Phase-change self-temperature-regulating rubber powder modified asphalt and preparation method thereof

Abstract

The invention discloses phase-change self-temperature-regulating rubber powder modified asphalt and a preparation method thereof, and belongs to the field of asphalt pavement materials, the phase-change self-temperature-regulating rubber powder modified asphalt comprises the following components in parts by weight: 100 parts of matrix asphalt, 1-5 parts of polyethylene glycol, 5-20 parts of rubber powder and an isocyanate-based compound, the matrix asphalt is heated to a molten state, a polyethylene glycol-rubber powder compound is added, mechanical stirring and mixing are performed, and the phase-change self-temperature-regulating rubber powder modified asphalt is obtained. Then putting the mixture into a drying oven for swelling, and finally performing high-speed shearing to obtain the phase-change self-temperature-regulating rubber powder modified asphalt. The isocyanate group in the isocyanate group compound reacts with the chain end of PEG and the hydroxyl group on the surface of CR, and CR and PEG are compounded through a chemical reaction, so that not only is the high-temperature performance of the phase change modified asphalt improved, but also the harm caused by PEG phase change leakage can be relieved, and the pavement quality and the high-temperature pavement performance can be improved.

Description

Technical Field

[0001] The present invention relates to the field of asphalt pavement materials, and particularly relates to a phase change self-regulating temperature crumb rubber modified asphalt and a preparation method thereof. Background Art

[0002] The absorption rate of asphalt to solar radiation is as high as 0.8 - 0.9, which easily causes high temperature on asphalt pavement in summer, resulting in problems such as reduced service life of the road, decreased driving safety, and deterioration of the urban ecological environment. All along, scientific researchers have been constantly exploring how to cope with the negative impacts caused by temperature changes on asphalt pavement. As an important functional medium of latent heat energy storage technology, phase change materials have a high energy storage density within a certain temperature range, and complete the melting and solidification cycles through reversible latent heat storage processes, thereby achieving heat absorption and heat release to achieve the temperature regulation effect. Therefore, using the characteristics of phase change materials to absorb a large amount of heat during the phase change process while keeping the temperature constant to regulate the pavement temperature is an active and effective method to solve the high temperature problem of asphalt pavement.

[0003] Currently, the phase change modifiers used more are paraffin, polyethylene glycol (PEG), n-tetradecane, fatty acids, etc. The phase change temperatures of these pure phase change materials meet the road use requirements and have relatively high latent heat enthalpy values. Solid-liquid phase change materials have the advantage of high phase change latent heat, but after reaching the phase change temperature, they become liquid and are easy to flow. This leakage problem generated during the phase change process not only reduces the high temperature performance of the modified asphalt but also brings inconvenience to its use. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a phase change self-regulating temperature crumb rubber modified asphalt and a preparation method thereof, which retain and exert the temperature regulation function of polyethylene glycol and the performance advantages of crumb rubber modified asphalt, and contribute to improving the pavement quality and enhancing the high temperature pavement performance.

[0005] The purpose of the present invention is achieved as follows: A phase change self-regulating temperature crumb rubber modified asphalt includes the following components by weight: 100 parts of matrix asphalt, 1 - 5 parts of polyethylene glycol, 5 - 20 parts of crumb rubber, and an isocyanate group compound. The softening point of the matrix asphalt is 47.4°C, the ductility at 5°C is 0.7 cm, and the penetration at 25°C is 68.8 dmm, where 1 dmm = 0.1 mm.

[0006] Further, the molecular weight of the polyethylene glycol is one of 2000, 4000, 6000, 8000, and 10000.

[0007] Further, the crumb rubber is a waste rubber product, sourced from one of waste tires, rubber shoes, conveyor belts, V-belts, and waste rubber sheets, and the particle size of the crumb rubber is one of 5 mesh, 10 mesh, 20 mesh, 40 mesh, 60 mesh, and 80 mesh.

