JP3747219B2 - Air purification pavement structure and air purification pavement construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pavement structure having an air purification function and a construction method thereof.
[0002]
[Problems to be solved by the invention]
Nitrogen oxide (NO _x ), which continues to be exhausted in large quantities from automobiles every day, is considered to be a major cause of air pollution, and countermeasures are urgently needed.
[0003]
In recent years, titanium oxide photocatalysts (hereinafter, also simply referred to as photocatalysts) have been found to exert a remarkable effect on air purification, and have attracted a great deal of attention. This photocatalyst is already well known, but here, for reference, the air purification function it has will be briefly described.
[0004]
A photocatalyst is a general term for substances that exhibit photocatalysis upon photoexcitation. This photocatalyst placed in contact with the atmosphere combines nitrogen oxides in the atmosphere with, for example, calcium, which is the main component of the photocatalyst fixing material, when receiving sunlight (particularly ultraviolet light having a wavelength of 380 nm or less). , Turning it into neutral calcium nitrate (nitrate). The nitrate thus produced without interruption stays on the surface of the photocatalyst and accumulates there, which means that the nitrogen oxides in the atmosphere are consumed continuously. For these reasons, the atmosphere polluted by nitrogen oxides is gradually purified by the action of the photocatalyst.
[0005]
Note that the nitrate deposited on the surface of the photocatalyst dissolves in rainwater during the rain, separates into nitrate ions and calcium ions (metal ions), and is washed away from the surface of the photocatalyst. As a result, the photocatalyst returns to an initial state where no deposit is present on the surface. That is, in this way, the gradually decreasing air purification capacity is completely restored to the original state, and the photocatalyst exhibits its original function again.
[0006]
By the way, when it is going to purify air | atmosphere using a photocatalyst, it will be very convenient if the road surface which receives exhaust gas directly is comprised using this photocatalyst. By doing so, the photocatalyst always comes into contact with a gas having a high nitrogen oxide concentration, and high purification efficiency is obtained. Examples of conventional techniques for constructing a road surface using a photocatalyst include those disclosed in Japanese Patent Application Laid-Open No. 2000-45208.
[0007]
This technology sprays cement mortar in which fine powder of titanium oxide is dispersed on the surface of the road on which drainage pavement has been applied, that is, the road surface is coated with a very thin layer having an air purification function. Features. Although the roads thus obtained certainly contribute to the purification of the air to some extent, they have the following problems.
[0008]
For example, on major main roads where large vehicles such as trucks and other heavy traffic are used, roads are rapidly worn in uphill or downhill sections and intersections, as well as in parking areas where vehicles frequently stop and start. Proceed to Therefore, even if an air purification function is imparted to the road surface at such a location using the above technique, the function (in other words, the layer having the air purification function) disappears in an extremely short period of time.
[0009]
Of course, the life of the layer having the air purification function is very short even in other places. Therefore, until now, it has been necessary to frequently perform the operation of spraying cement mortar containing fine powder of titanium oxide at fairly short intervals.
[0010]
Therefore, the problem to be solved by the present invention is to provide an air purification pavement structure that exhibits an excellent air purification function over a long period of time. In particular, it is to provide an air purification pavement structure that has high pavement strength and good durability and exhibits an excellent air purification function over a long period of time.
[0011]
[Means for Solving the Problems]
The above problem is that the base layer portion provided on the roadbed,
; And a asphalt mixture layer having voids therein which constitutes a road surface provided on said base portion,
The problem is solved by an air purification pavement structure characterized in that titanium oxide fine powder and a fixing material for fixing the titanium oxide fine powder are filled in the voids of the asphalt mixture layer .
[0012]
In addition, a base layer provided on the roadbed,
Comprising an asphalt mixture layer having a void inside the road surface provided on the base layer portion;
The asphalt mixture layer having voids inside the road surface,
A first asphalt mixture layer located on the upper side;
A second asphalt mixture layer located below the first asphalt mixture layer and integral with the first asphalt mixture layer
And consist of
The voids of the first asphalt mixture layer are filled with titanium oxide fine powder and a fixing material for fixing the titanium oxide fine powder,
The second asphalt mixture layer is solved by the air purification pavement structure characterized by not being filled with titanium oxide .
