JPH0995904A - Perforated surface layer using ceramics sintered compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress a rise of road surface temperature by forming a perforated surface layer provided with either or both of water or air permeable capacities with porous structure ceramics with permeability and water holding property. SOLUTION: A pavement body is formed with a perforated surface layer 10 comprising a porous structure ceramics with permeability and water holding property and a water storing layer 20 which is located under the perforated surface layer 10, provided with a water storing capacity and a function to supply stored water as vapor to the perforated surface layer 10 in fine day, and also which comprises crushed stone base materials or permeable asphalt mixture and of which void percentage is 15 to 30% in volume. By this, the water holding capacity of the perforated surface layer 10 is increased. Thus, the effect of suppressing the temperature rise of the surface of the perforated surface layer and the atmospheric temperature near the surface of it can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perforated surface layer using a ceramic sintered body as a perforated surface layer of a pavement having a function of suppressing a rise in road surface temperature in road pavement under hot summer weather.

[0002]

2. Description of the Related Art The surface temperature of a road pavement, especially the road surface temperature of an asphalt pavement under a hot summer in the midsummer may absorb solar heat and reach nearly 60 ° C. because of its black color tone. In addition, the road surface temperature of concrete pavement tends to rise more easily than that of natural ground soil, although it is not as high as that of asphalt pavement. Table 1 attached below records the changes in the temperature on the day of midsummer and the surface temperatures of asphalt pavement, concrete pavement and soil.

Further, Table 2 records the surface temperature of the pavement body, which changes due to the heat of vaporization of water when there is rainfall under such a condition, and can be judged from these tables as well. When the surface of the asphalt pavement is in a wet state, the rise in the surface temperature of the pavement is temporarily suppressed by the heat of vaporization of water.

[0004]

[Table 1]

[0005]

[Table 2]

Based on these results, various methods and pavement structures have been proposed for suppressing an increase in the road surface temperature of the pavement using heat of vaporization of water, cooling air, etc.
As a particularly effective means for suppressing the increase in the road surface temperature, the pavement described in the specification of the patent application of “Paving object having the function of suppressing the increase in the road surface temperature” in Japanese Patent Application No. 7-16885 by the applicant of the present application There is a structure.

The invention according to this application is a pavement having a perforated surface layer and a water storage layer, wherein the water on the surface of the perforated surface layer permeates into the lower water storage layer and is stored when raining or the like. Alternatively, it is characterized by having a function of storing moisture supplied from the outside in a moisture reservoir via a water supply device arranged on the pavement, and when the weather is fine, the moisture is supplied from the moisture reservoir by capillary action. The feature is that the generated water is released as water vapor from the surface of the perforated surface layer into the atmosphere to suppress the rise in the road surface temperature.

Specific examples of the material of the perforated surface layer include a water-permeable asphalt mixture, a cement mortar, a cement mortar, a petroleum resin mixture, or a porous molded block using these materials.

Voids are formed inside the perforated surface layer material. When the temperature of the atmosphere rises or the surface temperature of the perforated surface layer rises due to direct sunlight, the moisture in the perforated surface layer becomes moist. The water in the water storage layer located below the perforated surface layer is vaporized or vaporized by the action of raising the capillaries to form water vapor on the surface of the perforated surface layer or in the voids of the perforated surface layer, whereby smooth movement of water is performed. The heat of vaporization at this time takes away the latent heat of the perforated surface layer or the heat of the atmosphere near the surface of the perforated surface layer,
It suppresses an increase in road surface temperature.

[0010]

Therefore, the selection of the material used for the perforated surface layer is extremely important. If the selection of the material does not allow an effective function of suppressing the rise in the road surface temperature to be achieved. There is also. As mentioned above, it is no exaggeration to say that the voids formed inside the material of the perforated surface layer determine the water retention capacity of the perforated surface layer, but because it exerts the road temperature rise suppression function more effectively. In addition, it is desired that the surface layer with pores be further improved in terms of the material that can efficiently generate a large amount of water vapor in the atmosphere.

