Porous rubber-sbs composite modified asphalt, porous rubber-sbs composite modified asphalt mixture and preparation method thereof

Abstract

The application discloses a kind of porous rubber-SBS composite modified asphalt, drainage asphalt mixture and preparation method thereof, the preparation method of the porous rubber-SBS composite modified asphalt is as follows: porous rubber powder is obtained by surface pore-forming to rubber powder;Nano light-resistant agent treated by silane coupling agent is filled into the pore of porous rubber powder;The obtained compound is modified by shearing process to matrix asphalt with SBS, and the porous rubber-SBS composite modified asphalt is obtained.The drainage asphalt mixture is prepared by mixing the porous rubber-SBS composite modified asphalt with proper content and the aggregate mixture with intermittent gradation.The porous rubber-SBS composite modified asphalt is used as the binder of the drainage asphalt mixture, which has good high and low temperature resistance, high viscosity, stability and anti-aging performance.The drainage asphalt mixture prepared by the porous rubber-SBS composite modified asphalt can make the drainage asphalt pavement have good long-term road performance, reduce the occurrence of loose disease, and increase economic and environmental benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of road engineering, and particularly relates to a porous rubber-SBS composite modified asphalt, a drainage asphalt mixture and a preparation method thereof. BACKGROUND

[0002] Compared with the traditional dense-graded asphalt concrete pavement, the drainage asphalt pavement has the advantages of preventing road surface water accumulation, resisting vehicle slip, reducing driving water mist and reducing road noise. The drainage asphalt mixture is a functional surface layer for providing a flow path for rainwater in the drainage section. The interconnected void structure not only gives it the drainage function, but also causes it to be easily affected by environmental factors, resulting in loose diseases and greatly reducing the performance and functional characteristics of the drainage asphalt pavement.

[0003] To ensure the road performance of the drainage asphalt mixture, the drainage asphalt mixture needs to increase the amount of coarse aggregate, avoid or reduce the amount of fine aggregate, and form a skeleton type interlocking structure to achieve the purpose of large voids. However, the internal friction of this structure is large, and the cohesion is small. In order to obtain greater strength and resistance to external damage, the bonding performance of the binder is particularly important. The performance of ordinary modified asphalt cannot meet the use requirements, and high-tack asphalt is often used as the binder of the drainage asphalt mixture, but the cost of common high-tack modifiers is high, which is not suitable for popularization from the economic point of view. In addition, engineering application shows that the drainage pavement using high-tack asphalt often has scattering diseases. Analysis shows that high-tack asphalt mixture is prone to bonding failure under the combined action of light, rain and oxygen. Therefore, in order to ensure the engineering effect of the drainage pavement, it is necessary to improve the water resistance and aging resistance of the drainage asphalt pavement.

[0004] According to the literature research, in order to improve the durability of the drainage asphalt mixture, patent CN115650636A proposes to use nano silicon nitride, coupling agent, etc. to improve the viscosity of the asphalt and the water resistance of the asphalt, but the cost is high and the dispersion uniformity of the nano material in the high-viscosity asphalt is difficult to guarantee; patent CN109705365A uses a quick-dissolving gel mother liquor and SBS to prepare a SBS and rubber powder composite modified asphalt, which is found to have the high-tack and high-toughness requirements of high-tack asphalt. The rubber powder improves the aging resistance of the asphalt, but the high amount of modifier added, combined with the poor storage stability of rubber asphalt, poses risks such as segregation in use, which will greatly limit its use in actual engineering. Both patents increase the viscosity and durability of the binder to some extent through formula adjustment and the use of additives, but do not substantially change the existing process and do not propose the advantages of combining material performance, which cannot solve the problems of poor dispersion uniformity and poor long-term stability in the joint use of nano materials and economical rubber materials. SUMMARY

[0005] The technical problems solved: In order to solve the above technical problems, the application provides a porous rubber-SBS composite modified asphalt, a drainage asphalt mixture and a preparation method thereof. The porous rubber-SBS composite modified asphalt is used as a binder of the drainage asphalt mixture, has good high and low temperature resistance, high viscosity, stability and aging resistance, and the prepared drainage asphalt mixture can make the drainage asphalt pavement have good long-term road performance, reduce the occurrence of loose diseases, and increase economic and environmental benefits.

