raw materials in this application effectively improves the self-healing ability of rubber asphalt, while also enabling the rubber asphalt to have good high and low temperature performance and softness, thereby effectively improving the fatigue resistance of rubber asphalt. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the examples.

[0036] Asphalt is generally composed of four parts: asphaltenes, colloids, saturates and aromatics. During the actual use of asphalt pavement, asphalt ages due to natural conditions such as temperature and oxidation. From a component perspective, the content of saturates and aromatics in asphalt decreases, while asphalt increases, making the asphalt brittle and hard, and prone to cracks during vehicle driving. Asphalt regeneration can be seen as the reverse process of aging. If lightweight components can be added to the asphalt to make up for the parts lost during the aging process of the asphalt, the self-repairing properties of the asphalt can be enhanced to a certain extent. The regeneration agent contains more saturates and aromatics. After mixing with asphalt, it can improve the rheological properties of the aged asphalt and restore its performance.

[0037] Solid waste aggregate includes coarse aggregate and fine aggregate. Fine aggregate accounts for 60% of the total solid waste aggregate. The crushing value of coarse aggregate is 9%, the apparent relative density is 2.567%, the water absorption rate is 0.2%, and the content of needle-like particles is 5%. The apparent relative density of fine aggregate is 2.681, the mud content (the content of particles less than 0.075mm) is 1.2%, and the sand equivalent is 60%.

[0038] Preparation Example 1.1

[0039] A method for preparing microcapsules comprises the following steps:

[0040] (1) adding sodium alginate into water and stirring to dissolve to form a sodium alginate solution with a concentration of 1.2 wt%;

[0041] (2) adding expanded perlite powder to the sodium alginate solution and shearing at a rotation speed of 4000 r / min for 30 min to form a suspension, wherein the expanded perlite powder is 0.4 times the dry weight of the sodium alginate;

[0042] (3) Mixing the asphalt regeneration agent and Tween 80 at 40°C and stirring for 10 minutes to form a mixture;

[0043] (4) adding the mixture obtained in step (2) to the suspension of step (2), and shearing for 5 min at a temperature of 40° C. and a rotation speed of 14,000 r / min to obtain a mixed solution, wherein the asphalt regeneration agent is 10% by weight of the sodium alginate solution, and the amount of Tween 80 added is 5% by weight of the asphalt regeneration agent;

[0044] (5) The mixed solution was dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 12 hours to form capsules. The capsules were rinsed with clean water and dried at room temperature to form microcapsules.

[0045] Preparation Example 1.2

[0046] A method for preparing microcapsules comprises the following steps:

[0047] (1) adding sodium alginate into water and stirring to dissolve to form a sodium alginate solution with a concentration of 2.0 wt%;

[0048] (2) adding expanded perlite powder to the sodium alginate solution and shearing for 30 min at a rotation speed of 0.000 r / min to form a suspension, wherein the expanded perlite powder is 1.5 times the dry weight of the sodium alginate;

[0049] (3) Mixing the asphalt regeneration agent and Tween 80 at 50°C and stirring for 15 minutes to form a mixture;

[0050] (4) adding the mixture obtained in step (2) to the suspension of step (2), and shearing for 10 min at a temperature of 40° C. and a rotation speed of 14,000 r / min to obtain a mixed solution, wherein the asphalt regeneration agent is 10% by weight of the sodium alginate solution, and the amount of Tween 80 added is 5% by weight of the asphalt regeneration agent;

[0051] (5) The mixed solution was dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 12 hours to form capsules. The capsules were rinsed with clean water and dried at room temperature to form microcapsules.

