JP2005068900A - Water retentive pavement structure, its construction method and its water retentive function maintaining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water retentive pavement structure capable of retaining water by absorbing moisture in outside air; a construction method of the water retentive pavement structure; and a water retentivity maintaining method of the water retentive pavement structure. <P>SOLUTION: This water retentive pavement structure 1 has an opening grain size mixture layer 5 having a continuous void inside, and a water retentive and hygroscopic filler 10 filled in this continuous void, and formed by mixing water retentive grout 11 and a hygroscopic material 12; and is characterized by retaining moisture by the water retentive grout 11, by absorbing the moisture in the outside air by the hygroscopic material 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water retentive pavement structure, a construction method for a water retentive pavement structure, and a method for maintaining a water retentive function of a water retentive pavement structure.

  The surface temperature of asphalt pavement under the hot summer heat is easy to absorb sunlight because the color of the asphalt is black, and may reach 60 ° C. or higher. Especially in urban areas where the road pavement ratio is high, it is one of the causes of the heat island phenomenon. Therefore, how to lower the surface temperature of asphalt pavement is an important issue in mitigating the heat island phenomenon.

  Conventionally, in order to solve such a problem, a water-retaining pavement structure having a water retention function has been proposed. According to such a water-retaining pavement structure, when the surface temperature rises due to an increase in the temperature of the outside air or direct sunlight, the retained water vaporizes. As the moisture vaporizes, the heat of the outside air near the surface of the water retentive pavement structure or the heat of the water retentive pavement structure itself is deprived, thereby suppressing the rise of the surface of the water retentive pavement structure.

In connection with such a technique, the present applicant has proposed a perforated surface layer (water-retaining pavement structure) in which an internal void is filled with a silt-based filler (water-retaining grout) having water retention and water permeability. (See Patent Document 1).
Japanese Patent No. 3156151 (page 3-14, Fig. 1-3)

  However, the conventional water-retaining pavement structure has a problem that it cannot retain water unless it is caused by artificial watering, rainfall, or the like.

  Then, this invention makes it a subject to provide the water retention pavement structure which can absorb and hold | maintain the water | moisture content in external air, the construction method of a water retention pavement structure, and the water retention maintenance method of a water retention pavement structure.

  As a means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that an open particle size mixture layer having continuous voids therein and a water retention grout and a moisture absorbent filled in the continuous voids are mixed. A water-retaining pavement structure characterized in that it has a moisture-absorbing filler, moisture in the outside air is absorbed by the moisture-absorbing material, and the moisture can be retained by the water-retaining grout.

Here, as long as the open particle size mixture layer has continuous voids therein, the type and aspect of the mixture are not particularly limited. For example, an open particle size asphalt mixture layer, an open particle size cement mixture layer, an open particle size resin mixture layer, etc. Can be mentioned.
When the open particle size mixture layer is an open particle size asphalt mixture layer, the mixing ratio of the aggregate, the amount of asphalt binder, the porosity, the density, etc. may be any. Moreover, the open-graded asphalt mixture layer may be constructed once or may be constructed multiple times. Furthermore, in the case of an open-graded asphalt mixture layer that has been applied multiple times, the types of each open-graded asphalt mixture that forms this open-graded asphalt mixture layer may be different.

According to such a water-retaining pavement structure, the hygroscopic material absorbs moisture in the outside air, and the absorbed moisture is retained by the water-retaining grout. Therefore, it is possible to retain water with a water retention grout without depending on watering such as rainfall.
Further, the hygroscopic material is filled in the continuous voids of the open particle size mixture as a water-holding and hygroscopic filler having water retention and moisture absorption mixed with the water retention grout. Therefore, the hygroscopic material adheres to the water retention grout and also to the open particle size mixture, and it is possible to suitably prevent the hygroscopic material from eluting.

  The invention according to claim 2 is a water retentive / hygroscopic filler which is filled with a water retentive / hygroscopic filler formed by mixing a water retentive grout and a hygroscopic material from the surface of an open particle size mixture layer having continuous voids therein. It is the construction method of the water-retaining pavement structure characterized by including a filling process.

