KR102311081B1 - Manufacturing Method of modified Ascon using waste plastic components - Google Patents

Abstract

The present invention provides a method for producing asphalt concrete, comprising the steps of providing asphalt to a mixer; Aggregate providing step of providing the aggregate to the mixer; a heating step of raising the temperature of the mixer to 160 to 190°C; And it characterized in that it comprises a waste plastic providing step of injecting a low-melting-point waste plastic having a melting point below the heating step into the mixer in an amount of 0.1 to 6% by weight of the total weight of the asphalt concrete.

Description

Manufacturing Method of modified Ascon using waste plastic components

The present invention relates to a method for producing asphalt concrete, and more particularly, to a method for producing asphalt concrete that can reduce environmental pollution, modify properties of asphalt concrete, and secure economic feasibility by utilizing waste plastic components.

General asphalt concrete (asphalt concrete) consists of asphalt and aggregate. At this time, asphalt is a bituminous petroleum-based asphalt obtained from crude oil refining and is used for pavement asphalt. However, when asphalt is produced using only asphalt, plastic deformation and cracking occur, and the resistance to temperature is insufficient.

Common modifiers include simple compound modifiers such as thermosetting rubber and thermoplastic resin, physical and chemical compound modifiers such as thermoplastic polymers, regenerated rubber modifiers and chemical modifiers that are inorganic acids or metal catalysts, and additive modifiers such as fibrous or natural asphalt. .

On the other hand, plastic has become an indispensable product in daily life due to its convenient processing and low price, and although more than 10 million tons of plastic waste is generated annually, less than half of it is recycled and the rest is landfilled and incinerated.

Accordingly, domestic waste plastics are continuously increasing, and as regulations to reduce the amount of waste plastics are strengthened, interest in the treatment of generated waste plastics is also increasing.

Waste plastics discharged as industrial wastes are easy to collect by type and can be recycled relatively easily. .

After separation and collection, crushing into small pieces, there are cases in which relatively low solubility is separated through specific gravity separation, and then melted and molded.

A new method for recycling waste plastics is needed, and one sector is recycling it by using it as an asphalt mixture for paving the road.

Korean Patent Registration No. 770785 proposes a modified asphalt binder in which plastic is made into wax and the wax component is mixed with asphalt. However, there was a difficulty in using the plastic due to the high cost of the wax manufacturing process.

Republic of Korea Patent Registration No. 10-770785

An object of the present invention is to provide an efficient method for producing asphalt concrete by using waste plastic, but by minimizing the burden of screening waste plastic and simplifying the process.

The present invention is a method for producing ascon,

Asphalt providing step of providing asphalt to a blender;

Aggregate providing step of providing the aggregate to the mixer;

a heating step of raising the temperature of the mixer to 160 to 190°C; and

The low melting point waste plastic having a melting point below the heating step and the high melting point waste plastic having a melting point higher than the heating step are injected into the mixer, and the low melting point waste plastic is 0.1 to 6% by weight of the total weight of the total asphalt concrete Including the step of providing waste plastic injected into,

The waste plastic providing step,

An extruding step of injecting a mixture of high melting point waste plastic and low melting point waste plastic into an extruder that can only melt low melting point waste plastic, melting the low melting point waste plastic, and compressing the high melting point waste plastic,

Recovering the low-melting-point waste plastic dropped in a molten state and providing it to a mixer, and cutting the compressed high-melting-point waste plastic and providing it to a mixer,

The low melting point waste plastic may be one selected from the group consisting of polypropylene, polyethylene, polystyrene, EVA, ABS, and PVC,

As the high-melting-point waste plastic, one selected from the group consisting of insulating layers of wires and cables, cured rubber, PET, PPO, high-melting-point polyamide, nylon, and PMMA may be used.

Ascon manufacturing method according to one aspect of the present invention provides a method for manufacturing asphalt concrete with a simple process and low manufacturing cost while injecting waste plastic by maximizing the existing asphalt concrete manufacturing process.

In addition, the method for producing asphalt concrete according to another aspect of the present invention provides a method for producing asphalt concrete that can minimize the waste plastic component classification process. That is, both high-melting-point asphalt and low-melting-point asphalt can be recycled. High-melting-point asphalt functions as a substitute for aggregate, and low-melting-point asphalt functions as artificial asphalt.

Waste plastics with high melting points such as intrinsic PET and PPO or thermosetting waste plastics are granulated and used as a substitute for aggregates. By providing the plastic powder of the asphalt concrete to the mixer, it is melted into a liquid to improve the adhesion between the aggregate and the high-melting-point plastic and asphalt.

The low melting point thermoplastic waste plastic is partially melted and induces molecular bonding with the asphalt binder, so it contributes to the development of adhesive strength. The waste plastics with it increase the resistance to compressive stress in the asphalt composition.

1 is a flowchart of an asphalt concrete manufacturing method according to an embodiment of the present invention.
Figure 2 is a view showing the measurement experimental results of the melting point Marshall stability of the specimen according to the manufacturing method of asphalt according to an embodiment of the present invention.
3 is a view showing an extrusion apparatus for extruding waste plastic while maintaining a high temperature.

