JP4517357B2 - Water supply type water retaining pavement structure and its construction method - Google Patents

Description

  The present invention relates to a water supply type water-retaining pavement structure in which rainwater is retained in a pavement, the road surface is cooled by evaporating the rainwater retained in fine weather to remove vaporization heat, and the heat island phenomenon is alleviated.

  In recent years, heat island phenomenon where temperature rises due to heat from asphalt pavement or concrete buildings, radiation heat from reflection, exhaust heat from air conditioning of buildings, etc. has been seen as a problem in urban areas and densely populated areas. ing.

  As measures to mitigate this heat island phenomenon, various proposals have been made in recent years to keep rainwater in the pavement by water-retaining pavement, and to take away the heat of the road surface by the heat of vaporization when moisture evaporates in fine weather and suppress the temperature rise. It is made.

  For example, in Patent Document 1 below, cement milk made of water, cement, fibers, and a surfactant in a pavement void having 15-30% voids in a surface layer portion of a road pavement located on a roadbed or a base layer A road pavement filled with is proposed.

  Also, in Patent Document 2 below, after forming a porous cured body (open particle size asphalt mixture), a slurry-like filler containing cement, clay-based fine powder, water, etc. is filled into the continuous voids of the porous cured body. A pavement has been proposed. In this case, as the clay-based fine powder, for example, one or more inorganic powders selected from clay minerals such as montmorillonite, blast furnace slag fine powder, fly ash, silica stone powder, limestone powder, and silica fume are used.

  Furthermore, in the following Patent Document 3, the water retention mixture layer constituting the surface layer of the road, the water supply roadbed provided below the water retention mixture layer to supply moisture to the water retention mixture layer, and the water provided under the water supply roadbed It comprises a water supply material that can be impregnated and a water storage part for storing water to be supplied to the water supply material, and the water supplied to the water supply material from the water storage part is supplied to the water retention mixture layer through the water supply channel board, thereby A water supply type water retaining pavement for cooling has been proposed.

  Moreover, in the following patent document 4, it was laid so that it might wave in the longitudinal section in the crushed stone reservoir layer laminated | stacked on the water-impervious sheet | seat, the crushed stone reservoir layer laminated | stacked on the impervious sheet, and laid on the roadbed A water-absorbing sheet made of a nonwoven fabric, a horizontal water-absorbing sheet laminated on the water-absorbing sheet, a sand layer, and a water-permeable pavement structure having a water-absorbing function have been proposed.

In the following Patent Document 5, a pavement having a perforated surface layer and a water reservoir layer, the perforated surface layer penetrating moisture into the lower moisture reservoir layer or storing water from a water supply device in the moisture reservoir layer during rainfall. In addition, there has been proposed a pavement having a structure having a continuous gap that releases moisture supplied from a lower moisture storage layer as water vapor to the atmosphere from the pavement surface during fine weather. In this case, as the perforated surface layer, asphalt mixture, cement concrete, cement mortar, petroleum resin mixture or a porous molding block using these materials, the moisture storage layer is a material having voids, Asphalt mixture, cement mortar, petroleum resin mixture, gravel, crushed stone, sand, artificial aggregate, etc. that have been stabilized with cement or lime are used.
JP 2003-184014 A JP 2003-201705 A JP 2005-2575 A JP 2000-45206 A JP-A-8-209613

  However, since the paving bodies described in Patent Document 1 and Patent Document 2 ensure water retention only by the paving bodies, the amount of water retention such as rainwater is small and the cooling duration is short, so that clear weather If it lasts for a long time, it is not sufficient as a mitigation measure for the heat island phenomenon.

  On the other hand, the pavement structures described in Patent Documents 3 to 5 have a moisture storage portion, that is, a water supply material that can be impregnated with water in Patent Document 3, a water absorbing sheet in Patent Document 4, a moisture storage layer in Patent Document 5, and a surface layer. It is a pavement structure provided separately from the water retentive pavement, and is excellent in that a long cooling duration is ensured by securing a water retention amount. However, the pavement structure where water supply materials such as water supply materials and water supply sheets are laid, and auxiliary facilities such as water tanks and water pipes must be installed in order to supply water to the water supply materials, is quick workability. Is not suitable as a pavement structure that requires a lot of pavement area to be finished at night time, and there is concern about durability, cost reduction cannot be achieved, and maintenance in the future There was a problem such as needing.

