Odor-removing smoke suppressant modified asphalt and preparation method thereof

Abstract

The invention discloses an odorless smoke suppressant modified asphalt and a preparation method thereof, and belongs to the field of asphalt pavement materials. Firstly, an odorless smoke suppressant and an SBS modifier are subjected to melt blending through a plasticator to obtain a compound of the odorless smoke suppressant and the SBS modifier, and then the compound and matrix asphalt heated to a molten state are subjected to wet blending to obtain the odorless smoke suppressant modified asphalt. After mechanical stirring, high-temperature swelling and high-speed shearing, adding a stabilizer into the mixture for mechanical stirring, and finally transferring the mixture into a drying oven for development to obtain the odor-free smoke suppressant modified asphalt. The smoke suppression rate of the odorless smoke suppression modified asphalt prepared by the invention can reach 95% and is obviously superior to that of matrix asphalt and modified asphalt obtained by using a single odorless smoke suppression agent, the smoke suppression effect of the asphalt is improved, and meanwhile, the high and low temperature performance and the storage stability of the asphalt during use are improved.

Description

Technical Field

[0001] The present invention relates to the field of asphalt pavement materials, and particularly relates to a net-smell and smoke-suppressing agent modified asphalt and a preparation method thereof. Background Art

[0002] In China, the consumption of asphalt is still increasing continuously. It is not only used in the road field, but also has many applications in other industries, such as waterproofing and rubber. However, in today's social background where both industry and environmental protection are emphasized, the problems of odor and a large amount of harmful flue gas generated during the production, transportation and construction stages of asphalt have gradually become the focus of attention of the public and environmental protection agencies. According to the literature, the typical components of asphalt fumes include volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), particulate matter (PM), sulfur oxides, nitrogen oxides and carbon oxides. These pollutants can pose potential risks to the health of construction workers when inhaled through the respiratory tract or directly contacted with the skin. Long-term exposure may be harmful to the respiratory tract, lungs, liver and kidneys, and even induce cancer.

[0003] To improve the safety of asphalt pavements and reduce the flue gas emissions during the production and paving of asphalt mixtures, researchers have proposed various methods for treating asphalt fumes. Among them, modifying asphalt with a net-smell and smoke-suppressing agent can effectively achieve the net-smell and smoke-suppression of asphalt materials. Hydroxides of alkali metals such as magnesium hydroxide can absorb a large amount of heat when heated to reduce the temperature of asphalt, reduce the generation of flue gas, and at the same time produce a dense isolation layer to isolate oxygen from asphalt to achieve the effects of flame retardancy and smoke suppression; expanded graphite (EG) is a new type of adsorbent. Research shows that after adding expanded graphite to road asphalt, at a temperature of 180 °C, the light components and polycyclic aromatic hydrocarbons in the asphalt can partially insert into the expanded graphite lamellae and form nuclear crystallization, and at the same time adsorb on the surface of the expanded graphite. The action of lattice energy and van der Waals force inhibits the release of asphalt fumes; zeolite, also known as silicon-aluminum molecular sieve, has a porous structure, similar to activated carbon, but its crystal structure is a three-dimensional framework structure formed by silicon (aluminum) oxygen tetrahedrons, and there are various cavities and channels of different sizes and shapes in the framework. Since the cavities existing in the zeolite lattice can absorb or filter molecules of different sizes, and it has the characteristics of being stable at high temperatures and having a persistent adsorption property, it is considered a potential VOCs adsorbent. In recent years, compounding different types of smoke-suppressing agents with different properties and characteristics in a certain proportion to prepare a composite smoke-suppressing agent has become the mainstream of the research on smoke-suppressing asphalt. There is a synergistic effect between different types of smoke-suppressing agents, and it has a better smoke-suppressing effect than a single smoke-suppressing agent.