[0013]
In addition, a base layer provided on the roadbed,
Comprising an asphalt mixture layer having a void inside the road surface provided on the base layer portion;
The asphalt mixture layer having voids inside the road surface,
A first asphalt mixture layer located on the upper side;
A second asphalt mixture layer located below the first asphalt mixture layer and integral with the first asphalt mixture layer
And consist of
The voids of the first asphalt mixture layer are filled with titanium oxide fine powder and a fixing material for fixing the titanium oxide fine powder,
The second asphalt mixture layer is filled with a filler, but is not filled with titanium oxide, which is solved by an air purification pavement structure.
[0015]
Examples of the fixing material for fixing the fine powder of titanium oxide include a solidified grout material obtained by mixing at least cement, aggregate, and water. Similarly, examples of the fixing material for fixing the fine powder of titanium oxide include a solidified grout material obtained by mixing at least a resin and an aggregate.
[0016]
Furthermore, in the present invention, the surface layer portion may have water impermeability, or the surface layer portion may have water permeability. Whether the surface layer portion is impervious or water-permeable is selected in consideration of the situation of each place where pavement is applied and the characteristics required there.
[0017]
For example, when paving a bridge, imperviousness is imparted to the surface layer so that rainwater does not penetrate inside. On the other hand, in other parts of the road, basically, water permeability is given to the surface layer portion in order to improve drainage of the road surface. By the way, adjustment of the water permeability (if the water permeability is zero, the surface layer part has impermeableness) is, for example, integrating the particle size of the aggregate, which is the raw material of the grout material, and the like. This is done by changing the type of binder (cement mortar, resin, etc.) or by using an additive.
[0018]
Moreover, for constructing an air purification pavement having the above-described structure (particularly, the surface layer portion is an asphalt mixture layer, and the space of the asphalt mixture layer is filled with fine powder of titanium oxide and a fixing material). A method,
A step of forming a base layer on the roadbed;
B step of forming an asphalt mixture layer having voids inside on the base layer portion;
An air purification pavement construction comprising a C step of filling a titanium oxide-containing grout material obtained by dispersing fine powder of titanium oxide in a grout material in the voids of the asphalt mixture layer Solved by the method.
[0019]
In addition, the structure (particularly, the surface layer portion includes a first asphalt mixture layer and a second asphalt mixture layer, and the titanium oxide fine powder and the titanium oxide fine powder are placed in the voids of the first asphalt mixture layer. An air purification pavement that is filled with a fixing material for fixing powder, and that has a structure in which the filler is filled in the space of the second asphalt mixture layer but is not filled with titanium oxide). A method for building,
A step of forming a base layer on the roadbed;
B step of forming an asphalt mixture layer having voids inside on the base layer portion;
C step of filling a grouting material into the voids of the asphalt mixture layer up to the height of the boundary surface between the first asphalt mixture layer and the second asphalt mixture layer;
After the step C, a step D in which a titanium oxide-containing grout material obtained by dispersing fine powder of titanium oxide in a grout material is filled in the voids of the asphalt mixture layer up to the surface height of the asphalt mixture layer. It is solved by an air purification pavement construction method characterized by comprising:
[0020]
As described above, when the surface layer portion (especially the first layer) provided on the base layer portion and constituting the road surface is formed of a material containing titanium oxide that functions as a photocatalyst, the vehicle passes. Even when the road surface is worn, a new surface in which titanium oxide is scattered, that is, a surface having an air purification function, constantly appears. Therefore, the problem that the air purification function on the road surface disappears in a short period of time does not occur as before, and the air purification ability on the road surface becomes semi-permanent.
[0021]
That is, when the air purification pavement structure according to the present invention is employed, an excellent air purification function is exhibited over a long period of time. Furthermore, when the space of the asphalt mixture layer constituting the surface layer portion is filled with a fixing material (or filler) for fixing the fine powder of titanium oxide therein, the surface layer portion resulting from the presence of the space As a result, the strength of the surface layer, and thus the pavement, is greatly improved. In general, by using the technology according to the present invention, an air purification pavement structure having high pavement strength and good durability and exhibiting an excellent air purification function over a long period of time is realized.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the first embodiment of the present invention will be specifically described with reference to FIGS. 1 and 2. In addition, in FIG. 1, the structure of the air purification pavement which concerns on this embodiment is shown with a cross section, and the procedure at the time of constructing the air purification pavement is shown to FIG. 2 (a)-(c).
[0023]
The air purification pavement in which the air purification pavement structure according to the present embodiment is adopted includes a base layer portion 2 provided on the roadbed 1 and a road surface provided on the base layer portion 2, as can be seen from FIG. The surface layer part 3 which comprises.