[0008] Furthermore, the isocyanate group compound is one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

[0009] The present invention also discloses a preparation method of phase change self-regulating temperature rubber powder modified asphalt, which includes the following steps: heating 100 parts of matrix asphalt to a molten state, adding polyethylene glycol-rubber powder composite, mechanically stirring at a rotation speed of 600 rpm for 15 min, then putting it into an oven at 170 °C for swelling for 90 min, and finally, performing high-speed shearing at a rotation speed of 6000 rpm for 60 min, and controlling the temperature during high-speed shearing at 160-190 °C;

[0010] Among them, the preparation steps of the polyethylene glycol-rubber powder composite are as follows: maintaining magnetic stirring, dispersing polyethylene glycol and rubber powder in ethanol, with a stirring speed of 1000 rpm, after stirring for 30 min, adding the isocyanate group compound and continuing to stir for 10 min, then putting the solid-liquid mixture into a blast drying oven at a constant temperature of 50 °C to dry until the ethanol is completely volatilized, weighing until the weight remains unchanged, and then heating to 80 °C for reaction for 1 h to prepare the polyethylene glycol-rubber powder composite.

[0011] Furthermore, the addition amount of the isocyanate group compound is 1-3 wt% of the total mass of polyethylene glycol and rubber powder.

[0012] When the present invention works, using polyethylene glycol (PEG) as the phase change material, first, PEG and rubber powder CR are compounded through solution co-mixing grafting reaction, and then modified asphalt is prepared, while retaining and exerting the temperature regulation function of PEG and the performance advantages of CR modified asphalt. The present invention has reference significance and reference value for improving the pavement quality, enhancing the high-temperature pavement performance, and researching the pavement temperature.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] First, through the present invention, phase change modified asphalt with an active temperature regulation function can be prepared, alleviating the high-temperature problem of asphalt pavement in summer, reducing pavement temperature diseases, and extending the service life of the pavement.

[0015] Second, the preparation method of the present invention chemically combines polyethylene glycol and rubber powder, and then prepares composite modified asphalt with matrix asphalt, which can alleviate the harm caused by the phase change leakage of polyethylene glycol.

[0016] Thirdly, the preparation method of the present invention not only gives full play to and retains the phase change temperature regulation function of polyethylene glycol and the performance advantages of crumb rubber modified asphalt, but also can effectively alleviate the environmental pollution problems brought by waste rubber products, realizes the recycling of non-renewable resources, and has considerable economic and environmental benefits. Description of the Drawings

[0017] Figure 1 It is the temperature-time change curve of matrix asphalt and phase change temperature regulation crumb rubber modified asphalt during the heating process.

[0018] Figure 2 The rutting factor of matrix asphalt and phase change temperature regulation crumb rubber modified asphalt at 64 °C. Detailed Embodiments

[0019] A preparation method of phase change self-temperature regulating crumb rubber modified asphalt comprises the following steps:

[0020] (1) Prepare the PEG-CR composite:

[0021] Under the action of magnetic stirring, 1-3 parts of PEG and 5-20 parts of CR are dispersed in ethanol, the stirring speed is 1000 rpm, after stirring for 30 min, 1-3 wt% of isocyanate group compound based on the total mass of PEG and CR is added, and stirring continues for 10 min. Then, the solid-liquid mixture is placed in a blast drying oven at 50 °C and dried to constant weight, that is, after ethanol is completely volatilized, the temperature is raised to 80 °C and reacted for 1 h to prepare the PEG-CR composite;

[0022] (2) Prepare the phase change self-temperature regulating crumb rubber modified asphalt:

[0023] After heating 100 parts of matrix asphalt to the molten state, the PEG-CR composite is added, and mechanical stirring is carried out at a rotation speed of 600 rpm for 15 min. Then, it is placed in an oven at 170 °C for swelling for 90 min. Finally, high-speed shearing is carried out at a rotation speed of 6000 rpm for 60 min.

[0024] The crumb rubber used in the embodiments of the present invention all comes from waste tires.

