JP2007002166A - Elastic pavement material and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic pavement material which has superior functionalities in comparison with conventional products by solving problems about an asphalt-based pavement, and improves both workability and slip resistance, and to provide its production method. <P>SOLUTION: The elastic pavement material contains a binder mainly composed of asphalt, an aggregate, rubber tips and/or a rubber powder, and a foaming agent. The amount of the foaming agent added is suitably in the range of 2-10 wt.% of the binder. The method of producing the material is carried out by premixing the binder and the foaming agent, followed by blending the remainder to be added thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an elastic pavement material and a method for producing the same, and more particularly to an elastic pavement material excellent in recyclability, workability, and economy, and a method for producing the same.

  In recent years, in place of conventional dense pavement, drainage pavement that reduces traffic noise by providing a gap inside the pavement is rapidly spreading. According to this drainage pavement, it is possible to reduce the noise by about 3 dB compared to the conventional one, but since there are many areas where this drainage pavement does not provide sufficient noise reduction, further noise reduction is possible. Technology is required.

  As a technology for this, for example, a soundproof wall has been proposed, but this has problems such as increased construction costs and places that cannot be installed due to landscape problems, so the road paving itself With regard to the improvement of the above, a technique capable of realizing a lower noise is desired.

  Pavements that can achieve superior low noise performance over drainage pavements can be broadly classified as follows: (1) Elastic pavement with waste vulcanized rubber added using urethane resin or epoxy resin binder instead of conventional asphalt binder Asphalt pavement material containing waste vulcanized rubber (for example, Patent Document 3, Patent Document 1, Patent Document 2) and (2) Waste vulcanized rubber added to asphalt binder pavement in powder or chip form Patent Document 4).

  Among these, in elastic pavement using a urethane resin binder, it is possible to reduce the noise by 6 to 10 dB compared to dense pavement because rubber can be highly filled, but on the other hand, (i) urethane, etc. Because of the long curing time of the binder, traffic regulation during construction must be performed for a long time (1-2 days), which may cause traffic congestion, etc. (ii) Because it is a curable binder , When recycling the pavement that has been constructed, it cannot be reused by heating, etc., as with asphalt, and (iii) it is expensive compared to asphalt, so it costs a lot when constructed over a large area such as a road There was a problem such as the occurrence of up.

  Among these problems, the problem of curing time has been devised to accelerate the curing reaction with a curing aid or the like, but if the curing time is too early, it depends on the curing reaction while mixing materials and constructing on the road. Thickening occurs, workability is remarkably lowered, and the finished pavement becomes poor in flatness, resulting in a trade-off that the degree of completion is low.

  In addition, in the asphalt pavement containing waste vulcanized rubber, since the asphalt binder is used, the above three problems in the urethane resin binder can be cleared. On the other hand, (i) asphalt and vulcanized rubber Since the adhesion with the rubber is very low, it causes problems such as rubber scattering, and the durability is lowered, so that high filling of rubber cannot be performed. (Ii) Asphalt and modified asphalt currently used The high-viscosity asphalt binder has problems such as low rigidity compared to the urethane resin binder, and it cannot withstand the weight of the vehicle when paved, and digging or the like is likely to occur.

  For this reason, in the asphalt rubber-containing pavement material, the volume ratio of the rubber to the whole is about 5% at most, and the present condition is that the asphalt pavement material highly filled with rubber has not been studied. As a result, the noise reduction effect obtained by these pavement materials is only the same level as or slightly improved from drainage pavement, and it has not been possible to achieve a sufficiently low noise.

  Therefore, the applicant of the present application can perform secondary recycling at low cost in order to simultaneously solve the problems of (1) paving material using a urethane resin binder and (2) paving material using an asphalt binder. As an elastic paving material using asphalt as a binder, a new additive for asphalt paving (Patent Document 5) and an asphalt-based elastic paving material (Patent Document 6) have been proposed.

In addition, as an improvement technique related to a pavement material using asphalt, for example, in Patent Document 7, for the purpose of enabling asphalt to be constructed at a lower temperature, an asphalt mixture containing asphalt and aggregate as essential components, A paving asphalt mixture to which a predetermined organic foaming agent and foaming aid are added is described.
Japanese Patent No. 2869459 Japanese Patent No. 2869458 JP-A-9-165248 JP-A-6-279684 JP 2002-201601 A JP 2002-201311 A JP 2001-131321 A

  However, the asphalt-based elastic pavement using an asphalt binder has a problem that workability is poor because a large amount of a modifier is required to maintain sufficient strength and the viscosity is high. Moreover, in the elastic pavement using such a rubber chip, there has been a problem that the sliding resistance on the wet surface is low.

  Therefore, an object of the present invention is to solve the above-mentioned problems related to asphalt-based elastic pavement, improve workability and increase slip resistance in the obtained elastic pavement, and thereby have a higher-performance elastic pavement material than before. And providing a manufacturing method thereof.

