JP2005016268A - Regenerated asphalt mixture that can be stored at room temperature and method for producing the same - Google Patents

Abstract

A recycled asphalt mixture that can be stored at room temperature is provided.
SOLUTION: There is an aggregate that is recovered and recovered from waste asphalt pavement, the surface of which is covered with an asphalt film, and cement powder is adhered to the outer surface of the asphalt film that covers the surface of the aggregate. A regenerated asphalt mixture that can be stored at room temperature. In the regenerated asphalt mixture of the present invention, the cement powder adheres to the asphalt film on the outer surface of the regenerated aggregate, so that the particles do not unite and can be stored at room temperature while being kept apart.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an asphalt mixture. More particularly, the present invention relates to a recycled asphalt mixture that can be stored at room temperature and recycled from waste asphalt mixture.
[0002]
[Prior art]
Asphalt pavement is generally applied to roads on which vehicles and humans pass in order to improve convenience and safety. Asphalt paved roads have a smooth surface and no irregularities on the road surface, so it is extremely convenient for traffic not only heavy vehicles such as automobiles but also light vehicles such as humans and bicycles. Has been.
[0003]
Asphalt pavement is formed from an asphalt mixture consisting of asphalt and aggregate. The asphalt mixture is produced, for example, by using a natural water content or a normal temperature aggregate whose water content has been adjusted, adjusting the particle size to a predetermined mixture, and then mixing the aggregate and asphalt with a mixer or the like. The asphalt mixture produced here has been applied on a crushed stone roadbed or on the base layer and / or surface layer of the asphalt mixture. The construction is performed by using an ordinary asphalt pavement construction machine, laying it on a roadbed or a base layer and / or a surface layer of an asphalt mixture, compacting with a roller, and then applying a seal coat.
[0004]
Asphalt pavement deteriorates over time as it is used, and cracks, deflections, irregular ridges and / or depressions occur on the pavement surface. Therefore, depending on the traffic volume, it is necessary to replace the pavement periodically. Along with this replacement, the separated waste asphalt pavement is treated as construction waste. The amount of waste asphalt pavement is about 15 million to 20 million tons per year, but about half is recycled and the rest is finally disposed of in landfills. One reason for the low recycling rate is the lack of waste asphalt pavement treatment plants.
[0005]
A large amount of aggregate is used not only in asphalt pavement but also in other civil engineering and construction work. Aggregates are generally used by quarrying natural stones from mountains, rivers, etc., pulverizing them with a pulverizer, and classifying them according to a predetermined size. However, quarrying natural stones from mountains and rivers tends to be suppressed from the viewpoint of protecting the natural environment. For this reason, the importance of collecting and reclaiming aggregate from waste asphalt pavement is increasing.
[0006]
For example, waste asphalt pavement can be recovered and reclaimed by crushing the recovered waste asphalt pavement with a crusher, removing foreign substances such as metals mixed in the crushed mixture, and separating the waste asphalt pavement for each predetermined size. It is processed into a recycled aggregate by processing at a processing plant. The recycled aggregate collected in this way is mixed with new asphalt and additives as needed in an asphalt plant and used as a recycled asphalt pavement.
[0007]
Another method for recovering and recycling waste asphalt pavement is described in Patent Document 1 and Patent Document 2, for example. According to these methods, the recovered waste asphalt pavement is pulverized and heated and stirred in an asphalt plant, in which seed powder for recovering asphalt (for example, powdered concrete, fly ash, powdered artificial zeolite, raw water washing sludge, By mixing a suitable amount of shirasu, calcium carbonate, slag powder, etc., the asphalt in the waste asphalt pavement is adsorbed to the seed powder, and separated from the waste asphalt pavement into coarse aggregate, fine aggregate and asphalt filler and collected. Since most of the asphalt is removed from the surface of the recovered and recycled coarse aggregate and fine aggregate by seed powder, these aggregates can be used as a new aggregate material in the civil engineering and construction fields in addition to asphalt pavement. But it can be used.
[0008]
[Patent Document 1]
Japanese Patent No. 2547510 [Patent Document 2]
Japanese Patent No. 3093923 [0009]
However, when the aggregate recovered and regenerated by the method described in the patent document is used again as aggregate for asphalt pavement, it must be re-mixed with new asphalt, and the amount of asphalt used cannot be reduced. . Therefore, the use of recycled aggregate does not necessarily reduce the cost of asphalt pavement.
