Disclosure of Invention
The invention aims to provide an open-graded wearing layer asphalt mixture with good ageing resistance, water damage resistance and wear resistance and a preparation method thereof.
The open-graded wearing layer asphalt mixture comprises the following components in parts by weight: 40-90 parts of aggregate, 10-50 parts of steel slag, 4-6 parts of SBS modified asphalt, 1-5 parts of talcum powder, 0.1-0.5 part of ethylhexyl methoxycinnamate, 0.1-0.5 part of tocopheryl acetate, 0.1-0.5 part of octocrylene and 0.4-0.8 part of warm mixing agent.
Preferably, the open-graded wearing layer asphalt mixture comprises the following components in parts by mass: 40-70 parts of 40-90% aggregate, 20-50 parts of steel slag, 5-6 parts of SBS modified asphalt, 3-5 parts of talcum powder, 0.15-0.25 part of ethylhexyl methoxycinnamate, 0.15-0.25 part of tocopherol acetate, 0.2-0.5 part of octocrylene and 0.4-0.6 part of warm mixing agent.
Further preferably, the open-graded wearing layer asphalt mixture comprises the following components in parts by mass: 40 parts of aggregate, 50 parts of steel slag, 5.5 parts of SBS modified asphalt, 3 parts of talcum powder, 0.25 part of ethylhexyl methoxycinnamate, 0.25 part of tocopheryl acetate, 0.5 part of octocrylene and 0.5 part of warm-mixing agent.
Further preferably, the open-graded wearing layer asphalt mixture comprises the following components in parts by mass: 40 parts of aggregate, 50 parts of steel slag, 5.5 parts of SBS modified asphalt, 2.5 parts of talcum powder, 0.5 part of ethylhexyl methoxycinnamate, 0.5 part of tocopherol acetate, 0.5 part of octocrylene and 0.5 part of warm-mixing agent.
The fineness of the talcum powder is 1100-1300 meshes, the content of silicon dioxide is 50-70%, and the content of magnesium oxide is 20-40%.
The purity of the ethylhexyl methoxycinnamate is more than 95 percent; the purity of the octocrilene is more than 95 percent.
The preparation method of the open-graded wearing layer asphalt mixture comprises the following steps:
1) heating SBS modified asphalt to a set temperature, adding a warm-mixing agent, and mixing in a mixing pot to obtain SBS modified warm-mixed asphalt a;
2) mixing and uniformly stirring ethylhexyl methoxycinnamate, tocopheryl acetate and octocrylene according to a ratio to obtain a mixed liquid b;
3) keeping the temperature of the asphalt a in the step 1) at a set temperature, adding the mixed solution b according to the formula proportion, and stirring in a stirring pot to obtain modified asphalt c;
4) mixing pulvis Talci, steel slag and the collecting materials uniformly, heating to a specified temperature to obtain a mixture
5) Adding the modified asphalt c obtained in the step 3) into the mixture which is heated to the specified temperature in the step 4) according to the formula proportion, and uniformly stirring to obtain the open-graded wearing layer asphalt mixture.
In the step 1), the set temperature is 125-140 ℃, the mixing speed is 400-700 r/min, and the mixing time is 80-120 s; in the step 2), the stirring speed is 500-700 r/min, and the stirring time is 1-3 min; in the step 3), the temperature is set to be 125-140 ℃, the stirring time is 75-100 s, and the stirring speed is 800-.
In the step 4), the specified temperature is 125-140 ℃; and in the step 5), stirring for 3-5 min.
The invention has the beneficial effects that: 1) according to the invention, ethylhexyl methoxycinnamate, tocopherol acetate and octocrylene are adopted as raw materials to further modify SBS modified asphalt, so that the anti-aging capacity of the asphalt is further improved, and the anti-aging performance of the open-graded wearing layer mixture under the environment and load action is further improved. 2) The steel slag adopted in the invention has higher hardness and good wear resistance, and can improve the recycling efficiency of the steel slag after replacing part of aggregate and simultaneously improve the wear resistance of the open-graded wearing layer mixture. 3) According to the invention, the ethylhexyl methoxycinnamate, the tocopherol acetate and the octocrylene which are oil-soluble can enhance the hydrophobicity of the asphalt, so that the water damage resistance of the asphalt concrete can be improved.