[0004] However, the odor and smoke suppressant will have an adverse impact on the road performance of asphalt. In recent years, researchers in this field have been continuously exploring various new materials to prepare new materials with significant odor and smoke suppression effects and less impact on road performance. After being compounded in a certain proportion, these new materials can achieve the best odor and smoke suppression effects and will not have an adverse impact on road performance. On the contrary, it may even be improved, showing broad application prospects. Summary of the Invention

[0005] The object of the present invention is to overcome the defects in the prior art and provide an odor and smoke suppressant modified asphalt and its preparation method, which can improve the odor and smoke suppression effect of asphalt while ensuring the road performance of asphalt.

[0006] An odor and smoke suppressant modified asphalt according to the present invention comprises the following components by weight: 1 - 10 parts of magnesium hydroxide, 0 - 1 part of zeolite, 1 - 3 parts of expanded graphite, 4 parts of SBS modifier, 100 parts of matrix asphalt, and 0.1 - 0.5 part of stabilizer. The softening point of the matrix asphalt is 46.2 °C, the ductility at 5 °C is 0.6 cm, and the penetration at 25 °C is 65.3 dmm, where 1 dmm = 0.1 mm.

[0007] Further, the SBS modifier is of a linear structure or a star structure.

[0008] Further, the stabilizer is sulfur or dicumyl peroxide.

[0009] A preparation method of an odor and smoke suppressant modified asphalt comprises the following steps:

[0010] Step 1: Prepare a composite of the odor and smoke suppressant and the SBS modifier. Manually mix nano magnesium hydroxide, zeolite, and expanded graphite for 1 min to obtain the odor and smoke suppressant. Heat the plasticator to the set temperature with a roller spacing of 1 mm, put the SBS modifier into the roller for plasticating. After the SBS modifier melts into a sheet and wraps around the roller, pour in the mixed odor and smoke suppressant and continue plasticating for 5 min until evenly mixed to obtain the composite of the odor and smoke suppressant and the SBS modifier.

[0011] Step 2: Mechanically crush the composite obtained in Step 1 and granulate it for standby.

[0012] Step 3: Heat the matrix asphalt to a molten state, add the composite of the odor and smoke suppressant and the SBS modifier, and mechanically stir at a speed of 600 rpm for 15 min. Then, put it into an oven at 170 °C for swelling for 90 min, and then perform high-speed shearing at a speed of 6000 rpm for 60 min. Then add the stabilizer and mechanically stir at a speed of 600 rpm for 15 min, and then transfer it to an oven at 170 °C for development for 60 min.

[0013] Further, the temperature of the plasticator in Step 1 is set at 130°C.

[0014] Further, the temperature during high-speed shearing in Step 3 is 160 - 190°C.

[0015] When the present invention works, first, a deodorizing and smoke-suppressing agent obtained by mixing nano magnesium hydroxide, zeolite, and expanded graphite is melt-blended with an SBS modifier through a plasticator to prepare a deodorizing and smoke-suppressing composite. Then, the deodorizing and smoke-suppressing composite and matrix asphalt are prepared into a deodorizing and smoke-suppressing modified asphalt by a wet method, improving the smoke suppression effect during the use of asphalt, and simultaneously improving the high and low temperature performance and storage stability of asphalt.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] First, the present invention simultaneously uses nano magnesium hydroxide, zeolite, and expanded graphite to modify asphalt, preparing a composite modified asphalt with a smoke-suppressing function. The smoke suppression rate can reach 95%. The smoke suppression rates of the modified asphalt prepared by using nano magnesium hydroxide, zeolite, and expanded graphite alone are 74%, 45%, and 57% respectively, and the deodorizing and smoke-suppressing effect is more excellent.

[0018] Second, during the preparation process of the deodorizing and smoke-suppressing modified asphalt of the present invention, first, the deodorizing and smoke-suppressing agent and the SBS modifier are melt-blended, and then mixed with the matrix asphalt to prepare the deodorizing and smoke-suppressing modified asphalt, greatly improving the high and low temperature performance (the softening point can reach 70.2°C, and the ductility at 5°C can reach 16 cm) during the use of the modified asphalt, and the segregation value is lower, improving the thermal storage stability. Description of the Drawings

[0019] Figure 1 It is a comparison chart of the smoke suppression rates of the matrix asphalt and the deodorizing and smoke-suppressing modified asphalt prepared by the present invention.