[0010]
In addition, when manufacturing recycled asphalt mixture consisting of recycled aggregate and asphalt, a simple small mixer is generally installed near the construction site where paving is performed, and it is manufactured on the spot and paved on the spot. Alternatively, after manufacturing at a manufacturing plant such as a large mixer at a location relatively close to the construction site, the product is transported to the construction site using a dump truck and then carried to the site and paved. Therefore, in order to make minor repairs to the road, the asphalt mixture had to be produced every time in a production plant or the like, and the surplus asphalt mixture was wasted. This is because, as the temperature decreases, the asphalts covering the aggregates combine to form a nodule, so that the remaining recycled asphalt mixture cannot be stored until the next use.
[0011]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an asphalt mixture that can be produced without adding new asphalt to aggregate recovered and recovered from waste asphalt pavement and that can be stored at room temperature.
[0012]
[Means for Solving the Problems]
The problem is that the aggregate is recovered and recycled from waste asphalt pavement, the surface of which is covered with an asphalt film, and cement powder is attached to the outer surface of the asphalt film that covers the surface of the aggregate. It is solved by a regenerated asphalt mixture that can be stored at room temperature.
[0013]
According to the present invention, the cement powder adheres to the asphalt film on the outer surface of the recovered recycled aggregate, so that the individual particles are not united and maintained in a disjoint state. Therefore, the recycled asphalt mixture that can be stored at room temperature. Is obtained.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described in more detail with reference to the drawings.
[0015]
FIG. 1 is a conceptual cross-sectional view of a reclaimed asphalt mixture that can be stored at room temperature according to the present invention. The regenerated asphalt mixture 1 that can be stored at room temperature of the present invention basically includes a regenerated aggregate 3, an asphalt film 5 that covers the outer surface of the regenerated aggregate 3, and a cement attached to the outer surface of the asphalt film 5. It is an aggregate of granules 9 made of powder 7.
[0016]
Since the asphalt film 5 covering the outer surface of the recycled aggregate 3 is sticky, when mixed with the cement powder 7, the cement powder 7 adheres to the outer surface of the asphalt film 5, and the asphalt film 5 becomes non-sticky. As a result, due to the presence of the layer or film of the cement powder 7, the particles 9 are maintained in a disjoint state. Therefore, the regenerated asphalt mixture 1 that can be stored at room temperature according to the present invention is filled by sealing the granules 9 in the separated state in a predetermined amount (for example, 10 kg to 30 kg) in a waterproof or moisture-proof bag. Can be stored at room temperature for a long period (for example, for 3 to 12 months).
[0017]
When pavement construction is performed using the asphalt mixture 1 that can be stored at room temperature of the present invention, as shown in FIG. 2, the regenerated asphalt mixture 1 that can be stored at room temperature is taken out from the sealed bag and spread on the roadbed 11 and spreader 13. Then, water is sprinkled or sprayed with asphalt emulsion to wet the cement powder layer 7 existing on the outermost surface of each granule 9, and then the roller 15 rolls. Alternatively, the recycled asphalt mixture 1 that can be stored at room temperature can be taken out from the sealed bag, mixed with an appropriate amount of water or asphalt emulsion, and then spread on the roadbed 11 and then rolled by the roller 15. By mixing water or an asphalt emulsion with the reusable asphalt mixture 1 that can be stored at room temperature of the present invention, the cement powder layer 7 existing on the outermost surface of each granule 9 is wetted, and the wetted cement layers 7 are mutually connected. The particles 9 are united and united to form a strong pavement 17.
[0018]
The amount of water or asphalt emulsion applied is preferably in the range of 1 to 100 parts by weight per 100 parts by weight of the reusable asphalt mixture that can be stored at room temperature. When the application amount is less than 1 part by weight, it is insufficient for wetting the cement powder, and when it exceeds 100 parts by weight, the cement is excessively liquefied and requires a long time for solidification.
[0019]
Since the asphalt film 5 exists between the cement layer 7 and the aggregate 3 in the room temperature storable recycled asphalt mixture 1 of the present invention, the pavement 17 formed as described above can be used for conventional concrete pavement or asphalt pavement. Compared with various features. For example, a pavement formed from the recycled asphalt mixture of the present invention has a higher bending strength and a higher bending strain than a conventional concrete pavement made of cement and aggregate. Furthermore, the strength is higher than that of asphalt pavement made of asphalt and aggregate.