The present invention has been made with the object of improving these points, and a pavement capable of continuously suppressing an increase in the temperature of the pavement by utilizing the heat of vaporization of water without water retention on the pavement surface. In the body structure, a perforated surface layer with a high water retention capacity in which a large number of minute voids for efficiently generating steam in the atmosphere from the surface of the perforated surface layer are continuous, and a material that can withstand the passage of traveling vehicles The object of the present invention is to provide a perforated surface layer using a ceramics sintered body, which uses the above-mentioned ceramics.

[0012]

The present invention has been accomplished in order to solve the above-mentioned problems, and a feature of the first invention is that it has a distribution capability of either one of water and air, or both. It has a perforated surface layer and a water storage capacity underneath this perforated surface layer and the function of supplying the stored water as steam to the perforated surface layer in fine weather, and it is a crushed roadbed material or a permeable asphalt mixture. In the pavement having a function of suppressing an increase in road surface temperature, which has a water storage layer having a porosity of 15 to 30 (volume%), the perforated surface layer has water permeability and a porosity having water retention. The structure is made of ceramics having a function of suppressing an increase in road surface temperature due to its quality structure.

A second aspect of the present invention is characterized in that the ceramic has a porous structure in which a large number of minute voids are continuous in the internal structure of the ceramic, which is formed into a block shape of a flat plate as viewed from the outside and is subjected to a firing treatment. The porosity is 25 to 45
It has a permeability of (volume%), absorbs water for 12 hours at normal pressure, and then has a water content ratio of 10 to 28 after standing in the atmosphere for 1 hour.
% Water retention and a road surface temperature rise suppression function.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A perforated surface layer of a ceramic block in a structure of a pavement having a road surface temperature rise suppressing function of the present invention will be described below with reference to the drawings.
Prior to the explanation, Table 3 shows the main raw materials and materials for the ceramics used for the perforated surface layer of the ceramic block in the structure of the present pavement, and Table 4 shows the water retention of the ceramic block made of such ceramics and other materials. test·
The comparison of water content measurement results is displayed.

[0015]

[Table 3]

[0016]

[Table 4]

Moisture on the surface of the perforated surface layer during rainfall or sprinkling is retained in the voids formed inside the perforated surface layer made of ceramic blocks without staying, and excess water is the moisture of the lower layer. It is stored in the reservoir. When there is rainfall that exceeds the storage capacity of the water reservoir, drainage treatment is performed by a permeable drainage facility. When the surface temperature of the perforated surface layer rises as the temperature of the atmosphere rises and the water in the pores of the perforated surface layer evaporates, the water in the water storage layer becomes the surface of the perforated surface layer or the pores of the perforated surface layer due to the capillary rising action. In, the water is transferred to become water vapor. The heat of vaporization at this time lowers the surface temperature of the perforated surface layer and the surface atmospheric temperature of the perforated surface layer.

FIG. 1 is an explanatory view showing the structure of the basic structure of a pavement having a road surface temperature rise suppressing function, and FIG. 2 is a state in which moisture such as rainfall penetrates in the pavement structure of FIG. 1, and It is explanatory drawing which shows the movement of vaporization of water | moisture content at the time of fine weather in the same pavement structure.

In FIG. 1, reference numeral 10 indicates a perforated hole having a structure having a continuous void for allowing water to permeate into the lower water reservoir and releasing the water vapor supplied from the lower water reservoir described below into the atmosphere. A surface layer, reference numeral 20 is a water storage layer having a porous structure having a storage capacity for water that permeates water from a perforated surface layer, the composition of which is a water-permeable asphalt mixture having a porosity of 27%. Reference numeral 30 is a water supply for enhancing the mutual water replenishment ability between the water storage layer 20 and the perforated surface layer 10 when the amount of water transferred from the water storage layer 20 to the perforated surface layer 10 is not sufficient. Reference numeral 40 is a layer, reference numeral 40 is a seal layer for strengthening the water retention function of water that has penetrated into the water storage layer 20, and reference numeral 50 is a drainage of excess water by preventing jetting of water retention onto the surface of the perforated surface layer 10. Permeable drainage system There, reference numeral 55 denotes a roadbed or subgrade.