[0020] Figure 2 It is a comparison chart of the storage stability of the deodorizing and smoke-suppressing modified asphalt prepared by the present invention. Detailed Embodiments

[0021] Example 1: Preparation of a Composite of a Deodorizing and Smoke-Suppressing Agent and an SBS Modifier

[0022] 10 parts of nano magnesium hydroxide, 1 part of zeolite, and 3 parts of expanded graphite are manually mixed for 1 min by weight to obtain a deodorizing and smoke-suppressing agent. The plasticator is heated to 130°C, the roller spacing is 1 mm, and 4 parts of a linear-structured SBS modifier are put into the roller for plasticating. After the SBS modifier is melted into a sheet and wraps around the roller, the mixed deodorizing and smoke-suppressing agent is poured in and plasticated for another 5 min. The plasticating temperature is controlled at 130°C until it is uniformly mixed to obtain a composite of the deodorizing and smoke-suppressing agent and the SBS modifier, and the composite is granulated by mechanical crushing for standby.

[0023] Example 2: Preparation of odorless and smoke-suppressing modified asphalt

[0024] Heat 100 parts of matrix asphalt to a molten state by weight, add the composite of the odorless and smoke-suppressing agent and SBS modifier prepared in Example 1, and mechanically stir for 15 min at a rotation speed of 600 rpm; then, place it in an oven at 170 °C for swelling for 90 min, and then perform high-speed shearing at a rotation speed of 6000 rpm for 60 min, with the shearing temperature being 180 °C. Then, add 0.1 part of sulfur, mechanically stir for 15 min at a rotation speed of 600 rpm, and then transfer it to an oven at 170 °C for development for 60 min.

[0025] Example 3: Preparation of odorless and smoke-suppressing modified asphalt

[0026] Heat 100 parts of matrix asphalt to a molten state by weight, add the composite of the odorless and smoke-suppressing agent and SBS modifier prepared in Example 1, and mechanically stir for 15 min at a rotation speed of 600 rpm; then, place it in an oven at 170 °C for swelling for 90 min, and then perform high-speed shearing at a rotation speed of 6000 rpm for 60 min, with the shearing temperature being 180 °C. Then, add 0.3 part of sulfur, mechanically stir for 15 min at a rotation speed of 600 rpm, and then transfer it to an oven at 170 °C for development for 60 min.

[0027] Example 4: Preparation of odorless and smoke-suppressing modified asphalt

[0028] Heat 100 parts of matrix asphalt to a molten state by weight, add the composite of the odorless and smoke-suppressing agent and SBS modifier prepared in Example 1, and mechanically stir for 15 min at a rotation speed of 600 rpm; then, place it in an oven at 170 °C for swelling for 90 min, and then perform high-speed shearing at a rotation speed of 6000 rpm for 60 min, with the shearing temperature being 180 °C. Then, add 0.5 part of sulfur, mechanically stir for 15 min at a rotation speed of 600 rpm, and then transfer it to an oven at 170 °C for development for 60 min.

[0029] Comparative Example 1: Preparation of a composite of an odorless and smoke-suppressing agent and an SBS modifier using only the single smoke-suppressing agent nano-magnesium hydroxide

[0030] Manually mix 10 parts of nano-magnesium hydroxide, 0 part of zeolite, and 0 part of expanded graphite by weight for 1 min to obtain an odorless and smoke-suppressing agent. Heat the plasticator to 130 °C, with the roller spacing being 1 mm. Put 4 parts of a linear-structured SBS modifier into the roller for plasticating. After the SBS modifier melts into a sheet and wraps around the roller, pour in the mixed odorless and smoke-suppressing agent and continue plasticating for 5 min, with the plasticating temperature controlled at 130 °C until it is uniformly mixed to obtain a composite of an odorless and smoke-suppressing agent and an SBS modifier. Granulate the composite by mechanical crushing for standby.