  According to the construction method of such a water retentive pavement structure, by filling a water retentive / hygroscopic filler formed by mixing a water retentive grout and a hygroscopic material into the continuous voids of the open particle size mixture layer (water retentive / Hygroscopic filler filling step), water retention grout and hygroscopic material can be fixed to the open particle size mixture. Therefore, it becomes possible to construct a water-retaining pavement structure that can prevent elution of the hygroscopic material.

  The invention according to claim 3 includes: (a) a hygroscopic material spraying step of spraying at least one of the hygroscopic material and the hygroscopic material solution in which the hygroscopic material is dissolved from the surface of the open particle size mixture layer having continuous voids therein; And a water retentive grout filling step of filling the continuous voids with a water retentive grout.

  According to the construction method of such a water-retaining pavement structure, after spraying at least one of the moisture-absorbing material and the moisture-absorbing material solution in which the moisture-absorbing material is dissolved from the surface of the open particle size mixture (moisture-absorbing material spraying step), the water-retaining grout is filled. By performing (water retention grout filling step), at least one of the moisture absorbent material and the moisture absorbent material solution is mixed with the water retention grout to produce a water retention / moisture absorption filler. The continuous voids of the open particle size mixture are filled. Therefore, it becomes possible to construct a water-retaining pavement structure that can prevent elution of the hygroscopic material.

  According to a fourth aspect of the present invention, at least one of a hygroscopic material and a hygroscopic material solution in which the hygroscopic material is dissolved is sprayed on a water retentive pavement structure in which a continuous water gap is filled in the internal continuous void, and the hygroscopic material is dispersed in the water retaining material. A water retention function maintaining method for a water retention pavement structure, comprising a moisture absorption material fixing step for fixing to a grout, recovering moisture absorption and maintaining the water retention function of the water retention grout.

  According to the water retention function maintaining method of such a water retentive pavement structure, the moisture absorbent is dispersed in the water retentive grout by spraying at least one of the moisture absorbent and the moisture absorbent solution on the water retentive pavement structure filled with the water retentive grout. It sticks to. Accordingly, the hygroscopicity is restored and the water retention function of the water retention grout can be maintained.

  ADVANTAGE OF THE INVENTION According to this invention, the water retention pavement structure which can absorb the water | moisture content in external air and can retain water, the construction method of a water retention pavement structure, and the water retention maintenance method of a water retention pavement structure can be provided.

Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the drawings.
In the description of each embodiment, the same constituent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[First Embodiment]
First, the water-retaining pavement structure according to the first embodiment will be described with reference to FIGS. 1 and 2. In the drawings to be referred to, FIG. 1 is a side sectional view schematically showing a water-retaining pavement structure according to the first embodiment. FIG. 2 is a side sectional view schematically showing a construction method of the water-retaining pavement structure according to the first embodiment.

(Configuration of water retentive pavement structure)
As shown in FIG. 1, the water-retaining pavement structure 1 is made of crusher run, steel slag, granular roadbed containing gravel or sand, etc., bitumen stable treated roadbed treated with straight asphalt, cement / lime stabilized treated roadbed, etc. Constructed on a water-impervious layer 52 composed of a dense-graded asphalt mixture laminated on 51, a continuous gap between an open-graded asphalt mixture layer 5 (open-graded mixture layer) serving as a base and an open-graded asphalt mixture layer 5 6 (see FIG. 2) and a solidified water-retaining and hygroscopic filler 10 filled therein. In addition, the porosity of the whole water-retaining pavement structure 1 in the present embodiment is set to 5% to 14% in consideration of water retention and permeability.

  The open-graded asphalt mixture layer 5 is formed to include a coarse aggregate, a fine aggregate, and a filler (hereinafter collectively referred to as “aggregate” and denoted by reference numeral 5a) as a skeleton, and an asphalt binder 5b that couples them. ing. If the composition of the aggregate 5a and the composite particle size and the addition amount of the asphalt binder 5b are such that the open particle size asphalt mixture layer 5 after compaction has continuous continuous voids 6 in the interior and flow resistance according to the construction location, etc. Any combination may be used.