[0052] Preparation Example 1.3

[0053] A method for preparing microcapsules comprises the following steps:

[0054] (1) adding sodium alginate into water and stirring to dissolve to form a sodium alginate solution with a concentration of 2.5 wt%;

[0055] (2) adding expanded perlite powder to the sodium alginate solution and shearing for 30 min at a rotation speed of 5000 r / min to form a suspension, wherein the expanded perlite powder is 2.5 times the dry weight of the sodium alginate;

[0056] (3) Mixing the asphalt regeneration agent and Tween 80 at a temperature of 50°C and stirring for 10 minutes to form a mixture;

[0057] (4) adding the mixture obtained in step (2) to the suspension of step (2), and shearing for 10 min at a temperature of 40° C. and a rotation speed of 15,000 r / min to obtain a mixed solution, wherein the asphalt regeneration agent is 10% by weight of the sodium alginate solution, and Tween 80 is 5% by weight of the asphalt regeneration agent;

[0058] (5) The mixed solution was dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 13 hours to form capsules. The capsules were rinsed with clean water and dried at room temperature to form microcapsules.

[0059] Preparation Example 1.4

[0060] A method for preparing microcapsules, which differs from Preparation Example 1.2 in that, in step (5), nano-titanium dioxide is added to the mixed solution and stirred and dispersed for 15 minutes, and then dropped into a 2.5% calcium chloride solution for reaction for 12 hours to form capsules. The capsules are rinsed with clean water and dried at room temperature to form microcapsules, wherein the amount of nano-titanium dioxide added is 1.1% by weight of the expanded perlite powder. Other conditions are the same as in Preparation Example 1.2.

[0061] Preparation Example 1.5

[0062] A method for preparing microcapsules, which differs from Preparation Example 1.2 in that, in step (5), nano-titanium dioxide is added to the mixed solution and stirred and dispersed for 15 minutes, and then dropped into a 2.5% calcium chloride solution for reaction for 12 hours to form capsules. The capsules are rinsed with clean water and dried at room temperature to form microcapsules, wherein the amount of nano-titanium dioxide added is 1.2% by weight of the expanded perlite powder. Other conditions are the same as Preparation Example 1.2.

[0063] Preparation Example 1.6

[0064] A method for preparing microcapsules, which differs from Preparation Example 1.2 in that, in step (5), nano-titanium dioxide is added to the mixed solution and stirred and dispersed for 15 minutes, and then dropped into a 2.5% calcium chloride solution for reaction for 12 hours to form capsules. The capsules are rinsed with clean water and dried at room temperature to form microcapsules, wherein the amount of nano-titanium dioxide added is 1.3% by weight of the expanded perlite powder. Other conditions are the same as Preparation Example 1.2.

[0065] Comparative Preparation Example 1.1

[0066] A method for preparing microcapsules is different from that of Preparation Example 1.2 in that an equal amount of attapulgite is used instead of expanded perlite powder, and the rest are the same as those of Preparation Example 1.2.

[0067] Preparation Example 2.1

[0068] A method for preparing an asphalt modifier comprises the following steps: mixing 300g of SBS, 180g of petroleum resin, 10g of an antioxidant and 5g of polyamide, and then melt-extruding and granulating the mixture to obtain the asphalt modifier.

[0069] Preparation Example 2.2

[0070] A method for preparing an asphalt modifier comprises the following steps: mixing 350g of SBS, 200g of petroleum resin, 15g of an antioxidant and 10g of polyamide, and then melt-extruding and granulating the mixture to obtain the asphalt modifier.

[0071] Preparation Example 2.3

[0072] A method for preparing an asphalt modifier comprises the following steps: mixing 400g of SBS, 220g of petroleum resin, 20g of an antioxidant and 15g of polyamide, and then melt-extruding and granulating the mixture to obtain the asphalt modifier.

[0073] Preparation Example 3.1

[0074] A method for preparing organic montmorillonite comprises the following steps:

[0075] S1. Add melamine and 2,3-epoxypropyltrimethylammonium chloride in a molar ratio of 1:6 to water, and add a catalyst at the same time, and react at 90° C. for 12 h to obtain a reaction mixture. Let the reaction mixture stand, filter, and then dry to obtain a powder;

[0076] S2. Add the powder and montmorillonite obtained in step S1 into water, ultrasonically disperse for 30 minutes, stir and react at 80±2° C. for 4 hours, let stand, filter, and dry to obtain organic montmorillonite, wherein the amount of the powder added is 10% by weight of the montmorillonite.