[0006] Technical scheme: A preparation method of a porous rubber-SBS composite modified asphalt comprises the following steps:

[0007] Step one: a chemical method is used to make pores on the surface of rubber powder to obtain porous rubber powder;

[0008] Step two: a nano light-resistant agent treated by a silane coupling agent is filled into the pores of the porous rubber powder;

[0009] Step three: a composite obtained in step two and SBS are used to modify a base asphalt by a shearing process, and the porous rubber-SBS composite modified asphalt is obtained.

[0010] Preferably, in step one, the chemical method is one or more of acid corrosion, oxidation, hydroxylation and radiation. Further, in step one, the chemical method is concentrated sulfuric acid corrosion.

[0011] Preferably, in step two, the amount of the nano light-resistant agent is 0.3% to 0.6% of the mass of the base asphalt.

[0012] Preferably, in step two, the nano light-resistant agent is one or more of nano zinc oxide, nano titanium dioxide and nano silver oxide. The main feature is that the nano light-resistant agent is an inorganic material with a light shielding effect.

[0013] Preferably, in step two, the amount of the silane coupling agent is 0.1% to 0.2% of the mass of the base asphalt. Further, in step two, the silane coupling agent is a mixed solution diluted by ethanol, and the mass fraction of the silane coupling agent in the mixed solution is 30% to 50%.

[0014] Preferably, in step two, the nano light-resistant agent is filled into the porous rubber powder by using a banbury mixer, and the mixing temperature is not higher than 60 DEG C.

[0015] Preferably, in step three, the amount of the composite is 15% to 20% of the mass of the base asphalt.

[0016] Preferably, in step three, the SBS is linear or star-shaped SBS, and the amount of the SBS is 3% to 5% of the mass of the base asphalt. Further, in step three, the SBS is linear SBS, and the molecular weight of the SBS is lower than 100000 g / mol.

[0017] Preferably, in the step three, the matrix asphalt is A-level 70# heavy cross petroleum asphalt. Further, in the step three, the matrix asphalt is Shuanglong 70# asphalt.

[0018] The porous rubber-SBS composite modified asphalt prepared by the above method, the application of the porous rubber-SBS composite modified asphalt in preparing drainage asphalt mixture, the specific method steps are as follows:

[0019] S1. Heating the porous rubber-SBS composite modified asphalt to 170-180℃;

[0020] S2. Heating the aggregate to 180-200℃, and then mixing with the mineral powder;

[0021] S3. Introducing the heated porous rubber-SBS composite modified asphalt into the mixture obtained in S2 for mixing, so as to obtain the drainage asphalt mixture;

[0022] Among them, the aggregate in S2 adopts discontinuous gradation design, and the mass percentage through each sieve hole is as follows:

[0023] 16mm: 100%,

[0024] 13.2mm: 90-100%,

[0025] 9.5mm: 60-80%,

[0026] 4.75mm: 12-30%,

[0027] 2.36mm: 10-22%,

[0028] 1.18mm: 6-18%,

[0029] 0.6mm: 4-15%,

[0030] 0.3mm: 3-12%,

[0031] 0.15mm: 3-8%,

[0032] 0.075mm: 2-6%.

[0033] The drainage asphalt mixture prepared by the above method is tested, and the porosity is 15-25%, the dynamic stability is not less than 5000mm / min, the intermediate-temperature flexibility index is not less than 10, and the low-temperature bending strain is not less than 2800 micro-strain.

[0034] Beneficial effects: The present application can ensure the uniform dispersion of nanomaterials under the combined action of force chemistry and interface connecting agent-silane coupling agent by making pores in rubber powder and then filling the nanometer light resistance agent with an internal mixer, and then the rubber powder-SBS composite modified asphalt is prepared by compounding and modifying the base asphalt through shearing process. On the one hand, the compatibility between the rubber powder and the base asphalt is increased, and the stability of the porous rubber-SBS composite modified asphalt system is ensured; on the other hand, the addition of the rubber powder increases the viscosity of the porous rubber-SBS composite modified asphalt, enhances the adhesion between the asphalt and the aggregate in the porous asphalt mixture, ensures the service life and road performance of the porous asphalt pavement, and has good economic benefits and environmental benefits. In addition, the addition of the nano zinc oxide increases the anti-UV aging performance of the porous rubber-SBS composite modified asphalt.

[0035] The porous rubber-SBS composite modified asphalt and the porous asphalt mixture have the following characteristics:

[0036] (1) The porous rubber-SBS composite modified asphalt contains rubber powder and SBS modifier, has good high-temperature performance and low-temperature performance, is beneficial to the normal use of the porous asphalt mixture in hot and high-temperature areas and seasonal frozen soil areas, and the high-viscosity characteristic also ensures the adhesion between the asphalt and the aggregate in the porous asphalt mixture under the action of environmental factors, and reduces the occurrence of loose diseases of the porous asphalt pavement.