  In this respect, the pavement having a two-layer structure composed of the perforated surface layer and the water reservoir described in Patent Document 5 has advantages such as a simple structure, excellent workability, and free maintenance. However, the perforated surface layer has continuous voids, and while the water vapor from the water reservoir layer can be released into the atmosphere, the continuous voids are gradually filled with dust, dust, soil particles, etc. over time. If it becomes a stage that causes clogging, the passage of water vapor is blocked, and the cooling effect can hardly be expected, and the water storage of the material constituting the water reservoir is not sufficient, and clear weather continues for a long time. There was a problem that the cooling effect could not be fully expected.

  On the other hand, a lot of coal ash is emitted as a by-product of thermal power generation using coal. Conventionally, the use of this coal ash has been mostly used as a substitute for cement clay. Along with the decline, it is no longer possible to cope with the increase in the amount of coal ash generated, and there is a strong demand for new effective use.

  Therefore, the main problem of the present invention is that it has a sufficient water storage function without using water supply materials and equipment such as a water supply sheet and a water supply pipe, can maintain a cooling function even in the case of fine weather, and has workability. Another object of the present invention is to provide a water supply type water-retaining pavement structure capable of maintaining the effect of mitigating the heat island phenomenon over a long period of time and a method for constructing the same.

In order to solve the above-mentioned problem, as the present invention according to claim 1, an asphalt water retention layer comprising a surface layer in which a gap mainly composed of coal ash is filled in a gap portion of an open-graded asphalt concrete, and a lower side of the asphalt water retention layer And a coal ash solidified crushed water reservoir mainly composed of coal ash solidified crushed stone and compacted to a predetermined density,
Slurry consisting mainly of the coal ash, coal ash, gypsum, lime or cement, and with mixing the water, a slurry prepared by adding a mixed wettable powder, an interface between the coal ash solidified crushed stone layer by self-priming And continuity of capillary action is ensured between the coal ash solidified crushed stone layer,
The coal ash solidified crushed stone is obtained by adding lime and gypsum to coal ash as additives, kneading with water, shaping, then curing the kneaded material, and then crushing the cured solidified material. A water supply type water-retaining pavement structure is provided.

  The present invention according to claim 1 is an asphalt water retention layer having a water retention function in which a slurry mainly composed of coal ash is filled in a gap portion of an open-graded asphalt concrete, and a coal ash located below the asphalt water retention layer It is a water-retaining pavement with a two-layer structure consisting mainly of solidified crushed stone and a coal ash solidified crushed stone reservoir that has been compacted to a predetermined density.

In the asphalt water retention layer, the open-graded asphalt concrete bears the traffic load, and the coal ash mixed slurry filled in the gap has water absorption and water retention due to the formation of an ettringite-based interstitial phase in the composition. While being excellent, the continuity of the capillary phenomenon is ensured between the structures of the asphalt water retention layer and the coal ash solidified crushed water reservoir. In rainy weather, it promotes water absorption / retention and penetration of rainwater, and in fine weather, it enables water absorption and retention from the coal ash solidified crushed stone reservoir. Specifically, a slurry consisting mainly of the coal ash, coal ash, gypsum, lime or cement, and with mixing the water, a slurry prepared by adding a mixed wettable powder, mainly comprising this coal ash The slurry is desirably filled into the gaps of the open-graded asphalt concrete by self-filling, that is, by natural osmosis due to gravity.