  In order to solve the above-mentioned problems, the elastic pavement material of the present invention comprises a binder mainly composed of asphalt, an aggregate, rubber chips and / or rubber powder, and a foaming agent. is there.

  In the present invention, the amount of the foaming agent added is preferably in the range of 2 to 10% by weight based on the binder. The foaming agent is any one or two selected from the group consisting of 1,1-azobisformamide, N, N-dinitrosopentamethylenetetramine and 4,4-oxybis (benzenesulfonylhydrazide). The above can be preferably used. The elastic pavement material of the present invention preferably further contains at least one of an alkaline earth metal hydroxide or a saturated fatty acid having 14 to 18 carbon atoms as a foaming aid.

  Moreover, the manufacturing method of the elastic pavement material of the present invention is characterized in that, in manufacturing the elastic pavement material, the binder and the foaming agent are mixed in advance, and then the remaining compound is mixed. Moreover, when manufacturing the elastic pavement material containing a foaming auxiliary agent, the said binder, a foaming agent, and a foaming auxiliary agent are mixed previously, and then the remaining compound is mixed.

  According to the present invention, by including a foaming agent in the asphalt-based elastic pavement, it is possible to obtain an elastic pavement having good workability and high slip resistance particularly on a wet surface. It has become possible to realize a high-performance elastic pavement material and a manufacturing method thereof.

Hereinafter, preferred embodiments of the present invention will be specifically described.
The elastic pavement material of the present invention contains a binder mainly composed of asphalt, an aggregate, rubber chips and / or rubber powder, and a foaming agent.

  The asphalt that can be used as a binder in the present invention is not particularly limited, and a conventional asphalt, for example, straight asphalt, semi-blown asphalt, blown asphalt, asphalt emulsion, or a cut added with tar, pitch, oil, etc. Back asphalt, recycled asphalt, etc. can be used. These can be used alone or in combination of two or more. The asphalt may be decolorized asphalt.

  As a material that can be used as a binder component other than asphalt, an ethylene vinyl acetate copolymer (EVA) can be preferably exemplified. As such EVA, for example, those commercially available as trade names EVA720, EVA680, and EVA710 (manufactured by Tosoh Corporation) can be suitably used. The vinyl acetate unit in EVA is preferably 10% by weight or more in order to enhance the adhesion to rubber. The durometer A hardness in accordance with EVA JIS K7215 is preferably 70 or more from the viewpoint of strength. In this invention, what mix | blended EVA 30-80 weight part with asphalt 20-70 weight part can be used suitably as a binder.

  In addition, other thermoplastic elastomers can be added to the binder, for example, in order to improve strength and the like. Examples of such other thermoplastic elastomers include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), and styrene-ethylene-butylene-styrene copolymer (SEBS). One type or a combination of two or more types can be appropriately selected and used. The compounding quantity of these other thermoplastic elastomers can be about 10-50 weight% with respect to all the binders, for example.

  The binder can contain 1 to 40% by weight of a low molecular weight petroleum resin (wax) in order to improve workability. Furthermore, the viscosity of the binder is preferably 10 Pa · s or less from the viewpoint of workability, and the binder may be in the form of pellets having a particle diameter of 5 to 10 mm or in the form of powder. The ratio of the binder in the elastic paving material of the present invention can be about 10 to 35% by weight.

  There is no restriction | limiting in particular as an aggregate used in this invention, Recycled aggregates, such as natural aggregates, such as river gravel and river sand, and crushed stone, slag, concrete, glass, and FRP, can be used. The stone, sand, and the like used for the aggregate are for ensuring the strength and wear resistance of the completed pavement and for exposing to 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 sharp object such as a crushed stone is suitable. Further, it is preferable to mix 5% by volume or more of fine aggregate having a particle size of 0.5 mm or less with respect to coarse aggregate having a particle size of 0.5 to 30 mm. The coarse aggregate mainly forms a porous structure in order to obtain water permeability, and a hard aggregate 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 proportion of aggregate in the elastic pavement material of the present invention is preferably 35 to 55% by weight. If this proportion is less than 35% by weight, the strength is not sufficient, while if it exceeds 55% by weight, sufficient elasticity and bass effect cannot be obtained, which is not preferable.

  The material of the rubber chip and / or rubber powder is not particularly limited, and natural rubber, isoprene rubber, styrene-butadiene rubber, butyl rubber, ethylene-propylene rubber, or the like can be used. Such rubber can be obtained from used waste materials such as rubber tires, weather strips, hoses, etc., unnecessary end materials generated during molding, molding defects, and the like.

