JP2008045274A - Elastic pavement body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic pavement body which ensures high slippage resistance (wet μ) in wet conditions not only in an initial service stage thereof but also after worn caused by long service life thereof. <P>SOLUTION: The elastic pavement body contains rubber, aggregate, and a urethane binder. The aggregate contains shirasu balloon. The content of the shirasu balloon is preferably in the range of 1 to 20 vol.%, and a particle diameter of the same is preferably in the range of 1 to 1,000 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an elastic pavement (hereinafter also simply referred to as “pavement”), and more particularly, to an elastic pavement related to improvement of slip resistance (wet μ) when wet.

  Conventionally, a low noise elastic pavement using a curable resin such as urethane or epoxy as a binder is known as a method of using vulcanized rubber in the form of powder or chips. In addition, an elastic pavement in which rubber chips are mixed with a binder and press-molded is used on sidewalks, playgrounds, roadways, and the like.

  The elastic pavement using these vulcanized rubbers has excellent effects such as shock absorption during walking and safety during falling due to the elasticity of the vulcanized rubber, and since it has voids inside, it has drainage and In addition to breathability, it also has excellent sound absorption, so it is also effective in reducing noise generated on tires and road surfaces, so it is also attracting attention as a functional elastic pavement material for reducing traffic noise in urban areas. .

Regarding such an elastic pavement material, for example, in Patent Document 1, as a technique for promoting material recycling, a crushed material of a thermosetting resin molded product and a rubber chip are mixed at a predetermined mixing ratio, and a urethane resin is used as a binder. Pavement materials formed into blocks or plates have been proposed. In Patent Document 2, a lightweight waste such as rubber or plastic is crushed to an appropriate size as an aggregate, and a composition obtained by mixing the aggregate and a binder such as urethane resin is cured. A pavement block is disclosed.
JP 2002-322602 A (Claims etc.) JP 2000-34702 A (Claims etc.)

  However, the elastic pavement using a urethane resin as a binder among the curable resins has a problem that the slip resistance (wet μ) in a wet state such as rainy weather is low. On the other hand, in the paving material described in Patent Document 1, excellent slip resistance is obtained by mixing a thermosetting resin molded product and a rubber chip with a urethane resin binder. Is considering only the slip resistance in an unused state, and it has been desired to realize a pavement that can obtain a good wet slip resistance even after wear due to use.

  Accordingly, an object of the present invention is to provide an elastic pavement that solves the above-described problems and can ensure slip resistance in a wet state not only in the initial use but also after wear.

  As a result of intensive studies, the inventor has mixed and used a shirasu balloon with a commonly used stone or sand as an aggregate for elastic pavement, so that it can be used both wet and after wear. The inventors have found that the slip resistance can be improved and have completed the present invention.

  That is, the elastic pavement of the present invention is an elastic pavement containing rubber, an aggregate, and a urethane binder, wherein the aggregate contains a shirasu balloon.

  In the elastic pavement of the present invention, the content of the shirasu balloon is preferably in the range of 1 to 20% by volume, and the particle size of the shirasu balloon is preferably in the range of 1 μm to 1000 μm. .

  The elastic pavement of the present invention preferably contains 30 to 60% by volume of the rubber, 50 to 5% by volume of the aggregate, and 20 to 35% by volume of the urethane binder.

  According to the present invention, the above configuration makes it possible to realize an elastic pavement that can ensure slip resistance not only in the initial stage of use but also in a wet state even after wear.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The elastic pavement of the present invention contains rubber, an aggregate, and a urethane binder, and is characterized by containing a shirasu balloon as a part of the aggregate.

  As a result, it is possible to improve the slip resistance in the wet state, which was difficult to ensure with the conventional urethane-based elastic pavement, and to obtain an elastic pavement that can exhibit excellent slip resistance during wet as well as in the initial use. It became possible.

  A shirasu balloon is a fine hollow structure obtained by foaming a shirasu by heating, and is easily available on the market. In the present invention, any shirasu balloon may be used, but one having a particle size of about 1 μm to 1000 μm is preferably used. If the particle size is too small, the workability deteriorates due to an increase in viscosity. On the other hand, if the particle size is too large, a sufficient improvement effect cannot be obtained, which is not preferable. Specifically, for example, trade name Shirasu Balloon Five Star manufactured by SK Life Co., Ltd., trade name Towanalite manufactured by Toyokazu Nao Co., Ltd. can be used.