  In the coal ash solidified crushed water reservoir, the compacted coal ash solidified crushed stone functions as a roadbed material, and also has an ettringite-based interstitial phase formed inside the coal ash solidified body to make it water absorbing and water retaining. Even if there is no water supply material and equipment such as a water supply sheet or a water supply pipe, it can function as a water storage layer having sufficient water storage capacity. Further, by compacting the coal ash solidified crushed stone (about the particle size distribution composition such as M40) to a predetermined density, the capillary phenomenon is promoted by the effect of fine voids of the coal ash solidified crushed stone, The stored water is continuously supplied to the asphalt water retention layer, and the cooling effect of the road surface is maintained. Specifically, the coal ash solidified crushed stone was obtained by adding lime and gypsum to coal ash as additives, kneading with water, shaping, then curing the kneaded material, and then crushing the cured solidified body. A crushed stone solidified body is used. This coal ash solidified crushed stone has sufficient strength characteristics as a roadbed material, and has a high water storage function and a function of promoting capillary action by forming a porous phase such as ettringite by adding gypsum. be able to.

  The water-retaining pavement structure having the above structure can be constructed by the same construction method as the conventional drainage pavement, and the coal ash mixed slurry is also placed in the gap by the self-filling method or the mechanical filling method using a vibrating roller etc. Excellent workability because it can be filled. In addition, since the gap portion of the open-graded asphalt concrete has a structure filled with the coal ash mixed slurry, it does not cause functional deterioration due to clogging, etc., and can maintain the mitigation effect of the heat island phenomenon over a long period of time. Become.

As the present invention according to claim 2, an asphalt water retention layer forming a surface layer in which a slurry mainly composed of coal ash is filled in a gap portion of an open-graded asphalt concrete, and located below the asphalt water retention layer, the coal ash It consists of a coal ash solidified crushed stone reservoir that is mainly composed of solidified crushed stone and compacted to a predetermined density,
The slurry mainly composed of coal ash is a slurry in which coal ash, gypsum, lime or cement, and water are mixed, and penetrates to the interface with the coal ash solidified crushed stone layer by self-filling, and the coal ash solidified. Capillary continuity is ensured between the crushed stone layer,
The coal ash solidified crushed stone is obtained by adding lime and gypsum to coal ash as additives, kneading with water, shaping, then curing the kneaded material, and then crushing the cured solidified material. A water supply type water-retaining pavement structure is provided.

The invention according to claim 2 is prepared without adding an admixture to a slurry mainly composed of coal ash.

As a third aspect of the present invention, there is provided a water supply type water-retaining pavement structure according to any one of the first and second aspects , wherein a fiber material is mixed in the coal ash solidified crushed stone.

According to the third aspect of the present invention, the fiber material is mixed when the coal ash solidified crushed stone is compacted. It becomes possible to promote the effect of capillary action by mixing the fiber material.

In the present invention according to claim 4 , after the coal ash solidified crushed stone is compacted at a predetermined thickness on the upper part of the existing roadbed, an open-graded asphalt concrete is laid on the upper surface of the coal ash solidified crushed stone layer at a predetermined thickness, and then the coal ash The water supply type water retention according to any one of claims 1 to 3 , wherein a slurry mainly comprising: is supplied from an upper surface of the open-graded asphalt concrete and is allowed to permeate to an interface with the coal ash solidified crushed stone layer by self-filling. A construction method for a pavement structure is provided.

  As described above in detail, according to the present invention, a sufficient water storage function can be provided without using water supply materials such as a water supply sheet and a water supply pipe, and the cooling function can be continuously maintained even when the weather continues. . Moreover, it is excellent in workability and does not deteriorate over time, and can maintain the effect of mitigating the heat island phenomenon over a long period of time.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Water supply type water retaining pavement structure]
As shown in FIG. 1, the water supply type water-retaining pavement structure according to the present invention is a slurry 4 (hereinafter, referred to as “coal ash”) mainly composed of coal ash in the gap portion of the open-graded asphalt concrete 3 (hereinafter simply referred to as “open-graded ascon”). Coal ash solidification, which is mainly composed of asphalt water retention layer 1 forming a surface layer filled with coal ash mixed slurry) and coal ash solidification crushed stone 5 located below this asphalt water retention layer 1 and compacted to a predetermined density It is a water-retaining pavement having a two-layer structure composed of a crushed stone reservoir 2. In the case of improving the normal asphalt pavement or the concrete pavement to the water retentive pavement of the present invention, it is desirable that this water supply type water retentive pavement is laid on the existing roadbed after removing only the existing surface pavement.