[0025] Example 1:

[0026] Under the action of magnetic stirring, 1 part of PEG with a molecular weight of 6000 and 20 parts of 60-mesh CR are dispersed in ethanol, and after stirring at a speed of 1000 rpm for 30 min, 3 wt% of hexamethylene diisocyanate (HDI) is added based on the total mass of PEG and CR, and stirring continues for 10 min. Then, the solid-liquid mixture is placed in a blast drying oven at 50 °C and dried to constant weight, that is, after ethanol is completely volatilized, the temperature is raised to 80 °C and reacted for 1 h to prepare the PEG-CR composite.

[0027] Example 2:

[0028] Under magnetic stirring, 3 parts of PEG with a molecular weight of 6000 and 20 parts of 60-mesh CR were dispersed in ethanol. After stirring at a speed of 1000 rpm for 30 min, hexamethylene diisocyanate (HDI) was added at 3 wt% of the total mass of PEG and CR, and stirring was continued for 10 min. Then, the solid-liquid mixture was placed in a forced-air drying oven at 50 °C and dried to a constant weight, i.e., after ethanol was completely volatilized, the temperature was raised to 80 °C and reacted for 1 h to prepare a PEG-CR composite.

[0029] Example 3:

[0030] Under magnetic stirring, 5 parts of PEG with a molecular weight of 6000 and 20 parts of 60-mesh CR were dispersed in ethanol. After stirring at a speed of 1000 rpm for 30 min, hexamethylene diisocyanate (HDI) was added at 3 wt% of the total mass of PEG and CR, and stirring was continued for 10 min. Then, the solid-liquid mixture was placed in a forced-air drying oven at 50 °C and dried to a constant weight, i.e., after ethanol was completely volatilized, the temperature was raised to 80 °C and reacted for 1 h to prepare a PEG-CR composite.

[0031] Example 4:

[0032] After heating 100 parts of matrix asphalt to a molten state, 20 parts of 60-mesh crumb rubber were added, and mechanical stirring was carried out at a speed of 600 rpm for 15 min. Subsequently, it was placed in an oven at 170 °C for swelling for 90 min. Finally, high-speed shearing was carried out at a speed of 6000 rpm for 60 min to prepare a modified asphalt with only crumb rubber.

[0033] Example 5:

[0034] After heating 100 parts of matrix asphalt to a molten state, the PEG-CR composite prepared in Example 1 was added, and mechanical stirring was carried out at a speed of 600 rpm for 15 min. Subsequently, it was placed in an oven at 170 °C for swelling for 90 min. Finally, high-speed shearing was carried out at a speed of 6000 rpm for 60 min to obtain a phase-change self-regulating temperature crumb rubber modified asphalt.

[0035] Example 6:

[0036] After heating 100 parts of matrix asphalt to a molten state, the PEG-CR composite prepared in Example 2 was added, and mechanical stirring was carried out at a speed of 600 rpm for 15 min. Subsequently, it was placed in an oven at 170 °C for swelling for 90 min. Finally, high-speed shearing was carried out at a speed of 6000 rpm for 60 min to obtain a phase-change self-regulating temperature crumb rubber modified asphalt.

[0037] Example 7:

[0038] After heating 100 parts of matrix asphalt to the molten state, the PEG-CR composite prepared in Example 3 was added, and mechanical stirring was carried out at a rotation speed of 600 rpm for 15 min. Subsequently, it was placed in an oven at 170 °C for swelling for 90 min. Finally, high-speed shearing was carried out at a rotation speed of 6000 rpm for 60 min to obtain phase-change self-regulating temperature rubber powder modified asphalt.

[0039] Comparative Example 1:

[0040] Under the action of magnetic stirring, 3 parts of PEG with a molecular weight of 6000 and 20 parts of 60-mesh CR were dispersed in an ethanol solution. After stirring at a stirring speed of 1000 rpm for 30 min, the solid-liquid mixture was placed in a blast drying oven at 50 °C and dried to a constant weight, that is, after the ethanol completely volatilized, the CR-PEG composite was prepared.

[0041] Comparative Example 2:

[0042] After heating 100 parts of matrix asphalt to the molten state, the PEG-CR composite prepared in Comparative Example 1 was added, and mechanical stirring was carried out at a rotation speed of 600 rpm for 15 min. Subsequently, it was placed in an oven at 170 °C for swelling for 90 min. Finally, high-speed shearing was carried out at a rotation speed of 6000 rpm for 60 min to obtain phase-change self-regulating temperature rubber powder modified asphalt.

