JP7595853B2 - Porous Asphalt Paving Mixture - Google Patents

Description

Patent Law Article 30, paragraph 2 applies 1) Presentation at a meeting [Date held] February 22, 2018 [Name of meeting, location] PM Study Group Pavement Subcommittee Meeting, Tsuru Gakuen Hiroshima Institute of Technology [Discloser] Yonekura Asia [Disclosed invention] In a presentation on porous asphalt pavement, it was announced that a carbide-added porous asphalt mixture to which waste carbon black has been added has improved performance compared to conventional methods. 2) Presentation at an explanatory meeting [Date held] February 28, 2018 [Name of meeting, location] Environmental business overseas expansion report meeting hosted by the Overseas Business Division of the Hiroshima Prefectural Bureau of Commerce, Industry and Labor, Rihga Royal Hotel Hiroshima [Discloser] Yonekura Asia [Disclosed invention] At an explanatory meeting aimed at expanding business into Indonesia, it was explained to Indonesians that a carbide-added porous asphalt mixture to which waste carbon black has been added has improved performance compared to conventional methods.

The present invention relates to a porous asphalt pavement mixture using polymer-modified asphalt and carbon black, which is used for pavements with water permeability.

As an invention of a porous asphalt pavement mixture using polymer-modified asphalt H type, Patent Document 1 discloses a recycled porous asphalt pavement mixture using recycled aggregate produced by demolishing an existing asphalt pavement consisting of an asphalt mixture composed of aggregate, filler, and asphalt-based binder, and implementing a washing process for washing and removing fine particles from granular asphalt waste material obtained by demolishing the existing asphalt pavement, and a grinding process for removing the asphalt adhering to the washed asphalt waste material. It also publishes the results of a Candabro test on recycled porous asphalt using polymer-modified asphalt H type.

JP 2008-208606 A

Normal asphalt pavement, dense-graded asphalt pavement, has a void ratio of 3-5%, so as shown in Figure 2, when there is rainfall 4, rainwater flows over the surface of the dense-graded asphalt pavement 2 as rainwater pavement surface flow 5b, causing the problem of water accumulating on the road pavement surface. To drain the road pavement surface, porous asphalt pavement 1 is an asphalt pavement with a void ratio of about 20%, increasing the number of voids in the asphalt pavement and improving the permeability so that rainfall 4 can drip through the voids in the asphalt within the pavement. In the case of porous asphalt pavement 1, as shown in Figure 1, rainfall 4 permeates through the asphalt pavement as shown in the rainwater infiltration flow 5a, flows over the impermeable layer 3, and flows into the drainage ditch.

The invention of Patent Document 1 states that the results of the Cantabro test, which evaluates the wear and resistance to aggregate scattering of recycled porous asphalt (polymer modified H type), are 8.0 to 11.4% compared to a standard loss rate of 20% in Table 19 of Patent Document 1. However, even if the standard loss rate of 20% is cleared, porous asphalt pavement is prone to aggregate scattering over many years of use due to its high void ratio, and its lifespan is only 60 to 70% compared to dense-graded asphalt pavement. For example, while normal asphalt pavement is repaired after about 12 years, porous asphalt pavement, as shown in Figure 4, has a problem in that the performance of the pavement decreases in about 9 years and no longer meets the required performance of asphalt pavement, and the surface layer must be repaired.

The current Cantabro test, which evaluates abrasion and aggregate scattering resistance, involves placing one specimen in the drum of a Los Angeles testing machine, rotating the drum 300 times without using steel balls, and then measuring the weight loss of the specimen to determine the amount of loss. It is usually performed at room temperature in a dry state, but it can also be performed at low temperatures or using specimens that have been immersed in water. This test does not stipulate that specimens be tested after exposure to ultraviolet light.

In addition, waste carbon black that falls onto the floor during the carbon black manufacturing process is collected by a dust collector, including the surrounding area, and is collected together with moisture and dust that has fallen onto the floor. This waste carbon black does not meet the shipping quality standards for carbon black and cannot be shipped, so it is incinerated, creating the problem of being discarded and not recycled.

