JPS6145206Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is designed to produce a heated asphalt mixture for pavement using modified asphalt, which is obtained by mixing asphalt with rubber, etc., as a binder, without melting the binder in advance. The present invention relates to a shaped bituminous pavement binder suitable for production by direct addition and mixing to heated aggregate.

Traditionally, heated asphalt mixtures for paving are produced in asphalt plants. Its production involves adding and mixing heated molten liquid asphalt to heated aggregate.

In this method, asphalt as a binder is heated and melted in advance and added to the heated aggregate, so the asphalt is kept in a heated and molten state for a long time. Therefore, the asphalt of the binder of the heated asphalt mixture is given a significant thermal history. Furthermore, the heated asphalt mixture produced in the asphalt plant
The reality is that it takes a considerable amount of time to transport it to the paving site and pave it. Furthermore, when using modified asphalt, which is obtained by mixing asphalt with rubber, etc., as a binder, the viscosity when melting is higher than that of ordinary paving asphalt at the same temperature, so It must be melted before use, which tends to cause thermal deterioration and thermal decomposition of rubber, etc. Therefore, the content of rubber, etc. in the modified asphalt used when producing a heated mixture in an asphalt plant is relatively small.

The present inventors have previously discovered that a heated asphalt mixture using modified asphalt mixed with a large amount of rubber, etc. as a binder is suitable for surface treatment of bituminous pavement and anti-slip pavement. We have developed a new method (Patent Application No. 157533-1983) that does not require a method to produce a good mixture without causing thermal deterioration of the binder.

In this method, a heated mixture is produced by adding and mixing modified asphalt, which is obtained by mixing asphalt with rubber, etc. and molding it into shapes such as cutters and plates, to heated aggregate. . In implementing this method, the molded modified asphalt was sticky, so it was wrapped in a release sheet, etc., and then peeled off before use. There was a problem that the material was hard and the material that was peeled off turned into scraps. After repeated experiments, we found that by using a polyethylene film instead of a release sheet, it could be used without having to be peeled off during use, and there was no problem with the melting of the binding material, and the polyethylene film melted into the binding material and became part of the binding material. It has been found that there is no decrease in physical properties, but rather that the workability of the mixture during high temperature melting and the deformation resistance after the mixture has been cooled are improved.

The present invention was devised based on such knowledge, and its purpose is to directly add and mix the binder in a solid state into heated aggregates without melting it in advance when producing a modified asphalt mixture. The present invention provides a bituminous pavement binder made of molded modified asphalt that can be easily handled.

The present invention is a modified asphalt made by mixing asphalt with rubber, etc., or a filler mixed with the modified asphalt, which is wrapped in a polyethylene film and molded into a plate shape. This paper focuses on the structure of the binder for blue pavement.

The present invention will be explained using figures. Figures 1 and 2 show an embodiment of the bituminous pavement binder shaped into a cut-out shape of the present invention, and Figures 3 and 4 show an embodiment of the bituminous pavement binder of the present invention.
The figure shows another shaped embodiment of the invention.

In the figure, 1 is a modified asphalt obtained by mixing asphalt with rubber or the like (hereinafter simply referred to as modified asphalt), or a mixture of the modified asphalt and a filler (hereinafter simply referred to as filler-mixed modified asphalt). be. 2 is a polyethylene film. 3 is powder particles such as filler.

Modified asphalt or filler mixed modified asphalt 1 is straight asphalt, semi-blown asphalt, blown asphalt,
This asphalt is modified by mixing rubber etc. into asphalt using one or more types of petroleum asphalt such as propane deasphalt asphalt and natural asphalt such as lake asphalt. Straight asphalt is mainly used as petroleum asphalt. As the rubber, natural rubber, synthetic rubber, thermoplastic polymer, etc., which are compatible with asphalt, are used. Some examples of rubber are natural rubber, gutta percha, cyclized rubber, isoprene rubber, styrene/isoprene rubber, butadiene rubber, styrene/butadiene rubber, chloroprene rubber, butyl rubber, polyisobutylene, butylene/isoprene block polymer rubber, styrene/isoprene rubber, etc. Butadiene block polymer rubber, polyethylene, ethylene/vinyl acetate copolymer,
There are ethylene/acrylate copolymers, polyacrylates, etc. Also, known methods are used for mixing, but the main example is to knead asphalt and rubber in advance to make a masterbatch, and then add and mix this to heated and melted asphalt to disperse and mix. A method in which a latex-like material such as rubber is added and mixed into heated and molten asphalt, and the water is evaporated by dispersing it. A method in which a granular material such as rubber is added and mixed into heated and molten asphalt and dispersed. There is a method in which a solution of rubber or the like is dissolved in a solvent is added to asphalt, and the dispersion solvent is evaporated. As the granular material such as rubber, fluidized rubber powder such as rubber tire powder can also be used. The content of rubber, etc. in the modified asphalt used is in the range of 4 to 25% by weight. The high content of rubber, etc. in modified asphalt is due to the adhesion of the modified asphalt mixture to aggregate as a binder, ability to grip aggregate,
Toughness, as well as heat resistance, cold resistance, abrasion resistance of the mixture,
This is to increase durability. However, due to the high content of rubber etc., the viscosity when melted becomes high, so
When the content exceeds 25% by weight, the paving properties of the modified asphalt mixture deteriorate due to extremely high viscosity, making it difficult to perform good construction.