[0031] Comparative Example 2: Preparation of a complex of odorless and smoke-suppressing agent and SBS modifier using only the single smoke-suppressing agent zeolite

[0032] Manually mix 0 parts of nano-magnesium hydroxide, 1 part of zeolite, and 0 parts of expanded graphite by weight for 1 min to obtain an odorless and smoke-suppressing agent. Heat the plasticator to 130°C with a roll spacing of 1 mm. Feed 4 parts of the linear-structured SBS modifier into the roll for plasticating. After the SBS modifier melts into a sheet and wraps around the roll, pour in the mixed odorless and smoke-suppressing agent and continue plasticating for 5 min with the plasticating temperature controlled at 130°C until evenly mixed to obtain a complex of odorless and smoke-suppressing agent and SBS modifier. Granulate the complex by mechanical crushing for standby use.

[0033] Comparative Example 3: Preparation of a complex of odorless and smoke-suppressing agent and SBS modifier using only the single smoke-suppressing agent expanded graphite

[0034] Manually mix 0 parts of nano-magnesium hydroxide, 0 parts of zeolite, and 3 parts of expanded graphite by weight for 1 min to obtain an odorless and smoke-suppressing agent. Heat the plasticator to 130°C with a roll spacing of 1 mm. Feed 4 parts of the linear-structured SBS modifier into the roll for plasticating. After the SBS modifier melts into a sheet and wraps around the roll, pour in the mixed odorless and smoke-suppressing agent and continue plasticating for 5 min with the plasticating temperature controlled at 130°C until evenly mixed to obtain a complex of odorless and smoke-suppressing agent and SBS modifier. Granulate the complex by mechanical crushing for standby use.

[0035] Comparative Example 4:

[0036] Heat 100 parts of matrix asphalt to the molten state, add the complex of odorless and smoke-suppressing agent and SBS modifier prepared in Comparative Example 1, and mechanically stir at a speed of 600 rpm for 15 min; then, place it in an oven at 170°C for swelling for 90 min, and then perform high-speed shearing at a speed of 6000 rpm for 60 min with the shearing temperature of 180°C. Then add 0.3 parts of sulfur, mechanically stir at a speed of 600 rpm for 15 min, and then transfer it to an oven at 170°C for development for 60 min.

[0037] Comparative Example 5:

[0038] Heat 100 parts of matrix asphalt to the molten state, add the complex of odorless and smoke-suppressing agent and SBS modifier prepared in Comparative Example 2, and mechanically stir at a speed of 600 rpm for 15 min; then, place it in an oven at 170°C for swelling for 90 min, and then perform high-speed shearing at a speed of 6000 rpm for 60 min with the shearing temperature of 180°C. Then add 0.3 parts of sulfur, mechanically stir at a speed of 600 rpm for 15 min, and then transfer it to an oven at 170°C for development for 60 min.

[0039] Comparative Example 6:

[0040] Heat 100 parts of matrix asphalt to a molten state by weight, add the complex of the odorless and smoke-suppressing agent and SBS modifier prepared in Comparative Example 3, and mechanically stir for 15 min at a rotation speed of 600 rpm; then, place it in an oven at 170 °C for swelling for 90 min, and then perform high-speed shearing at a rotation speed of 6000 rpm for 60 min, with the shearing temperature being 180 °C. Then, add 0.3 parts of sulfur, mechanically stir for 15 min at a rotation speed of 600 rpm, and then transfer it to an oven at 170 °C for development for 60 min.

[0041] Comparative Example 7:

[0042] Heat 100 parts of matrix asphalt to a molten state by weight, add 10 parts of nano-magnesium hydroxide, 1 part of zeolite, and 3 parts of expanded graphite, mechanically stir for 15 min at a rotation speed of 600 rpm, then perform high-speed shearing at a rotation speed of 6000 rpm for 60 min, with the shearing temperature being 180 °C. Then, add 0.3 parts of sulfur, mechanically stir for 15 min at a rotation speed of 600 rpm, and then transfer it to an oven at 170 °C for development for 60 min.