[0077] Preparation Example 3.2

[0078] A method for preparing organic montmorillonite comprises the following steps:

[0079] S1. Add melamine and 2,3-epoxypropyltrimethylammonium chloride in a molar ratio of 1:6 to water, and add a catalyst at the same time, and react at 90° C. for 12 h to obtain a reaction mixture. Let the reaction mixture stand, filter, and then dry to obtain a powder;

[0080] S2. Add the powder and montmorillonite obtained in step S1 into water, ultrasonically disperse for 30 minutes, stir and react at 80±2° C. for 4 hours, let stand, filter, and dry to obtain organic montmorillonite, wherein the amount of the powder added is 20% by weight of the montmorillonite.

[0081] Preparation Example 3.3

[0082] A method for preparing organic montmorillonite comprises the following steps:

[0083] S1. Add melamine and 2,3-epoxypropyltrimethylammonium chloride in a molar ratio of 1:6 to water, and add a catalyst at the same time, and react at 90° C. for 12 h to obtain a reaction mixture. Let the reaction mixture stand, filter, and then dry to obtain a powder;

[0084] S2. Add the powder and montmorillonite obtained in step S1 into water, ultrasonically disperse for 30 minutes, stir and react at 80±2° C. for 4 hours, let stand, filter, and dry to obtain organic montmorillonite. The amount of the powder added is 30% of the weight of the montmorillonite.

[0085] Example 1

[0086] A preparation process for self-healing rubber asphalt based on solid waste aggregates comprises the following steps:

[0087] S1, preparatory stage, 0.8kg desulfurized rubber powder is activated at 180℃ and set aside;

[0088] S2. Melt 3 kg of 70# matrix asphalt at 160°C, add the desulfurized rubber powder activated in step S1, 0.15 kg of the asphalt modifier obtained in Preparation Example 2.1, and 0.3 kg of tackifying resin, and stir at a speed of 3000 r / min for 25 min, wherein the tackifying resin is composed of polystyrene maleic anhydride resin and alkylphenol-formaldehyde resin in a weight ratio of 1:1;

[0089] S3. Add 0.1 kg of microcapsules obtained in Preparation Example 1.1, 0.6 kg of organic montmorillonite obtained in Preparation Example 3.1, 13 kg of solid waste aggregate, and 1.2 kg of mineral powder to step S2, and stir at a speed of 300 r / min for 30 minutes to obtain rubber asphalt.

[0090] Example 2

[0091] A preparation process for self-healing rubber asphalt based on solid waste aggregates comprises the following steps:

[0092] S1, preparatory stage, 1.2kg desulfurized rubber powder is activated at 180℃ and set aside;

[0093] S2. Melt 3.8 kg of 70# base asphalt at 160°C, add the desulfurized rubber powder activated in step S1, 0.21 kg of the asphalt modifier obtained in Preparation Example 2.1, and 0.5 kg of a tackifying resin, and stir at a speed of 3000 r / min for 20 min, wherein the tackifying resin is composed of polystyrene maleic anhydride resin and alkylphenol-formaldehyde resin in a weight ratio of 1:1;

[0094] S3. Add 0.17 kg of microcapsules prepared in Preparation Example 1.1, 0.9 kg of organic montmorillonite obtained in Preparation Example 3.1, 14 kg of solid waste aggregate, and 1.3 kg of mineral powder to step S2, and stir at a speed of 3000 r / min for 30 minutes to obtain rubber asphalt.

[0095] Example 3

[0096] A preparation process for self-healing rubber asphalt based on solid waste aggregates comprises the following steps:

[0097] S1, preparatory stage, 1.5kg desulfurized rubber powder is activated at 180℃ and then set aside;

[0098] S2. Melt 4.5 kg of 70# matrix asphalt at 160° C., add the desulfurized rubber powder activated in step S1, 0.26 kg of asphalt modifier, and 0.7 kg of tackifying resin, and stir at a speed of 3000 r / min for 20 min. The tackifying resin is composed of polystyrene maleic anhydride resin and alkylphenol formaldehyde resin in a weight ratio of 1:1.