[0024]
Of these, the roadbed 1 and the base layer 2 may be the same as those constituting the existing pavement, and need not be described in particular. On the other hand, the surface layer part 3 is comprised from the material containing the titanium oxide which functions as a photocatalyst.
[0025]
More specifically, as shown in FIG. 1, a part of the surface layer portion 3 is enlarged, and an open-graded asphalt mixture layer (hereinafter simply referred to as an asphalt mixture layer) 11 having voids inside, and titanium oxide. And a fixing material 13 for fixing the titanium oxide fine powder 12 in the voids of the asphalt mixture layer 11. In addition, the porosity of the asphalt mixture layer 11 is normally set to about 10 to 30%.
[0026]
Of these, the fixing material 13 is a solidified grout material (cement mortar) obtained by mixing cement, aggregate and water. In FIG. 1, reference numeral 11 a indicates an aggregate forming the asphalt mixture layer 11, not the above-described aggregate (this aggregate is not shown) which is a component of the grout material. The internal space of the asphalt mixture layer 11 is a space between the aggregates 11a.
[0027]
However, instead of the grout material having such a composition, for example, a grout material obtained by mixing an epoxy resin and an aggregate can be used. That is, examples of the fixing material for fixing the fine powder of titanium oxide include a material obtained by solidifying a grout material obtained by mixing this resin and aggregate.
[0028]
In addition, in this embodiment, water impermeability is imparted to the surface layer portion 3. However, if necessary, the surface layer portion 3 can be provided with water permeability. That is, when the fixing member 13 constituting the surface layer portion 3 is formed from a grout material obtained by mixing resin and aggregate, the surface layer portion 3 can be made water-permeable by using an appropriate type of resin or additive. To come out.
[0029]
The air purification pavement having the above structure is obtained by using the air purification pavement construction method according to the present embodiment, and this air purification pavement construction method is carried out by the following procedure. Hereinafter, the air purification pavement construction method, that is, the air purification pavement construction method according to the present embodiment (hereinafter referred to as the present construction method) will be described.
[0030]
In carrying out this construction method, first, the base layer portion 2 is formed on the roadbed 1 [step A: see FIG. 2 (a)]. Then, the asphalt mixture layer 11 which has a space | gap inside is formed on the base layer part 2 [B process: refer FIG.2 (b)]. In addition, until now, it becomes the work content similar to the case where the conventional pavement construction method is used.
[0031]
Now, when the asphalt mixture layer 11 is completed in this way, subsequently, in the voids of the asphalt mixture layer 11, grout material (here, cement, fast-hardening material, aggregate sand, resin, delay material) And titanium oxide-containing grout material 14 in which fine powder of titanium oxide is dispersed in water) (step C: see FIG. 2 (c)). Then, the filled grout material 14 is cured and solidified for a certain period of time, so that the surface layer portion 3 is completed. Therefore, the air purification pavement having the structure according to the present embodiment is completed.
[0032]
By the way, the air purification pavement thus obtained not only has an air purification function, but also has high strength (rigidity) because there is no void in the surface layer portion 3 as will be described later. In this embodiment, these features are regarded as important as the air purification function, and the mixing ratio (mass ratio) of fine powder of titanium oxide, cement, quick-hardening material, sand, resin, retarder, and water is 7:74:25. : 18: 5: 4: 67. By the way, the pavement having no voids in the interior thus obtained is called “semi-flexible pavement” regardless of whether it contains titanium oxide or not.
[0033]
On the other hand, when using what was obtained by mixing resin and aggregate as the grout material and further imparting water permeability to the surface layer portion, that is, when not giving much importance to pavement strength, a titanium oxide-containing grout material For example, the mixing ratio (mass ratio) of fine powder of titanium oxide, crushed stone as an aggregate, and epoxy resin is set to 6:12:88. Under this condition, water permeability is imparted to the surface layer portion as described above, and as a result, the finished air purification pavement has the required drainage characteristics.
[0034]
Thus, in this embodiment, the surface layer part 3 provided on the base layer part 2 and constituting the road surface is formed from a material containing titanium oxide that functions as a photocatalyst. For this reason, even if the road surface is worn by the passage of the vehicle, a new surface in which titanium oxide is scattered, that is, a surface having an air purification function constantly appears. Therefore, the problem that the air purification function on the road surface disappears in a short period of time does not occur as before, and the air purification ability on the road surface becomes semi-permanent.