[0037] (2) The SBS and the rubber powder are compounded and modified to the base asphalt through the shearing process, the stability of the porous rubber-SBS composite modified asphalt is enhanced, the mixing temperature is reduced, the addition of the rubber powder also greatly alleviates the problem of waste tire dumping, and promotes the reuse of tires.

[0038] (3) The porous rubber-SBS composite modified asphalt is combined with the skeleton structure of the intermittent gradation mineral mixture to not only ensure the functional characteristics of the porous asphalt pavement, but also make the porous asphalt pavement have good long-term road performance. At the same time, the rubber powder is used as a modifier to reduce the cost of the porous asphalt pavement and increase the economic benefits and environmental benefits of the porous asphalt pavement.

[0039] (4) The nano light resistance agent is added to the porous rubber-SBS composite modified asphalt as a light shielding agent, the nano light resistance agent mainly increases the resistance of the asphalt pavement to light through the principle of electron transition and scattering, and further enhances the anti-aging performance of the porous asphalt mixture. DETAILED DESCRIPTION

[0040] The present application will be further described below in combination with specific examples.

[0041] Example 1

[0042] The preparation method of the porous rubber-SBS composite modified asphalt and the drainage asphalt mixture comprises the following steps:

[0043] (1) Preparation of porous rubber-SBS composite modified asphalt: according to the mass of base asphalt as the reference, first, the rubber powder is corroded by concentrated sulfuric acid to obtain 10% porous rubber powder, then 0.5% nano zinc oxide and 0.2% silane coupling agent are filled into the pores by using a mixer at 60°C, so that the nano zinc oxide can be uniformly dispersed into the pores of the rubber powder. The silane coupling agent is a 50% ethanol-silane coupling dilute solution, and finally the obtained composite is compounded and modified with SBS by a shearing process on the base asphalt, wherein the amount of the composite is 16% of the mass of the base asphalt; the SBS is linear and the amount is 4% of the mass of the base asphalt; and the base asphalt is Shuanglong 70# petroleum asphalt.

[0044] (2) Aggregate pretreatment: the aggregate is dried to constant weight in a 100°C oven, and 100 parts by mass of each grade of aggregate according to Table 1 is weighed and heated to 180°C.

[0045] Table 1: Percentage of each sieve opening

[0046]

[0047] (3) 4.9 parts by mass of porous rubber-SBS composite modified asphalt is mixed with 100 parts by mass of aggregate for 90s, and then 4 parts by mass of mineral powder is added and mixed for 90s, and the temperature is controlled at 175°C.

[0048] The Kentorbury flying test and the Brookfield rotating viscosity test are carried out on the asphalt mixture prepared in Example 1 and the corresponding asphalt, and the results are shown in Tables 2, 3, 4 and 5. At the same time, the Japanese imported TPS high viscosity asphalt drainage mixture is used for comparison.

[0049] Table 2: UV aging flying results

[0050]

[0051]

[0052] As can be seen from Table 2, the drainage asphalt mixture prepared from the porous rubber-SBS composite modified asphalt in Example 1 has a smaller change range than the drainage asphalt mixture of high-viscosity asphalt, indicating that the drainage asphalt mixture of the porous rubber-SBS composite modified asphalt is more stable in performance under heat aging conditions; the drainage asphalt mixture of the porous rubber-SBS composite modified asphalt has a smaller final flying mass loss, indicating that the drainage asphalt mixture of the porous rubber-SBS composite modified asphalt has better long-term performance. In terms of the flying mass loss change range and the long-term performance, the drainage asphalt mixture of the porous rubber-SBS composite modified asphalt is more suitable for high-temperature and hot regions than the drainage asphalt mixture of high-viscosity asphalt.

[0053] Table 3: Flying results under freeze-thaw cycle aging

[0054]

[0055] As can be seen from Table 3, the drainage asphalt mixture of the porous rubber-SBS composite modified asphalt in Example 1 has a smaller change range of flying mass loss rate and better long-term anti-flying performance than the drainage asphalt mixture of high-viscosity asphalt under freeze-thaw cycle aging conditions, indicating that the drainage asphalt mixture of the porous rubber-SBS composite modified asphalt is more suitable for seasonal frozen soil regions.