In addition, because waste carbon black contains some moisture, there are problems with the risk of a steam explosion occurring during the process of mixing the moisture-containing waste carbon black with aggregate and stone powder heated to about 180°C in the production of asphalt mixtures; the ultrafine particles of waste carbon black form agglomerates, preventing the mixture from being mixed uniformly, making the quality of the mixture unstable; and the adhesive strength between the asphalt and aggregate that contains moisture-containing waste carbon black decreases. As a result, there are problems with waste carbon black that contains moisture and cannot be shipped as a product.

In addition, there was a problem in that the dry distillation charcoal containing moisture was predicted to pose a risk of steam explosion during the process of mixing aggregate and stone powder heated to approximately 180°C with waste carbon black containing moisture in the production of asphalt paving mixture.

The present invention was devised in light of these problems, and its objective is to provide a porous asphalt pavement mixture for road pavement that increases the porosity of the pavement, allowing rainwater to easily permeate, while preventing aggregate scattering.

The inventors noticed that the differences between dense-graded asphalt pavement mixtures using straight asphalt and porous asphalt pavement mixtures using polymer-modified asphalt H-type are that the void ratio is about 4 to 6 times larger, and that polymer-modified asphalt H-type adds polymers such as resin to straight asphalt. In addition, the inventors noticed that in the case of porous asphalt pavement mixtures 20 that do not contain carbon black (CB) as shown in Figure 3(a), the polymer-modified asphalt H-type 40a covers aggregates 30 such as gravel at the time of construction, but over the years, the polymer-modified asphalt H-type 40a deteriorates and the aggregates 30 become exposed as shown in Figure 3(b).

Carbon black also includes new carbon black, which is fine carbon particles with a diameter of about 3 to 500 nm that are manufactured under industrial quality control; waste carbon black, which is collected from carbon black that has fallen to the floor during the carbon black manufacturing process or during bagging work, or carbon black that has accumulated within the process; carbonized waste rubber; carbonized waste tire; and water-containing carbonized waste tire carbonized waste that has been passed through water when carbonized waste tire carbonized waste is separated into radial tire steel and carbonized waste tire.

Note that waste carbon black includes waste carbon black that does not contain moisture and waste carbon black that contains moisture, and waste rubber carbonized carbon does not contain moisture.

The porous asphalt pavement mixture according to claim 1 comprises polymer-modified asphalt H type, waste carbon black having a composition of 88.9 to 96.1% by weight of carbon black, 0.3 to 6% by weight of moisture, and 0.1 to 2.1% by weight of impurities such as dust and fine particles. It is characterized in that it is composed of a mixture of crushed stone , crushed sand, and stone powder.

The porous asphalt pavement mixture according to claim 2 is characterized in that the waste carbon black in claim 1 has a composition of 88.9 to 96.1% by weight of carbon black, 0.3 to 6% by weight of moisture, and 0.1 to 2.1% by weight of impurities such as dust and fine particles. The amount of the waste carbon black added to the porous asphalt pavement mixture is 0.01 to 10% by weight.

The inventors thought that while the current Cantabro test to evaluate wear and aggregate scattering resistance is performed without exposure to ultraviolet light, as asphalt pavement is exposed to ultraviolet light from sunlight, it would also be necessary to perform a Candabro test on the specimens after exposure to ultraviolet light. They decided to perform a Candabro test on the specimens after exposure to ultraviolet light, and for the ultraviolet light exposure, they used a weather resistance test device (Model Metal Weather KU-R5, manufactured by Daipla Wintes Co., Ltd.) and exposed the specimens to ultraviolet light under conditions of illuminance 75 mV/cm2, temperature 60°C, time 40 days, and filter KF-1 (for visible light and ultraviolet light), which is equivalent to 20 years of sunlight in Japan.

The Cantabro test is conducted without exposure to UV light, and the standard is a loss rate of 20% or less. When the Cantabro test was conducted on specimens that were not exposed to UV light and those that were exposed to UV light, as shown in Table 8, in the case of polymer modified asphalt type II, the specimen that had a loss rate of 19.6% without UV light exposure had a loss rate of 42.5% after UV light exposure, which did not meet the standard loss rate, and the specimen that had a loss rate of 15.2% without UV light exposure had a loss rate of 26.8% after UV light exposure, which did not meet the standard loss rate. This is consistent with the reality that aggregate scattering from porous asphalt pavement increases with long-term use.