[0035]
In other words, when the air purification pavement structure according to the present embodiment is adopted, an excellent air purification function is exhibited over a long period of time. Furthermore, in this embodiment, since the space | gap of the asphalt mixture layer 11 which comprises the surface layer part 3 was filled with the fixing material 13 for fixing the fine powder 12 of titanium oxide in the inside, the surface layer resulting from presence of this space | gap The brittleness of the part 3 is greatly improved. As a result, the strength of the surface layer portion 3 and thus the entire pavement is remarkably improved. As described above, by using the technology according to the present embodiment, an air purification pavement structure having high pavement strength and good durability and exhibiting an excellent air purification function over a long period of time is realized.
[0036]
Next, the second embodiment of the present invention will be specifically described with reference to FIGS. 3 and 4. Here, in FIG. 3, the structure of the air purification pavement according to this embodiment is shown in cross section, and FIGS. 4A to 4D show the procedure for constructing the air purification pavement. In this embodiment, the basic technical idea, the basic structure other than the main part, and the effects achieved by it are substantially the same as those in the first embodiment. Therefore, the following description will focus on differences from the first embodiment.
[0037]
The air purification pavement in which the air purification pavement structure according to the present embodiment is also adopted, as can be seen from FIG. 3, the base layer portion 22 provided on the roadbed 21 and the road surface provided on the base layer portion 22. The surface layer part 23 which comprises. And among these, the surface layer part 23 is comprised from the material containing the titanium oxide which functions as a photocatalyst.
[0038]
More specifically, the surface layer portion 23 includes a first layer 31 located on the upper side and a second layer 32 located below the first layer 31. However, both are integral and cannot be separated.
[0039]
Of the first layer 31 and the second layer 32 constituting the surface layer portion 23, the former, that is, the first layer 31 in contact with the atmosphere is made of a material containing titanium oxide as described above. On the other hand, the latter, that is, the second layer 32 not in contact with the atmosphere, is made of a material that does not contain titanium oxide. In the present embodiment, as described later in detail, the grout material is filled so that no voids are present in the second layer 32. However, depending on the case, the grout material and the like are filled at all. Instead, the air gap may be left as it is inside the second layer 32.
[0040]
Now, as shown in FIG. 3 with a part thereof enlarged, the first layer 31 is similar to the surface layer portion in the first embodiment, and the first asphalt mixture layer 41 having voids therein, and the oxidation. The fine powder 42 of titanium and the fixing material 43 for fixing the fine powder 42 of titanium oxide in the voids of the first asphalt mixture layer 41 are configured.
[0041]
Of these, the fixing material 43 is a solidified grout material (cement mortar) obtained by mixing cement, aggregate and water. In FIG. 3, reference numeral 41 a denotes an aggregate forming the first asphalt mixture layer 41, not the above-described aggregate (this aggregate is not shown) which is a component of this grout material. The internal space of the first asphalt mixture layer 41 is a space between the aggregates 41a.
[0042]
On the other hand, the second layer 32 has a second asphalt mixture layer 44 having a void inside and a void of the second asphalt mixture layer 44 as shown in FIG. It is comprised from the filler 45 which fills up. However, needless to say, the first asphalt mixture layer 41 and the second asphalt mixture layer 44 are inseparable.
[0043]
The filler 45 has the same components as the fixing material 43. That is, here, a solidified grout material in which titanium oxide is dispersed is called a “fixing material”, while a solidified grout material containing no titanium oxide is called a “filler”. In FIG. 3, what is indicated by 44a is not the above-mentioned aggregate (this aggregate is not shown), which is a component of this grout material, but an aggregate forming the second asphalt mixture layer 44. The internal voids of the second asphalt mixture layer 44 are voids between the aggregates 44a.
[0044]
However, instead of the grout material having such a composition, for example, a grout material obtained by mixing an epoxy resin and an aggregate can be used. That is, examples of the fixing material (or filler) for fixing the fine powder of titanium oxide include those obtained by solidifying a grout material obtained by mixing this resin and aggregate.
[0045]
In addition, in the present embodiment, water impermeability is imparted to the surface layer portion 23. However, if necessary, the surface layer portion 23 can be provided with water permeability by using a grout material obtained by mixing resin and aggregate.
[0046]
The air purification pavement having the above structure is obtained by using the air purification pavement construction method according to the present embodiment, and this air purification pavement construction method is carried out by the following procedure. Hereinafter, the construction method for the air purification pavement, that is, the air purification pavement construction method according to the present embodiment (hereinafter referred to as the construction method again) will be described.