Detailed Description
The preparation method of all the embodiments in the invention comprises the following steps:
1) heating SBS modified asphalt to 130 ℃, adding warm-mixing agent, and stirring in a stirring pot for 100 seconds to obtain SBS modified warm-mixed asphalt a, wherein the stirring speed is 550 r/min;
2) mixing and stirring ethylhexyl methoxycinnamate, tocopheryl acetate and octocrylene uniformly to obtain a mixed liquid b, wherein the stirring time is 2 minutes, and the stirring speed is 600 r/min;
3) keeping the temperature of the asphalt a at 130 ℃, adding the mixed solution b, and stirring in a mixing pot for 85 seconds to obtain modified asphalt c, wherein the stirring speed is 900 r/min;
4) uniformly mixing talcum powder, steel slag and the aggregate, and heating to 130 ℃ to obtain a mixture;
5) and adding the modified asphalt c into a mixture of 130 ℃ talcum powder, steel slag, aggregate and common mineral powder, and stirring for 4 minutes to obtain an open-graded wearing layer asphalt mixture.
In the embodiment, the fineness of the raw material talcum powder is 1100-1300 meshes, the content of silicon dioxide is 50-70%, and the content of magnesium oxide is 20-40%; the purity of the ethylhexyl methoxycinnamate is more than 95 percent; the purity of the octocrilene is more than 95 percent.
The open graded wearing course asphalt mixtures prepared in examples 1 to 4 and comparative example 1 were subjected to the test, and the test results are shown in table 2. Wherein the abrasion resistance is evaluated by the los Angeles abrasion test; the aging performance is that the asphalt is subjected to a rotary film oven heating test for 5 hours, and the penetration, ductility and softening point are tested at the beginning and after 5 hours; the split tensile ratio (TSR) was used to evaluate water damage performance.
Example 1
In this embodiment, the high-performance open-graded wearing layer asphalt mixture comprises the following raw materials in parts by mass: 70 parts of aggregate, 20 parts of steel slag, 5.5 parts of SBS modified asphalt, 3 parts of talcum powder, 0.25 part of ethylhexyl methoxycinnamate, 0.25 part of tocopheryl acetate, 0.5 part of octocrylene and 0.5 part of warm-mixing agent.
Example 2
In this embodiment, the high-performance open-graded wearing layer asphalt mixture comprises the following raw materials in parts by mass: 40 parts of aggregate, 50 parts of steel slag, 5.5 parts of SBS modified asphalt, 3 parts of talcum powder, 0.25 part of ethylhexyl methoxycinnamate, 0.25 part of tocopheryl acetate, 0.5 part of octocrylene and 0.5 part of warm-mixing agent.
Compared with the embodiment 1, the steel slag content in the embodiment 2 is improved by 30 parts, and the aggregate content is reduced by 30 parts.
In examples 1 and 2, it can be seen that when the steel slag content is increased from 20% to 50%, the los angeles abrasion value is reduced from 17% to 14%, which indicates that the steel slag significantly improves the abrasion resistance of the open-graded abrasion layer mixture; the other components are the same, so that the change of the anti-aging performance is not obvious; the TSR is increased from 85.7 percent to 88.4 percent, which shows that the water damage resistance is improved to a certain degree.
Example 3
In this embodiment, the high-performance open-graded wearing layer asphalt mixture comprises the following raw materials in parts by mass: 40 parts of aggregate, 50 parts of steel slag, 5.5 parts of SBS modified asphalt, 2.5 parts of talcum powder, 0.5 part of ethylhexyl methoxycinnamate, 0.5 part of tocopheryl acetate, 0.5 part of octocrylene and 0.5 part of warm-mixing agent.
Compared with example 2, the total amount of ethylhexyl methoxycinnamate, tocopheryl acetate and octocrylene in example 3 is increased by 0.5 parts, and the talc is reduced by 0.5 parts.
The total content of the ethylhexyl methoxycinnamate, the tocopherol acetate and the octocrylene in the example 3 is higher than that in the example 2, the aging performance index in the example 3 is obviously better than that in the example 2, and the aging performance of the asphalt is gradually improved along with the increase of the mixing amount of the ethylhexyl methoxycinnamate, the tocopherol acetate and the octocrylene.