  The open particle size ascon 3 of the asphalt water retention layer 1 is a heated mixture composed of coarse aggregate, fine aggregate, filler, and asphalt and has a 2.5 mm sieve passage in a synthetic particle size in the range of 15% to 30%. It is a pavement surface layer material that is generally used as drainage pavement, and provides load resistance against traffic loads.

  The coal ash mixed slurry 4 filled in the gaps of the open particle size ascon 3 uses fly ash as coal ash, and this is mixed with gypsum, lime or cement, water, and mixed to delay hardening as necessary. The agent is added. Due to the formation of an ettringite-based interstitial phase in the composition, for example, as shown in an experimental example described later, the solidified body of the coal ash mixed slurry was obtained by immersing 1/3 of the specimen in water. In this case, as shown by the fact that the saturation reaches 90% in about 2 hours due to the capillary phenomenon, it has very high water absorption and water retention. In addition, in the blending of the coal ash mixed slurry 4, when a large amount of cement is used (for example, half of fly ash by mass ratio), the water absorption and water retention are reduced although the strength is increased. The coal ash mixed slurry 4 ensures continuity of the capillary phenomenon between the asphalt water retaining layer 1 and the coal ash solidified crushed water reservoir 2, and penetrates to the coal ash solidified crushed water reservoir 2. It has fluidity and can be self-filled (filled by natural penetration) into the gaps of the open-graded ascon 3.

  In order to self-fill the coal ash mixed slurry 4 in the gap between the open-graded ascones 3, the P funnel flow value (the time required for the slurry to flow down from the P funnel) is 10 seconds or less (8 for water). .2 seconds) is preferably used. In order to adjust the P funnel flow value to 10 seconds or less, water and powder (fly ash (FA), gypsum (G), quicklime (QL) / slaked lime (SL) or cement (C) were mixed. It is made possible by adjusting the weight percentage (water powder ratio) of about 70 to 80%.

  On the other hand, the coal ash solidified crushed stone 5 constituting the coal ash solidified crushed water reservoir 2 is formed by adding lime and gypsum to the coal ash as additives, kneading with water, and then curing the kneaded product. It is a crushed stone-like solid body obtained by crushing a cured solid body. In addition, since the quality of the coal ash used as the material varies considerably due to fluctuations in the characteristics of the coal ash, as shown in Japanese Patent No. 3455184, in order to obtain a solidified body of stable quality while responding to the above-described fluctuations, A product produced by controlling and managing the fluid number of the kneader, the temperature of the kneaded product, the bulk specific gravity of the molded product, the compressive strength of the solidified body during curing, and the coarse particle ratio of the granular solidified body can be suitably used. .

  The coal ash solidified crushed water reservoir 2 adjusts the coal ash solidified crushed stone 5 with a particle size distribution of M40 or the like (pavement particle size regulation value) and compacts it with a predetermined density to ensure load resistance performance as a roadbed material. .

  The coal ash solidified crushed water reservoir 2 is composed of coal ash solidified crushed stone 5 and free water in the gaps. When the coal ash solidified crushed water reservoir 2 is in a wet state, the coal ash solidified crushed stone 5 is in a state of being retained by surface water and internal water. Free water, surface water, and internal water of the coal ash solidified crushed stone reservoir 2 rise to the asphalt water retention layer 1 through the capillaries formed by adjacent particle arrays. Most of the water stored in the coal ash solidified crushed water reservoir 2 is consumed for temperature cooling of the road surface by capillarity in the two-layer structure and evapotranspiration on the road surface.