[0047]
In carrying out this construction method, first, the base layer portion 22 is formed on the roadbed 21 [step A: see FIG. 4A]. Subsequently, an asphalt mixture layer 23 ′ having voids inside is formed on the base layer portion 22 [step B: see FIG. 4B]. In addition, until now, it becomes the work content similar to the case where the conventional pavement construction method is used.
[0048]
When the asphalt mixture layer 23 'is completed in this manner, the height of the boundary surface between the first asphalt mixture layer 41 and the second asphalt mixture layer 44 [one point in FIG. The gap of the asphalt mixture layer 23 'is filled with, for example, the grout material 46 (but not containing titanium oxide) having the same composition as that used in the first embodiment until it is indicated by a chain line [Step C]. : See FIG. 4 (c)].
[0049]
After the grout material 46 cured for a certain period of time and solidified in this C step is solidified to some extent (that is, after the second layer 32 is completed), the asphalt mixture layer 23 ′ further has a void in it. Titanium oxide-containing grout material 47 in which fine powder of titanium oxide is dispersed is filled in a grout material of the same quality as the previous one up to the surface height of this asphalt mixture layer 23 '[D step: see FIG. 4 (d) ]. Then, the filled grout material 47 is cured and solidified for a certain period of time, whereby the first layer 31 and thus the surface layer portion 23 are completed, and the air purification pavement having the structure according to the present embodiment is completed. Become.
[0050]
The air purification pavement thus obtained also exhibits an excellent air purification function over a long period of time. In addition to this, pavement strength is high and good durability is exhibited. In addition, the amount of titanium oxide that is a photocatalyst can be reduced as compared with the first embodiment.
[0051]
【The invention's effect】
According to the present invention, an air purification pavement structure that exhibits an excellent air purification function over a long period of time can be obtained. In particular, an air purification pavement structure having high pavement strength and good durability and exhibiting an excellent air purification function over a long period of time can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the structure of an air purification pavement according to a first embodiment of the present invention. FIGS. 2 (a) to (c) are for constructing the air purification pavement according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing the structure of an air purification pavement according to the second embodiment of the present invention. FIGS. 4A to 4D are views of the atmosphere according to the second embodiment of the present invention. Schematic diagram showing the procedure for building a clean pavement [Explanation of symbols]
1 Subbase 2 Base Layer 3 Surface Layer 11 Open-Grade Asphalt Mixture Layer (Asphalt Mixture Layer)
11a Aggregate 12 Titanium oxide fine powder 13 Fixing material 14 Titanium oxide-containing grout material

Claims (6)

A base layer provided on the roadbed;
Comprising an asphalt mixture layer having a void inside the road surface provided on the base layer portion;
The asphalt mixture layer is
A first asphalt mixture layer located on the upper side;
A second asphalt mixture layer located below the first asphalt mixture layer and integral with the first asphalt mixture layer;
Wherein the first air gap of the asphalt mixture layer, fixing material for fixing the titanium oxide fine powder and titanium oxide fine powder is filled,
The air purification pavement structure characterized in that the space in the second asphalt mixture layer is filled with a filler but not with titanium oxide . 2. The air purification pavement structure according to claim 1, wherein the fixing material for fixing the fine powder of titanium oxide is a solidified grout material obtained by mixing at least cement, aggregate, and water . The air purification pavement structure according to claim 1, wherein the fixing material for fixing the fine powder of titanium oxide is a solidified grout material obtained by mixing at least resin and aggregate . The air purification pavement structure according to any one of claims 1 to 3, wherein the surface layer portion is impermeable . The air purification pavement structure according to any one of claims 1 to 3, wherein the surface layer portion has water permeability . A method for constructing the air purification pavement of claim 1, comprising:
A step of forming a base layer on the roadbed;
B step of forming an asphalt mixture layer having voids inside on the base layer portion;
C step of filling a grout material not containing titanium oxide in the voids of the asphalt mixture layer up to the height of the boundary surface between the first asphalt mixture layer and the second asphalt mixture layer;
After Step C, Step D is used to fill the voids of the asphalt mixture layer with a titanium oxide-containing grout material obtained by dispersing fine powder of titanium oxide in the grout material up to the surface height of the asphalt mixture layer.
An air purification pavement construction method characterized by comprising:

Images