Example 4
In this embodiment, the high-performance open-graded wearing layer asphalt mixture comprises the following raw materials in parts by mass: 70 parts of aggregate, 20 parts of steel slag, 6 parts of SBS modified asphalt, 3 parts of talcum powder, 0.15 part of ethylhexyl methoxycinnamate, 0.15 part of tocopheryl acetate, 0.2 part of octocrylene and 0.5 part of warm-mixing agent.
The total amount of ethylhexyl methoxycinnamate, tocopheryl acetate, and octocrylene was reduced by 0.5 parts in example 4 compared to example 1.
The abrasion resistance and water damage resistance of example 4 were slightly inferior to those of example 1. The asphalt aging resistance in example 4 was significantly inferior to that of example 1, indicating that the asphalt aging performance index was significantly reduced with a decrease in the total amount of ethylhexyl methoxycinnamate, tocopheryl acetate and octocrylene.
Comparative example 1
The open-graded wearing layer asphalt mixture of the comparative example comprises the following raw materials in percentage by mass: 90 parts of aggregate, 6 parts of SBS modified asphalt, 3.5 parts of common mineral powder and 0.5 part of warm mixing agent. The formulation is currently the most common form of bituminous mix formulation.
The preparation method in this comparative example:
1) heating SBS modified asphalt to 130 ℃, adding warm-mixing agent, and stirring in a stirring pot for 100 seconds to obtain SBS modified warm-mixed asphalt a, wherein the stirring speed is 550 r/min;
2) uniformly mixing the aggregate and common mineral powder, and heating to 130 ℃ to obtain a mixture;
3) and adding the modified asphalt a into the mixture at the temperature of 130 ℃, and stirring for 4 minutes to obtain the open-graded wearing layer asphalt mixture.
Compared with the comparative example 1, the abrasion value of the los angeles in the case of the comparative example 1 without the adulterated steel slag is obviously higher in the example 4; from the anti-aging performance, the reduction of penetration and ductility is larger in comparative example 1, and the increase of softening point is larger, which shows that the anti-aging performance of asphalt is improved by the incorporation of ethylhexyl methoxycinnamate, tocopheryl acetate and octocrylene, and further, the split tensile strength is also improved by 4.5% in example 4 compared with that in comparative example 1.
Comparative example 2
The open-graded wearing layer asphalt mixture of the comparative example comprises the following raw materials in percentage by mass: 90 parts of aggregate, 6 parts of SBS modified asphalt, 3.5 parts of talcum powder and 0.5 part of warm mixing agent.
Comparative example 2 the process of comparative example 1 was similar except that the ordinary ore fines were replaced with talc.
Compared with comparative example 1, 3.5 parts of ordinary ore powder was replaced with 3.5 parts of talc powder. No slag, ethylhexyl methoxycinnamate, tocopheryl acetate and octocrylene were included in comparative example 2. As can be seen from comparison of comparative example 2 with the four examples, the abrasion value of los Angeles in comparative example 2 is higher, the anti-aging performance is deteriorated, and the water damage performance is also reduced to a certain extent.
Compared with the comparative example 1, the abrasion resistance, the ageing resistance and the water damage resistance of the comparative example 2 are not obviously different from those of the comparative example 1, and are even improved to a certain extent, so that the talc powder does not bring adverse consequences when replacing the common mineral powder.
TABLE 1 raw material composition table (%)
TABLE 2 wear resistance, aging behavior and Water damage behavior of open-graded wearing course asphalt mixture
Note: "-" represents decrease; "+" indicates an increase.
According to the embodiment, the invention provides the high-performance open-graded wearing layer asphalt mixture and the preparation method thereof. According to the method, the ethylhexyl methoxycinnamate, the tocopherol acetate and the octocrylene are used for modifying the SBS asphalt, so that the anti-aging performance of the asphalt is improved. The steel slag is used for replacing part of aggregate, the wear resistance of the asphalt mixture of the open-graded wearing layer is improved, and the waste resource utilization of the steel slag is realized. The incorporation of ethylhexyl methoxycinnamate, tocopheryl acetate, octocrylene, and steel slag also improved the resistance of asphalt mixtures to water damage.
The specific embodiments described herein are merely illustrative of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.