As coarse aggregate and fine aggregate, for example, crushed stone, gravel, steel slag, sand and recycled aggregate can be used as appropriate, and as filler, stone powder obtained by pulverizing limestone and other rocks, slaked lime, Cement, recovered dust, fly ash, etc. can be used.
The composite particle size of the aggregate 5a is, for example, in the particle size range shown in the following Table 1 when the maximum particle size of the aggregate 5a to be used is 13 mm (that is, the coarse aggregate having the maximum particle size to be used is No. 6 crushed stone). If so, the set porosity is 15 to 35%, and the water-retaining / hygroscopic filler 10 can be sufficiently filled, which is preferable.

  The asphalt binder 5b is preferably a high-viscosity modified asphalt binder to which an anti-peeling agent such as an amine is added in consideration of the peel resistance to water and the scattering resistance of the aggregate 5a.

The solidified water-retentive / hygroscopic filler 10 has hygroscopicity and water-retentive properties, and the water-retentive grout 11 and the moisture-absorbent 12 are mixed in a predetermined composition, filled into the continuous voids 6, and then cured / dried. And has a large number of minute voids (not shown) capable of retaining water.
In the first embodiment, the water retention / hygroscopic filler 10 is filled up to the height position near the surface of the open-graded asphalt mixture layer 5, but the present invention is not limited to this and may be changed as appropriate.

  The water retention grout 11 has water permeability and water retention, and for example, “silt filler” described in Japanese Patent No. 3156151 (Patent Document 1) by the applicant of the present application can be used. More specifically, the water retention grout 11 is obtained by mixing water, a cement-based solidifying material, a silt-based powder, a water reducing agent and a setting retarder as additives, and curing and drying the mixture.

Here, the silt-based powder is obtained by cracking rocks and collecting dust.
The cement-based solidifying material may be appropriately selected from super fast-hardening cement, ordinary Portland cement, ultra-high strength cement, early strength cement, blast furnace cement and the like in consideration of construction conditions.
Further, as for the additive, a water reducing agent such as a carboxylic acid type or a melanin type is suitable as a water reducing agent, and an SBR type, acrylic type or vinyl acetate type polymer emulsion can be suitably used as a setting retarder. is there.

  In addition, the formulation of the water-retaining grout 11 is that the silt content with a particle size of 5 μm to 75 μm is 50% or more by mass percentage, and the cement solidified material is mass percentage by mass percentage. 5% to 50%, preferably 25% to 50% by weight of water and further mixed with a water reducing agent or a setting retarder 0.1% to 5% by weight. In the case of blending, the water retention grout 11 after solidification is suitably formed with the above-mentioned fine voids (not shown), and can exhibit good water retention.

The hygroscopic material 12 has a hygroscopic property that absorbs moisture, and is formed of a hygroscopic material such as calcium chloride, silica gel, activated alumina, or zeolite having hygroscopic properties, for example.
Further, the moisture absorbent material 12 is attached to and bonded to the water retention grout 11 and is fixed to the open-graded asphalt mixture layer 5 via the water retention grout 11. Therefore, the hygroscopic material 12 is difficult to elute due to watering such as rain.

  It is preferable that the addition amount of the hygroscopic material 12 (hygroscopic material addition rate) is in the range of 5 to 40% by mass with respect to the sum of the mass of the water constituting the water retention grout 11 and the mass of the water reducing agent. If the amount of the hygroscopic material 12 is less than 5% by mass, it is difficult to obtain a sufficient amount of moisture absorption. On the other hand, if it exceeds 40% by mass, the hygroscopic amount does not increase effectively despite the increase in cost. It is.

  Moreover, it is preferable that the hygroscopic material 12 is distributed so that the density becomes high on the surface side of the water-retaining pavement structure 1. When the moisture absorbent material 12 is distributed in this way, moisture in the outside air can be more efficiently absorbed by the moisture absorbent material 12 on the surface side. Such a distribution of the hygroscopic material 12 is prepared, for example, by preparing several types of water-retaining and hygroscopic fillers 10 in which the amount of the hygroscopic material 12 added is changed, and in order from the water-retaining and hygroscopic filler 10 having a smaller amount of addition. It is possible to carry out by filling in.

  Further, it is preferable that half of the hygroscopic material 12 is fixed to the water retaining grout 11 and the other half is exposed. In such a state, moisture in the outside air is absorbed by the exposed portion of the moisture absorbent 12, and the moisture absorbed is easily retained in the water retention grout 11.

