JP2510399B2 - Permeable pavement structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pavement structure having a water permeable function and capable of withstanding a heavy load of a vehicle.

[0002]

2. Description of the Related Art Conventional water-permeable pavement (without an impermeable layer,
(The water that permeates the surface layer permeates the roadbed and roadbed)
Is used only for paving pedestrian roads because it cannot withstand the heavy load of vehicles. And the pavement of the roadway is all drainage pavement (a water impermeable layer is provided on the lower surface of the surface layer, and the water that permeates the surface layer does not permeate into the pavement below it, but is drained outside the road).

[0003]

However, the drainage pavement requires the installation of a drainage facility separately. Rainwater from the drainage pavement further flows into the sewerage facility from the drainage facility, but there is a risk that the rainwater from the drainage pavement will exceed the capacity of the sewerage facility during a heavy rainfall due to a typhoon or the like. In addition, in the creation of new development projects, parts of forests and fields were changed to roads, etc., and the pavement would cause a great change in the natural environment, and the amount of rainwater flowing into sewer facilities would also suddenly increase. large. Then, the subject of this invention is providing the water-permeable pavement structure which has the strength which can endure the heavy load condition of a vehicle.

[0004]

[Means for Solving the Problems] In order to solve the above problems,
The water-permeable pavement structure according to claim 1 has a surface layer which is a water-permeable asphalt mixture and an upper layer roadbed under the surface layer,
This upper layer roadbed contains 70-80 parts by weight of single-grain crushed stone S-13 and / or S-20, 15-30 parts by weight of granulated blast furnace slag, 2-4 parts by weight of alkaline stimulant, and 1-minute granulated blast-furnace slag. It is characterized in that it is formed on the basis of a roadbed material obtained by mixing 3 parts by weight, and has a lower roadbed under the upper roadbed, and the lower roadbed is a granulated blast furnace slag 90-
It is characterized in that it is formed on the basis of a roadbed material obtained by mixing 97 parts by weight, 1.8 to 6 parts by weight of an alkaline stimulant, and 1.2 to 4 parts by weight of granulated blast furnace granulated slag.

The water-permeable asphalt mixture is a commercially available material used for the surface layer of conventional drainage pavement,
Compared to dense-grained asphalt, it has coarser mesh and can pass rainwater, and it has strength against heavy load and abrasion. The above-mentioned single-grain crushed stone S-13 and / or S-20 is the S-13 of crushed stone grain size (JIS K50011988) of the asphalt pavement summary (edited by the Japan Road Association).
And / or S-20 crushed stone. Further, single-grain crushed stone means crushed stone that does not include fine-grained particles that pass through a certain class sieve. Depending on the thickness of the layer formed using the roadbed material of the present invention, only single-grain crushed stone S-13 or S-20 may be used, or these may be mixed and used. And single grain crushed stone S-
13 or single-grain crushed stone S-20 alone 70 to 80 parts by weight or a total amount of 70 to 80 parts by weight of a mixture thereof is used to provide excellent water permeability and strength. A roadbed material can be obtained.

The granulated blast furnace slag is a white sandy vitreous substance produced by rapidly cooling molten slag generated from a blast furnace with water, and has the property of hardening when mixed with an alkaline stimulant and water. are doing. The chemical components, particle size and characteristic values of this granulated blast furnace are shown in Table 1, Table 2 and Table 3, respectively.

[0007]

[Table 1]

[0008]

[Table 2]

[0009]

[Table 3]

The physical properties of the granulated blast furnace (particle size, particle size, obtained by the cooling method and cooling rate of the blast furnace raw material or blast furnace slag)
There are some fluctuations in (density etc.) and they are classified into hard and soft, for example. Both hard and soft roadbed materials can be used for the roadbed material of the upper layer, but harder ones are more preferable because the particles are less likely to be crushed and therefore the particle gaps are less likely to be narrowed. As described above, granulated blast furnace slag has a slight variation in physical properties, but its particle size is mostly 1.3-
It has a size of 0.3 mm and a single grain size. And 1 granulated blast furnace slag
By using 5 to 30 parts by weight, it is possible to obtain the roadbed material of the upper layer roadbed even if it has a slight variation in physical properties.

The alkaline stimulant is a material which dissolves (swells) the glassy portion of the granulated blast furnace slag with an appropriate water content, recrystallizes it, and hardens it. For example, quick lime, slaked lime and / or ordinary port. There are cements such as land and blast furnace cements B and C.

The fine granulated blast furnace slag is obtained by drying the blast furnace granulated slag after drying and sieving.
Means granulated blast furnace granulated slag of 0.3 mm or less, 0.074 mm
It is more preferable to use the following ultrafine particles.