[Construction of water retentive pavement]
In the water-retaining pavement described above, the coal ash solidified crushed stone 5 is compacted to a thickness of 5 to 10 cm in order to ensure the sustainability of the cooling effect, and the coal ash solidified crushed stone reservoir 2 After that, an open-graded ascon 3 is laid on the upper surface of the coal ash solidified crushed water reservoir 2 so that the layer thickness is preferably 5 cm or more. After that, the coal ash mixed slurry 4 is self-filled into the gaps of the open-graded ascon 3 and penetrates to the interface with the coal ash solidified crushed stone reservoir 2 to have a two-layer continuity. Since gypsum is used for the coal ash mixed slurry, the surface layer portion that comes into contact with air within 3 hours becomes clay-like, so that the clay-like surplus solidified solid body present on the road surface is cleaned. According to this construction method, traffic can be opened in about 3 hours from the filling of the coal ash mixed slurry 4 and the construction can be performed quickly.

[Cooling mechanism of this water supply type water retaining pavement]
During rainwater, as shown in Fig. 2 (A), rainwater penetrates into the lower layer while being retained in the asphalt reservoir 1, and is stored in the coal ash solidified crushed reservoir 2 and surplus water penetrates into the existing roadbed To do. When the temperature is high in midsummer, as shown in FIG. 2 (B), moisture is taken away from the surface of the asphalt water retaining layer 1 as heat of vaporization, and an increase in the surface temperature is suppressed. The water is continuously supplied from the coal ash solidified crushed water reservoir 2 to the asphalt water retention layer 1 by the capillary phenomenon in the two-layer structure, and the cooling effect of the road surface temperature is maintained. As for the road surface cooling effect, the coal ash mixed slurry 4 is set and the layer thickness of the asphalt water retention layer 1 is set so that the summer road surface temperature can be maintained at 40 ° C. or lower for at least four consecutive days. It is desirable to set the composition of the crushed stone 5 and its layer thickness.

<Characteristics of coal ash mixed slurry>
In order to confirm the water absorption and water retention characteristics of coal ash mixed slurry 4, seven specimens CASE1 to CASE7 with different formulations shown in Table 1 below were prepared, and the correlation between P funnel flow value and water powder ratio Water absorption performance test and water retention performance test were conducted. In addition, fly ash was used as coal ash.

1. FIG. 3 shows the relationship between the P funnel flow value and the water powder ratio for each of the six specimens CASE-1 to CASE-6 in the table. From the figure, in order to adjust the P funnel flow value to 10 seconds or less, water and powder (fly ash (FA), gypsum (G), quicklime (QL), slaked lime (SL) or cement (C) It is understood that the weight percentage (water powder ratio) of the mixture may be adjusted to about 70 to 80%.

2. Water Absorption of Coal Ash Mixing Slurry Various experiments were conducted to verify the water absorption and water retention of the coal ash mixing slurry 4.

[Experiment (Part 1)]
In the experiment (No. 1), about CASE-1 specimen (φ5 cm × 10 cm), 1/3 of the specimen was immersed in water, and the water absorption state due to capillary action was observed from the discoloration state due to water absorption of the specimen. The result is shown in FIG. From the figure, it was confirmed that the saturation reached 90% in about 2 hours due to the capillary phenomenon, and showed very high water absorption performance.

[Experiment (Part 2)]
Among the specimens, the above experiment (part 1) was tested for CASE-1 containing gypsum and quicklime in addition to coal ash, and CASE-7 containing only coal ash and cement. Examined. As a result, as shown in FIG. 5, it was confirmed that there was a great difference in the effect of capillary action between the two. That is, it was confirmed that the rate of capillary action can be adjusted by blending gypsum (G), quicklime (QL) / slaked lime (SL), or cement (C).

[Experiment (Part 3)]
In addition, among the specimens having the composition shown in Table 1 above, the mixing conditions of CASE-2, 5, 6, and 7 were selected, and specimens shown in Table 2 below were prepared.

  The above four specimens were subjected to a capillary phenomenon confirmation test. The test was set so that the water level of the test stand on which the gauze was spread was 5 mm, and a steady state was obtained, and the speed of the capillary action of the test sample by each formulation was measured. Note that the initial conditions of the specimens were in a dry state, and it was visually confirmed that the specimens were discolored with respect to the state of moisture arrival. As a result, as shown in FIG. 6, with respect to the specimens of CASE-2, CASE-5, and CASE-6, the moisture due to the capillary phenomenon increased to 5 cm as a general asphalt pavement thickness within 1 hour. CASE-5 and CASE-6 required about 20 minutes to increase the water content of 5 cm, and CASE-2 required twice 40 minutes. CASE-7 took twice more 80 minutes.