In contrast, in the case of the polymer modified asphalt H type of the present invention, as shown in Table 8, when waste carbon black was not added, the test specimen with a loss rate of 7.8% without UV exposure had a loss rate of 19.3% after UV exposure, which barely cleared the standard loss rate, but when waste carbon black was added, the test specimen with a loss rate of 6.7% without UV exposure had a loss rate of 10.3% after UV exposure, which was a significant effect that far exceeded the standard loss rate. This shows that even if the test specimen without UV exposure clears the standard loss rate of 20% in the Cantabro test, wear increases due to UV exposure and aggregate scattering resistance deteriorates. Considering the fact that aggregate scattering in actual porous asphalt pavement is greater than in dense-graded asphalt pavement, it was shown that a Cantabro test of the test specimen after UV exposure is necessary.

In addition, there is a remarkable effect that the waste carbon black or the dry-distilled carbonized material containing moisture can be recycled, and when the waste carbon black is incinerated for disposal, a large amount of _CO2 is discharged into the atmosphere, but this can be prevented, which has the effect of preventing global warming.

There was concern that a large amount of dust would be generated when carbon black was mixed with aggregate heated to 180°C and stone powder and then dry-mixed in a mixer, but in the case of waste carbon black or dry-distilled charcoal containing moisture, there was a remarkable effect in that no dust was generated. Because waste carbon black or dry-distilled charcoal containing moisture contains moisture, it is believed that this moisture suppresses the generation of dust. This makes it possible to create a safe and healthy environment where no dust-related accidents occur.

Furthermore, no steam explosion occurred. This is believed to be because the moisture contained in the waste carbon black or the dry-distilled carbide containing moisture was dispersed when the waste carbon black or the dry-distilled carbide containing moisture was put into a mixer together with aggregate and stone powder heated to 180°C and mixed dry.

Furthermore, new carbon black costs more than 300,000 yen per ton, so waste carbon black is cheaper in comparison because it is reused from waste materials that had been disposed of. Also, the amount of cheap waste carbon black added can be within the range of 0.01-10%, so it is even cheaper than expensive carbon black.

Conventional porous asphalt road pavements have high porosity and therefore have water permeability, but their lifespan is only 60-70% of that of dense-graded asphalt road pavements. However, the porous asphalt road pavement of the present invention has the remarkable effect of being water permeable and having a lifespan equal to or greater than that of dense-graded asphalt road pavements even when exposed to ultraviolet light.

FIG. 2 is a cross-sectional view illustrating the infiltration and flow of rainwater through a porous asphalt pavement. FIG. 2 is a cross-sectional view illustrating the flow of rainwater over the surface of a dense-graded asphalt pavement. FIG. 1 is an explanatory diagram of the deterioration state of the polymer-containing asphalt covering the aggregate in the surface layer of the porous asphalt pavement mixture, in which (a) is an explanatory diagram showing the state in which the polymer-containing asphalt (polymer-modified asphalt H type) covers the aggregate surface at the start of construction, (b) is an explanatory diagram showing the state in which the polymer-modified asphalt H type peels off from the surface of the surface aggregate in the case of a porous asphalt pavement mixture using a conventional polymer-modified asphalt H type without carbon black (CB) several years later, and the state in which the surface aggregate is scattered, and (c) is an explanatory diagram showing the state in which the polymer-modified asphalt H type still remains on the surface of the surface aggregate and covers the aggregate surface in the case of a porous asphalt pavement mixture using the polymer-modified asphalt H type containing carbon black (CB) of the present invention several years later. FIG. 1 is an explanatory diagram comparing the asphalt of a porous asphalt pavement mixture in the case of a polymer-modified asphalt H-type that does not contain carbon black (CB) with that in the case of a polymer-modified asphalt H-type that contains CB of the present invention, in which (a) is an explanatory diagram showing the relationship between performance deterioration, repair implementation, and number of years that have passed, and (b) is an explanatory diagram showing the relationship between construction and repair costs and number of years that have passed, and shows the difference in life cycle costs after 20 years.

