Low-volatility modified asphalt and preparation method thereof

Abstract

The invention belongs to the field of modified asphalt, and discloses low-volatility modified asphalt and a preparation method thereof. The low-volatility modified asphalt comprises the following components: modified asphalt, an organic-inorganic hybrid porous adsorbent and polyphosphoric acid, the organic-inorganic hybrid porous adsorbent comprises the following components: a sodium alginate aqueous solution, activated carbon, calcium hydroxide, a ferric chloride aqueous solution, a calcium chloride aqueous solution and a sodium hydroxide saturated calcium hydroxide solution. The method fundamentally inhibits the generation of asphalt waste gas (and rubber powder waste gas), reduces the emission of harmful gas, and is environment-friendly.

Description

Technical Field

[0001] The present invention belongs to the field of modified asphalt, and more specifically, relates to a low-volatile modified asphalt and a preparation method thereof. Background Art

[0002] Modified asphalt needs high temperature or fire heating during the production and construction of modification. The heating temperature is not less than 180℃ and the fire baking temperature is more than 300℃. At this high temperature, the asphalt in the commonly used rubber powder modified asphalt will inevitably release asphalt smoke, which contains harmful gases such as polycyclic aromatic hydrocarbons, nitrogen, sulfur and other heterocyclic compounds. The rubber powder in the rubber powder modified asphalt will release harmful gases such as carbon, nitrogen, sulfur, etc. at high temperature, which will cause harm to the surrounding environment and people's health.

[0003] The chemical composition of asphalt varies depending on its source, but most asphalt contains sulfur, which is the third largest element in asphalt after carbon and hydrogen. The sulfur content of some petroleum asphalt can be as high as 9%. Rubber powder modified asphalt uses a wider source of rubber powder, and the original formula of rubber powder is messy and different, and the harmful gases released are mainly nitrogen and sulfur. During the production or construction process of rubber powder modified asphalt, if these nitrogen and sulfur elements generate nitric oxide, nitrogen dioxide, hydrogen sulfide or sulfur oxide and are discharged into the environment, it will cause huge pollution to the environment. Therefore, it is urgent to prepare a new type of ecological and environmentally friendly rubber powder modified asphalt with no smell or slight smell, design an ecological and environmentally friendly rubber powder modified asphalt large-scale production process, and solve the problem of volatile odor during asphalt production and construction.

[0004] The active suppression technology of modified asphalt waste gas currently includes four methods: fragrance masking, source improvement, cooling construction and deodorization. Except for the fragrance masking method, the other three methods have their own obvious advantages and are worth developing vigorously. Among them, the deodorization method is to add additives to the asphalt so that it reacts chemically with the volatile substances in the asphalt to generate new non-emission substances and reduce harmful gas emissions. Because the deodorization method has a good application effect and is simple to operate, it is currently the main development direction of the active suppression technology of modified asphalt waste gas.

[0005] Regarding the suppression of waste gas from rubber powder modified asphalt, in addition to asphalt waste gas, rubber powder also produces waste gas. There is little research on the deodorization method for suppressing waste gas from rubber powder. Therefore, there is an urgent need to increase the research on the reaction capacity of deodorizers, and then prepare environmentally friendly rubber powder modified asphalt materials, so that the application field of rubber powder modified asphalt will be broader. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies of the prior art and to provide a low-volatile modified asphalt and a preparation method thereof. The present invention fundamentally inhibits the generation of asphalt waste gas (and rubber powder waste gas), reduces the emission of harmful gases, and is environmentally friendly.

[0007] In order to achieve the above-mentioned object, the present invention provides a low-volatility modified asphalt on one hand, wherein the low-volatility modified asphalt comprises the following components: modified asphalt, organic-inorganic hybrid porous adsorbent and polyphosphoric acid;

[0008] The organic-inorganic hybrid porous adsorbent comprises the following components: sodium alginate aqueous solution, activated carbon, calcium hydroxide, ferric chloride aqueous solution, calcium chloride aqueous solution and sodium hydroxide saturated calcium hydroxide solution.

[0009] According to the present invention, preferably, the low volatility modified asphalt comprises the following components in parts by weight: 80-98 parts of modified asphalt, 3-10 parts of organic-inorganic hybrid porous adsorbent and 1-8 parts of polyphosphoric acid.