Next, the movement state of water in the water retention pavement structure 1 will be described.
When water is retained in the water retention grout 11, when the outside air temperature rises due to clear weather or the like and the temperature of the water retention pavement structure 1 rises, water is retained in the water retention grout 11 from the surface of the water retention pavement structure 1. Water vaporizes. Since the latent heat of vaporization of water accompanying this vaporization is taken away from the water retention pavement structure 1 and the outside air, an increase in the road surface temperature of the water retention pavement structure 1 is suppressed.

  On the other hand, when water is not retained in the water retention grout 11 and the humidity of the outside air is high, the hygroscopic material 12 absorbs moisture in the outside air. The moisture absorbed by the moisture absorbent 12 is retained in the water retaining grout 11. Therefore, the water retentive pavement structure 1 can spontaneously maintain the water retentive function regardless of watering or the like.

(Construction method of water retentive pavement structure)
Then, the construction method of the water retention pavement structure which concerns on 1st Embodiment is demonstrated with reference to FIG.
The construction method of the water-retaining pavement structure 1 includes an open-graded asphalt mixture layer construction step for constructing an open-graded asphalt mixture layer 5 as a base material, and a water-retaining and hygroscopic filler 10 in the continuous voids 6 of the open-graded asphalt mixture layer 5. It is comprised including the water-retentive and hygroscopic filler filling step.

(Open grain size asphalt mixture layer construction process)
As shown in FIG. 2 (a), an asphalt finisher or the like is spread on the water-impervious layer 52, and after spreading an asphalt mixture having a predetermined composition, a road roller, a vibration roller, a tamper, etc. The open-graded asphalt mixture layer 5 having a predetermined density, a predetermined thickness, and a predetermined porosity is constructed.
If the water-impervious layer 52 and the periphery of the road shoulder, etc. do not have sufficient water-impervious properties, water-stopping treatment such as spraying a high-concentration rubber-filled asphalt emulsion before spreading the open-graded asphalt mixture It is preferable to apply.

(Water retention and hygroscopic filler filling process)
The water-retaining grout 11 and the hygroscopic material 12 are agitated and mixed before injection by an appropriate mixing means such as a grout mixer (not shown) to produce a liquid water-retaining and hygroscopic filler 10 having fluidity. The viscosity of the water-retaining and hygroscopic filler 10 is preferably 9 to 15 seconds in the P funnel test, and such a viscosity can be suitably filled into the continuous voids 6 of the open particle size asphalt mixture layer 5. It is.

Thereafter, the water-retentive / hygroscopic filler 10 is continuously formed using an injection hopper (not shown) having a funnel-like hopper, as shown in FIG. Inject into the gap 6. Then, the water-retentive / hygroscopic filler 10 having fluidity is gradually filled from the lower part of the continuous gap 6.
Further, if vibration is applied to the open-graded asphalt mixture layer 5 using a vibrating roller or the like while injecting the water-retaining and hygroscopic filler 10, the continuous gap 6 can be filled without forming a gap. preferable.

  By injecting the water-retaining and hygroscopic filler 10 in which the water-retaining grout 11 and the hygroscopic material 12 are mixed in this way, the hygroscopic material 12 is easily filled in a state of being dispersed throughout the continuous gap 6.

  After injecting the water retentive / hygroscopic filler 10 and curing for a predetermined time, the water retentive grout 11 is dried and solidified, and the water retentive pavement structure 1 is constructed (see FIG. 2 (c)).

[Second Embodiment]
Then, the construction method of the water retention pavement structure which concerns on 2nd Embodiment of this invention is demonstrated with reference to FIG. FIG. 3 is a side sectional view showing a construction method of the water-retaining pavement structure according to the second embodiment.
Here, since the water retention pavement structure 1 constructed | assembled by the construction method of the water retention pavement structure which concerns on 2nd Embodiment is the same as the water retention pavement structure 1 which concerns on 1st Embodiment, the description is abbreviate | omitted.

  As shown in FIG. 3, the construction method of the water-retaining pavement structure according to the second embodiment includes an open-graded asphalt mixture layer construction process (see FIG. 3 (a)), a hygroscopic material spraying process, and a water-retaining grout filling process. It is comprised including.