Regarding the composition of the carbon black of the present invention, the composition of the waste carbon black is 88.9-96.1% carbon black, 0.3-11.0% moisture, and 0.1-2.1% impurities such as dust and fine particles, the composition of the carbonized waste rubber is about 70% carbon black and about 30% lime-based impurities, the composition of the carbonized waste tire containing moisture is 75-85% carbon black, about 15% impurities, and 5-10% moisture, the composition of the carbonized waste tire is about 85% carbon black and about 15% impurities, and the composition of the new carbon black is 100% carbon black.

The porous asphalt pavement mixture of the present invention contains either new carbon black, waste carbon black, waste rubber carbonized carbonized waste tire carbonized carbonized waste tire carbonized carbonized water-containing waste tire, and polymer-modified asphalt type H.

The amount of carbon black added to the porous asphalt pavement mixture is 0.01 to 10%. It is preferably 0.1% to 5%. It is more preferably 0.1% to 3%, and even more preferably 0.1% to 0.5%. When the amount added is up to 5%, the brittleness of the porous asphalt pavement mixture is not noticeable, but when the amount added exceeds 10%, the porous asphalt pavement mixture becomes brittle.

An example of the blending ratio of the porous asphalt pavement mixture (c-d) of the present invention and the blending ratios of the comparative examples (a, b) are shown in Table 1. In Table 1, specimens a and b are polymer-modified asphalt type II used for indoor tests and full-scale plant tests, specimen c is polymer-modified asphalt type H used for indoor tests and full-scale plant tests, specimen d is polymer-modified asphalt type H used for full-scale plant tests, and specimen e is polymer-modified asphalt type H used for indoor tests.

As can be seen from Table 1, the porous asphalt pavement mixture of the present invention contains polymer modified asphalt type H, waste carbon black, No. 6 crushed stone, crushed sand, and stone powder. Horn Health was used for the No. 6 crushed stone and crushed sand, and limestone powder was used for the stone powder.

First, quality tests were conducted on the asphalt pavement mixture in laboratory tests. Specifically, a Cantabro test was conducted to evaluate the aggregate scattering resistance of the asphalt pavement mixture, a wheel tracking test that has a good correlation with actual road rutting, and a Marshall stability test was conducted to evaluate the maximum load and deformation amount when the asphalt pavement mixture breaks under load.

In the Cantablo test, a sample of porous asphalt pavement mixture was placed in a Los Angeles tester at room temperature, the drum was rotated 300 times without using steel balls, and the amount of loss of the sample after the test was measured. The Cantablo test results were performed on the porous asphalt pavement mixture of the present invention using polymer modified asphalt H type and the comparative example of porous asphalt pavement mixture using polymer modified asphalt II type, with different moisture contents relative to the waste carbon black. The results of the laboratory test are shown in Table 2.

As can be seen from Table 2, in the case of porous asphalt pavement mixtures using polymer modified asphalt type II, the cantabro loss rate was 10.8% to 13.5%, and the cantabro loss rate increased as the moisture content of the waste carbon black increased, but all were significantly below the standard value of 20% for the cantabro loss rate.

In addition, in the case of a porous asphalt pavement mixture using polymer modified asphalt type H, the moisture content of the waste carbon black was 0%, but the cantabro loss rate was 6.3%, while the cantabro loss rate of a porous asphalt pavement mixture using polymer modified asphalt type II, which has a moisture content of 0% for the waste carbon black, was 10.8%. This shows that the cantabro loss rate is reduced by about half when polymer modified asphalt type H is used compared to when polymer modified asphalt type II is used.

In addition, when looking at polymer modified asphalt type II, the quality of the porous asphalt pavement mixture to which waste carbon black with a moisture content of 6% was added was almost the same as that with a moisture content of 0%, and no deterioration in quality due to moisture was observed.

Next, in the wheel tracking test, a small iron wheel (diameter 20 cm, width 5 cm, ground pressure 6.4 kg/ ^cm2 ) loaded on a specimen of a specified size (30 x 30 x 5 cm) of porous asphalt pavement mixture was repeatedly run back and forth at a specified temperature (60 ° C), a specified time, and a specified speed (21 round trips/min for a distance of 23 cm), and the dynamic stability (rounds/mm) was calculated from the deformation per unit time (rutting). The wheel tracking test, which measures rutting and indicates dynamic stability, was compared with polymer modified asphalt type II and polymer modified asphalt type H to confirm the difference in the effect of adding waste carbon black (WCB). The results of the laboratory test are shown in Table 3.