[0020]
FIG. 3 is a conceptual partial enlarged cross-sectional view of the pavement 17 formed as shown in FIG. The cement powder 7 wetted with water or asphalt emulsion becomes a fluid state, bonds to each other, and solidifies. In some cases, a cavity 21 that is not completely filled with cement in a fluidized state may be generated at the bonding boundary between the solidified cement layers 19 that are mutually bonded. Due to thermal stress or mechanical stress applied to the pavement 17, the solidified cement layer 19 may repeatedly expand and contract, and a crack 23 may be generated in the solidified cement layer 19. When such a crack 23 is generated, the asphalt film 5 present on the surface of the aggregate 3 is softened, and the crack 23 can be backfilled. This phenomenon is called asphalt healing effect. Due to the asphalt healing effect, the pavement 17 can maintain a strong unity state over a long period of time.
[0021]
Next, the manufacturing method of the reproduction | regeneration asphalt mixture which can be stored at normal temperature of this invention is demonstrated. First, the recycled aggregate 3 is prepared. The recycled aggregate 3 is recovered from the waste asphalt pavement as described above. The collection method itself of the recycled aggregate 3 is not particularly limited. Recycled aggregates recovered by any method known to those skilled in the art or known and commonly used can be used as appropriate. However, a necessary condition for the recycled aggregate 3 used in the present invention is that the aggregate surface is recovered with the asphalt film still covered. The residual amount of the asphalt film is preferably about 1 to 20 parts by weight of the asphalt film with respect to 100 parts by weight of the aggregate based on the weight of the aggregate itself. If the remaining amount of the asphalt film is less than 1 part by weight, an exposed part not covered with the asphalt film is formed on a part of the aggregate surface, and a healing effect by asphalt cannot be expected. On the other hand, when the residual amount of the asphalt film exceeds 20 parts by weight, an excessive amount of asphalt flows down from the aggregate surface, which is not preferable.
[0022]
When the recycled aggregate 3 is recovered by the method of the patent invention as described in Patent Document 1 and Patent Document 2, the recovered asphalt pavement is pulverized and heated and stirred at a temperature of 140 ° C. to 180 ° C. in an asphalt plant. Asphalt is obtained by mixing a suitable amount of seed powder (eg, powdered concrete, fly ash, powdered artificial zeolite, raw stone washed sludge, shirasu, calcium carbonate, slag powder, etc.) and stirring for 3 to 10 minutes. Recycled aggregate covered with the membrane can be recovered. The stirring time with the seed powder is inversely proportional to the heating temperature. Therefore, when the heating temperature is 180 ° C., the stirring time is about 3 minutes, when the heating temperature is 160 ° C., the stirring time is about 5 minutes, and when the heating temperature is 140 ° C., the stirring time is About 10 minutes. If the stirring time with the seed powder at a predetermined heating temperature is longer than this, the residual amount of the asphalt film on the surface of the aggregate may be less than 1 part by weight, which is not preferable. When the remaining amount of the asphalt film is less than 1 part by weight, asphalt can be newly added as necessary.
[0023]
When the recycled aggregate 3 is recovered by the method of this patent invention, in addition to the recycled aggregate (including both coarse aggregate and fine aggregate) 3, asphalt adheres to the seed powder added at the time of recovery. Asphalt filler is also obtained at the same time. In the present invention, this asphalt filler may be mixed together with the recycled aggregate 3. Therefore, in the present invention, the collected waste asphalt pavement can be used in a mixed state without being classified regardless of the recovery method.
[0024]
Next, when the temperature of the pulverized waste asphalt pavement heated to recover the recycled aggregate 3 is lowered from 110 ° C. to about 40 ° C., 1 part by weight of cement powder per 100 parts by weight of the recovered asphalt mixture Add about 10 parts by weight, and mix so that the cement powder uniformly adheres to the asphalt film on the surface of the regenerated aggregate and the particles are in pieces. When the added amount of cement powder is less than 1 part by weight, it becomes difficult to uniformly adhere the cement powder to the asphalt film on the surface of the recycled aggregate, and there is a possibility that the particles are partially bonded and aggregated. . On the other hand, when the added amount of cement powder exceeds 20 parts by weight, the amount that remains without being attached to the asphalt film increases, which is uneconomical. As described above, when asphalt filler is mixed, this asphalt filler is also coated with cement powder and loses its adhesiveness.
[0025]
Mixing the recycled aggregate 3 and the cement powder can be easily carried out using a conventional mixer or the like (including this asphalt filler when an asphalt filler is mixed). Alternatively, in an asphalt plant for recovering recycled aggregate from waste asphalt pavement, cement powder can be directly mixed with the recovered material.