[0099] S3. Add 0.22 kg of the microcapsules prepared in Preparation Example 1.1, 1.1 kg of the organic montmorillonite obtained in Preparation Example 3.1, 15 kg of solid waste aggregate, and 1.5 kg of mineral powder to step S2, and stir at a speed of 3000 r / min for 30 minutes to obtain rubber asphalt.

[0100] Example 4

[0101] A preparation process for self-healing rubber asphalt based on solid waste aggregates comprises the following steps:

[0102] S1, preparatory stage, 1.2kg of desulfurized rubber powder was activated at 210℃ and then set aside;

[0103] S2. Melt 3.8 kg of 70# matrix asphalt at 170°C, add the desulfurized rubber powder activated in step S1, 0.21 kg of the asphalt modifier obtained in Preparation Example 2.1, and 0.5 kg of a tackifying resin, and stir at a speed of 4000 r / min for 25 min, wherein the tackifying resin is composed of polystyrene maleic anhydride resin and alkylphenol-formaldehyde resin in a weight ratio of 1:1;

[0104] S3. Add 0.17 kg of microcapsules prepared in Preparation Example 1.1, 0.9 kg of organic montmorillonite obtained in Preparation Example 3.1, 14 kg of solid waste aggregate, and 1.3 kg of mineral powder to step S2, and stir at a speed of 4000 r / min for 40 minutes to obtain rubber asphalt.

[0105] Example 5

[0106] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that the organic montmorillonite obtained in Preparation Example 3.1 is heated at 130°C for 30 minutes and then added in step S3. The rest is the same as Example 2.

[0107] Example 6

[0108] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that the organic montmorillonite obtained in Preparation Example 3.1 is heated at 140°C for 30 minutes and then added in step S3. The rest is the same as Example 2.

[0109] Example 7

[0110] A preparation process for self-healing rubber asphalt based on solid waste aggregates is different from Example 5 in that the microcapsules are the microcapsules obtained in Preparation Example 1.2, the asphalt modifier is the asphalt modifier obtained in Preparation Example 2.2, and the organic montmorillonite is the organic montmorillonite obtained in Preparation Example 3.2. The rest are the same as in Example 5.

[0111] Example 8

[0112] A preparation process for self-healing rubber asphalt based on solid waste aggregates is different from Example 5 in that the microcapsules are the microcapsules obtained in Preparation Example 1.3, the asphalt modifier is the asphalt modifier obtained in Preparation Example 2.2, and the organic montmorillonite is the organic montmorillonite obtained in Preparation Example 3.2. The rest are the same as in Example 5.

[0113] Example 9

[0114] A preparation process for self-healing rubber asphalt based on solid waste aggregates is different from Example 5 in that the microcapsules are the microcapsules obtained in Preparation Example 1.4, the asphalt modifier is the asphalt modifier obtained in Preparation Example 2.2, and the organic montmorillonite is the organic montmorillonite obtained in Preparation Example 3.2. The rest are the same as in Example 5.

[0115] Example 10

[0116] A preparation process for self-healing rubber asphalt based on solid waste aggregates, which differs from Example 5 in that the microcapsules are the microcapsules obtained in Preparation Example 1.5, the asphalt modifier is the asphalt modifier obtained in Preparation Example 2.2, and the organic montmorillonite is the organic montmorillonite obtained in Preparation Example 3.2. The rest are the same as in Example 5.

[0117] Example 11

[0118] A preparation process for self-healing rubber asphalt based on solid waste aggregates, which differs from Example 5 in that the microcapsules are the microcapsules obtained in Preparation Example 1.6, the asphalt modifier is the asphalt modifier obtained in Preparation Example 2.2, and the organic montmorillonite is the organic montmorillonite obtained in Preparation Example 3.2. The rest are the same as in Example 5.