[0010] According to the present invention, preferably, the low volatility modified asphalt comprises the following components in parts by weight: 80-95 parts of modified asphalt, 4-10 parts of organic-inorganic hybrid porous adsorbent and 2-6 parts of polyphosphoric acid.

[0011] According to the present invention, preferably, the modified asphalt is at least one of SBR modified asphalt, SBS modified asphalt, rubber powder modified asphalt and recycled rubber powder modified asphalt.

[0012] According to the present invention, preferably, based on the total weight of the polyphosphoric acid, the polyphosphoric acid is prepared by polymerization of 100-120 wt % of phosphoric acid and >80 wt % of phosphorus pentoxide.

[0013] According to the present invention, preferably, the method for preparing the organic-inorganic hybrid porous adsorbent comprises the following steps:

[0014] S1: soaking the activated carbon in the sodium hydroxide saturated calcium hydroxide solution to obtain soaked activated carbon;

[0015] S2: mixing and dispersing the soaked activated carbon and the sodium alginate aqueous solution uniformly to obtain a dispersed system and performing a cooling treatment;

[0016] S3: adding calcium hydroxide to the dispersed system after cooling in step S2 until saturated, cooling the system to obtain a hybrid mixed solution, and extruding the mixed solution by injection molding to obtain a spherical and / or blocky material;

[0017] S4: uniformly mixing the spherical and / or block material, the ferric chloride aqueous solution and the calcium chloride aqueous solution, and sequentially solidifying and vacuum-freezing to obtain the organic-inorganic hybrid porous adsorbent.

[0018] According to the present invention, preferably, in the step S1, the soaking time is 2-5h;

[0019] In the step S2, the cooling treatment is to reduce the temperature of the dispersed system to 10-15°C;

[0020] In step S3, the temperature reduction treatment is to reduce the temperature of the hybridization mixed solution to 0-5°C.

[0021] According to the present invention, preferably, the usage ratio of the activated carbon to the sodium hydroxide saturated calcium hydroxide solution is (95-105): (950-1050) g / mL;

[0022] The ratio of the total volume of the ferric chloride aqueous solution and the calcium chloride aqueous solution, the volume of the sodium alginate aqueous solution and the volume of the sodium hydroxide saturated calcium hydroxide solution is (0.8-1.2):(0.8-1.2):(0.8-1.2);

[0023] The sodium hydroxide saturated calcium hydroxide solution is prepared by mixing sodium hydroxide solid with a saturated calcium hydroxide solution; the mass fraction of sodium hydroxide in the sodium hydroxide saturated calcium hydroxide solution is 8-12%;

[0024] The particle size of the activated carbon is at least one of 100 mesh, 200 mesh and 325 mesh;

[0025] The concentration of the sodium alginate aqueous solution is 0.015-0.035 g / mL; in the present invention, the sodium alginate aqueous solution is prepared by mixing sodium alginate solid with water at 40-60° C. so that the sodium alginate is completely dissolved in the water;

[0026] The mass fraction of the ferric chloride aqueous solution is 2-4%;

[0027] The mass fraction of the calcium chloride aqueous solution is 1-3%.

[0028] Another aspect of the present invention provides a method for preparing the low volatility modified asphalt, the method comprising the following steps:

[0029] (1) heating the modified asphalt to a liquid state;

[0030] (2) The liquid modified asphalt obtained in step (1) is mixed and stirred with an organic-inorganic hybrid porous adsorbent and polyphosphoric acid to obtain the low-volatile modified asphalt.

[0031] According to the present invention, preferably, the temperature for heating the modified asphalt is 165-170°C.

[0032] According to the present invention, preferably, the mixing and stirring temperature is 165-170° C. and the time is 40-120 min.