[0026]
Examples of the additional asphalt added as necessary to produce the room temperature storable recycled asphalt mixture of the present invention include straight asphalt, blown asphalt, semi-blown asphalt, natural asphalt, material deasphalted asphalt, tar, pitch, etc. Bitumen, A, B and C heavy oil. Modified asphalt in which SBS, SBR, SIS, EVA, EEA, CR, IR, etc. are mixed with these can also be used. Further, a rubber latex, a synthetic polymer latex, a synthetic polymer emulsion, or a mixture of water-soluble synthetic resins alone or in combination may be added to the emulsifier as a modifier, or may be added after the emulsion is produced. When using asphalt, it is preferable to use a penetration of about 10 to 300. The evaporation residue (solid content) of the bitumen emulsion is generally 50 to 70%, but in the present invention, it can be applied to those having a concentration of 40 to 75%.
[0027]
Examples of the cement used for producing the room temperature storable recycled asphalt mixture of the present invention include ordinary Portland cement, blast furnace cement, early strong cement, ultra early strong cement, jet cement and the like.
[0028]
The water used when paving the room temperature storable reclaimed asphalt mixture of the present invention is any water such as tap water (tap water), middle water (sewage treated water), rain water, river water or ground water. Can do. The asphalt emulsion is a mixture of asphalt, water and a surfactant, and is classified into a cationic, anionic or nonionic asphalt emulsion depending on the type of the surfactant used. In the present invention, any of a cationic, anionic or nonionic asphalt emulsion can be used. In general, asphalt emulsions include various types of asphalt emulsions for roads described in Japanese Industrial Standard JIS K-2208, as well as asphalt emulsions with rubber or modified asphalt emulsions (rubber and / or resin, etc.) of JEAAS standards. Any type of emulsion can be used in the present invention. In the present invention, a known and commonly used asphalt emulsion can be appropriately selected and used according to the purpose and / or application. For example, MK-2, MK-3, PK-1, PK-2, PK-3, PK-4, PKR-S or PKR-T should be appropriately selected according to the purpose and / or use. Can do. Needless to say, other known and commonly used asphalt emulsions can also be used.
[0029]
The regenerated asphalt mixture that can be stored at room temperature of the present invention can be used directly for the formation of a paved road through which pedestrians or vehicles pass, or it can be used as an underlayer for block paving. When the regenerated asphalt mixture that can be stored at room temperature according to the present invention is used to form a paved road through which pedestrians or vehicles pass, it has the advantage that traffic can be released within a relatively short time after construction due to the fast curing of cement. Have. Further, when used as a base layer for block paving, the base layer is flexible, so that the block placed on the upper surface does not become uneven.
[0030]
【Example】
Hereinafter, production of a reclaimed asphalt mixture capable of being stored at room temperature and pavement construction using the mixture will be specifically illustrated by examples.
[0031]
Example 1
The waste asphalt pavement generated by the refurbishment work on the general national road asphalt pavement is pulverized with a crusher. Metals are removed from the obtained pulverized product, put into an asphalt plant without classification, and heated to 180 ° C while being heated. Stir and mix for minutes. The residual amount of asphalt film on the aggregate surface at this stage was 10 parts by weight. When the temperature of the mixture is lowered to a temperature in the range of 110 ° C. to 40 ° C., 10 parts by weight of cement is charged into the plant, and the whole is uniformly mixed, and the asphalt coating of the recycled aggregate is removed. Cement powder was applied to the entire surface. Thereafter, every 30 kg, the moisture-proof bag was filled and sealed, and stored in a warehouse.
The thus obtained room temperature storage regenerated asphalt mixture of the present invention thus obtained was averaged to a thickness of 5 cm on the roadbed after 3 months from the production, and then 1 m ^{3 of} tap water was sprinkled on it, and then rolled with a roller. Formed a paved road.
[0032]
Example 2
The waste asphalt pavement generated by the refurbishment work of the general national road asphalt pavement is crushed with a crusher, the metals are removed from the obtained pulverized product, put into the asphalt plant as it is without classification, and concrete as seed powder in this plant The powder was added and mixed with stirring for 3 minutes while heating to 180 ° C. The residual amount of asphalt film on the aggregate surface at this stage was 5 parts by weight. When the temperature of the mixture is lowered to a temperature in the range of 110 ° C. to 40 ° C., 5 parts by weight of cement is charged into the plant, and the whole is uniformly mixed, and the asphalt coating of the recycled aggregate is removed. Cement powder was applied to the entire surface. Thereafter, every 30 kg, the moisture-proof bag was filled and sealed, and stored in a warehouse.