[0043] The softening point, ductility and penetration of matrix asphalt and phase-change self-regulating temperature rubber powder modified asphalt were tested under the same conditions, and the results are shown in Table 1:

[0044] Table 1 Test results of performance indicators of matrix asphalt and phase-change temperature-regulating rubber powder modified asphalt

[0045]

[0046]

[0047] Compared with the performance of matrix asphalt, the softening point and ductility of the rubber powder modified asphalt prepared in Example 4 are higher than those of matrix asphalt, and the penetration is lower than that of matrix asphalt, which indicates that the addition of rubber powder can improve the high and low temperature performance of matrix asphalt at the same time. Comparing the softening point, ductility and penetration of the phase-change self-regulating temperature rubber powder modified asphalt prepared in Examples 4 to 7, it is found that after compounding PEG6000 and CR, the softening point decreases, while the ductility and penetration increase, indicating that the high temperature performance of the modified asphalt decreases and the low temperature performance increases; however, with the increase of the content of PEG6000, the changes of the three major indicators do not show good regularity; generally speaking, the softening point shows a downward trend, the ductility remains stable, and the penetration shows an upward trend. This may be because PEG6000 and CR are compounded through chemical reactions, and the degree of reaction or the compounding effect affects the performance of the modified asphalt.

[0048] The phase-change self-regulating temperature rubber powder modified asphalt prepared in Example 6 and Comparative Example 3 was compared. By the reaction of the isocyanate group and the hydroxyl group in HDI, PEG6000 and CR were compounded and then used to prepare modified asphalt, which could increase the softening point of the modified asphalt, while the ductility and penetration decreased, that is, the high-temperature performance was improved and the low-temperature performance was reduced.

[0049] Figure 1 is the temperature-time change curve of the matrix asphalt and the phase-change temperature-regulating rubber powder modified asphalt during the heating process. The heating rates of the phase-change temperature-regulating rubber powder modified asphalt prepared in Examples 4, 5, 6 and 7 were significantly lower than that of the matrix asphalt, and with the increase of the PEG6000 content, the heating rate of the modified asphalt became slower, indicating that the prepared modified asphalt had excellent temperature-lowering effect. From the beginning of heating, the heating rate of the modified asphalt was slower than that of the matrix asphalt, which might be because the thermal conductivity coefficients of the modified asphalt were different; when the temperature rose to around 50 °C, the temperature difference between the matrix asphalt and the rubber powder modified asphalt prepared in Example 4 (without PEG6000) and the phase-change temperature-regulating rubber powder modified asphalt prepared in Examples 5, 6 and 7 became more and more obvious, because around 50 °C, PEG began to play the role of phase-change temperature regulation, changing from the crystalline state to the amorphous state and absorbing the external heat, thus delaying the heating rate of the modified asphalt.

[0050] Figure 2 is the rutting factor of the matrix asphalt, the phase-change temperature-regulating rubber powder modified asphalt prepared in Examples 4, 6 and Comparative Example 2 at 64 °C. It can be seen that the rutting factor of the phase-change temperature-regulating rubber powder modified asphalt was significantly higher than that of the matrix asphalt, indicating that the phase-change temperature-regulating rubber powder modified asphalt had excellent high-temperature deformation resistance. Comparing the rutting factors of the phase-change temperature-regulating rubber powder modified asphalt prepared in Example 4 and Example 6 with that in Comparative Example 2, it can be seen that after PEG6000 and CR were compounded, the high-temperature performance of the modified asphalt decreased, because 64 °C was higher than the phase-change temperature of PEG6000 and PEG had changed from the solid state to the liquid state, which would increase the fluidity of the asphalt. However, comparing Example 6 with Comparative Example 2, the rutting factor of the former was higher than that of the latter, indicating that compounding PEG6000 and CR through chemical reaction was beneficial to improving the high-temperature performance of the phase-change modified asphalt. This might be because through the bridging effect of HDI, PEG6000 was fixed in the CR phase, reducing the risk of leakage.

