JPH0115642B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a heating mixture for paving that uses modified asphalt as a binder containing a large amount of rubber, thermoplastic polymer, etc., with high thermal efficiency by preventing deterioration of the binder and quality deterioration. It relates to a manufacturing method.

The present inventors first discovered that asphalt pavement in snowy and cold regions is subject to significant wear and damage due to winter spike tires, tire chains, etc.
For wear-resistant pavements that can sufficiently withstand these effects,
In addition, potholes on the road surface, whether in cold or warm regions,
We have researched and developed a heating mixture for pavement that is suitable for long-lasting repair of ruts and cracks, correction of differences in level between structures such as manholes and road surfaces, and thin-layer wear-resistant non-slip pavement for high-grade pavements and urban pavements. The characteristics of these heated mixtures for paving are that, as a binder,
Compared to conventionally used paving asphalt and asphalt that is modified by mixing rubber, resin, etc. with asphalt, asphalt has rubber, resin, etc.
The problem is that modified asphalt mixed with a large amount of thermoplastic polymer is used. Modified asphalt, which is modified by mixing large amounts of these rubbers, thermoplastic polymers, etc., has excellent elasticity, caking properties, extensibility, impact resistance, etc. at low temperatures. However, since the softening point is 75℃ or higher and the viscosity when heated and melted is extremely high, the temperature when producing heated paving mixtures that use these as binders and the leveling temperature during paving are about 200℃. Quite expensive. Furthermore, due to the high viscosity of the binder, the amount of binder in the heated mixture is also higher than in conventional mixtures.

These heated mixtures for paving have extremely good properties after paving, but the conventional production method of melting the binder by heating and making it into a liquid state and adding it to the heated aggregate and mixing it is not suitable for bonding. It takes a long time to melt the material, and since it has a high viscosity, it is necessary to raise the heating melting temperature, and the bonding material is heated at high temperatures for a long time, causing the rubber, thermoplastic polymer, etc. in the bonding material to deteriorate. There was a risk of depolymerization and thermal deterioration.
In particular, when making a heated mixture for paving at a plant, the binder is melted in a large-capacity melting pot, which has the disadvantage of being repeatedly and continuously heated for a long time, and furthermore, the heated mixture for paving must be transported to the paving site. Since it must be kept at a high temperature until it is paved, there is a risk of thermal deterioration. Furthermore, the thermal energy required for heating, keeping warm, etc. is large. Depolymerization of polymeric substances due to thermal deterioration of the binder may cause the pavement to flop after being paved, since the amount of binder being mixed is large.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, prevent thermal deterioration of the binding material, reduce energy consumption, and use modified asphalt mixed with a large amount of rubber, thermoplastic polymer, etc. as the binding material. The present invention provides a method for producing a heated paving mixture.

In the method of the present invention, modified asphalt, which is obtained by mixing asphalt with one or more selected from rubber and thermoplastic polymers, is added to the aggregate heated to a temperature of 180°C or higher. Weight 1
The gist of this invention is a method for producing a heated mixture for paving, characterized in that after adding and mixing lumps of 1 kg or less in solid form, the lumps of modified asphalt are melted and mixed with the aggregate. be.

The aggregate used in the present invention is coarse aggregate, fine aggregate, filler, etc. used in asphalt pavement. Crushed stone is used as the coarse aggregate, but crushed stones, gravel, slag, etc. can also be used. As fine aggregate, sand such as river sand, sea sand, mountain sand, etc. is used, but iron sand, crushed stone screening, etc. can also be used. In addition, light-colored aggregates (for example, Luxovite, Sinopal, etc.) and hard aggregates (for example, emery, silica sand, nickel slag, etc.) can be used. As the filler, stone powder obtained by crushing limestone or igneous rocks is used, but other rock powders, carbonated lime powder, lime, gypsum, fly ash, cement, incineration ash, etc. can also be used. Also, carbon black, graphite, pigments, etc. can be used. Furthermore, short fibers such as asbestos, glass fiber, rock wool, synthetic fiber, carbon fiber, mica powder, etc. can also be used as a part of the filler.

The asphalt used in the present invention is one or two selected from rubber and thermoplastic polymers.
Modified asphalt (hereinafter simply referred to as modified asphalt) is a thermoplastic product in which asphalt is mixed with a large amount of rubber, thermoplastic polymer, etc. (dissolved or dispersed and integrated). It is a modified asphalt with a softening point of 75 to 120℃. The amount of rubber, thermoplastic polymer, etc. in the modified asphalt is usually within the range of 8 to 35% by weight. Further, anti-aging agents, antioxidants, anti-scaling agents, fillers (described above), etc. can also be added to the modified asphalt as appropriate.