[0119] Example 12

[0120] A preparation process for self-healing rubber asphalt based on solid waste aggregates is different from Example 5 in that the microcapsules are the microcapsules obtained in Preparation Example 1.5, the asphalt modifier is the asphalt modifier obtained in Preparation Example 2.3, and the organic montmorillonite is the organic montmorillonite obtained in Preparation Example 3.3. The rest are the same as in Example 5.

[0121] Example 13

[0122] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from that of Example 10 in that 0.3 kg of polyphosphoric acid is added to step S2, and the rest are the same as those of Example 10.

[0123] Example 14

[0124] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from that of Example 10 in that 0.5 kg of polyphosphoric acid is added to step S2, and the rest are the same as those of Example 10.

[0125] Example 15

[0126] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from that of Example 10 in that 0.6 kg of polyphosphoric acid is added to step S2, and the rest are the same as those of Example 10.

[0127] Example 16

[0128] A preparation process of self-healing rubber asphalt based on solid waste aggregates is different from Example 2 in that an equal amount of SBS modifier is used as the asphalt modifier instead of the asphalt modifier obtained in Preparation Example 2.1, and the rest are the same as Example 2.

[0129] Example 17

[0130] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that only alkyl phenolic resin is used as the tackifying resin, and the rest are the same as Example 2.

[0131] Example 18

[0132] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that only polystyrene maleic anhydride resin is used as the tackifying resin, and the rest are the same as Example 2.

[0133] Example 19

[0134] A preparation process of self-healing rubber asphalt based on solid waste aggregates, which is different from Example 2 in that the tackifying resin is composed of polystyrene maleic anhydride resin and terpene resin in a weight ratio of 1:1, and the rest are the same as Example 2.

[0135] Example 20

[0136] A preparation process of self-healing rubber asphalt based on solid waste aggregate, which is different from Example 2 in that the organic montmorillonite is a commercially available alkyl quaternary ammonium salt modified high-purity montmorillonite with a specific gravity of 1.8 g / cm 3 , bulk density <0.3g / cm 3 , the rest are the same as in Example 2.

[0137] Example 21

[0138] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that an equal amount of nano-silica is used to replace the organic montmorillonite obtained in Preparation Example 3.1, and the rest are the same as Example 2.

[0139] Comparative Example 1

[0140] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that organic montmorillonite is missing from the raw materials, and the rest are the same as Example 2.

[0141] Comparative Example 2

[0142] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that the microcapsules are the microcapsules obtained in Comparative Preparation Example 1.1, and the rest are the same as Example 2.

[0143] Comparative Example 3

[0144] A preparation process of self-healing rubber asphalt based on solid waste aggregate is different from Example 2 in that there is no tackifying resin in the raw materials, and the rest are the same as Example 2.

[0145] Performance testing

[0146] The softening point, ductility, self-healing performance and fatigue resistance of the rubber asphalt obtained in the above examples and preparation examples were tested. The test results are shown in Table 1.

[0147] The self-healing performance is based on the fatigue self-healing percentage. According to the four-point bending fatigue test in T0739-2011, the asphalt mixture specimens are fatigue tested with a strain control valve at 500 microstrain and 15°C. After fatigue failure, the specimens are placed in a 50°C constant temperature box for healing and curing for 4 hours, and then kept warm at 15°C for 24 hours. Fatigue tests are then carried out under the same conditions. The ratio of the fatigue life after healing to the initial fatigue life is the self-healing percentage.

[0148] The fatigue resistance test was carried out in accordance with the relevant provisions of T0739-2011 "Four-point Bending Fatigue Life Test of Asphalt Mixture". The asphalt mixture specimens were fatigue tested under 500 microstrain and 15°C conditions. The test termination condition was the number of loading cycles corresponding to the bending stiffness modulus being reduced to 50% of the initial bending stiffness modulus.

[0149] Softening point test: Place the asphalt mixture sample obtained above in a metal ring, place a steel ball on it, and place it in 5℃ water. Raise the temperature at a rate of 5±0.5℃ / min until the steel ball sinks to 25.4mm. The temperature of the asphalt mixture is recorded as the softening point. The higher the softening point, the more resistant the asphalt mixture is to high temperatures.