As can be seen from Table 3, the dynamic stability (DS value) of polymer modified asphalt type II was 5,730 times/mm to 6,300 times/mm, which was significantly higher than the standard value of 3,000 times/mm and was good. The dynamic stability (DS value) of polymer modified asphalt type H was 15,750 times/mm, despite the small amount of waste carbon black (WCB) added of 1%, which is about three times higher than that of polymer modified asphalt type II, indicating a significant improvement in dynamic stability (DS value) performance. In other words, it was shown that rutting hardly occurs even after long-term use.

In addition, when looking at polymer modified asphalt type II, the quality of the porous asphalt pavement mixture to which waste carbon black with a moisture content of 6% was added was almost the same as that with a moisture content of 0%, and no deterioration in quality due to moisture was observed.

Next, in the Marshall stability test, the sides of a cylindrical specimen of porous asphalt pavement mixture (diameter 101.6 mm, thickness 63.5 mm) were clamped between two arc-shaped loading heads, and a load was applied in the diameter direction at a specified temperature (60°C) and a specified loading rate (50 mm per minute). The maximum load (stability kN) that the cylindrical specimen showed before breaking and the corresponding deformation amount (flow value 1/100 cm) were measured. A Marshall stability test was conducted to compare polymer modified asphalt type II and polymer modified asphalt type H to confirm the difference in the effect of adding waste carbon black (WC). The results of the laboratory test are shown in Table 4.

Table 4 shows that polymer modified asphalt type H, which contains 1% waste carbon black, has slightly higher stability and residual stability values than polymer modified asphalt type II, which contains 3% waste carbon black, and therefore has higher performance.

In addition, when looking at polymer modified asphalt type II, the quality of the porous asphalt pavement mixture to which waste carbon black with a moisture content of 6% was added was almost the same as that with a moisture content of 0%, and no deterioration in quality due to moisture was observed.

The results of the above indoor tests, the Cantabro test, the wheel tracking test and the Marshall stability test, showed that, first, porous asphalt pavement mixtures containing waste carbon black are effective for asphalt pavement, second, when polymer modified asphalt H type is used, the performance of the porous asphalt pavement mixture can be improved even if the amount of waste carbon black added is significantly reduced, and third, the quality of the porous asphalt pavement mixture to which waste carbon black with a moisture content of 6% was added was almost the same as that with a moisture content of 0%, and no deterioration in quality due to moisture was observed.

Next, a porous asphalt pavement mixture was produced in an actual plant, and the produced porous asphalt pavement mixture was used as a test specimen to carry out a Cantabro test, a Marshall stability test, and a wheel tracking test. During the porous asphalt pavement mixture production process in an actual plant, even when a porous asphalt pavement mixture to which waste carbon black containing 6% moisture had been added was mixed in a mixer in the actual plant, there was almost no dust being thrown up, and no risk of a steam explosion was observed.

First, a wheel tracking test was conducted on the porous asphalt pavement mixture produced in the actual plant, and the results are shown in Table 5.

Table 5 shows that the dynamic stability of polymer-modified asphalt type II increased from 2,100 times/mm to 4,200 times/mm by adding 3% waste carbon black, and that of polymer-modified asphalt type H increased from 7,000 times/mm to 9,000 times/mm, approximately 1.3 to 2 times. It was also shown that the dynamic stability of polymer-modified asphalt type H (9,000 times/mm) with 0.5% waste carbon black added was approximately 2.1 times higher than that of polymer-modified asphalt type II (4,200 times/mm) with 3% waste carbon black added. Polymer-modified asphalt type H with 0.5% waste carbon black added had a dynamic stability of 9,000 times, which is enough to create a 1 mm rut, and the coefficient of variation, which evaluates the variation, showed almost no change, indicating that a porous asphalt pavement mixture with extremely high dynamic stability can be produced.

Next, Marshall stability tests were conducted on the porous asphalt pavement mixture produced in the actual plant, and the results are shown in Table 6.