The asphalt used in the modified asphalt may be one or more of straight asphalt, semi-blown asphalt, blown asphalt, cat blown asphalt, propane deasphalt, rock asphalt, lake asphalt, and the like. Straight asphalt is generally used. Bituminous materials such as tar and pitch can also be added to these asphalts to improve their properties.

Rubbers and thermoplastic polymers used in modified asphalt include, for example, natural rubber, gutta-percha, cyclized rubber, styrene-butadiene rubber, styrene-isoprene rubber, isoprene rubber, polyisobutylene rubber, butadiene rubber, chloroprene rubber, butyl rubber, Rubbers such as halogenated butyl rubber, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene propylene rubber, EPT rubber, Alfine rubber, styrene/butadiene block polymer rubber, styrene/isoprene block polymer rubber, and ethylene/vinyl acetate copolymer , thermoplastic polymers such as ethylene/acrylate copolymer, polyethylene, and vinyl acetate/acrylate copolymer. One or more of these may be used. Further, rubber and thermoplastic polymers are used in various shapes and forms. For example, various shapes such as powder, granular, latex, cut-out, etc. are used, and new materials are used.
It comes in various forms and types, including recycled, unvulcanized, semi-vulcanized, and used crushed products. Examples of methods for mixing rubber, thermoplastic polymers, etc. with asphalt are as follows. A method in which a mixture of rubber, elastomer, etc. and bituminous material, etc. is kneaded using a rubber roll, Banbury mixer, etc. (master batch) and then added to the heated and molten bituminous material and mixed by heating. A method in which latex or emulsion is added to heated and molten bitumen, and the water is evaporated by heating and mixing. Rubber powder (e.g. powdered rubber for automobile tires), thermoplastic rubber (e.g. styrene/butadiene block polymer rubber, styrene/isoprene block polymer rubber), and ethylene/vinyl acetate copolymer are added to the heated and melted bituminous material and mixed by heating. There are methods such as melting and dispersing. These methods are also used in combination. The temperature at which rubber, thermoplastic polymers, etc. are dissolved and dispersed in the bituminous material is 160 to 230°C.

Along with the above rubbers, thermoplastic polymers, etc.
In order to improve adhesion and compatibility, thermoplastic solid resins, shape rubbers, liquid resins, softeners, plasticizers, and the like may be added as tackifiers. For example, rodin and its derivatives, terpene resins, petroleum resins and their derivatives, alkyd resins, alkylphenol resins, terpene phenol resins, coumaron indene resins, synthetic terpene resins (for example, manufactured by Nippon Zeon, trade name Quinton), alkylene resins,
Polyisobutylene, polybutane diene, polybutene, copolymer of isobutylene and butadiene (for example, SK Polymer 1000 (manufactured by Tonen Petrochemical, trade name),
Quintol (manufactured by Nippon Zeon, trade name)), polybutene, mineral oil, process oil, pine oil, anthracene oil, pine oil, plasticizer, animal and vegetable oil, polymerized oil, etc. Antioxidants, antioxidants, sulfur, etc. can also be added.

In addition to the above-mentioned modified asphalt, rubberized asphalt used as a heated injection joint material for concrete pavement can be used as the modified asphalt used in the present invention. Furthermore, the modified asphalt can be mixed with a filler.

In the present invention, the above-mentioned modified asphalt is used in the form of a lump of about 1 kg or less in weight (hereinafter referred to as a lump of modified asphalt). The size of the lumps is preferably small so that they can be easily handled and melted by heating. Even if it is large, it should be less than 1 kg in weight. If the weight exceeds about 1 kg, it takes time to heat and melt, making it difficult to mix the aggregate, prolonging the production time of the heated mixture, and causing thermal deterioration of the modified asphalt. Further, the shape of the lump may be any shape as long as it is easy to handle. Examples include mochi-shaped, plate-shaped, rod-shaped, rope-shaped, granular, etc.