[0150] Ductility test: used to detect plasticity. Specifically, the asphalt mixture sample is made into an 8-shaped standard specimen and stretched to the length (cm) at the breaking speed of 50 mm per minute at a temperature of 10°C. The higher the ductility, the better the plasticity of the asphalt mixture. The prepared asphalt sample is not easy to break at low temperature and has strong crack resistance.

[0151] Table 1 Rubber asphalt mixture test results

[0152] project Softening point / ℃ Elongation / cm Self-healing rate / % Fatigue life / times Example 1 81 32 70 91765 Example 2 84 33 73 93654 Example 3 83 33 72 93425 Example 4 84 32 73 93586 Example 5 86 33 75 97876 Example 6 86 33 74 97251 Example 7 87 36 79 100789 Example 8 85 33 77 99673 Example 9 90 37 81 102745 Example 10 92 40 85 105761 Example 11 89 38 83 105324 Example 12 91 40 85 105476 Example 13 93 40 85 106863 Example 14 94 42 85 107987 Example 15 94 42 85 107764 Example 16 76 28 71 90965 Example 17 78 29 70 89896 Example 18 79 29 70 89126 Example 19 81 30 71 91432 Example 20 80 29 71 90589 Example 21 80 29 70 91435 Comparative Example 1 74 26 68 88542 Comparative Example 2 77 28 65 89587 Comparative Example 3 75 26 70 85321

[0153] From the table above we can see that:

[0154] The softening point of the rubber asphalt mixture obtained in Examples 1-15 of the present application is above 80°C, the ductility is 32 cm or above, the self-healing rate is 70% or above, and the fatigue life is more than 90,000 times, indicating that the rubber asphalt mixture obtained in the present application not only has good self-healing ability, but also has good high and low temperature performance and fatigue resistance.

[0155] Compared with Example 2, when only SBS modifier is used as the asphalt modifier, the softening point and ductility of the asphalt mixture obtained in Example 16 are significantly reduced, the self-healing rate is slightly reduced but the change is not large, and the fatigue life is also significantly reduced. It can be seen that the asphalt modifier prepared by the present application can effectively improve the high and low temperature performance and fatigue resistance of asphalt.

[0156] Compared with Example 2, in Examples 17-18, when only polystyrene maleic anhydride resin or alkylphenol-formaldehyde resin is used as the tackifying resin, the high and low temperature performance and fatigue resistance of the rubber asphalt mixture obtained in Examples 17-18 are significantly reduced; in Example 19, compared with Example 2, when the tackifying resin is composed of polystyrene maleic anhydride resin and terpene resin, the various properties of the rubber asphalt mixture obtained in Example 19 are slightly lower than those of the rubber asphalt mixture obtained in Example 2. This further illustrates that the combined use of the two tackifying resins in this application can effectively improve the various properties of the asphalt mixture.

[0157] Compared with Example 2, when commercially available organic montmorillonite or nano-silica is used instead of the organic montmorillonite obtained in Preparation Example 3.1, the low-temperature performance and fatigue life of the rubber asphalt mixture obtained in Examples 20-21 are significantly reduced, indicating that the combined use of the various raw materials in this application effectively improves the various properties of the rubber asphalt mixture.

[0158] Compared with Example 2, the softening point, ductility, self-healing rate and fatigue life of the asphalt mixtures obtained in Comparative Examples 1-3 are significantly reduced. It can be seen that the combination of the raw materials in this application effectively ensures the high and low temperature performance, self-healing performance and fatigue resistance of the rubber asphalt mixture.