(Hygroscopic material application process)
As in the first embodiment, after constructing the open grain size asphalt mixture layer 5, as shown in FIG. 3B, appropriate means (for example, scoop, bamboo broom, etc.) are provided on the surface of the open grain size asphalt mixture layer 5. In use, a predetermined amount of the powdered moisture absorbent 12 is dispersed in consideration of dispersibility. The sprayed hygroscopic material 12 penetrates into the continuous gap 6 and is dispersed.

(Water retention grout filling process)
Thereafter, as shown in FIG. 3 (c), a predetermined amount of water retaining grout 11 is injected from the surface of the open particle size asphalt mixture layer 5. The injected water retention grout 11 flows in the continuous void 6 and is mixed with the moisture absorbent material 12 to produce the water retention and moisture absorbent filler material 10. Then, the water-retentive / hygroscopic filler 10 is further flowed and filled below the continuous gap 6.

  As described above, in the second embodiment, unlike the first embodiment, the hygroscopic material 12 can be separately sprayed, so that the amount of the hygroscopic material 12 can be easily changed according to the construction location. That is, for example, the amount of hygroscopic material 12 can be changed according to the construction location, sunshine conditions, humidity conditions (for example, there is a fountain around), and the hygroscopicity can be set freely.

  Thereafter, after curing for a predetermined time, the water-retentive / hygroscopic filler 10 is dried and solidified, and the water-retaining pavement structure 1 is constructed.

[Third Embodiment]
Next, the construction method of the water retention pavement structure concerning 3rd Embodiment is demonstrated with reference to FIG.
In the construction method of the water-retaining pavement structure according to the third embodiment, the hygroscopic material spraying step for spraying the powdery hygroscopic material 12 in the second embodiment is preliminarily dissolved in water as shown in FIG. It is the construction method replaced with the hygroscopic material solution spraying step of spraying the predetermined concentration of the hygroscopic material solution 13.
By using the hygroscopic material solution 13 in this way, even the hygroscopic material solution 13 having a low concentration can be spread over a wide range. Further, when the hygroscopic material solution 13 is sprayed, it can be sprayed in a wider range by using the nozzle 21 of the sprayer 20 or the like.

[Fourth Embodiment]
(Water retention function maintenance method of water retention pavement structure)
Next, a water retention function maintaining method (hereinafter referred to as “water retention function maintaining method”) of the water retention pavement structure according to the fourth embodiment will be described.
In the water retention function maintaining method, the moisture absorbing material solution 13 in which the moisture absorbing material 12 and the moisture absorbing material 12 are dissolved in water is added to the water retaining pavement structure 1 in which the continuous void 6 is filled with the water retaining grout 11 or the water retaining and moisture absorbing filler 10. A hygroscopic material fixing step of spraying at least one of (see FIG. 4) and fixing the hygroscopic material 12 to the water retaining grout 11 is configured.

Thus, by adhering the moisture absorbent 12 to the water retaining grout 11, the hygroscopicity is restored and the water retaining function of the water retaining grout 11 can be maintained.
Moreover, before spraying the hygroscopic material 12 and the hygroscopic material solution 13, a liquid binder having water permeability may be sprayed to increase the fixing force of the hygroscopic material 12 to the water retention grout 11.

  Hereinafter, based on an Example, this invention is demonstrated further more concretely.

(Example 1)
A cylindrical specimen having a porosity of 25% and a diameter of 10 cm and a height of 20 cm was used as the matrix-open-size asphalt mixture layer.
In addition, water, a cement-based solidifying material, and a silt-based filler were mixed at a compounding ratio shown in Table 1 to be described later, and a water reducing agent and a setting retarder were further added and mixed to prepare a water retention grout.
And after adding the moisture absorbing material ((645 kg + 18.8 kg) × 0.05 = 33 kg) in which the moisture absorbing material addition rate is 5% by mass with respect to the sum of the mass of water and the mass of the water reducing agent. And mixed to prepare a water-retentive and hygroscopic filler.
Here, Cosmic RD (R) (manufactured by Denki Kagaku Kogyo Co., Ltd.) as the cement-based solidifying material, fine mineral powder from Tsuchiya Kaolin Kogyo Co., Ltd. as the silt-based powder, and Denka FT-80 (R) (as the water reducing agent) Denka Setter D-200 (R) (manufactured by Denki Kagaku Kogyo Co., Ltd.) was used as a setting retarder, and commercially available granular calcium chloride was used as a hygroscopic material.

