CN102766339A - Carbon nanotube-styrene block copolymers (CNT-SBS) modified asphalt - Google Patents

Abstract

The CNT-SBS modified asphalt relates to a modified asphalt. The invention solves the problems that the existing CNT-SBS modified asphalt has insignificant effect on improving the ductility and softening point temperature compared with the SBS modified asphalt, and the problem of inaccurate composition ratio. The CNT-SBS modified asphalt of the present invention is made of 95.97% of base asphalt, 4% of linear styrene-butadiene-styrene block copolymer powder and 0.03% of carbon nanotubes according to the mass percentage. Compared with SBS modified asphalt, the CNT-SBS modified asphalt prepared by the present invention has a ductility increased by 31.3%, a softening point increased by 16.9%, and has the advantages of high compression resistance, high crack resistance, good plasticity and low temperature sensitivity , can better adapt to the environmental conditions in areas with large temperature differences, expand the working temperature and area range, and improve the high temperature and compression resistance of asphalt. The invention is suitable for industrialized production of modified asphalt.

Description

CNT-SBS modified asphalt

technical field

The invention relates to a modified asphalt

Background technique

Asphalt is the main pavement material used in road and bridge projects at home and abroad. Modern road traffic is characterized by large traffic flow, fast speed and high load capacity, so the requirements for road surface quality are also constantly increasing. Ordinary asphalt materials generally have the disadvantages of high penetration, low ductility, and low softening point within the engineering range, which are specifically manifested in asphalt compression resistance, poor crack resistance, poor plasticity, high temperature sensitivity, and narrow operating temperature range. Because ordinary asphalt is difficult to meet the requirements of modern road traffic for road surface quality, modified asphalt with better performance than ordinary asphalt has appeared in recent years. Among the existing asphalt modifiers, styrene-butadiene-styrene block copolymer, namely SBS, has become the most used asphalt modifier due to its good performance, so SBS modified asphalt has also become the most commonly used modified asphalt varieties. However, due to the large particle size of SBS itself, it is difficult to achieve uniform dispersion in asphalt, resulting in poor stability of modified asphalt. Published in "Forest Engineering" 2011, No. 27 (5), "Research on Carbon Nanotubes to Improve the Performance of SBS Modified Asphalt", it is disclosed that carbon nanotubes with conjugated π bonds and ring structures, that is, CNTs, are used as Stabilizer, when the addition of SBS is 4%, and the addition of CNT is 0, 0.005%, 0.01%, 0.02%, 0.04% and 0.08%, the ductility (5°C) is 41cm, 43cm, 46cm, 50cm, 52cm respectively and 50cm, the softening points are 77°C, 78°C, 79°C, 79°C, 82°C and 82°C. According to the results, it can be seen that within the range of the CNT addition amount, the degree of improving the ductility and softening point of the modified asphalt is limited, and an accurate and optimal CNT addition amount has not been determined. the

Contents of the invention

The present invention aims to solve the problems that the existing CNT-SBS modified asphalt has no obvious effect on improving ductility and softening point temperature compared with SBS modified asphalt, and the problem of inaccurate composition ratio, and provides a CNT-SBS modified asphalt. SBS modified asphalt. the

The CNT-SBS modified asphalt of the present invention is made of 95.97% matrix asphalt, 4% linear styrene-butadiene-styrene block copolymer powder and 0.03% carbon nanotubes by mass percentage; wherein, matrix asphalt It is No. 110 petroleum asphalt; the fineness of linear styrene-butadiene-styrene block copolymer powder is 60-100 mesh. the

The preparation method of CNT-SBS modified asphalt is achieved through the following steps: 1. First, use a pulverizer to crush the linear styrene-butadiene-styrene block copolymer particles to a powder with a fineness of 60-100 mesh shape to obtain linear SBS powder; 2. uniformly mix the linear SBS powder obtained in step 1 with carbon nanotubes at a mass ratio of 400:3 to obtain a CNT-SBS composite modifier; 3. mix the matrix in an oven Heat the asphalt to 110-130°C, then add the CNT-SBS composite modifier accounting for 4.2% by mass of the base asphalt to the base asphalt, and continue heating the above mixture to 160-180°C in the asphalt enamel cup, and use The asphalt shearing machine cuts at a speed of 3000-5000r/min for 3-10 minutes, and then stirs with a mixer at a speed of 600-900r/min for 2-5 minutes to obtain CNT-SBS modified asphalt. the