When a filler is mixed with the modified asphalt and made into a lump, the filler becomes part of the aggregate filler of the heated paving mixture. Addition of filler prevents the lump from deforming during storage, improves the mixing of the filler and binder during the production of heated mixtures for paving, and facilitates the mixing of aggregate. When producing modified asphalt, a lump of modified asphalt is made into a lump by an appropriate method when heated and molten or mixed with an appropriate amount of filler and cooled. For agglomeration, the molten material is poured into a plate shape or molded into a plate shape and cooled.
This is then cut, crushed, etc. Alternatively, it is extruded using an extruder and cooled. Various methods can be used, such as granulating it in a cooling liquid and cooling it. These lumps are solid at room temperature, but to prevent them from sticking, stone powder or a peeling sheet can be applied to the surface.

Next, a method for producing a heated mixture for paving (hereinafter simply referred to as a mixture) of the present invention will be explained.

The composition of the mixture is selected depending on the purpose of use, conditions of use, etc. The aggregate particle size is based on the particle size of a general asphalt mixture for pavement, but various other combinations can be selected as necessary.

Preferably, the mixture is prepared at or near the paving site in a mixer equipped with a heating device. It is advantageous to equip the mixer with a heating device, such as in a Kutzker car. However, a normal plant etc. can of course also be used.

Production is carried out by putting a predetermined amount of heated aggregate into a mixer, or by putting the aggregate into a mixer and heating it, and adding a predetermined amount of chunks of modified asphalt to it while stirring. Divide into several batches. Normally, the heating temperature of aggregate is around 180°C to 230°C, and when modified asphalt chunks are added to this, they are melted by the heat of the aggregate and mixed with the aggregate. Heating is also performed as necessary to prevent temperature drop. The mixing time varies depending on the mixing volume of one batch, but if the batch is about 1 to 2 tons, the modified asphalt lumps are added in several batches and mixed in solid form for about 20 minutes. By mixing for about 5 minutes after addition, the aggregate and binder are mixed uniformly, and the mixture of the present invention can be obtained. These mixtures can be paved immediately.

In the method for producing a mixture of the present invention, the heating and melting of the binder and mixing with the aggregate are carried out at the same time, so the time for which the binder is heated at a high temperature is greatly shortened. Thermal deterioration and depolymerization of polymers, etc., are prevented. Therefore, since there is no deterioration or quality deterioration of the binder, it is possible to produce a mixture that takes full advantage of the excellent physical properties of the rubber and thermoplastic polymer that are mixed in large amounts. The amount of binder in the mixture is considerably higher than that of ordinary asphalt heated mixtures, but since there is no depolymerization of rubber, etc., there is no need to worry about flashing in the summer, and there is no embrittlement in the winter, so it has good wear resistance and resistance. It is possible to create pavement with excellent impact resistance, slip resistance, etc. Furthermore, with regard to the consumption of fuel required for producing the mixture, there are excellent functions and effects, such as a significant saving, since heating and melting and mixing with the aggregate are carried out at the same time without heating the binder for a long time.

Next, the method for producing the mixture of the present invention will be explained with reference to Examples.

Example 1 A lump of modified asphalt: 85 parts by weight of heated and melted straight asphalt (penetration 60-80), 10 parts by weight of ethylene/ethyl acrylate copolymer, and 2 parts of styrene/butadiene block polymer rubber.
Add 3 parts by weight of petroleum resin and heat at 180 to 200℃.
The mixture was mixed for about 2 hours to obtain modified asphalt with a uniform composition (softening point: 87°C). This modified asphalt 100
A mixture of 20 parts by weight of limestone powder and 0.2 parts by weight of anti-peeling agent is poured into a plate shape approximately 10 mm thick, cooled, and shaped into a rectangular shape (width 15 cm x length 30 cm) (weight approx.
Cut into pieces (590g), cover with release paper or polyethylene sheet, and package in a cardboard box. This lump of modified asphalt is used as a binder for a mixture by removing the paper or polyethylene sheet.

Production of the mixture: A truck equipped with a mixer with a heating device that has the capacity to produce 2 tons of mixture per batch.
Add 700 kg of Silica Sand No. 3 and 100 kg of limestone powder, heat and mix to bring the temperature to 220-230°C, add and mix 200 kg of modified asphalt lumps in solid form over about 20 minutes, and then Approximately 5
By heating and mixing for a minute, it was possible to obtain a uniformly mixed mixture of binder and aggregate at approximately 200°C. This mixture has good physical properties without deterioration of the binder, and can be used as thin layer pavement (6 thick) on existing asphalt pavement.
mm) and for level difference correction, and is used in traffic, but has no flashing and has good wear and slip resistance.