In FIG. 2, reference numeral 11 indicates the permeation of water from the perforated surface layer 10 into the water storage layer 20 due to rainfall, and reference numeral 12 indicates water movement from the water storage layer 20 to the perforated surface layer 10 due to vaporization or capillary rise. Further, reference numeral 13 indicates a state in which drainage treatment is carried out when the perforated surface layer 10 is supplied with water exceeding the water retention capacity limit.

Here, the essential structure of the pavement having a road surface temperature rise suppressing function, that is, the perforated surface layer 10 and the water storage layer 20, which are structures that must be provided as a road surface temperature rise suppressing function, will be described. .

The perforated surface layer 10 has continuous pores that allow the water on the surface of the perforated surface layer 10 to permeate into the lower water reservoir and to allow the lower water reservoir 20 to move up by capillarity or vaporize. The structure has a structure corresponding to a surface layer portion of a normal pavement, and is a layer provided for traffic of a vehicle wheel or a pedestrian. Therefore, it is necessary to select a material for the paving material of the perforated surface layer 10 that allows the bending caused by the load of the vehicle or the like and is excellent in the permeability of water and the like.

The raw material of the perforated surface layer of the ceramic block of the present invention uses ceramics, and as shown in Table 3, it is produced by the manufacturing method filed by the applicant of the present application by Japanese Patent Application No. 7-126549. Is. The ceramic block manufactured by this manufacturing method uses silicate coarse particles whose volume is expanded by heating as skeleton particles,
A flat plate block-shaped porous sintered body characterized by having a material structure in which a silicate composition whose volume is shrunk by heating is sinter-bonded and a large number of through gaps are formed between skeletal particles. Is formed in.

The porosity is set to 25 to 45 (volume%).
In addition to having permeability, the internal structure is a structure in which a large amount of minute voids of about several tens of microns are continuously formed, and after being soaked in water at normal pressure for 12 hours to absorb water, it is exposed to the atmosphere for 1 hour. It is characterized by having a water retention capacity such that the water content after standing is 10 to 28%.

Other materials suitable as a perforated surface layer are water permeable asphalt mixtures, water permeable cement concrete,
Alternatively, some water-permeable cement mortars, water-permeable petroleum resin mixtures and the like have voids of the same degree,
For example, a water-permeable asphalt mixture having a porosity of 20% or 30% shown in Table 4 is immersed in water at normal pressure for 12 hours to absorb water, and then allowed to stand in the atmosphere for 1 hour to have a water content ratio of 2.1 and It is 4.5%, and in comparison of the water holding capacity, the ceramic block can hold a larger amount of water.

Next, the water storage layer 20 is a layer for storing water in the perforated surface layer 10 as described above, and
It is necessary to select a material having a strength capable of withstanding a load such as a vehicle through the perforated surface layer 10 which is the surface layer. Therefore, a structure having a large number of continuous voids is required to store water, and a porous material having continuous voids or a porous block may be used. Specifically, permeable asphalt mixture, permeable cement concrete, permeable cement mortar, permeable petroleum resin mixture, gravel, crushed stone,
Sand, artificial aggregate, gravel stabilized with cement or lime, crushed stone stabilized with cement or lime, sand stabilized with cement or lime, and stabilized with cement or lime Of course, similar materials can be obtained by selecting materials that match the design conditions of the construction site as long as the material such as artificial aggregate has a porosity of 15 to 30%.

In FIGS. 1 and 2, reference numeral 30 is a water supply layer for enhancing the mutual water replenishment ability between the water storage layer 20 and the perforated surface layer 10, and reference numeral 40 is the water storage layer 20. Reference numeral 50 is a water-permeable drainage facility 50 for draining surplus water by preventing spouting of stagnant water on the surface of the perforated surface layer 10 and a reference numeral 55. Although it is a roadbed or a roadbed, the material and the shape of the roadbed are selected depending on the construction site, construction situation, and the like.

Here, in order to evaluate the suppressing effect of the road surface temperature on the ceramic block provided as the perforated surface layer, a pseudo solar radiation test by artificial lamp irradiation was carried out.
The test results will be described.