2. Water retention performance of coal ash mixed slurry 4

[Experiment (Part 4)]
In the experiment (No. 4), the maximum water absorption rate was examined for each specimen shown in Table 2 above.
The maximum water absorption was the percentage of the difference between the surface dry weight and the dry weight with respect to the dry weight of the cylindrical specimen of φ5 cm × 10 cm. Here, the surface dry weight was the weight in the surface dry state after the specimen was immersed in water for 24 hours or more, and the dry weight was the weight when the surface-dried specimen was dried in a drying furnace at 40 ° C. for 24 hours or more. .

As a result of the test, the maximum water absorption rate of each specimen was as shown in FIG. From the figure, CASE-2 has a maximum water absorption of 46%.
CASE-5, which contains cement instead of slaked lime used in CASE-2, has a maximum water absorption rate of 30%. In addition, looking at CASE-6 and CASE-7, which contain only fly ash and cement, CASE-6 with a small amount of cement has a maximum water absorption of 38% and a ratio of cement to fly ash of 1: 2. The maximum water absorption of -7 was 30%. In CASE-6 and CASE-7, the specimen did not solidify at a predetermined height of 10 cm, and the influence of bleeding became a problem.

  From the above, it can be seen that when cement is added to the coal ash mixed slurry 4, the maximum water absorption rate and water absorption rate are reduced.

[Experiment (Part 5)]
In the experiment (No. 5), the coal ash mixed slurry of CASE-2,5,6 blended among the blends shown in Table 2 was self-filled into an open grained ascon placed in a steel container with an inner diameter of φ10 cm. The maximum water content of the asphalt water reservoir was investigated.

  The maximum water retention amount is defined as the ratio of the difference between the surface dry weight and the dry weight with respect to the area of the specimen. The surface dry weight is the weight in the surface dry state after the specimen is immersed in water for 24 hours or more. The weight of the specimen that had been dried was dried for 24 hours or more in a 40 ° C. drying oven.

As a result of the test, the maximum water retention amount (CASE-2, CASE-5, CASE-6) of the asphalt reservoir is 7.1, 6.5, 7.3 kg / m ² , respectively, as shown in FIG. Both cases were 6 kg / m ² or more, and for example, the results fully satisfied the performance standard value of 5 kg / m ² in ordering performance requirements in Tokyo.

  From the above test results, it was confirmed that the coal ash mixed slurry according to the present invention has high water absorption and water retention in a state where the coal ash mixed slurry is filled in the gaps of the open particle size ascon.

<Characteristics of coal ash solidified crushed stone>

1. Water retention performance of coal ash solidified crushed stone About the coal ash solidified crushed stone and the general crushed stone according to the present invention, the water content ratio and wet density during compaction and water retention were investigated. In the test, after being immersed in water for one day, the water content ratio (%) and the wet density (g / cm ³ ) were examined after being left for one day to drain excess water. The results are shown in Table 3 below.

From Table 3, the difference between wet density and water compaction of coal ash solidified crushed stone (water retention performance: 0.155 g / cm ³ ) is 2.3 times that of general crushed stone mixture (0.067 g / cm ³ ). It became. That is, it was found that the coal ash solidified crushed water reservoir can retain more surface water than the general crushed stone reservoir.

2. Water absorption performance of coal ash solidified crushed stone Coal ash solidified crushed stone is obtained by adding quick lime and gypsum to coal ash, kneading and forming with water, solidifying by steam curing, crushing the solidified body, and adjusting the particle size. As shown in Fig. 9, the water content of coal ash solidified crushed stone (diameter 26.5-37.5mm) was 13% in the air (natural state) but increased to 35% in one day of water immersion. To do. Thus, it can be seen that coal ash solidified crushed stone is a material having high water absorption performance. Here, the water absorption performance is defined as storing water inside the crushed stone.