In addition to the above, low-molecular solid resins, liquid resins, liquid rubbers, polymerized oils, plasticizers, process oils, animal and vegetable oils, etc. can also be added to modified asphalt.
Furthermore, anti-aging agents, antioxidants, anti-peeling agents, coupling agents, etc. can also be mixed.

The filler used in the filler mixed modified asphalt 1 is limestone powder or crushed igneous rocks, but diatomaceous earth, mica powder, slate powder, slaked lime, fly ash, cement, etc. can also be used. Further, some short fibers such as asbestos, polyester, and glass fibers can also be used.

The amount of filler mixed in the filler-mixed modified asphalt is approximately 70% by weight or less. Generally, 50
It is best to use about % by weight.

The polyethylene film 2 may be made of polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, etc. Generally, a polyethylene film is used. The thickness is about 0.02 to 0.1 mm.

The polyethylene film melts and becomes compatible with the modified asphalt when the molded bituminous pavement binder of the present invention is melted. The amount of polyethylene film at this time is approximately 1% by weight of the modified asphalt.

In addition to the filler described above, silica powder, glass powder, iron sand, silica sand powder, etc. are used as the powder particles 3 such as filler.

To specifically explain the embodiments shown in Figures 1 and 2, the molded bituminous pavement binder has a plate shape with a thickness of approximately 10 mm, a width of approximately 10 cm, and a length of approximately 30 cm. The plate-shaped modified asphalt or filler mixed asphalt 1 with polyethylene film 2 (thickness, for example, 0.03 mm) adhered to both sides is cut into a size of about 10 cm wide x about 30 cm long,
Powder particles 3 such as filler are attached to the cut end. In this type of product, heated and melted modified asphalt or filler-mixed modified asphalt 1 is poured between two polyethylene films 2, 2, and simultaneously cooled with water and passed between two rollers.
Furthermore, it can be made continuously by cooling with water to make a plate of a constant thickness, cutting this, and then dusting it with powder.

FIG. 3 shows a polyethylene bag 2 into which a filler-mixed modified asphalt 1 is poured and cooled to form a plate. FIG. 4 shows a cylindrical polyethylene film 2.
The figure shows a modified asphalt mixture 1 poured into a mold and cooled to form a rod. The molded bituminous pavement binder of this invention can be in the form of a plate, rod, or granule. The polyethylene film 2 can also be wrapped around the entire surface of the modified asphalt or filler-mixed modified asphalt 1, or it can wrap most of the modified asphalt and have filler or other powder particles applied to the unwrapped portion.

Next, in order to clarify the effects of the molded bituminous pavement binder of the present invention, an example will be described in which it was used in a modified asphalt mixture.

[Blend of modified asphalt mixture] Molded product (thickness 10 mm, width 10 cm, length
30cm) 14% by weight These were heated and stirred using a chutsuka with a mixer, and each batch was mixed with 2 tons of No. 7 crushed stone and sand at 180±
The temperature was maintained at 10°C, and a predetermined amount of filler-mixed modified asphalt molded product was added and mixed while the polyethylene film was still attached. Approximately 5 minutes to add the binder, an additional 5 minutes to melt the binder, and an additional 10 minutes to thoroughly mix the binder and aggregate.
The aggregate and binder are uniformly mixed in about 20 minutes in total.
A heated mixture with good physical properties could be obtained. This heated mixture was used to treat asphalt concrete pavement with a thin layer of less than 10 mm in thickness for anti-slip construction, which was then opened to traffic immediately, and it showed very good slip resistance, abrasion resistance, and durability.

The molded bituminous pavement binder of the present invention is easy to handle because it can be directly added to the heated aggregate, and the polyethylene film used for packaging dissolves into the binder and its components As a result, it has excellent effects such as improving the workability and workability of the heated mixture and contributing to deformation resistance when the mixture is compacted into a thin layer pavement without impairing the original physical properties of the binder. be.

[Brief explanation of drawings]

The figures show an example of the molded bituminous pavement binder of the present invention. Figure 1 is a partially cutaway perspective view of the example molded into a cut-out shape, and Figure 2 is a cross-sectional view thereof. 3 is a sectional view of an embodiment formed into a bag shape, and FIG. 4 is a perspective view of an embodiment formed into a rod shape. In the figure, 1 is modified asphalt or filler-mixed modified asphalt, 2 is polyethylene film, and 3 is powder such as filler.

Claims (1)

[Scope of utility model registration request] A molded bituminous pavement binder made by wrapping modified asphalt obtained by mixing rubber or the like with asphalt or mixing a filler with a polyethylene film and forming it into a plate shape or the like.