[0043] Comparative Example 8:

[0044] Heat 100 parts of matrix asphalt to a molten state by weight, add 10 parts of nano-magnesium hydroxide, 1 part of zeolite, 3 parts of expanded graphite, and 4 parts of linear structure SBS modifier, mechanically stir for 15 min at a rotation speed of 600 rpm, then place it in an oven at 170 °C for swelling for 90 min, then perform high-speed shearing at a rotation speed of 6000 rpm for 60 min, with the shearing temperature being 180 °C. Then, add 0.3 parts of sulfur, mechanically stir for 15 min at a rotation speed of 600 rpm, and then transfer it to an oven at 170 °C for development for 60 min.

[0045] Perform a smoke suppression rate test on the matrix asphalt, the odorless and smoke-suppressing modified asphalt of Example 3 prepared in the present invention, and Comparative Examples 4 to 6. The results are as Figure 1 shown. Using nano-magnesium hydroxide, zeolite, and expanded graphite alone all have a smoke suppression effect on the matrix asphalt, and the smoke suppression rates are 74%, 45%, and 57% respectively; when the three odorless and smoke-suppressing agents are compounded and used in a weight ratio of 10:1:3, the odorless and smoke-suppressing effect is significantly better than that of single use, and the smoke suppression rate can reach 95%.

[0046] Figure 2The segregation test results of several odorless and smoke-suppressing modified bitumens prepared according to the present invention are as follows. By adding different weight parts of the stabilizer sulfur, as the sulfur addition amount increases, the storage stability of the odorless and smoke-suppressing modified bitumen becomes better. Comparing Example 3 with Comparative Example 8, it is found that by first melt-blending the odorless and smoke-suppressing agent with the SBS modifier to prepare a composite, and then mixing it with the matrix bitumen to obtain the odorless and smoke-suppressing modified bitumen (Example 3), it has better stability than directly adding the odorless and smoke-suppressing agent and the SBS modifier to the matrix bitumen (Comparative Example 8). Although the stabilizer sulfur is added in both cases, the segregation value of the odorless and smoke-suppressing modified bitumen prepared in Example 3 is lower, indicating better storage stability.

[0047] The softening point, ductility, and penetration of the matrix bitumen and the odorless and smoke-suppressing modified bitumens of Example 3, Comparative Example 7, and Comparative Example 8 prepared according to the present invention were tested, and the results are shown in Table 1.

[0048] Table 1 Test results of the performance indexes of the matrix bitumen and the odorless and smoke-suppressing modified bitumen

[0049]

[0050] It can be seen that the softening point (70.2 °C) and ductility (16 cm) of the odorless and smoke-suppressing modified bitumen prepared in Example 3 are significantly higher than those of the matrix bitumen (softening point 46.2 °C, ductility 0.6 cm), and its penetration (37.4 mm) is lower than that of the matrix bitumen (penetration 65.3 mm). This indicates that the composite of the odorless and smoke-suppressing agent and the SBS modifier significantly improves the high and low temperature performance of the matrix bitumen.

[0051] The softening point of the odorless and smoke-suppressing modified bitumen prepared in Comparative Example 7 is 61.4 °C, which is higher than that of the matrix bitumen, but the ductility index has not been improved. Comparing Example 3 with Comparative Example 7, it is found that the softening point (70.2 °C) and ductility (16 cm) of the odorless and smoke-suppressing modified bitumen prepared in Example 3 are both higher than those of the odorless and smoke-suppressing modified bitumen prepared in Comparative Example 7 (softening point 61.4 °C, ductility 0.4 cm). This indicates that the excellent high and low temperature comprehensive performance of the odorless and smoke-suppressing modified bitumen largely benefits from the SBS modifier. Comparing Example 3 with Comparative Example 8, the softening point (70.2 °C) of the odorless and smoke-suppressing modified bitumen prepared in Example 3 is lower than that of the odorless and smoke-suppressing modified bitumen prepared in Comparative Example 8 (softening point 77.3 °C), and its ductility is 16 cm, which is higher than that of the odorless and smoke-suppressing modified bitumen prepared in Comparative Example 8 (ductility 13.3 cm). This may be due to the fact that during the preparation of the composite of the odorless and smoke-suppressing agent and the SBS modifier, under the action of mechanical and heat, there is a certain degradation of the SBS modifier, which is not conducive to the high temperature performance of the modified bitumen.