3. Water loss of coal ash solidified crushed stone
a) Influence of ambient temperature and humidity The water loss in coal ash solidified crushed stone under constant temperature and humidity conditions is shown in FIGS. When the humidity is constant, as shown in FIG. 10, it can be seen that the moisture loss in the coal ash solidified crushed stone is not affected by the temperature. Next, when the temperature was constant, as shown in FIG. 11, the moisture loss increased as the humidity decreased. That is, the moisture in the coal ash solidified crushed stone is considered to move to the outside when the moisturized state of the surrounding environment decreases.

b) Influence of wet and dry conditions in the surrounding environment Figure 13 shows the relationship between moisture loss in coal ash solidified crushed stone and dry and wet conditions in the surrounding environment (water content of surrounding crushed stone). As shown in Fig. 12, the water content of the crushed stone layer in the surrounding environment is set to three levels of 0, 2, and 7%, and the coal ash solidified crushed stone is saturated (water content is about 35%). It was embedded in the layer and the change in water content after 7 days was measured. It can be seen that the coal ash solidified crushed stone has water loss when the water content of the surrounding environment is 0% (dry conditions). That is, it is considered that the moisture in the coal ash solidified crushed stone moves to the outside during the process of changing the surrounding environment from wet to dry.

《Cooling effect as water-retaining pavement structure》
Next, in order to confirm the performance of the water-retaining pavement structure according to the present invention, an experimental apparatus simulating the water-retaining pavement structure of the present invention shown in FIG. 14 and the conventional dense particle size shown in FIG. 15 for comparison. An experimental device simulating pavement was produced and a comparative test was conducted.

  As shown in FIG. 14, the experimental apparatus simulating the water-retaining pavement structure compacted coal ash solidified crushed stone, and then asphalt water retention layer (5 cm thick) with its upper surface surrounded by mountain sand. ). Moreover, in order to measure the temperature of the pavement bottom surface-1 cm, a layer of coal ash mixed slurry is formed on the surface layer with a thickness of 1 cm, and the temperature sensor is the surface layer, surface layer-1 cm, boundary position between asphalt water retention layer and coal ash solidified crushed stone Were installed at three locations. On the other hand, as shown in FIG. 15, the experimental apparatus simulating dense grain paving has a structure in which, after compacting general crushed stones, a fine grained ascon with a thickness of 4 cm is laid on the upper surface. The temperature sensor was installed in two places, the surface layer, and the boundary position between dense grained ascon and general crushed stone. The diameters of the water-retaining pavement and dense-grain pavement specimens are both 15 cm. In addition, the coal ash mixed slurry used for the water-retaining material pavement was a composition corresponding to CASE-2 in Table 1 above.

  And the water absorption to the pavement specimen of a water retention pavement structure was performed over 63 hours from the opening part formed in the specimen bottom face. Thereafter, light irradiation experiments were performed for 6 cycles. Light irradiation was set so that the maximum temperature in the air on the pavement surface was 52 to 57 ° C.

  Among the test results, FIG. 16 shows the test result of the water-retaining pavement structure according to the present invention, and FIG. 17 shows the test result of the dense grain pavement structure. When the maximum atmospheric temperature on water-retaining pavement and dense-graded pavement is 52-57 ° C, the maximum temperature above the coal ash solidified crushed stone layer on the water-retentive pavement is 33-36 ° C, the maximum above the crushed stone layer on the dense-graded pavement The temperature was 48-55 ° C. The temperature difference between the two was 15-19 ° C., confirming the temperature control effect of the water-retaining pavement. Further, in the case of the water-retaining pavement structure, the maximum surface temperature (according to the embedded temperature sensor) was 45 to 47 ° C., which was kept 7 to 10 ° C. lower than the air temperature.