Prior to describing the present invention in detail below, it is to be understood that the terminology used herein is for the purpose of describing specific embodiments and is not intended to limit the scope of the present invention, which is limited only by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art, unless otherwise stated.

Throughout this specification and claims, unless stated otherwise, the term comprise, comprises, comprising is meant to include the stated object, step or group of objects, and steps, and any other object. It is not used in the sense of excluding steps or groups of objects or groups of steps.

On the other hand, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the accompanying drawings.

1 is a flowchart of an asphalt concrete manufacturing method according to an embodiment of the present invention.

The method for producing asphalt concrete according to an embodiment of the present invention includes an asphalt providing step, an aggregate providing step, a heating step, and a waste plastic providing step.

The asphalt providing step (S1) is a step of supplying asphalt, which is a raw material for manufacturing asphalt, to a mixer, and the asphalt used at this time is unmodified asphalt, and the asphalt remaining after fractional distillation from crude oil is usually used. Such asphalt has been commercialized and sold as a commodity, for example, SK Energy's Superphalt.

The aggregate providing step (S2) is a step of providing aggregate, which is the main raw material of asphalt concrete. Aggregate is the basic composition of asphalt concrete, and generally the aggregate contains 85 to 90% by weight. These aggregates include coarse aggregate, fine aggregate, filler material and sand. It may include, and as the filler (filler), limestone powder, Portland cement, slaked lime, fly ash, recovered dust, steelmaking dust, casting dust, etc. may be used.

In one embodiment, the aggregate may include 6% by weight of crushed stone of a particle size of 20mm, 32% by weight of crushed stone of a particle size of 13mm, 46% by weight of sand, 12% by weight of steelmaking slag as a filler, and 4% by weight of silica sand.

In the embodiments of the present invention, the content according to the type of aggregate is not significantly limited, but the input ratios of coarse aggregate, fine aggregate, and filler are complementary to each other.

As will be described later, in one embodiment of the present invention, the high-melting-point plastic does not melt in the asphalt concrete composition, and may function as a fine aggregate or filler. Therefore, when high-melting plastic is injected, the content of fine aggregate or filler may be less than that of general asphalt concrete.

The heating step (S3) is a step of heating the mixed asphalt and aggregate to 160 to 190 degrees Celsius.

A first embodiment of the waste plastic providing step (S4) is a step of injecting the waste plastic at a predetermined temperature in the heating step, and in this step, the low melting point waste plastic having a melting point below the predetermined heating temperature is injected.

Low melting point waste plastics that can be used in this embodiment are polypropylene, polyethylene, polystyrene, EVA, ABS, PVC, and the like. The low-melting-point waste plastic is melted into liquid in a mixer and functions as artificial asphalt.

On the other hand, conventional waste plastics contain a mixture of low-melting-point waste plastics and high-melting-point waste plastics, and conventionally, the cost required to separate them is high and it is difficult to recycle. Even if it is included, if it undergoes a step of cutting it to a predetermined size or less, the portion containing the high melting point waste plastic may act as a filler.

Therefore, in the case of waste plastic in which the low-melting-point waste plastic and the high-melting-point waste plastic are mixed, it is preferable to cut the waste plastic to 0.5 mm or less and inject it. In addition, at this time, it is preferable to inject the low-melting plastic waste in an amount of 0.1 to 6% by weight of the total weight of asphalt concrete. If it is less than 0.1% by weight, there is no effect of replacing asphalt, and if it is 6% by weight or more, there is a problem in that the flow rate is deteriorated.

A second embodiment of the waste plastic providing step includes a first crushing step, a second crushing step, and a mixing step. The second embodiment can be preferably used when the waste plastic can be separated into a high melting point and a low melting point. In this case, the high melting point waste plastic may be a plastic having a melting point of 180° C. or higher, such as thermosetting plastics such as insulating layers of wires and cables, heat shrinkable packaging, and curing rubber, PET, PPO, high melting point polyamide, nylon, PMMA, and the like.

The first crushing step is a step of pulverizing in accordance with the regulations of KS F 3501 (filling material for asphalt pavement) of KS F 2357 (aggregate for asphalt mixture) in order to use high-melting-point waste plastics as fine aggregates or fillers.

Since the high melting point waste plastic does not melt at the temperature of the mixer, it remains in a solid state and can function as a fine aggregate or a filler. At this time, since the low-melting-point waste plastic, which may be partially contained in the high-melting-point waste plastic, is melted in a mixer and functions as artificial asphalt, there is no problem.

The second pulverizing step is a step of pulverizing the low-melting-point waste plastic to a predetermined size. If it is composed of only low-melting-point waste plastics, pulverization is not required, but as described in the first embodiment, some high-melting-point waste plastics may be included, so pulverization is performed. However, pulverization is an energy-consuming process, and the pulverization for high-melting-point waste plastics included in some of the low-melting-point waste plastics in this step is pulverized to comply with the KS F 2357 (Asphalt Mixture Aggregate) standard, which does not need to be pulverized to a smaller size. It is preferable to do

The low-melting-point waste plastic is melted into a liquid phase, and the adhesion between the aggregate and the high-melting-point plastic and asphalt is improved.