This pseudo-solar radiation test was carried out for the purpose of grasping the state of latent heat transfer of moisture in the pavement, and the specimen molded in the room was irradiated with a lamp (pseudo-solar radiation).
Then, the state of temperature change due to the difference in water content of the specimen is measured to grasp the state of latent heat transfer of water.

FIG. 3 shows a test device for carrying out a pseudo solar radiation test. The test piece 60, a lamp (light projector 500W) 61 which is an artificial sun, a stand (not shown) of this lamp, a platform scale 63, and a personal computer. 64, a light-shielding base 65, a lamp cover 66, a CBR mold 67, and a thermocouple 68.
And a data logger 69 which is a measurement recording device.

Further, the specimen 6 which is the object of the measurement of this test
0 was 2 types of ceramic blocks having different water retention properties and 1 type of permeable asphalt mixture which was a conventional perforated surface layer for comparison. A total of 3 types were used. Rate 2
A 5% water reservoir was provided. Table 5 below shows the details of the specifications of the test piece having the perforated surface layer.

[0032]

[Table 5]

First, the test piece 60 of the ceramic block is cut into a core having a diameter of 150 mm from a ceramic plate made of the above-mentioned main material, and then dried to give a dry state, which is then molded into a CBR mold. Immobilization was performed on the water reservoir inside the bottom 67.
After the measurement of the dry state was completed, the sample 60 was soaked in water for 1 hour or more so as to be in a wet state.

Next, the water-permeable asphalt mixture is cut out from a specimen (length 300 mm × width 600 mm × height 50 mm) 60 as a core having a diameter of 150 mm and a thickness of 50 mm.
Then, after the core is dried, the core is fixed on the water reservoir inside the lower part of the CBR mold 67 formed into a cylindrical shape having a diameter of 150 mm. In addition, the specimen 60 and the water reservoir in the wet state are subjected to a treatment such as covering with a bag of vinyl or the like in order to prevent water leakage from the bottom of the specimen, and in the dry state, the specimen and the water content are kept. Both reservoirs were dried.

A lamp that is an artificial sun (light projector 500W)
61, a calibration method for measuring the infrared radiation amount that approximates the solar radiation amount will be described. Specimen 6
0 The infrared radiometer sensor is installed at a height equivalent to the installation height of the surface, and a paper cylinder of the same type as the CBR mold 67 (diameter 1
50 mm x height 175 mm) and a lamp cover 66 are arranged, and the lamp 61 is installed on the upper part thereof. next,
The height of the lamp 61 was adjusted so that the amount of solar radiation of the lamp 61 was the height H _{1 at} which the amount of infrared radiation (R ₀ = 0.5 to 0.7 KW / m ² ) was an approximate value of sunlight.

The height of the lamp 61 satisfying the range of the infrared radiation amount R ₀ was determined by such calibration of the measurement of the infrared radiation amount, and the pseudo-solar radiation test of the test piece 60 was conducted by the following steps. .

As shown in FIG. 3, first, the CBR is placed on the platform scale 63.
The specimen 60 to which the mold 67 was attached was placed. The measurement environment at this time was a constant temperature and humidity room, which is a place that is not affected by the outside temperature and wind.

Next, thermocouples 68 were attached to the upper and lower surfaces of the test piece 60 with adhesive tape. After this process is completed, the shading table 65 and the lamp cover 66 are provided on the top of the test piece 60.
Was placed, and the lamp 61 was fixed at a position of 45 cm from the surface of the test piece 60, which is a height corresponding to the lamp height H ₁ .

The power of the lamp 61 was turned on to start irradiation, and temperature data measured at 2 minute intervals from the test piece 60 was input to the data logger 69 and weight data was input to the personal computer 64 for recording. The irradiation time of the lamp 61 was continuously irradiated until the temperature change of the test piece 60 was about ± 1 ° C. per hour.

The temperature suppression effect data of the test piece 60 obtained by such a measuring method are attached to the following Tables 6 to 14, and Tables 6 to 8 show the ceramic block (A).
Table 9 to Table 11 are the measured values of the ceramic block (B), and Tables 12 to 14 are the measured values of the permeable asphalt mixture sample. . The measured values in Tables 6 to 7, Tables 9 to 10, and Tables 12 to 13 are obtained by time-sequentially measuring the temperatures of the upper surface and the lower surface of the ceramic block specimen 60. In the table, “X” indicates that the water content of the test piece 60 is 0%, that is, the temperature of the test piece 60 in the dry state is recorded by “◯”, and the water content at the start of measurement is the ceramic block ( A) is 16.3%, the ceramic block (B) is 25.3%, and the water-permeable asphalt mixture is 2.1%.