[0052] Comparative Example 9:

[0053] On the basis of Example 3, only the shear temperature when the matrix asphalt is mixed with the complex of the odorless and smoke-suppressing agent and the SBS modifier is changed, and then the performance test is carried out. The results are shown in Table 2.

[0054] Table 2 Influence of Shear Temperature on the Performance of Odorless and Smoke-Suppressing Modified Asphalt

[0055]

[0056] As can be seen from Table 2, as the shear temperature increases, the softening point and 5℃ ductility of the odorless and smoke-suppressing modified asphalt gradually increase. However, when the shear temperature rises above 180℃, the softening point and 5℃ ductility gradually decrease. This may be because with the increase of the shear temperature, the mutual penetration and fusion between the asphalt and the SBS modifier are promoted, and the enhanced phase interface makes a contribution; while when the shear temperature is too high, the asphalt and the SBS modifier are aged and degraded, resulting in a decline in performance; the softening point reflects the high-temperature resistance performance of the asphalt, and the ductility reflects the low-temperature performance of the asphalt. When the shear temperature is 180℃, the softening point of the odorless and smoke-suppressing modified asphalt prepared in Example 3 is 70.2℃, and the 5℃ ductility is 16.0 cm, showing good high and low temperature performance;

[0057] The penetration reflects the viscosity and hardness of the asphalt. As the shear temperature increases, the penetration of the asphalt will gradually decrease. This may be because the degradation of the asphalt and the SBS modifier plays a dominant role;

[0058] Taking into account the influence of the softening point, ductility and penetration factors, when the matrix asphalt is mixed with the complex of the odorless and smoke-suppressing agent and the SBS modifier, the shear temperature is preferably 160 - 190℃, and the optimal value is 180℃.

[0059] The present invention is not limited to the above embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and deformations of some technical features according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A odorless and smoke-suppressing modified asphalt, characterized in that: The invention comprises the following components by weight: 1 to 10 parts of magnesium hydroxide, 0 to 1 part of zeolite, 1 to 3 parts of expanded graphite, 4 parts of SBS modifier, 100 parts of base asphalt and 0.1 to 0.5 parts of stabilizer. The softening point of the base asphalt is 46.2°C, the elongation at 5°C is 0.6 cm, the needle penetration at 25°C is 65.3 dmm, wherein 1 dmm=0.1mm.

2. The odorless and smoke-suppressing modified asphalt according to claim 1, characterized in that: The SBS modifier has a linear structure or a star structure.

3. The odorless and smoke-suppressing modified asphalt according to claim 1, characterized in that: The stabilizer is sulfur or dicumyl peroxide.

4. A method for preparing odorless and smoke-suppressing modified asphalt, characterized in that: The steps include: Step 1: Prepare a composite of a clean smoke suppressant and an SBS modifier, manually mix nano magnesium hydroxide, zeolite and expanded graphite for 1 min to obtain a clean smoke suppressant, heat the plasticizer to a set temperature, set the roller spacing to 1 mm, add the SBS modifier into the roller for plasticizing, wait for the SBS modifier to melt into a sheet and wrap the roller, then pour the mixed clean smoke suppressant into it and continue plasticizing for 5 min until the mixture is evenly mixed to obtain a composite of the clean smoke suppressant and the SBS modifier; Step 2: Mechanically crushing the composite obtained in step 1 and granulating it for later use; Step 3: Heat the base asphalt to a molten state, add the complex of the odorless smoke suppressant and the SBS modifier, and mechanically stir at 600 rpm for 15 min; then, put it into an oven at 170°C to swell for 90 min, then high-speed shear it at 6000 rpm for 60 min, add the stabilizer, mechanically stir it at 600 rpm for 15 min, and then transfer it to an oven at 170°C for development for 60 min.

5. The method for preparing a odorless and smoke-suppressing modified asphalt according to claim 4, characterized in that: The temperature of the plasticator described in step 1 was set to 130°C.

6. The method for preparing a odorless and smoke-suppressing modified asphalt according to claim 4, characterized in that: The temperature during the high-speed shearing described in step 3 is 160-190°C.

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