The mixing step is a step of mixing the waste plastics after the first crushing step and the second crushing step as an optional step. Dispersion in the mixer can be made easier than when the mixing step is performed.

A third embodiment of the waste plastic providing step includes a first crushing step and a coating step.

Since the first crushing step is the same as in the above-described first embodiment, a detailed description thereof will be omitted.

The coating step is a step of melting the low-melting-point waste plastic and coating it on the surface of the high-melting-point waste plastic after the first crushing step.

For example, the low-melting-point waste plastic is put into an organic solvent, heated to melt, and then mixed with the high-melting-point waste plastic particles that have undergone the first crushing step by at least one of spraying, dipping, and high-speed stirring, followed by drying to the high melting point. It can be coated on the surface of the waste plastic particles.

A fourth embodiment of the waste plastic providing step is an embodiment when the high melting point waste plastic is a waste fishing net, and the fourth embodiment includes a cutting step and a coating step.

The cutting step is a step of cutting the waste fishing net to 1 to 5 mm. Waste fishing nets are usually made of high melting point waste plastics made of polyamide, polyester, and PE. When the waste fishing net is cut, it is cut into short fibers and can function as a filler to increase the bonding force between the aggregate and asphalt. That is, the short fibers of the waste fishing net are maintained as they are in the asphalt concrete composition, thereby inducing a bridging effect while increasing the meshing stress between aggregates, thereby contributing to the expression of tensile or shear strength.

The coating step is a step of melting the low melting point waste plastic and coating the surface of the waste fishing net short fibers after the first crushing step.

For example, after putting short pair mesh fibers in an organic solvent and heating them to melt, spray, dipping, and high-speed stirring to mix with short pair mesh fibers that have undergone the first grinding step, and then dry to close the high melting point It can be coated on the surface of plastic particles.

A fifth embodiment of the waste plastic providing step is used when the high melting point waste plastic and the low melting point waste plastic are difficult to separate at all, and includes an extrusion step. 3 shows a concept for the step of extruding waste plastic while maintaining a high temperature.

The extruding step is a step of injecting the waste plastic in a mixed state of the high melting point waste plastic and the low melting point waste plastic into an extruder that can only melt the low melting point waste plastic, melting the low melting point waste plastic, and compressing the high melting point waste plastic.

For example, the extrusion step is a crushing step of pulverizing waste plastics that are not distinguished from high melting points and low melting points to a size of 20 mm or less, 1 to 2 mm rolls of two rolls 10 maintaining a temperature of 180 to 200 ° C. Waste plastic is supplied between the gaps so that compression and melting occur at the same time.

At this time, the low-melting-point waste plastic dropped in a molten state may be recovered and provided to the mixer, and the compressed high-melting-point waste plastic may be additionally cut and provided to the mixer.

<Experimental example>

Ascon specimens of 6% 20mm aggregate, 32% 13mm aggregate, 46% crushed sand, 12% steelmaking slag, 4% silica sand, and 5.4% low-melting polymer were prepared, and the Marshall stability measurement test results are shown in FIG. 2 . According to this, it can be confirmed that the stability value is in an excellent range.

Characteristics, structures, effects, etc. provided in the above-described method for preparing each asphalt concrete and the composition thereof, can be combined or modified by those skilled in the art. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

S1 : Asphalt provision stage
S2: Aggregate provision stage
S3: heating step
S3: Waste plastic provision stage

Claims (5)

As a method for producing ascon,
Asphalt providing step of providing asphalt to a blender;
Aggregate providing step of providing the aggregate to the mixer;
a heating step of raising the temperature of the mixer to 160 to 190°C; and
The low melting point waste plastic having a melting point lower than the heating step and the high melting point waste plastic having a melting point higher than the heating step are injected into the mixer, and the low melting point waste plastic is 0.1 to 6% by weight of the total weight of the total asphalt concrete Including the step of providing the waste plastic injected into,
The waste plastic providing step,
An extruding step of injecting a mixture of high melting point waste plastic and low melting point waste plastic into an extruder that can only melt low melting point waste plastic, melting the low melting point waste plastic, and compressing the high melting point waste plastic,
A method of producing asphalt concrete by recovering the low-melting-point waste plastic dropped in a molten state and providing it to a mixer, and cutting the compressed high-melting-point waste plastic to a blender. The method of claim 1,
The low-melting-point waste plastic is one selected from the group consisting of polypropylene, polyethylene, polystyrene, EVA, ABS, and PVC. 3. The method of claim 2,
The high melting point waste plastic is one selected from the group consisting of an insulating layer of wire and cable, cured rubber, PET, PPO, high melting point polyamide, nylon, and PMMA. The method of claim 1,
The extrusion step pulverizes waste plastics that are not distinguished from high melting points and low melting points to a size of 20 mm or less, and supplies waste plastics between 1 to 2 mm roll spacing of two rolls maintaining a temperature of 180 to 200 ° C. A method of manufacturing asphalt that allows both and melting to occur at the same time. Ascon prepared according to the method for manufacturing asphalt of any one of claims 1 to 4.

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