[0033] The beneficial effects of the technical solution of the present invention are as follows: the organic-inorganic hybrid porous adsorbent of the present invention can eliminate hydrogen sulfide, nitric oxide, and nitrogen dioxide generated by the modified asphalt during the production or construction process through chemical reactions, wherein the activated carbon adsorbs TVOC gas, and the activated carbon is treated with polyphosphoric acid for a second time to increase the TVOC adsorption performance of the activated carbon, thereby obtaining a low-volatile modified asphalt. The process of the present invention is simple and suitable for large-scale promotion. The prepared asphalt fundamentally inhibits the generation of asphalt waste gas (and rubber powder waste gas), reduces the emission of harmful gases, and is environmentally friendly. Specifically:

[0034] (1) The organic-inorganic hybrid porous adsorbent material of the present invention, wherein: activated carbon can physically adsorb harmful TVOC gas; the organic material sodium alginate carries reaction molecules to react with nitrides and sulfides; sodium hydroxide can react with nitric oxide and nitrogen dioxide to reduce the nitride content; iron ions react with hydrogen sulfide; calcium hydroxide reacts with sulfur dioxide to reduce the sulfide content; the organic-inorganic hybrid porous adsorbent material of the present invention reduces the emission of harmful gases in the production or construction process of modified asphalt through physical adsorption chemical reactions;

[0035] (2) The present invention prepares an organic-inorganic hybrid porous adsorbent material by a physical and chemical method, specifically: using a sodium hydroxide saturated calcium hydroxide solution to clean the activated carbon, then adding a sodium alginate-calcium hydroxide aqueous solution and a ferric chloride calcium chloride mixed solution to react, and placing it in an ultra-low temperature vacuum freezer to prepare an organic-inorganic hybrid porous adsorbent;

[0036] (3) The modified asphalt of the present invention uses an organic-inorganic hybrid porous adsorbent and then adds the acidic material polyphosphoric acid, which improves the compatibility between rubber powder and asphalt. At the same time, the acidic material polyphosphoric acid has a pickling effect on the activated carbon, so that the activated carbon can continue to adsorb harmful substances and reduce the emission of harmful gases.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0039] In the following embodiments and comparative examples:

[0040] Polyphosphoric acid was purchased from Thermo Fisher Scientific, C19695.

[0041] The rubber powder modified asphalt (comparative sample 2) is prepared by mixing commercially available ordinary rubber powder with asphalt and stirring at 180°C for 60 minutes;

[0042] The SBS modified asphalt (comparative sample 1) is prepared by mixing SBS and asphalt and stirring at 180° C. for 60 minutes;

[0043] The recycled rubber powder modified asphalt is prepared by mixing recycled rubber powder with asphalt and stirring at 180° C. for 60 minutes.

[0044] Example 1

[0045] This embodiment provides a low-volatile modified asphalt, which includes the following components: 90 parts of rubber powder modified asphalt, 6 parts of organic-inorganic hybrid porous adsorbent and 4 parts of polyphosphoric acid;

[0046] Based on the total weight of the polyphosphoric acid, the polyphosphoric acid is prepared by polymerization of 118 wt % of phosphoric acid and 86 wt % of phosphorus pentoxide.

[0047] The organic-inorganic hybrid porous adsorbent comprises the following components: sodium alginate aqueous solution, 200 mesh activated carbon, calcium hydroxide, ferric chloride aqueous solution, calcium chloride aqueous solution and sodium hydroxide saturated calcium hydroxide solution. The preparation method of the organic-inorganic hybrid porous adsorbent comprises the following steps:

[0048] S1: 100 g of activated carbon is placed in 1000 mL of sodium hydroxide saturated calcium hydroxide solution (the mass fraction of sodium hydroxide is 10%) and soaked for 4 hours to obtain the soaked activated carbon;

[0049] S2: mixing and dispersing the soaked activated carbon and the sodium alginate aqueous solution (0.02 g / mL) uniformly to obtain a dispersed system and cooling the system to 15° C.;

[0050] S3: adding calcium hydroxide to the dispersed system after cooling in step S2 until saturated, cooling to 5° C. to obtain a hybrid mixed solution, and extruding by injection molding to obtain a spherical and / or blocky material;

[0051] S4: uniformly mixing the spherical and / or block material with 1000 mL of a mixed solution of an aqueous ferric chloride solution (3% by mass) and an aqueous calcium chloride solution (2% by mass), and sequentially solidifying and vacuum-freezing to obtain the organic-inorganic hybrid porous adsorbent.

[0052] The method for preparing the low volatility modified asphalt comprises the following steps:

[0053] (1) heating the rubber powder modified asphalt to 170° C. so that the rubber powder modified asphalt is in liquid state;

[0054] (2) The liquid modified asphalt obtained in step (1) is mixed with the organic-inorganic hybrid porous adsorbent and stirred at 170° C. for 50 min, and then polyphosphoric acid is added and mixed and stirred at 170° C. for 50 min. The low volatility modified asphalt is obtained by cooling.