Example 2 Modified asphalt lump: 20 parts by weight of styrene-butadiene block polymer rubber was added to 70 parts by weight of heated and melted straight asphalt (penetration 60-80), and heated at about 170-190°C. After mixing and melting the rubber, add 10 parts by weight of powdered rubber from automobile tires (passed through a 1.2 mm sieve) to make a mixture of 170 to 200.
℃ for about 1 hour to obtain modified asphalt (softening point: 105℃). This modified asphalt is thick
After pouring it into a 15mm thick tube and cooling it, it is cut into rectangular pieces 10cm wide x 30cm long (weighing about 460g), wrapped in release paper or polyethylene sheets, and packaged in a cardboard box.
This modified asphalt mass was peeled off from the paper or polyethylene sheet and used as a binder for the mixture.

Production of mixture: 600 kg of coarse aggregate (hard sandstone No. 7 crushed stone particle size 5-2.5 mm), fine aggregate (coarse river sand)
500Kg and 100Kg of limestone powder were put into the mixer equipped with a heating device used in Example 1 and heated and mixed to yield approximately 220Kg of limestone powder.
The modified asphalt lumps are kept at 300 °C.
By adding and mixing Kg as a solid for about 20 minutes and then heating and mixing for about 5 minutes, it was possible to obtain a mixture at about 200°C in which the binder and aggregate were uniformly mixed. This mixture has good physical properties without deterioration of the binder, and has been applied in a thin layer to wear-resistant asphalt pavement in snowy and cold regions, and is extremely elastic and has extremely good wear resistance.

Comparative Example 1 A modified asphalt lump similar to that used in Example 1 was heated and melted using an asphalt melting kettle to form a liquid at 180 to 200°C, and silica sand 6 was added to the mixer equipped with the heating device used in Example 1. No. 200
Kg, silica sand No. 3 700Kg and limestone powder 100Kg
200 kg of heated and melted modified asphalt was added to this for about 5 minutes or more, and mixed for about 2 minutes to combine the binder and bone. Obtain a uniformly mixed mixture of materials at approximately 200°C.

It took about 2 hours to melt 200 kg of the above-mentioned modified asphalt lumps. In addition, there is a risk of loss due to adhesion to the inner wall of the kettle or adhesion to the container during measurement, and if the kettle is emptied, the modified asphalt may catch fire, so melt the modified asphalt lumps in excess of the required amount. I had to.

Comparative Example 2 A modified asphalt lump similar to that used in Example 2 was heated and melted using an asphalt melting kettle to form a liquid at a temperature of 180 to 200°C.
600 kg of coarse aggregate (No. 7 crushed stone), 500 kg of fine aggregate (coarse river sand), and 100 kg of limestone powder were put into the mixer equipped with a heating device used in the above, and heated and mixed to 200 to 210℃.
temperature, add 300 kg of the above heat-molten modified asphalt for about 6 minutes, and mix for about 2 minutes to obtain a uniformly mixed mixture of binder and aggregate at about 200°C. .

It took about 2 hours to melt 300 kg of the above-mentioned modified asphalt lumps. In addition, there is a risk of loss due to adhesion to the inner wall of the kettle or adhesion to the container during measurement, and if the kettle is emptied, the modified asphalt may catch fire, so melt the modified asphalt lumps in excess of the required amount. I had to.

In Comparative Example 1 and Comparative Example 2, it took about 2 hours to melt the modified asphalt, so it took about 5 times as long to produce the mixture as in Example 1 and Example 2, respectively. Therefore, since the bonding material is heated for a long time, thermal deterioration may occur. Furthermore, if the kettle is emptied, there is a risk that the modified asphalt remaining in the kettle will catch fire, so a certain amount of the modified asphalt will remain in the kettle, and the modified asphalt will be affected by heat accordingly. There is also loss of modified asphalt due to adhesion to the inner wall of the kettle or adhesion to the container during measurement. Furthermore, when measuring and adding modified asphalt to a mixer equipped with a heating device, it is difficult to handle because the modified asphalt is in a highly viscous liquid state.
Therefore, it took a considerable amount of time even though it was melted.

Claims (1)

[Claims] 1. Modified asphalt, which is obtained by mixing asphalt with one or more selected from rubber and thermoplastic polymers, into aggregate heated to a temperature of 180°C or higher, into a lump of approximately 1 kg or less in weight. 1. A method for producing a heated mixture for paving, comprising: adding and mixing the modified asphalt in a solid state, and then melting the bulk modified asphalt and mixing it with the aggregate.