[0051] The present invention also found through multiple experiments that:

[0052] (1) When the molecular weights of PEG were 2000, 4000, 8000 and 10000, after being compounded with the rubber powder and then used to prepare the phase-change temperature-regulating modified asphalt, the performance change rules were the same, so the examples were not listed one by one for elaboration.

[0053] (2) When the rubber powder is sourced from any one of waste tires, rubber shoes, conveyor belts, V-belts, and waste rubber sheets, after being compounded with PEG and then used to prepare phase change temperature-regulating modified asphalt, it has a similar effect and consistent performance change pattern as that sourced from waste tire rubber powder. Therefore, the examples will not be listed one by one for elaboration.

[0054] (3) When the particle size of the rubber powder is any one of 5 mesh, 10 mesh, 20 mesh, 40 mesh, and 80 mesh, after being compounded with PEG and then used to prepare phase change temperature-regulating modified asphalt, it has a similar effect and consistent performance change pattern as that of 60-mesh rubber powder. Therefore, the examples will not be listed one by one for elaboration.

[0055] (4) When the isocyanate group compound is any one of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI), it has a similar effect and consistent performance change pattern as that of hexamethylene diisocyanate (HDI). Therefore, the examples will not be listed one by one for elaboration.

[0056] The present invention is not limited to the above embodiments. Based on the disclosed technical solutions of the present invention, those skilled in the art can make some substitutions and deformations to some technical features without creative labor according to the disclosed technical content, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A phase change self-regulating temperature rubber powder modified asphalt, characterized in that, It comprises the following components by weight parts: 100 parts of matrix asphalt, 1 - 5 parts of polyethylene glycol, 5 - 20 parts of rubber powder and isocyanate - based compound. The softening point of the matrix asphalt is 47.4 °C, the ductility at 5 °C is 0.7 cm, and the penetration at 25 °C is 68.8 dmm, where 1 dmm = 0.1 mm.

2. The phase change self-regulating temperature rubber powder modified asphalt according to claim 1, wherein: The molecular weight of the polyethylene glycol is one of 2000, 4000, 6000, 8000 and 10000.

3. A phase change self-regulating temperature rubber powder modified asphalt according to claim 1, characterized in that: The rubber powder is a waste rubber product, sourced from one of waste tires, rubber shoes, conveyor belts, V - belts and waste rubber sheets. The particle size of the rubber powder is one of 5 mesh, 10 mesh, 20 mesh, 40 mesh, 60 mesh and 80 mesh.

4. A phase change self-regulating temperature rubber powder modified asphalt according to claim 1, characterized in that: The isocyanate - based compound is one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.

5. A preparation method of phase change self-regulating temperature rubber powder modified asphalt, characterized in that, It includes the following steps: Heat the matrix asphalt to the molten state, add the polyethylene glycol - rubber powder complex, 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. Finally, perform high - speed shearing at a speed of 6000 rpm for 60 min.

6. The preparation method of a phase change self-regulating temperature rubber powder modified asphalt according to claim 5, characterized in that: The temperature during high - speed shearing is controlled at 160 - 190 °C.

7. The preparation method of a phase change self-regulating temperature rubber powder modified asphalt according to claim 5, characterized in that: The preparation of the polyethylene glycol - rubber powder complex includes the following steps: Keep magnetic stirring, disperse the polyethylene glycol and the rubber powder in ethanol, with a stirring speed of 1000 rpm. After stirring for 30 min, add the isocyanate - based compound and continue stirring for 10 min. Then, place the solid - liquid mixture in a blast drying oven at a constant temperature of 50 °C and dry until the ethanol completely evaporates, and the weight remains unchanged. Then, raise the temperature to 80 °C and react for 1 h to prepare the polyethylene glycol - rubber powder complex.

8. The preparation method of a phase change self-regulating temperature rubber powder modified asphalt according to claim 7, characterized in that: The addition amount of the isocyanate - based compound is 1 - 3 wt% of the total mass of the polyethylene glycol and the rubber powder.

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