  And after filling the space | gap of a test body with a water retention and a hygroscopic filler and making it dry, it was set as Example 1. FIG. That is, this process corresponds to the water retention / hygroscopic filler filling process in the first embodiment.

(Evaluation methods)
Example 1 was dried with a dryer at 60 ° C. for 2 days, and then left in a room at room temperature of 20 ° C. and a humidity of 95% to measure changes in moisture absorption. The amount of moisture absorption was calculated by the following equation (1). FIG. 5 shows a change in moisture absorption with time.

(Examples 2 to 4, Comparative Example 1)
Examples in which the hygroscopic material was added to the water retaining grout so that the above-described hygroscopic material addition ratios were 10% by mass, 20% by mass, and 40% by mass were respectively Example 2, Example 3, and Example 4. . A sample having a moisture absorption material addition rate of 0 mass% (no moisture absorption material added) was defined as Comparative Example 1. And the evaluation test similar to Example 1 was done, and the time-dependent change of moisture absorption is shown in FIG.
Here, the compounding ratios of Examples 1 to 4 and Comparative Example 1 are summarized in Table 2.

(Comparative Example 2, Comparative Example 3)
A test piece having a diameter of 10 cm and a height of 20 cm used in Example 1 was dried with a dryer at 60 ° C. for 2 days, and then a 20 wt% calcium chloride prepared by dissolving a moisture absorbent (calcium chloride) in water. A comparative example 2 was obtained by impregnating an aqueous solution (hygroscopic material solution) for 24 hours and then drying it as it was without filling the water retaining grout. Note that the step of impregnating the specimen with the calcium chloride aqueous solution corresponds to the hygroscopic material solution spraying step in the third embodiment. Moreover, when producing Comparative Example 2, it was assumed that Comparative Example 2 had a moisture-absorbing material addition rate (40% by mass) corresponding to Example 4.
Further, Comparative Example 3 was obtained by impregnating with an aqueous calcium chloride solution (hygroscopic material solution) but not with water.
The same evaluation test as in Example 1 was performed for Comparative Example 2 and Comparative Example 3. The result is shown in FIG.

(Evaluation results)
As is clear from FIG. 5, it was found that the amount of moisture absorption was higher in Examples 1 to 4 to which the hygroscopic material was added than in Comparative Example 1 in which the hygroscopic material was not added. Further, it has been found that the amount of moisture absorption increases as the amount of the hygroscopic material added increases. Furthermore, in the range where the hygroscopic material addition rate is 5 to 40% by mass (Examples 1 to 4), for example, after 1400 minutes, the moisture absorption amount is within the range of 3 to 5.5%, which is favorable. It was.

  In Comparative Example 2 impregnated with the hygroscopic material solution, the amount of moisture absorption was higher than that of Comparative Example 3 impregnated in water, but the result was lower than that of Examples 1-4. This seems to be because the hygroscopic material was not fixed to the specimen because Comparative Example 2 did not have a water retention grout, and the hygroscopic material itself eluted with the passage of time.

  Therefore, after adding a water-absorbing material to the water-holding grout, mixing it, and once preparing a water-holding and hygroscopic filler, filling it with the specimen (open grain size asphalt mixture layer), the water-holding pavement structure It has been clarified that by producing (constructing) higher hygroscopicity. This is because the hygroscopic material is filled over the entire continuous void of the specimen and fixed to the specimen through the water retaining grout, so that the hygroscopic material is difficult to elute and the moisture absorbed is successively retained in the water retaining grout. It is thought to be for this purpose.

  As mentioned above, although an example was described about suitable embodiment of this invention, this invention is not limited to the said embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably.