Tables 8, 11 and 14 show that the water content of the test piece 60 at the start of measurement was 16.3% for the ceramic block (A) and 2 for the ceramic block (B).
5.3% and 2.1% for water-permeable asphalt mixture
Is a time-series change in the water content of the sample 60 after the start of measurement. The water content of the sample 60 in the wet state was calculated by the following formula.

[0042]

[Formula 1] Moisture content = weight of water contained in specimen / dry weight of specimen × 100 (%)

[0043]

[Table 6]

[0044]

[Table 7]

[0045]

[Table 8]

[0046]

[Table 9]

[0047]

[Table 10]

[0048]

[Table 11]

[0049]

[Table 12]

[0050]

[Table 13]

[0051]

[Table 14]

From the results of the simulated solar radiation test, the temperature control effect was compared between the data of the test pieces 60 of two types of ceramic blocks and the data of the test piece 60 of one type of the water-permeable asphalt mixture, in the dry state and the wet state. About the time from the start to 4 to 6 hours,
The temperature difference on the upper surface of the test piece 60 of the ceramic block is 18 to 20 ° C., whereas the temperature difference on the upper surface of the test piece 60 of the water-permeable asphalt mixture is less than 5 ° C.
A large difference was observed in the effect of suppressing the temperature rise on the surface of the sample between the two types of ceramic blocks and one type of water-permeable asphalt mixture due to the difference between the dry state and the wet state of the sample.

The difference in the effect of suppressing the temperature rise when the upper surface of the test piece 60 was wet was determined for the test pieces 60 of two kinds of ceramic blocks and one kind of water-permeable asphalt mixture. Regarding, the ceramic block test piece 60 was found to be superior to the water permeable asphalt mixture test piece 60 in the effect of suppressing a temperature rise of 5 to 15 ° C.

Next, Tables 15 to 16 show the measurement results obtained by applying the present invention on an actual road. These were constructed by applying a pavement body having a function of suppressing an increase in road surface temperature incorporating a porous surface layer of the ceramic block of the present invention and a water supply layer having a porosity of 18 (volume%) made of crushed stone roadbed material. Surface pavement composed of permeable asphalt mixture pavement constructed as general pavement, crushed roadbed pavement, and pavement prepared by burying Kanto loam as soil was constructed for comparison, and changes in pavement surface temperature with time Is measured and displayed.

The types of ceramic blocks used for paving the perforated surface layer of the ceramic blocks in Tables 15 to 16 were the same as the ceramic block (A) shown in Table 5. Table 15 shows when the weather is fine in midsummer,
It shows the change over time of the pavement surface temperature for 5 days during rainfall and in fine weather after raining. Table 16 shows the change over time of the pavement surface temperature when water is sprayed on the pavement with a water spray amount of 5 mm. It is shown.

[0056]

[Table 15]

[0057]

[Table 16]

Comparison of the road surface temperature rise suppressing ability of each pavement with reference to Tables 15 to 16 shows that the pavement body using the perforated surface layer of the ceramic block of the present invention has a road surface temperature rise suppressing function. , The maximum temperature of the road surface can be reduced by about 20 ° C compared to the conventional general asphalt pavement, and the temperature rise of the road surface can be moderated. As can be judged from Tables 15 to 16, it is similar to the temperature change of the road surface of natural soil that is close to the measurement result of Kanto Loam.

Based on Tables 15 to 16, a comparison between the perforated surface layer of the ceramic block and other pavements with respect to the effect of rainfall on the increase in road surface temperature is shown in Table 1.
In No. 5, the road surface temperature decreases similarly on each pavement on a clear day following the rainfall, but as the time passes on the 2nd and 3rd days after the rainfall, the surface layer pavement with perforated ceramic blocks is It is shown that the effect of suppressing the rise in road surface temperature can be continuously exhibited compared to the pavement of the above.