The invention adopts the CNT-SBS composite modifier to modify the matrix asphalt, and the addition amount of carbon nanotubes is selected as 0.03%, and the prepared CNT-SBS modified asphalt has achieved unexpected technical effects. The ductility (5°C) of the CNT-SBS modified asphalt prepared by the present invention is 63cm, which is 31.3% higher than that of the SBS modified asphalt without adding CNTs under the same conditions. The ductility (5 ℃) of CNT-SBS modified asphalt reached the maximum value when the temperature was 0.04, which was 52 cm, which was only increased by 26.8% compared with the SBS modified asphalt without adding CNT under the same conditions; the CNT-SBS prepared by the present invention The softening point of the modified asphalt is 83°C, which is 16.9% higher than that of the SBS modified asphalt without adding CNTs under the same conditions. In the published literature, when the addition of CNTs is 0.08, the CNT-SBS modified asphalt has a The softening point reaches a maximum value of 82°C, which is only 6.5% higher than that of the SBS modified asphalt without adding CNTs under the same conditions. Compared with the prior art, the modification effect of the present invention is significantly improved, and the optimized ratio of CNT-SBS modified asphalt is precise, and at the same time, the cost can be greatly saved due to the reduction of CNT consumption. the

The CNT-SBS modified asphalt prepared by the invention complies with national standards, has the advantages of high compression resistance, high crack resistance, good plasticity and low temperature sensitivity, can better adapt to the environmental conditions in areas with large temperature differences, and expands the working temperature And regional scope, improve the high temperature compression resistance of asphalt. the

The invention is suitable for industrialized production of modified asphalt. the

Description of drawings

Figure 1 is a graph showing the change of ductility of modified asphalt with the amount of CNT added;

Fig. 2 is a curve diagram of the softening point of modified asphalt with the amount of CNT added;

Figure 3 is a graph showing the variation of the penetration of modified asphalt with the amount of CNT added. the

Detailed ways

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments. the

Embodiment 1: The CNT-SBS modified asphalt of this embodiment is characterized in that the CNT-SBS modified asphalt is composed of 95.97% base asphalt and 4% linear styrene-butadiene-styrene block by mass percentage The copolymer powder and 0.03% carbon nanotube are made; wherein, the base asphalt is No. 110 petroleum asphalt; the fineness of the linear styrene-butadiene-styrene block copolymer powder is 60-100 mesh. the

The preparation method of CNT-SBS modified asphalt is achieved through the following steps: 1. First, use a pulverizer to crush the linear styrene-butadiene-styrene block copolymer particles to a powder with a fineness of 60-100 mesh shape to obtain linear SBS powder; 2. uniformly mix the linear SBS powder obtained in step 1 with carbon nanotubes at a mass ratio of 400:3 to obtain a CNT-SBS composite modifier; 3. mix the matrix in an oven Heat the asphalt to 110-130°C, then add the CNT-SBS composite modifier accounting for 4.2% by mass of the base asphalt to the base asphalt, and continue heating the above mixture to 160-180°C in the asphalt enamel cup, and use The asphalt shearing machine cuts at a speed of 3000-5000r/min for 3-10 minutes, and then stirs with a mixer at a speed of 600-900r/min for 2-5 minutes to obtain CNT-SBS modified asphalt. the

Specific embodiment two: the difference between this embodiment and specific embodiment one is: in the step 3 of the preparation method of CNT-SBS modified asphalt, cut 5min with the rotating speed of 4000r/min with asphalt shearer, then use mixer to The rotating speed of 800r/min was stirred for 3min, and other steps and parameters were the same as in Embodiment 1. the

Verify beneficial effect of the present invention by following test:

The test is divided into control group and test group, wherein test one is the control group, and tests two to six are the test groups. The modifier in the control group is linear SBS powder, and the modifier in the test group is CNT-SBS composite modifier. the

Test 1: The SBS modified asphalt in this test is achieved through the following steps: First, use a pulverizer to break the linear SBS particles into a powder with a fineness of 60-100 meshes to obtain linear SBS powder; The base asphalt is heated to 120°C, and then the modifier linear SBS powder accounting for 4.17% by mass of the base asphalt is added to the base asphalt, and the above mixture is continuously heated to 180°C in an asphalt enamel cup, and the The machine sheared at a speed of 4000r/min for 5min, and then stirred with a mixer at a speed of 800r/min for 3min to obtain SBS modified asphalt. The base asphalt is No. 110 petroleum asphalt. the

Utilize the ductility meter (model SYD-4508C) to measure the ductility of the CNT-SBS modified asphalt obtained in the test, the specific measurement method is as follows:

1. Take the CNT-SBS modified asphalt sample obtained from the test, heat it to a fluid state, pour the internal test surface into the gap between the side mold and the end mold of the test mold coated with a release agent, and form a ring-shaped asphalt specimen; 2. After cooling at room temperature for 30 minutes, put it in a constant temperature water bath at 5°C for 30 minutes, cut off the asphalt that is higher than the test mold with a hot scraper, make the surface of the asphalt smooth and flush with the test mold, and then immerse the test mold together with the bottom plate in a 5°C water bath Keep it in a constant temperature water bath for 1 hour; 3. Set the tensile speed to 5cm/min; The holes at both ends of the test mold are set on the metal posts of the slide plate and the groove end fixing plate respectively, and the side molds are removed; 5. Start the ductility meter, and when the test piece is broken, read the degree on the scale indicated by the pointer. Among them, if the asphalt filaments are found to float on the water surface or sink to the bottom of the tank during the test, alcohol or salt should be added to the water, and the density of the water should be adjusted to be similar to that of the sample, and then the test should be repeated. the

Utilize the softening point tester (model SYD-2806G) to measure the softening point of the CNT-SBS modified bitumen obtained by the test, and the specific measuring method is as follows:

1. Place the sample ring on the sample bottom plate coated with glycerol talcum powder release agent. According to the method specified in T0602, slowly inject the CNT-SBS modified asphalt sample obtained from the test into the sample ring until it is slightly higher than the ring surface; 2. After the sample is cooled at room temperature for 30 minutes, clamp the sample with a ring clamp Cup, and use a hot scraper to scrape off the sample on the ring surface, so that it is flush with the ring surface; 3. Put the sample ring with the sample and the sample bottom plate in a constant temperature water tank of 5°C water for 15 minutes. Metal brackets, steel balls, steel ball positioning rings, etc. are also placed in the same water tank; 4. Fill the beaker with freshly boiled and cooled distilled water to 5°C, and the water surface is slightly lower than the depth mark on the vertical pole; 5. From the constant temperature water tank Take out the sample ring containing the sample and place it in the round hole of the middle plate of the bracket, put the positioning ring on it, then put the whole ring rack into the beaker, adjust the water level to the depth mark, and keep the water temperature at 5°C, without any bubble. Insert the thermometer vertically from the center hole of the upper plate, and the bottom of the ring is flush; 6. Move the beaker filled with water and the ring frame to the resistance furnace with the asbestos net, and then place the steel ball on the sample in the middle of the positioning ring In the center, start the vibrating stirrer immediately to make the water oscillate slightly, and start heating at a constant heating rate of 5°C/min. After 3 minutes, the heating rate should reach 5°C/min±0.5°C/min; if the temperature rises If the rate exceeds 5°C/min±0.5°C/min, it is judged that the test has failed; 7. When the sample is softened by heat and gradually falls to the surface of the lower bottom plate, read the temperature immediately, accurate to 0.5°C. the

Utilize the penetration of the CNT-SBS modified asphalt that the asphalt penetration tester (model SYD-2801F) measurement test obtains, and concrete measurement method is as follows:

1. Pour the CNT-SBS modified asphalt sample obtained from the test into the sample pan at one time. The height of the sample is 10mm higher than the expected penetration value, and cover the sample pan to prevent dust from falling into it; 2. Put the Cool the sample dish containing the sample at room temperature for 1 hour, then move it into a constant temperature water bath at 25°C for 1 hour; 3. Adjust the penetrometer to make it level, check the needle connecting rod and guide rail to confirm that there is no water and other foreign objects, No visible friction. Clean the standard needle with trichlorethylene and wipe dry. Insert the standard needle into the connecting rod of the needle, tighten it with screws, and add an additional weight of 5g; 4. Take out the sample dish in the constant temperature water tank at 25°C, and move it into the tripod stand in the flat bottom glass dish with the water temperature at 25°C , the depth of the water layer above the surface of the sample is not less than 10mm; 5. Place the flat-bottomed glass dish containing the sample on the platform of the automatic penetrometer, slowly lower the needle connecting rod, and use a reflector at an appropriate position or Light reflection observation, so that the needle tip is just in contact with the surface of the sample; 6. Pull down the pull rod of the dial to make it lightly touch the top of the needle connecting rod, and adjust the pointer of the dial or depth indicator to zero; 7. Press Press the button, the timing will start at the same time as the standard needle falls into the sample, and it will stop automatically at 5s, pull down the dial pull rod to contact the top of the needle connecting rod, and read the reading of the dial pointer or displacement indicator, accurate to 0.1mm. Among them, in the penetration measurement test, the same sample is tested in parallel three times, and the distance between each test point and the edge of the sample dish is not less than 10mm; after each test, the flat-bottomed glass dish containing the sample dish should be removed Put it into a constant temperature water tank to keep the water temperature in the flat-bottomed glass dish at the test temperature; for each test, a clean standard needle should be replaced or the standard needle should be removed and wiped clean with cotton or cloth dipped in trichlorethylene solvent, and then wiped with dry cotton or cloth Wipe dry; when the difference between the maximum value and the minimum value of the 3 parallel test results of the same sample is within the following allowable deviation range, calculate the average value of the 3 test results, take 0.1mm as the unit, and take the integer as the penetration test result ; Among them, the penetration rate is 0~49, 50~149, 150~49, 250~500. When the test value does not meet this requirement, it should be repeated. the