In the first embodiment described above, the water retentive pavement structure 1 is filled with the water retentive / hygroscopic filler 10 up to a height position near the approximate surface of the open-graded asphalt mixture layer 5, as shown in FIG. However, for example, as shown in FIG. 6, the water-retaining and hygroscopic filler 10 is filled up to a substantially middle height position of the open-graded asphalt mixture layer 5 and is opened above the middle height. The water-retaining pavement structure 2 in which a film of the water-retaining and hygroscopic filler 10 is formed on the surface of the particle size asphalt mixture may be used.
That is, the water retentive pavement structure 2 filled with such a water retentive / hygroscopic filler 10 up to a substantially intermediate height position has an upper layer 2a having a high porosity and a lower layer 2b having a low porosity. Yes. According to such a water-retaining pavement structure 2, since the void ratio of the continuous gap 6 a in the upper layer 2 a is large, it has a noise reduction function during traveling of the vehicle and a road surface drainage function during rainfall.
In the case of such a water-retaining pavement structure 2, the composite particle size of the aggregate 5a and the filling amount of the water-retentive / hygroscopic filler 10 are changed as appropriate, for example, the porosity of the upper layer 2a is 15% to 35%. Within the range, it is possible to suitably exhibit the noise reduction function and the road surface drainage function. Moreover, when the porosity of the lower layer 2b is in the range of 5% to 14%, it has more suitable rigidity, which is preferable because the flow resistance of the water-retaining pavement structure 2 as a whole is improved.

  In the above-described embodiment, the open particle size mixture layer is the open particle size asphalt mixture layer 5 in which the open particle size asphalt mixture is compacted. However, for example, an open particle size cement mixture layer obtained by hardening the open particle size cement mixture ( Porous concrete), an open particle size resin mixture layer formed using an epoxy resin, an acrylic resin, or the like as a binder may be used.

  In the above-described embodiment, the newly constructed open-graded asphalt mixture layer 5 is filled with the water retention / humidity-absorbing filler 10. A water-retaining pavement structure may be constructed by filling the water-retentive / hygroscopic filler 10 after appropriately performing a gap cleaning process or the like for cleaning with water or air.

It is a sectional side view which shows the water retention pavement structure which concerns on 1st Embodiment. (A)-(c) is a sectional side view which shows the construction method of the water retention pavement structure which concerns on 1st Embodiment. (A)-(c) is a sectional side view which shows the construction method of the water retention pavement structure which concerns on 2nd Embodiment. It is a sectional side view which shows the moisture-absorbing material solution spraying process which concerns on 3rd Embodiment. It is a graph which shows a time-dependent change of moisture absorption. It is a sectional side view which shows the modification of the water retention pavement structure which concerns on 1st Embodiment.

Explanation of symbols

1, 2 Water-retaining pavement structure 5 Open grain size asphalt mixture layer (open grain size mixture layer)
5a Aggregate 5b Asphalt binder 6, 6a Continuous void 10 Water retention / hygroscopic filler 11 Water retention grout 12 Hygroscopic material 13 Hygroscopic solution 20 Sprayer 21 Nozzle

Claims (4)

An open particle size mixture layer having continuous voids therein;
A water-retaining and hygroscopic filler filled with the water-holding grout and a hygroscopic material filled in the continuous voids,
A water-retaining pavement structure characterized in that moisture in the outside air is absorbed by the moisture-absorbing material, and the water can be retained by the water-retaining grout. From the surface of the open particle size mixture layer having continuous voids inside,
A construction method for a water-retaining pavement structure comprising a water-retaining and hygroscopic filler filling step of filling a water-retaining and hygroscopic filler formed by mixing a water-retaining grout and a hygroscopic material. From the surface of the open particle size mixture layer having continuous voids inside,
(A) a hygroscopic material spraying step for spraying at least one of a hygroscopic material and a hygroscopic material solution in which the hygroscopic material is dissolved;
(B) a water retention grout filling step of filling the continuous voids with a water retention grout;
The construction method of the water-retaining pavement structure characterized by including. In the water-retaining pavement structure in which the continuous voids inside are filled with water-retaining grout,
Spraying at least one of a hygroscopic material and a hygroscopic material solution in which the hygroscopic material is dissolved, and including a hygroscopic material fixing step of fixing the hygroscopic material to the water retaining grout;
A method for maintaining a water retention function of a water retentive pavement structure, comprising recovering moisture absorption and maintaining the water retention function of the water retention grout.

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