As can be seen from Table 6, when comparing at 0% waste carbon black content, the stability of Polymer Modified Asphalt Type II is 4.68 kN compared to Polymer Modified Asphalt Type H at 6.42 kN, which is greater, and the residual stability of Polymer Modified Asphalt Type II is 90.4% compared to Polymer Modified Asphalt Type H at 92.4%, which is greater. This shows that without the addition of waste carbon black, Polymer Modified Asphalt Type H has slightly higher performance in both stability and residual stability than Polymer Modified Asphalt Type II.

In addition, when looking at the effect of adding waste carbon black in terms of stability, for polymer modified asphalt type II, the strength increased from 4.68 kN with 0% waste carbon black to 6.05 kN with the addition of 3% waste carbon black, and for polymer modified asphalt type H, the strength increased slightly from 6.42 kN with 0% waste carbon black to 6.79 kN with the addition of 0.5% waste carbon black, indicating that adding waste carbon black increases stability.

Regarding residual stability, for polymer modified asphalt type II, the 90.4% with 0% waste carbon black was reduced to 82.5% with the addition of 3% waste carbon black, and for polymer modified asphalt type H, the 92.4% with 0% waste carbon black was reduced slightly to 90.1% with the addition of 0.5% waste carbon black. In the case of polymer modified asphalt type H, the reduction was slight and the standard value was far cleared, so there is no problem.

Next, a Cantablo test was conducted on the porous asphalt pavement mixture produced in the actual plant, and the results are shown in Table 7.

From Table 7, in the case of polymer modified asphalt type II, which contains 3% of waste carbon black, the Cantabro loss rate is reduced from 19.6% without waste carbon black to 15.2%, and in the case of polymer modified asphalt type H, which contains 0.5% of waste carbon black, the Cantabro loss rate is reduced from 7.8% without waste carbon black to 6.7%. It is also shown that the Cantabro loss rate is extremely small at 6.7%, even though only 0.5% of waste carbon black is added to polymer modified asphalt type H.

Next, a Candabro test was conducted on the porous asphalt pavement mixture produced in the actual plant after exposure to ultraviolet light, since roads are always exposed to sunlight. A Candabro test was conducted on the porous asphalt pavement mixture of the present invention using polymer modified asphalt H type and the comparative example of the porous asphalt pavement mixture using polymer modified asphalt II type, with the waste carbon black having a moisture content of 6%. The results are shown in Table 8.

The Cantabro test shown in Table 8 shows the results after a weather resistance test in which the material was exposed to UV rays for 40 days. The amount of UV rays from this 40-day continuous exposure is equivalent to the amount of UV rays that an actual road would be exposed to from sunlight for 20 years.

Table 8 shows that the Cantabro loss rate increases for all test specimens when exposed to UV light. For example, the Cantabro loss rate when polymer modified asphalt type II is used without adding waste carbon black is 19.6%, but increases to 42.5% after exposure to UV light.

The Cantabro loss rate is smaller when polymer modified asphalt H type is used than when polymer modified asphalt II type is used. Also, when comparing cases where no waste carbon black (WCB) is included, the Cantabro loss rate is 19.6% when polymer modified asphalt II type is used, while the Cantabro loss rate is 7.8% when polymer modified asphalt H type is used, which is about one-third of the 19.6%.

In addition, when the effect of waste carbon black (WCB) was confirmed, the cantabro loss rate when polymer modified asphalt type II was used was 19.6% without UV exposure when no waste carbon black was added, but 42.5% after UV exposure, a change of 22.9%, and when 3% waste carbon black was added, the cantabro loss rate was 15.2% without UV exposure, but 26.8% after UV exposure, a change of 11.6%. In addition, when polymer modified asphalt type H was used, the cantabro loss rate was 7.8% without UV exposure when no waste carbon black was added, but 19.3% after UV exposure, a change of 11.5%, and when 0.5% waste carbon black was added, the cantabro loss rate was 6.7% without UV exposure, but 10.3% after UV exposure, a change of 3.6%, a remarkable effect.