The ductility (25°C) of the SBS modified asphalt obtained in Test 1 was 48cm, the softening point was 71°C, and the penetration (25°C, 0.1mm) was 68.5. the

Test 2: The CNT-SBS modified asphalt in this test is achieved through the following steps: First, use a pulverizer to crush the linear SBS particles into a powder with a fineness of 60-100 meshes to obtain a linear SBS powder; Mix the linear SBS powder and CNT obtained in step 1 with a mass ratio of 200:1 in a glass grinding bottle to obtain a CNT-SBS composite modifier; in an oven, the base asphalt is heated to 120 ° C, and then The CNT-SBS composite modifier accounting for 4.19% of the mass percentage of the base asphalt is added to the base asphalt, and the above mixture is heated to 180°C in the asphalt enamel cup, and the asphalt shearing machine is used to cut at a speed of 4000r/min 5min, and then stirred with a mixer at a speed of 800r/min for 3min to obtain SBS modified asphalt. The base asphalt is No. 110 petroleum asphalt. the

Measure the ductility, softening point and penetration of the CNT-SBS modified asphalt obtained in Test 2, and the specific measurement method is the same as Test 1. the

The ductility (25°C) of the CNT-SBS modified asphalt obtained in the second test was 53cm, the softening point was 78°C, and the penetration (25°C, 0.1mm) was 69. the

Test 3: The CNT-SBS modified asphalt in this test is achieved through the following steps: First, use a pulverizer to crush the linear SBS particles into a powder with a fineness of 60-100 meshes to obtain a linear SBS powder; Mix the linear SBS powder and CNT obtained in step 1 with a mass ratio of 400:3 in a glass grinding bottle to obtain a CNT-SBS composite modifier; in an oven, the base asphalt is heated to 120 ° C, and then The CNT-SBS composite modifier accounting for 4.20% of the mass percentage of the base asphalt is added to the base asphalt, and the above mixture is heated to 180°C in the asphalt enamel cup, and the asphalt shearing machine is used to cut at a speed of 4000r/min 5min, and then stirred with a mixer at a speed of 800r/min for 3min to obtain SBS modified asphalt. The base asphalt is No. 110 petroleum asphalt. the

Measure the ductility, softening point and penetration of the CNT-SBS modified asphalt obtained in Test 3, and the specific measurement method is the same as Test 1. the

The ductility (25°C) of the CNT-SBS modified asphalt obtained in Test 3 was 63cm, the softening point was 83°C, and the penetration (25°C, 0.1mm) was 70. the

Test 4: The CNT-SBS modified asphalt in this test is achieved through the following steps: First, use a pulverizer to crush the linear SBS particles into a powder with a fineness of 60-100 meshes to obtain a linear SBS powder; The linear SBS powder obtained in step 1 and CNT are uniformly mixed with a mass ratio of 100:1 in a glass grinding bottle to obtain a CNT-SBS composite modifier; the matrix pitch is heated to 120 ° C in an oven, and then The CNT-SBS composite modifier accounting for 4.21% of the mass percentage of the base asphalt was added to the base asphalt, and the above mixture was heated to 180°C in the asphalt enamel cup, and the asphalt shear was cut at a speed of 4000r/min. 5min, and then stirred with a mixer at a speed of 800r/min for 3min to obtain SBS modified asphalt. The base asphalt is No. 110 petroleum asphalt. the

Measure the ductility, softening point and penetration of the CNT-SBS modified asphalt obtained in Test 4, and the specific measurement method is the same as Test 1. the

The ductility (25°C) of the CNT-SBS modified asphalt obtained in Test 4 was 57cm, the softening point was 83°C, and the penetration (25°C, 0.1mm) was 73.5. the