[0055] Example 2

[0056] This embodiment provides a low-volatile modified asphalt. The difference between this embodiment and embodiment 1 is only that:

[0057] The low-volatile modified asphalt comprises the following components: 94 parts of SBS modified asphalt, 4 parts of organic-inorganic hybrid porous adsorbent and 2 parts of polyphosphoric acid;

[0058] The method for preparing the low volatility modified asphalt comprises the following steps:

[0059] (1) heating the SBS modified asphalt to 165° C. so that the SBS modified asphalt is in liquid state;

[0060] (2) The liquid modified asphalt obtained in step (1) is mixed with the organic-inorganic hybrid porous adsorbent and stirred at 165° C. for 60 min, and then polyphosphoric acid is added and mixed and stirred at 165° C. for 60 min, and the temperature is lowered to obtain the low-volatile modified asphalt.

[0061] Example 3

[0062] This embodiment provides a low-volatile modified asphalt. The difference between this embodiment and embodiment 1 is only that:

[0063] The low-volatile modified asphalt comprises the following components: 85 parts of recycled rubber powder modified asphalt, 9 parts of organic-inorganic hybrid porous adsorbent and 6 parts of polyphosphoric acid;

[0064] The method for preparing the low volatility modified asphalt comprises the following steps:

[0065] (1) heating the recycled rubber powder modified asphalt to 165° C. so that the recycled rubber powder modified asphalt is in a liquid state;

[0066] (2) The liquid modified asphalt obtained in step (1) is mixed with the organic-inorganic hybrid porous adsorbent and stirred at 165° C. for 40 minutes, and then polyphosphoric acid is added and mixed and stirred at 165° C. for 40 minutes, and the temperature is lowered to obtain the low-volatile modified asphalt.

[0067] Comparative Example 1

[0068] This comparative example provides a low-volatile modified asphalt. The only difference between this comparative example and Example 1 is that the low-volatile modified asphalt includes the following components: 90 parts of rubber powder modified asphalt and 4 parts of polyphosphoric acid, without organic-inorganic hybrid porous adsorbent.

[0069] Comparative Example 2

[0070] This comparative example provides a low-volatile modified asphalt. The only difference between this comparative example and Example 1 is that the low-volatile modified asphalt includes the following components: 92 parts of rubber powder modified asphalt and 8 parts of organic-inorganic hybrid porous adsorbent, without polyphosphoric acid.

[0071] Test Case

[0072] This test example tests the above embodiments and comparative examples, wherein:

[0073] The test methods for conventional asphalt indicators were carried out in accordance with the test methods of JTG E20-2011;

[0074] A handheld portable VOC detector produced by Hunan Riko Instrument Co., Ltd. was used to detect asphalt smoke (the test item was asphalt, and the test data were hydrogen sulfide, nitric oxide, nitrogen dioxide and TVOC.)

[0075] The results are shown in Tables 1 and 2.

[0076] Table 1 Conventional indicators of asphalt

[0077]

[0078] Table 2

[0079] sample Hydrogen sulfide, ppm Nitric oxide, ppm TVOC, ppm Nitrogen dioxide, ppm Comparison sample 1 78.02 184.3 25.07 207.69 Comparison sample 2 83.2 195.31 29.3 220.4 Example 1 21.34 68.7 2.1 32.4 Example 2 27.57 72.28 2.49 37.49 Example 3 17.34 53.47 1.03 26.3 Comparative Example 1 45.23 120.54 17.46 174.45 Comparative Example 2 30.85 85.98 5.38 50.78

[0080] From the test data of modified asphalt performance indicators in Table 1, it can be seen that with the increase of organic-inorganic hybrid porous adsorbent and polyphosphoric acid, the softening point of low volatility modified asphalt increases, the viscosity decreases, and the ductility does not change much, but overall the performance indicators are basically not greatly affected.

[0081] From the data in Table 2, it can be seen that the average value of the volatile flue gas of the low-volatility modified asphalt samples is significantly lower than that of the sample asphalt, which effectively reduces the volatilization of organic matter in the asphalt. Therefore, the present invention can effectively reduce the volatilization of harmful gases through chemical reactions and physical adsorption, thereby improving the environmental performance of modified asphalt.