  The proportion of rubber in the elastic pavement material of the present invention is preferably 20 to 70% by weight. If this proportion is less than 20% by weight, the effect as an elastic paving material is not sufficient. On the other hand, if it exceeds 70% by weight, sufficient physical properties for application to asphalt pavement cannot be obtained, which is not preferable. The oil used at the time of mixing is not particularly limited. For example, among petroleum oils having three compositions of an aromatic ring, a naphthene ring, and a paraffin chain, an aromatic having an aromatic carbon with a ring analysis result of 36% or more. System oil can be used preferably.

  In the elastic pavement material of the present invention, it is necessary to contain a foaming agent in addition to the binder, the aggregate and the rubber component. By including a foaming agent, good workability can be realized, and the slip resistance of the resulting pavement can be increased, especially on the wet surface, to realize a more functional elastic pavement. It has become possible. The amount of the foaming agent added is preferably 2 to 10% by weight, particularly 3 to 6% by weight, based on the binder. If the amount added is too small, the effect of the present invention may be insufficient. On the other hand, if the amount is too large, no further effect can be expected. Examples of the foaming agent that can be used in the present invention include 1,1-azobisformamide, N, N-dinitrosopentamethylenetetramine, 4,4-oxybis (benzenesulfonylhydrazide), and the like. One or more of these can be preferably used.

  Moreover, it is preferable that the elastic pavement material of this invention contains at least 1 sort (s) of an alkaline-earth metal hydroxide or a C14-C18 saturated fatty acid as a foaming adjuvant. The amount of the foaming aid added is usually about 10 to 500 parts by weight with respect to 100 parts by weight of the foaming agent. For example, as a mixture of these foaming agents and foaming aids, a medium warming agent (Morishita Sangyo Co., Ltd., AMS2000ss, AMS3000) can be suitably used.

  It is preferable that a silane coupling agent is further added to the pavement material of the present invention. Since the adhesion of the stone surface is also obtained by the action of the silane coupling agent, the durability can be further increased. In this case, there is no restriction | limiting in particular in the kind of silane coupling agent to be used, What is necessary is just to select an optimal thing according to the system of the object mixture.

  In the production of the elastic pavement material of the present invention, all the ingredients can be mixed at the same time, but the binder, the foaming agent and, if desired, the foaming aid are premixed and then the remaining composition is mixed. Thus, a method of obtaining a composite material is suitable, and the temperature at the time of mixing is optimally about 180 ° C.

Hereinafter, the present invention will be described based on examples.
As a binder, 50% by weight of EVA680 (manufactured by Tosoh Corporation) and 50% by weight of straight asphalt 60-80 were mixed by stirring at 180 ° C. Elastic pavement materials for each example and comparative example were prepared. First, a binder and a foaming agent were charged and stirred in a stirrer (made by Nikken Co., Ltd.) whose temperature was adjusted to 180 ° C., and then the aggregate and rubber powder were charged, followed by stirring for 20 minutes.

(Evaluation of workability)
The evaluation of the workability was performed by sensory evaluation of the stirrability in the asphalt mixer, the spreadability and the like for each elastic paving material mixture. ○ indicates good and Δ indicates slightly bad.

(Slip resistance measurement)
Moreover, in order to evaluate slip resistance about the pavement obtained from each elastic pavement material, the value of BPN was measured using the pendulum type skid resistance tester according to the standard (KODAN221, KODAN222).
These results are also shown in Table 1 below.

１）森下産業（株）製、ＡＭＳ−２０００
２）森下産業（株）製、ＡＭＳ−３０００

1) Morishita Sangyo Co., Ltd., AMS-2000
2) AMS-3000 manufactured by Morishita Sangyo Co., Ltd.

  From the results of Table 1 above, in the elastic pavement materials of Examples 1 to 3 containing a foaming agent, the workability is better than the elastic pavement material of the comparative example, and the obtained pavement is slippery. It was confirmed that the resistance value was high.

Claims (6)

  An elastic pavement material comprising a binder mainly composed of asphalt, an aggregate, rubber chips and / or rubber powder, and a foaming agent.   The elastic pavement material according to claim 1, wherein the amount of the foaming agent added is in the range of 2 to 10 wt% with respect to the binder.   The foaming agent is at least one selected from the group consisting of 1,1-azobisformamide, N, N-dinitrosopentamethylenetetramine and 4,4-oxybis (benzenesulfonylhydrazide). Item 3. An elastic pavement material according to item 1 or 2.   Furthermore, the elastic pavement material as described in any one of Claims 1-3 which contains at least 1 sort (s) of an alkaline-earth metal hydroxide or a C14-C18 saturated fatty acid as foaming adjuvant.   In producing the elastic pavement material according to any one of claims 1 to 3, the binder and the foaming agent are mixed in advance, and then the remaining compound is mixed. Method.   5. A method for producing an elastic pavement material according to claim 4, wherein the binder, the foaming agent and the foaming aid are mixed in advance, and then the remaining compound is mixed.