[0056] Table 4: Asphalt viscosity at 20°C under ultraviolet aging conditions

[0057]

[0058] As can be seen from Table 4, the change range of the 20°C viscosity of the porous rubber-SBS composite modified asphalt in Example 1 is smaller than that of high-viscosity asphalt, indicating that the stability of the porous rubber-SBS composite modified asphalt is better than that of the high-viscosity asphalt under heat aging conditions; the long-term 20°C asphalt viscosity of the porous rubber-SBS composite modified asphalt is higher than that of the high-viscosity asphalt, indicating that the porous rubber-SBS composite modified asphalt has better long-term performance. In terms of the asphalt viscosity change range and the long-term asphalt viscosity, the porous rubber-SBS composite modified asphalt is better than the high-viscosity asphalt.

[0059] Table 5: Asphalt viscosity at 20°C under freeze-thaw cycle aging conditions

[0060]

[0061] As can be seen from Table 5, the 20°C asphalt viscosity of the porous rubber-SBS composite modified asphalt in Example 1 is higher than the long-term 20°C asphalt viscosity of the high-viscosity asphalt, indicating that the porous rubber-SBS composite modified asphalt has better long-term performance under freeze-thaw cycle aging conditions.

[0062] The test results of Tables 2-5 show that the bonding properties of the drainage asphalt mixture prepared according to the application are obviously increased compared with the market products, and the water resistance and aging resistance are also obviously superior, and the drainage asphalt mixture is a more ideal type.

Claims

1. A method for preparing porous rubber-SBS composite modified asphalt, characterized in that: The steps are as follows: Step 1: using concentrated sulfuric acid to corrode the rubber powder to create pores on its surface to obtain porous rubber powder; Step 2: Fill the pores of the porous rubber powder with the nano-light-blocking agent treated with a silane coupling agent under a mechanochemical action, specifically, using an internal mixer to fill the nano-light-blocking agent into the porous rubber powder, and the internal mixer temperature is not higher than 60° C.; Step 3: Compounding the composite obtained in step 2 with SBS to modify the matrix asphalt through a shearing process, thereby obtaining the porous rubber-SBS composite modified asphalt.

2. The method for preparing a porous rubber-SBS composite modified asphalt according to claim 1, characterized in that: In the step 2, the amount of the nano-light blocking agent used is 0.3% to 0.6% of the mass of the matrix asphalt.

3. The method for preparing a porous rubber-SBS composite modified asphalt according to claim 1, characterized in that: In the step 2, the amount of the silane coupling agent used is 0.1% to 0.2% of the mass of the base asphalt.

4. The method for preparing a porous rubber-SBS composite modified asphalt according to claim 1, characterized in that: In the step 2, the nano-light blocking agent is one or more of nano-zinc oxide, nano-titanium dioxide, and nano-silver oxide.

5. The method for preparing a porous rubber-SBS composite modified asphalt according to claim 1, characterized in that: In the step 3, the amount of the composite is 15% to 20% of the mass of the matrix asphalt.

6. The method for preparing a porous rubber-SBS composite modified asphalt according to claim 1, characterized in that: In the step 3, the SBS is a linear or star-shaped SBS, and the amount used is 3% to 5% of the mass of the base asphalt.

7. The method for preparing a porous rubber-SBS composite modified asphalt according to claim 1, characterized in that: In the step 3, the matrix asphalt is grade A 70# heavy traffic petroleum asphalt.

8. The use of the porous rubber-SBS composite modified asphalt according to claim 1 in preparing drainage asphalt mixture, characterized in that: The specific steps are as follows: S1. Heat the porous rubber-SBS composite modified asphalt to 170-180°C; S2. Heat the aggregate to 180-200°C and mix with the mineral powder; S3. The heated porous rubber -SBS composite modified asphalt is poured into the mixture obtained in S2 and mixed to obtain the drainage asphalt mixture; The aggregate in S2 adopts a discontinuous gradation design, and the mass percentage passing through each sieve hole is as follows: 16mm: 100%, 13.2mm: 90~100%, 9.5mm: 60~80%, 4.75mm: 12~30%, 2.36mm: 10~22% 1.18mm: 6~18%, 0.6mm: 4~15%, 0.3mm: 3~12%, 0.15mm: 3~8%, 0.075mm: 2~6%.

9. The drainage asphalt mixture obtained by the application of claim 8, characterized in that: The porosity of the drainage asphalt mixture is 15-25%, the dynamic stability is not less than 5000 mm / min, the medium-soft flexibility index is not less than 10, and the low-temperature bending strain is not less than 2800 microstrain.

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