[0082] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A low volatility modified asphalt, characterized in that: The low-volatile modified asphalt comprises the following components: modified asphalt, organic-inorganic hybrid porous adsorbent and polyphosphoric acid; The organic-inorganic hybrid porous adsorbent comprises the following components: sodium alginate aqueous solution, activated carbon, calcium hydroxide, ferric chloride aqueous solution, calcium chloride aqueous solution and sodium hydroxide saturated calcium hydroxide solution.

2. The low volatility modified asphalt according to claim 1, wherein: The low-volatile modified asphalt comprises the following components in parts by weight: 80-98 parts of modified asphalt, 3-10 parts of organic-inorganic hybrid porous adsorbent and 1-8 parts of polyphosphoric acid.

3. The low volatility modified asphalt according to claim 2, wherein: The low-volatile modified asphalt comprises the following components in parts by weight: 80-95 parts of modified asphalt, 4-10 parts of organic-inorganic hybrid porous adsorbent and 2-6 parts of polyphosphoric acid.

4. The low volatility modified asphalt according to claim 1, wherein: The modified asphalt is at least one of SBR modified asphalt, SBS modified asphalt, rubber powder modified asphalt and recycled rubber powder modified asphalt.

5. The low volatility modified asphalt according to claim 1, wherein: Based on the total weight of the polyphosphoric acid, the polyphosphoric acid is prepared by polymerization of 100-120 wt % of phosphoric acid and >80 wt % of phosphorus pentoxide.

6. The low volatility modified asphalt according to claim 1, wherein: The preparation method of the organic-inorganic hybrid porous adsorbent comprises the following steps: S1: soaking the activated carbon in the sodium hydroxide saturated calcium hydroxide solution to obtain soaked activated carbon; S2: mixing and dispersing the soaked activated carbon and the sodium alginate aqueous solution uniformly to obtain a dispersed system and performing a cooling treatment; S3: adding calcium hydroxide to the dispersed system after cooling in step S2 until saturated, cooling the system to obtain a hybrid mixed solution, and extruding the mixed solution by injection molding to obtain a spherical and / or blocky material; S4: uniformly mixing the spherical and / or block material, the ferric chloride aqueous solution and the calcium chloride aqueous solution, and sequentially solidifying and vacuum-freezing to obtain the organic-inorganic hybrid porous adsorbent.

7. The low volatility modified asphalt according to claim 6, wherein: In step S1, the soaking time is 2-5 hours; In the step S2, the cooling treatment is to reduce the temperature of the dispersed system to 10-15°C; In step S3, the temperature reduction treatment is to reduce the temperature of the hybridization mixed solution to 0-5°C.

8. The low volatility modified asphalt according to claim 1, 6 or 7, wherein: The ratio of the activated carbon to the sodium hydroxide saturated calcium hydroxide solution is (95-105): (950-1050) g / mL; The ratio of the total volume of the ferric chloride aqueous solution and the calcium chloride aqueous solution, the volume of the sodium alginate aqueous solution and the volume of the sodium hydroxide saturated calcium hydroxide solution is (0.8-1.2):(0.8-1.2):(0.8-1.2); The sodium hydroxide saturated calcium hydroxide solution is prepared by mixing sodium hydroxide solid with a saturated calcium hydroxide solution; the mass fraction of sodium hydroxide in the sodium hydroxide saturated calcium hydroxide solution is 8-12%; The particle size of the activated carbon is at least one of 100 mesh, 200 mesh and 325 mesh; The concentration of the sodium alginate aqueous solution is 0.015-0.035 g / mL; The mass fraction of the ferric chloride aqueous solution is 2-4%; The mass fraction of the calcium chloride aqueous solution is 1-3%.

9. The method for preparing low volatility modified asphalt according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) heating the modified asphalt to a liquid state; (2) The liquid modified asphalt obtained in step (1) is mixed and stirred with an organic-inorganic hybrid porous adsorbent and polyphosphoric acid to obtain the low-volatile modified asphalt.

10. The method for preparing low volatility modified asphalt according to claim 9, wherein: The temperature of heating the modified asphalt is 165-170° C.; The mixing temperature is 165-170°C and the time is 40-120 minutes.

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