  Further, the content of the shirasu balloon in the elastic pavement of the present invention is preferably 1 to 20% by volume, more preferably 4 to 10% by volume. If the content of the shirasu balloon in the elastic pavement is too small, the effect of improving the wet μ according to the present invention may be insufficient. On the other hand, if the content is too large, the workability deteriorates, which is not preferable.

  In the elastic pavement of the present invention, any shirasu balloon may be used as a part of the aggregate, and other points can be appropriately configured according to a conventional method, and are not particularly limited. .

  Rubber such as rubber chips and rubber powder used in the present invention is blended in an elastic pavement to give elasticity to the pavement surface, and the material is not particularly limited, natural rubber or isoprene rubber, Styrene-butadiene rubber, butyl rubber, ethylene-propylene rubber or the like can be used. Such rubber chips and rubber powders can also be obtained from waste materials of used vulcanized rubber products such as rubber tires, weather strips, hoses, etc., unnecessary end materials generated during molding, molding defects, and the like. As the rubber chip and rubber powder, fine particles having a particle size of 1 mm or less to those having a particle size of about 10 mm can be used as appropriate, and those having a particle size of about 1 to 5 mm are particularly suitable for elasticity and void formation. It is more preferable because it is effective in terms.

  The compounding quantity of the rubber in the elastic pavement of this invention is 30-60 volume%, Preferably it is 40-55 volume%. If this proportion is less than 30% by volume, the effect as an elastic pavement is not sufficient, while if it exceeds 60% by volume, sufficient physical properties for application to pavement cannot be obtained.

  In the present invention, as the aggregate used in addition to the above Shirasu balloon, conventional natural aggregate can be used, specifically, for example, natural aggregate such as silica sand, river gravel, river sand and crushed stone, Examples include recycled aggregates such as slag, concrete, glass, and FRP. The stone, sand, etc. used for these aggregates are intended to ensure the strength and wear resistance of the finished pavement and to be exposed on the surface to obtain an anti-slip effect. The stone materials preferably have a function of meshing with each other to disperse the load. For this reason, a hard stone having a sharp shape such as crushed stone is suitable.

  Moreover, it is preferable to mix 5 volume% or more of fine aggregates with a particle size of 0.5 mm or less with respect to the coarse aggregate with a particle size of 0.5-30 mm normally. As the coarse-grained aggregate, a hard one having a sharp shape like a crushed stone that meshes with each other to form a gap is suitable. On the other hand, the fine-grained aggregate adheres to the surface of the large-sized coarse-grained aggregate and brings about an anti-slip action (polishing effect like sandpaper) on the tire or the like.

  The blending amount of the aggregate in the elastic pavement of the present invention is 50 to 5% by volume, preferably 30 to 10% by volume as the total amount of the shirasu balloon and other aggregates. If the ratio of the aggregate in the elastic pavement is less than 5% by volume, the strength is not sufficient, while if it exceeds 50% by volume, sufficient elasticity and bass effect cannot be obtained.

  The urethane binder is used to bind aggregates or rubber chips to form a pavement, and particularly as a two-component urethane binder, preferably an isocyanate group terminal prepolymer and a polyol are hydroxyl group / isocyanate group. For example, a mixture of 0.2 to 0.8 is used. The one-component urethane binder is very difficult to adjust the curing time compared to the two-component urethane binder, is not versatile, and has a difficulty in shortening the curing time.

  In addition, as an example of the isocyanate terminal group prepolymer of a two-component urethane binder, the isocyanate content is 5 to 25%, the viscosity is 1000 to 5000 cP (25 ° C.), and the average number of functional groups of the isocyanate terminal group prepolymer is 2 to 3. Things. Examples of the isocyanate for the prepolymer include diphenylmethane diisocyanate polyisocyanate. As the active hydrogen compound used for modification, polyalkylene glycol having a molecular weight of about 1000 to 3000 is usually used.

  On the other hand, as an example of the polyol, it is preferable that the average number of functional groups is 2 to 6, the average molecular weight is 1000 or less, and more than half of the hydroxyl groups are primary hydroxyl groups from the viewpoint of reactivity. Examples include glycol, diethylene glycol, and polyalkylene ether glycol.