[0159] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A self-healing rubber asphalt based on solid waste aggregate, characterized by: The rubber asphalt comprises the following raw materials in parts by weight: 30-45 parts of base asphalt, 8-15 parts of desulfurized rubber powder, 1.5-2.6 parts of asphalt modifier, 1-2.2 parts of microcapsules, 3-7 parts of tackifying resin, 6-11 parts of nanofiller, 130-150 parts of solid waste aggregate, 12-15 parts of mineral powder, and 3-6 parts of polyphosphoric acid; The tackifying resin is composed of polystyrene maleic anhydride resin and alkylphenol-formaldehyde resin in a weight ratio of 1:1; The nanofiller is organic montmorillonite, which is prepared by the following method: S1. Add melamine and 2,3-epoxypropyltrimethylammonium chloride to water, add a catalyst, and react at 90° C. for 12 h to obtain a reaction mixture. Let the reaction mixture stand, filter, and then dry to obtain a powder. S2. Add the powder and montmorillonite obtained in step S1 into water, ultrasonically disperse for 30 minutes, stir and react at 80±2°C for 4 hours, let stand, filter, and dry to obtain organic montmorillonite; The microcapsules are prepared by the following method: (1) Add sodium alginate to water and stir to dissolve to form a sodium alginate solution with a concentration of 1.2-2.5 wt%; (2) adding expanded perlite powder to the sodium alginate solution and shearing for 20-30 minutes at a rotation speed of 4000-5000 r / min to form a suspension, wherein the expanded perlite powder is 0.4-2.5 times the dry weight of the sodium alginate; (3) Mixing the asphalt regeneration agent and the surfactant at a temperature of 40-50°C and stirring for 10-15 minutes to form a mixture; (4) adding the mixture obtained in step (3) to the suspension obtained in step (2), and shearing for 5-10 min at a temperature of 40-50° C. and a rotation speed of 14,000-15,000 r / min to obtain a mixed solution, wherein the asphalt regeneration agent is 10% of the sodium alginate solution, and the surfactant is 5% of the asphalt regeneration agent content; (5) The mixed solution was dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 12-13 hours to form capsules. The capsules were rinsed with clean water and dried at room temperature to form microcapsules.

2. The self-healing rubber asphalt based on solid waste aggregate according to claim 1, characterized in that: In the step (5), nano-titanium dioxide is added to the mixed solution and stirred to disperse evenly, and then dropped into a calcium chloride solution with a mass concentration of 2.5% and reacted for 12-13 hours to form capsules. The capsules are rinsed with clean water and dried at room temperature to form microcapsules. The amount of nano-titanium dioxide added is 1.1-1.3% of the weight of the expanded perlite powder.

3. The self-healing rubber asphalt based on solid waste aggregate according to claim 2, characterized in that: The surfactant used is Tween 80.

4. The self-healing rubber asphalt based on solid waste aggregate according to claim 1, characterized in that: The asphalt modifier is prepared by mixing 30-40 parts by weight of SBS, 18-22 parts by weight of petroleum resin, 1-2 parts by weight of antioxidant and 0.5-1.5 parts by weight of polyamide, followed by melt extrusion and granulation.

5. The self-healing rubber asphalt based on solid waste aggregate according to claim 1, characterized in that: The molar ratio of melamine to 2,3-epoxypropyltrimethylammonium chloride is 1:

6.

6. The self-healing rubber asphalt based on solid waste aggregate according to claim 1, characterized in that: The amount of the powder obtained in step S1 is 10-30% of the weight of the montmorillonite.

7. A process for preparing a self-healing rubber asphalt based on solid waste aggregate according to any one of claims 1 to 6, characterized in that: The steps include: S1, preparatory stage, the desulfurized rubber powder is activated at 180-210℃ and then set aside; S2. Melt the matrix asphalt at a temperature of 160-170° C., add the desulfurized rubber powder, asphalt modifier, and tackifying resin activated in step S1, and stir at a speed of 3000-4000 r / min for 20-25 minutes; S3. Add microcapsules, nanofillers, solid waste aggregates, mineral powder and 3-6 parts by weight of polyphosphoric acid to step S2, and continue stirring at a rotation speed of 3000-4000 r / min for 30-40 minutes to obtain rubber asphalt.

8. The process for preparing a self-healing rubber asphalt based on solid waste aggregate according to claim 7, characterized in that: The nanofiller is heated at 130-140° C. for 30 minutes and then added into step S3.