The thus obtained room temperature storage regenerated asphalt mixture of the present invention thus obtained was averaged to a thickness of 5 cm on the roadbed after 3 months from the production, and then 1 m ^{3 of} tap water was sprinkled on it, and then rolled with a roller. Formed a paved road.
[0033]
Comparative Example 1
No. 6 crushed stone was used as the aggregate, and 10 parts by weight of cement was used per 100 parts by weight of the aggregate. Aggregate and cement were put into a mixer and mixed thoroughly. Thereafter, 5 parts by weight of tap water was put into the mixer, and the whole was uniformly mixed to prepare a cement mixture.
The cement mixture thus obtained was smoothed to a thickness of 5 cm on the roadbed to form a cement pavement. After the bitumen emulsion compositions 1 liter ^{/ m} 2, 7 No. crushed stone of the present invention was 0.5 m ^3/100 m ² sparging, the specimen of those 24 hours aging at 60 ° C.,
[0034]
Comparative Example 2
No. 6 crushed stone was used as the aggregate, and 10 parts by weight of asphalt emulsion was used per 100 parts by weight of the aggregate. Aggregate and asphalt emulsion were put into a mixer and sufficiently stirred and mixed while heating to 140 ° C. to prepare a heated asphalt mixture.
The heated asphalt mixture thus obtained was smoothed to a thickness of 5 cm on the roadbed and then rolled with a roller to form an asphalt pavement.
[0035]
The bending strength, bending strain and strength of each paved road formed as described above were measured. As a result, the pavement formed using this asphalt mixture is more than the cement pavement formed from the conventional cement mixture, even after the room temperature storable recycled asphalt mixture of the present invention is stored for three months from the production. It was confirmed that the bending strength and bending strain were large, and the strength was higher than that of an asphalt pavement formed from a conventional heated asphalt mixture.
[0036]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a recycled asphalt mixture that can be stored at room temperature, and when this recycled asphalt mixture is paved as compared with conventional cement mixtures or heated asphalt mixtures. Thus, a paved road having excellent bending strength, bending strain and strength can be obtained.
[Brief description of the drawings]
FIG. 1 is a conceptual cross-sectional view of a recycled asphalt mixture of the present invention.
FIG. 2 is a schematic diagram when pavement construction is performed using the recycled asphalt mixture of the present invention shown in FIG.
FIG. 3 is a conceptual partial enlarged cross-sectional view of the pavement 17 formed as shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Regenerated asphalt mixture 3 Recycled aggregate 5 Asphalt film 7 Cement powder 9 Granule 11 Subbase 13 Spreader 15 Roller 17 Pavement 19 Solidified cement layer 21 Cavity 23 Crack

Claims (4)

It is recovered and reclaimed from waste asphalt pavement, and has an aggregate whose surface is covered with an asphalt film, and cement powder is attached to the outer surface of the asphalt film that covers the surface of the aggregate Recycled asphalt mixture that can be stored at room temperature. The cement powder adheres to the asphalt film on the outer surface of the recycled aggregate, so that the particles do not unite and can be stored at room temperature while being kept apart. Recycled asphalt mixture that can be stored at room temperature. (A) crushing the waste asphalt pavement with a crusher, removing foreign substances such as metals, and stirring and mixing while heating at 160 to 180 ° C. in a processing plant;
(B) When the temperature of the mixture in the treatment plant is lowered to a temperature in the range of 110 ° C. to 40 ° C., cement powder is introduced into the mixture and mixed, and the cement powder is applied to the asphalt film on the surface of the recycled aggregate. A process for producing a reusable asphalt mixture that can be stored at room temperature, comprising the step of bringing each particle into a disaggregated state by uniformly adhering. (A) A waste asphalt pavement is crushed with a crusher to remove foreign substances such as metals, and at least selected from the group consisting of powdered concrete, fly ash, powdered artificial zeolite, rough water washed sludge, shirasu, calcium carbonate and slag powder Adding one kind of seed powder and stirring and mixing in a processing plant while heating to 160 ° C to 180 ° C;
(B) When the temperature of the mixture in the treatment plant is lowered to a temperature in the range of 110 ° C. to 40 ° C., cement powder is introduced into the mixture and mixed, and the cement powder is applied to the asphalt film on the surface of the recycled aggregate. A process for producing a reusable asphalt mixture that can be stored at room temperature, comprising the step of bringing each particle into a disaggregated state by uniformly adhering.

Images