  The blending amount of such a urethane binder is 20 to 35% by volume, preferably 20 to 30% by volume from the viewpoint of the binding strength of the aggregate.

  In addition, in the elastic pavement of the present invention, the organic silane is added in an amount of 0.1 to 10% by volume with respect to the urethane binder, thereby increasing the bonding strength between the urethane binder and the aggregate, thereby improving the strength and durability. Improvements can be made. As such an organic silane, an epoxy silane, mercapto silane or the like can be used.

  Furthermore, the elastic pavement of the present invention may contain a urethane binder curing accelerator and other additives such as antioxidants and ultraviolet absorbers.

  The elastic pavement of the present invention can be obtained by mixing a urethane binder and an additive that is added as necessary, to a mixture of aggregate containing a shirasu balloon and rubber. The mixing method in this case is not particularly limited, and any method that can uniformly mix these may be used. The temperature at the time of addition and mixing of the urethane binder to the aggregate may be normal temperature, but curing is delayed at a low temperature, and curing is accelerated at a high temperature. Therefore, it is preferable to adjust the temperature as necessary.

  Such an elastic pavement is usually constructed and cured in a thickness of about 10 to 50 mm so that voids with a porosity of about 10 to 40% are formed.

  The elastic pavement of the present invention may be one (primary construction type) in which a pavement surface is formed by laying directly after applying a primer treatment to a road surface to be constructed as necessary. A block-shaped molded product (press-molded product) molded and cured in a predetermined shape with a mold may be laid on the construction surface, and is not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Sample preparation)
Mixed silica sand as aggregate (3: 5: 6: 7: 3: 3: 3: 2.5 (weight ratio)) and Shirasu Balloon (trade name Shirasu Balloon Five Star manufactured by SK Life Co., Ltd.) , Particle size 10-500 μm, average particle size 170 μm), rubber powder (particle size 2-5 mm), urethane binder (main agent RB-08 / curing agent Hex-2 (both manufactured by Nippon Polyurethane Industry Co., Ltd.)) = 95/5 (weight ratio)) were mixed in the formulation shown in Table 1 below, and the mixture was put into a mixer and stirred at room temperature for 5 minutes. Then, this was filled in a 50 × 50 × 2.5 cm rectangular parallelepiped mold and cured for 2 to 3 days to prepare a sample.

(DFT measurement)
About the obtained sample, the slip resistance test in the wet state at the time of 60 km / h driving | running | working was done with the dynamic friction tester (DFT). Further, in order to measure the wet μ after wear, the sliding tester (accelerated wear tester) shown in FIG. 1 (load of 50 kg manufactured by Nakajima Technical Sales, tire 11: tire for small truck, rotation speed of table 10: The surface of the specimen was worn at 2000 rpm at 17 rpm (free) and the rotation speed of the tire 11 was 10 rpm, and wet μ was measured again by DFT. In the testing machine shown in the figure, the sample 1 is placed on a disk-shaped table 10 and the tire 11 is rotated at a fixed position while a load of 50 kg is applied via the arm 12 that fixes the tire 11. At the same time, the table 10 is rotated to wear a position having a radius of 15 cm on the sample 1 as a measurement position by DFT.
These results are also shown in Table 1 below.

  As shown in Table 1 above, it was confirmed that in the elastic pavement of the example containing the shirasu balloon as the aggregate, high slip resistance in the wet state was obtained both in the initial stage and after the wear. On the other hand, in the elastic pavement of the comparative example which does not contain the shirasu balloon, although good wet slip resistance is obtained in the initial stage, the wet slip resistance after wear is reduced. I understand that.

It is the schematic which shows the accelerated abrasion tester used in the Example.

Explanation of symbols

1 Elastic pavement sample (test body)
10 Table 11 Tire 12 Arm

Claims (4)

  An elastic pavement containing rubber, an aggregate, and a urethane binder, wherein the aggregate contains a shirasu balloon.   The elastic pavement according to claim 1, wherein the content of the shirasu balloon is in the range of 1 to 20% by volume.   The elastic pavement according to claim 1 or 2, wherein a particle diameter of the shirasu balloon is in a range of 1 µm to 1000 µm.   The elastic pavement according to any one of claims 1 to 3, wherein the rubber is contained at 30 to 60% by volume, the aggregate is contained at 50 to 5% by volume, and the urethane binder is contained at 20 to 35% by volume.

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