Further, in Table 16, the pavement of the perforated surface layer of the ceramic block after the water sprinkling on the road surface has a lower temperature drop due to water sprinkling than the other pavement materials, and the suppression of the increase in the road surface temperature after the drop and the sustainability of the drop. Both of them are large, and are close to the measurement results of the road surface on which the Kanto loam is packed, and are similar to the temperature change of the road surface of natural soil.

[0061]

The perforated surface layer using the ceramics sintered body of the present invention has the following effects. Due to rainfall, water sprinkling or supply from the water supply device provided on the pavement,
Moisture can be retained and retained in the voids formed inside the perforated surface layer using the ceramic sintered body, and can also be retained in the moisture storage tank. Since the voids in the perforated surface layer using this ceramic sintered body have a structure in which a large amount of microscopic voids are continuous compared to the material used for the conventional perforated surface layer, it is possible to further improve the water retention capacity. . Therefore, when the surface temperature of the perforated surface layer increases as the temperature of the atmosphere rises, water vapor generated by vaporization of the water retained in the surface of the perforated surface layer or the voids of the perforated surface layer is generated.
Furthermore, the heat of vaporization lowers the surface temperature of the perforated surface layer and the atmospheric temperature near the surface of the perforated surface layer due to the continuous movement of water inside the perforated surface layer due to the rise of water capillaries. It will be. At this time, the surface temperature of the perforated surface layer and the temperature of the atmospheric temperature near the surface of the perforated surface layer rise due to the large water retention capacity due to the structure in which a large amount of microscopic voids in the perforated surface layer using a ceramic sintered body are continuous The effect of suppressing the temperature rise can be further improved, and the effect of suppressing the temperature increase can be further stably maintained.

That is, since the perforated surface layer using the ceramics sintered body can stably generate a large amount of steam continuously, it is possible to obtain the effect of suppressing the increase in road surface temperature similar to that of natural soil. .

[0063]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a basic structure of a pavement having a function of suppressing a rise in road surface temperature.

FIG. 2 is an explanatory view showing a state of water permeation such as rainfall in the pavement structure of FIG. 1 and a vaporized state of water in the pavement structure during fine weather.

FIG. 3 is an explanatory diagram showing a test device for a pseudo solar radiation test.

[Explanation of symbols]

 10 Perforated Surface Layer 20 Moisture Reserving Layer 30 Moisture Supply Layer 40 Sealing Layer 50 Permeable Drainage Equipment 55 Roadbed or Roadbed 60 Specimen 61 Lamp 63 Units Scale 64 Personal Computer 66 Lamp Cover 67 CBR Mold 68 Thermocouple 69 Data Logger

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shoichi Sato Inventor Shoichi Sato 3-13-1, Kyobashi, Chuo-ku, Tokyo Yuraku Building Taisei Rotec Co., Ltd. (72) Inventor Hideo Igami Kawachi-cho, Kawachi-gun, Tochigi Prefecture Shimookamoto 3728-8 Clay Burn Ceramics Co., Ltd.

Claims (2)

[Claims] 1. A perforated surface layer having a flow capacity of either or both of moisture and air, and a perforated surface layer below the perforated surface layer, which has a water storage capacity and water stored in fine weather as water vapor. A pavement that has a function of supplying to the surface layer and also has a function of suppressing an increase in road surface temperature having a water storage layer that is a crushed roadbed material, a water-permeable asphalt mixture, or the like and has a porosity of 15 to 30 (volume%). In the body, the perforated surface layer is made of ceramics having water permeability and a water-retaining porous structure having a function of suppressing an increase in road surface temperature. Surface layer. 2. The ceramic is formed into a block shape of a flat plate as viewed from the outside, is subjected to a firing treatment, and has an internal structure of a porous structure in which a large amount of minute voids are continuous, and the porosity is 25 to 45 ( (% By volume), and has a water retention ratio of 10 to 28% after absorbing water at normal pressure for 12 hours and then leaving it in the air for 1 hour to retain the road surface temperature. A perforated surface layer using the ceramics sintered body according to claim 1, characterized by being provided.