Test 5: The CNT-SBS modified asphalt in this test is realized through the following steps: First, use a pulverizer to crush the linear SBS particles into a powder with a fineness of 60-100 meshes to obtain a linear SBS powder; Mix the linear SBS powder and CNT obtained in step 1 with a mass ratio of 80:1 in a glass grinding bottle to obtain a CNT-SBS composite modifier; in an oven, the base asphalt is heated to 120 ° C, and then The CNT-SBS composite modifier accounting for 4.22% of the mass percentage of the base asphalt is added to the base asphalt, and the above mixture is heated to 180°C in the asphalt enamel cup, and the asphalt shearing machine is used to cut at a speed of 4000r/min 5min, and then stirred with a mixer at a speed of 800r/min for 3min to obtain SBS modified asphalt. The base asphalt is No. 110 petroleum asphalt. the

Measure the ductility, softening point and penetration of the CNT-SBS modified asphalt obtained in Test 5, and the specific measurement method is the same as Test 1. the

The ductility (25°C) of the CNT-SBS modified asphalt obtained in Test 5 was 58cm, the softening point was 81°C, and the penetration (25°C, 0.1mm) was 76. the

Test 6: The CNT-SBS modified asphalt in this test is achieved through the following steps: First, use a pulverizer to crush the linear SBS particles into a powder with a fineness of 60-100 meshes to obtain a linear SBS powder; The linear SBS powder and CNT obtained in step 1 are uniformly mixed with a mass ratio of 200:3 in a glass grinding bottle to obtain a CNT-SBS composite modifier; the matrix pitch is heated to 120°C in an oven, and then The CNT-SBS composite modifier accounting for 4.23% of the mass percentage of the base asphalt is added to the base asphalt, and the above mixture is heated to 180°C in the asphalt enamel cup, and the asphalt shearing machine is used to cut at a speed of 4000r/min 5min, and then stirred with a mixer at a speed of 800r/min for 3min to obtain SBS modified asphalt. The base asphalt is No. 110 petroleum asphalt. the

Measure the ductility, softening point and penetration of the CNT-SBS modified asphalt obtained in Test 6. The specific determination method is the same as Test 1. the

The ductility (25°C) of the CNT-SBS modified asphalt obtained in Test 6 was 62cm, the softening point was 62°C, and the penetration (25°C, 0.1mm) was 75. the

Based on the above tests, the ductility, softening point and penetration of modified asphalt measured in tests 1 to 6 were compared, and the results are shown in Table 1. According to Table 1, draw the change curve of modified asphalt ductility with the amount of CNT added, as shown in Figure 1; draw the change curve of modified asphalt softening point with the amount of CNT added, as shown in Figure 2; draw the modified asphalt penetration with CNT The curve diagram of the amount of addition is shown in Figure 3. From Fig. 1, Fig. 2 and Fig. 3, it can be concluded that when the amount of CNT added is 0.03%, various indicators are considered comprehensively, and the performance of the obtained CNT-SBS modified asphalt reaches the optimal value. the

Table 1

Claims (2)

1. CNT-SBS modified asphalt is characterized in that CNT-SBS modified asphalt is made up of 95.97% base asphalt, 4% linear styrene-butadiene-styrene block copolymer powder and 0.03% by mass percentage Made of carbon nanotubes; wherein, the base asphalt is No. 110 petroleum asphalt; the fineness of linear styrene-butadiene-styrene block copolymer powder is 60 to 100 mesh; the preparation method of CNT-SBS modified asphalt is It is achieved through the following steps: 1. First, use a pulverizer to crush the linear styrene-butadiene-styrene block copolymer particles into a powder with a fineness of 60 to 100 meshes to obtain a linear SBS powder; 2. The linear SBS powder obtained in step 1 is uniformly mixed with carbon nanotubes at a mass ratio of 400:3 to obtain a CNT-SBS composite modifier; 3. Heat the base pitch to 110-130° C. in an oven, and then The CNT-SBS composite modifier accounting for 4.2% of the mass percentage of the base asphalt is added to the base asphalt. In the asphalt enamel cup, continue to heat the above mixture to 160-180°C, and use an asphalt shearing machine at 3000-5000r/min The speed of shearing is 3-10 minutes, and then the mixer is stirred at a speed of 600-900r/min for 2-5 minutes to obtain CNT-SBS modified asphalt. 2. CNT-SBS modified asphalt according to claim 1, is characterized in that in the step 3 of the preparation method of CNT-SBS modified asphalt, shears 5min with the rotating speed of 4000r/min with asphalt shearing machine, then uses The mixer was stirred at a speed of 800r/min for 3min.

Images