In addition, when the effect of waste carbon black was confirmed by the cantabro loss rate after exposure to ultraviolet light, the cantabro loss rate when polymer modified asphalt type II was used was 42.5% without the addition of waste carbon black, decreasing to 26.8% with the addition of 3% waste carbon black, and the cantabro loss rate when polymer modified asphalt type H was used was 19.3% without the addition of waste carbon black, decreasing to 10.3% with the addition of 0.5% waste carbon black.

In addition, it has been shown that the cantabro loss rate after exposure to ultraviolet light for polymer modified asphalt type II, which contains 3% added waste carbon black, is 26.8%, while the cantabro loss rate after exposure to ultraviolet light for polymer modified asphalt type H, which contains only 0.5% added waste carbon black, is extremely small at 10.3%.

In addition, the results of the Cantabro test after exposure to ultraviolet light when 0.5% waste carbon black (WCB) was added to polymer modified asphalt type H showed that the Cantabro loss rate was reduced to 10.3%, which is smaller than the Cantabro loss rate (26.8%) when 3% waste carbon black (WCB) was added to polymer modified asphalt type II. This shows that the UV degradation prevention effect of adding waste carbon black (WCB) is greater for polymer modified asphalt type H than for polymer modified asphalt type II.

The above-mentioned laboratory tests and actual plant tests showed that the quality of the porous asphalt pavement mixture to which waste carbon black with a moisture content of 6% was added did not decrease due to moisture content, compared to the porous asphalt pavement mixture with a moisture content of 0%. It was also shown that polymer modified asphalt type H produced higher quality than polymer modified asphalt type II.

As a result of the above, it is expected that the porous asphalt pavement mixture 10 using the polymer-modified asphalt 40b containing carbon black (CB) of the present invention will have the aggregate 30 firmly covered with the polymer-modified asphalt 40b even after about 20 years, as shown in Figures 3(c) and 4(a).

As a result, as shown in FIG. 4(a), when the asphalt of the porous asphalt pavement mixture 20 is polymer-modified asphalt H type 40a that does not contain carbon black (CB), repairs are required twice every 20 years, whereas when the asphalt of the porous asphalt pavement mixture 10 of the present invention is polymer-modified asphalt H type 4b that contains CB, the asphalt 40b will not peel off for about 20 years, and it is expected that there will be no need to repair the surface layer. The reason that no repairs are required for 20 years is because the performance standards were met in a Cantablo test on a test specimen that was exposed to ultraviolet rays equivalent to the amount of ultraviolet rays irradiated from sunlight for 20 years.

As a result, as shown in Figure 4 (b), the initial cost of constructing a porous asphalt pavement 10 using the polymer modified asphalt H-type containing CB of the present invention is only about 1% higher than that of a porous asphalt pavement 20 using the polymer modified asphalt H-type not containing CB, but the life cycle cost (construction and repair costs) over 20 years is expected to be reduced by more than 40%.

The above tests were conducted using discarded carbon black, but because the effect is due to carbon black, the same effect can be expected from new carbon black, waste rubber carbonized charcoal, waste tire carbonized charcoal, or moisture-containing waste tire carbonized charcoal, which contain carbon black.

1. Porous asphalt pavement (surface layer)
2. Dense-grained asphalt pavement (surface layer)
3 Impermeable layer 4 Rainfall 5a Rainwater infiltration flow 5b Rainwater flow on pavement surface 10 Porous asphalt pavement mixture 20 Porous asphalt pavement mixture 30 Aggregate 40a Polymer modified asphalt H type 40b Polymer modified asphalt H type + CB (carbon black)

Claims (2)

Polymer modified asphalt H type;
A porous asphalt pavement mixture characterized by being composed of waste carbon black having a composition of 88.9 to 96.1% by weight of carbon black, 0.3 to 6% by weight of moisture, and 0.1 to 2.1% by weight of impurities such as dust and fine particles , crushed stone, crushed sand, and stone powder. The waste carbon black has a composition of 88.9 to 96.1% by weight of carbon black, 0.3 to 6% by weight of moisture, and 0.1 to 2.1% by weight of impurities such as dust and fine particles. The amount of the waste carbon black added to the porous asphalt pavement mixture is 0.01 to 10% by weight. Porous asphalt pavement mixture according to claim 1.

Images