It is a schematic diagram of the water supply type water retention pavement structure which concerns on this invention. It is a figure for demonstrating the cooling mechanism of this water supply type water-retaining pavement, (A) is a figure at the time of rainy weather, (B) is a figure which shows at the time of fine weather. It is a figure which shows the relationship between the P funnel flow value and water powder ratio of each specimen. It is a figure which shows the water absorption performance by the capillary phenomenon of coal ash mixing slurry. It is a figure (the 1) which shows the experimental result which verified the difference in the capillary phenomenon by mixing | blending. It is a figure (the 2) which shows the experimental result which verified the difference in the capillary phenomenon by mixing | blending. It is a figure which shows the experimental result which verified the difference in the water absorption of the coal ash mixing slurry by mixing | blending. It is a figure which shows the experimental result which verified the difference in the maximum water absorption of the coal ash mixing slurry by mixing | blending. It is a figure which shows the experimental result which verified the water absorption performance of coal ash solidification crushed stone. It is a figure which shows progress of the moisture loss of coal ash solidification crushed stone when ambient temperature is changed. It is a figure which shows progress of the water loss of coal ash solidification crushed stone when peripheral humidity is changed. It is the schematic of the water loss experiment at the time of changing surrounding environment (water content ratio of crushed stone). It is a figure which shows the result of the water | moisture-content loss experiment at the time of changing surrounding environment (the water content ratio of a crushed stone). It is the schematic of the experimental apparatus which simulated the water supply type water retention pavement structure which concerns on this invention. It is the schematic of the experimental apparatus which simulated the conventional dense grained pavement. It is a time-dependent temperature change figure in the case of the water supply type water retention pavement structure of this invention. It is a time-dependent temperature change figure in the case of the conventional dense grained pavement structure.

  DESCRIPTION OF SYMBOLS 1 ... Water supply type water retention layer (asphalt water retention layer), 2 ... Water supply type water storage layer (coal ash solidification crushed water storage layer), 3 ... Open grained asphalt concrete, 4 ... Coal ash mixed slurry, 5 ... Coal ash solidification crushed stone

Claims (4)

An asphalt water retention layer that forms a surface layer in which a slurry mainly composed of coal ash is filled in the gaps of open-graded asphalt concrete, and is located below this asphalt water retention layer, and is mainly composed of coal ash solidified crushed stones to a predetermined density Consisting of a compacted coal ash solidified crushed water reservoir,
Slurry consisting mainly of the coal ash, coal ash, gypsum, lime or cement, and with mixing the water, a slurry prepared by adding a mixed wettable powder, an interface between the coal ash solidified crushed stone layer by self-priming And continuity of capillary action is ensured between the coal ash solidified crushed stone layer,
The coal ash solidified crushed stone is obtained by adding lime and gypsum to coal ash as additives, kneading with water, shaping, then curing the kneaded material, and then crushing the cured solidified material. A water supply type water-retaining pavement structure characterized in that is used. Asphalt water retention layer that forms a surface layer filled with slurry mainly composed of coal ash in the gap of open grained asphalt concrete, and located below this asphalt water retention layer, and mainly composed of coal ash solidified crushed stone to a predetermined density Consisting of a compacted coal ash solidified crushed water reservoir,
The slurry mainly composed of coal ash is a slurry in which coal ash, gypsum, lime or cement, and water are mixed, and penetrates to the interface with the coal ash solidified crushed stone layer by self-filling, and the coal ash solidified. Capillary continuity is ensured between the crushed stone layer,
The coal ash solidified crushed stone is obtained by adding lime and gypsum to coal ash as additives, kneading with water, shaping, then curing the kneaded material, and then crushing the cured solidified material. A water supply type water-retaining pavement structure characterized in that is used. The water supply type water-retaining pavement structure according to claim 1 , wherein a fiber material is mixed in the coal ash solidified crushed stone. After the coal ash solidified crushed stone is compacted to the upper part of the existing roadbed with a predetermined thickness, an open-graded asphalt concrete is laid on the upper surface of the coal ash solidified crushed stone layer with a predetermined thickness, and then the slurry mainly composed of coal ash The construction method for a water supply type water-retaining pavement structure according to any one of claims 1 to 3 , wherein the asphalt concrete is supplied from the upper surface and penetrates to an interface with the coal ash solidified crushed stone layer.

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