The alkaline stimulant and the finely granulated granulated blast furnace slag are mixed in an amount of 2 to 4 parts by weight and 1 to 3 parts by weight, respectively, by mixing in the above range amounts to be used in the upper layer roadbed in claim 1. This is because water permeability and strength, which are the effects of the roadbed material, are generated. That is, according to the roadbed material used for the upper layer roadbed of the present invention, since a certain amount of single-grain crushed stones having a constant particle size is present, the crushed stones have a large gap, and further, this gap has good permeability to blast furnace granulation. Due to the presence of slag, this roadbed material has good water permeability. Furthermore, an appropriate amount of alkaline stimulant dissolves (swells) the glassy part of the granulated blast furnace slag, recrystallizes it and hardens it (hereinafter this property is called hydraulic), so that the particle contact surface of crushed stone Chemically bond. Therefore, unlike conventional roadbed materials that retain their strength due to the frictional force and compression force between the constituent particles, the roadbed material used in the upper layer roadbed of the present invention retains its strength due to the chemical bonding of the particle contact surface of crushed stone. Therefore, even if a large amount of rain penetrates between the crushed stone particles, its strength can be kept good. Further, according to the roadbed material used for the upper layer roadbed of the present invention, since the granulated blast furnace granulated slag is mixed in an appropriate amount, the reaction of the alkaline stimulating material is promoted, the curing speed becomes faster, and the hardness also becomes larger, The strength of the roadbed material also increases. Therefore, the roadbed material of the present invention can be used as a water-permeable roadbed material even on a road with heavy traffic. The roadbed material used for the lower layer roadbed of the present invention uses 90-97 parts of granulated blast furnace slag having good water permeability, and therefore has good water permeability, and 1.8 to 6 parts of alkaline stimulant and fine particles. The presence of 1.2 to 4 parts of granulated blast-furnace slag causes the hydraulic properties of the granulated blast-furnace slag to be rapidly and stronger, and the chemical bond causes the strength of the subgrade. Therefore, even if a large amount of rain penetrates the roadbed material of the lower layer roadbed of the present invention, its strength can be kept good. The roadbed material used for the lower layer roadbed can be used on a weak roadbed because a prescribed rolling force is generated by a smaller rolling pressure than that of the upper layer roadbed. Further, since this roadbed material has a smaller specific gravity than the roadbed material used for the upper layer roadbed, it can be used on a weak roadbed. Note that the roadbed material used for the lower layer roadbed has lower strength than the roadbed material used for the upper layer roadbed, but since the upper layer roadbed having excellent strength is present above, the load of the vehicle or the like is dispersed in the lower layer roadbed. Therefore, even if the strength of the lower roadbed is weak, it is sufficient. The surface layer,
The thickness of the upper and lower roadbeds is calculated by the T _A method in the asphalt pavement guideline according to the design CBR of the roadbed and the design traffic volume, so that each layer does not fall below the target T _A (equal equivalent thickness). The thickness of can be determined.

[0014]

According to the water-permeable pavement structure having the above-mentioned structure, since the surface layer, the upper roadbed and the lower roadbed have water permeability, rain passes through these layers and moves to the roadbed to become groundwater. Even if a large amount of rain falls and all the rain cannot move to the roadbed, the upper and lower roadbeds also have water storage because the gap between the roadbed materials is large. Rainwater stored in the subgrade moves to be groundwater. Further, since the surface layer and the upper layer roadbed have excellent strength, they can withstand the load of the vehicle, and the upper layer roadbed disperses the load of the vehicle and transmits it to the lower layer roadbed. The lower layer roadbed has a strength capable of withstanding the distributed load, and the roadbed material used for the lower layer roadbed can be compacted with a smaller rolling pressure than the upper layer roadbed, and the specific gravity is small, so that the roadbed is weak. A lower layer roadbed can be provided on the floor, and an upper layer roadbed that is compacted with a greater rolling pressure can be provided on the lower layer roadbed.

[0015]

Example 1 As shown in FIG. 1, the structure of the water-permeable pavement of Example 1 is, in order from the upper layer, a surface layer 1 (thickness: 5 cm) and an upper layer roadbed 2 (thickness: 35 c).
m), lower roadbed 3 (thickness 35 cm) and roadbed improvement part 4
(Thickness 20 cm), the roadbed improvement part 4 is a roadbed 5
It is installed just above (about 1 m). As a material for the surface layer 1, a conventional asphalt mixture for drainage paving was used. Surface layer 1 has a water permeability of 10 ^-2 cm / sec or more and a porosity of 1
It was 8%. Immediately below the surface layer 1 is an upper layer roadbed 2 having a thickness of about 35 cm. As the material for this upper layer roadbed 2, the water-permeable roadbed material is prepared by mixing the materials shown in Table 4 in respective compounding amounts in a pug mill type mixing plant. used. Table 5 shows the characteristic values of this water-permeable roadbed material.

[0016]

[Table 4]

[0017]

[Table 5]

In Table 4, single-grain crushed stones are single-grain crushed stones S-13 and / or S-20, either alone or as a mixture. Also, lime has a particle size of 3 mm or less. In Table 5, the particle size is within the standard particle size range as a result of the particle size test (sieving test) of JIS A-1120, when particles of each particle size of the material used for the water-permeable roadbed material are mixed in respective amounts. This means that the actually measured particle size of the water-permeable roadbed material was included in the range of the specified particle size obtained by calculation.

In Table 5, the uniaxial compressive strength was measured on the 14th day of the age when the compaction degree was 95% by the method based on the As pavement guideline. As for the method of making the specimen, the mold has an inner diameter of 10 cm, a height of 12.7 cm, and a rammer weighs 4.
The weight was 5 kg and the drop height was 45 cm, and the number of times of compaction was 42 times / layer (3 layers). In addition, the curing method of the specimen is as follows: curing in a constant temperature room at a temperature of 20 ° C for 13 days and then in water at a temperature of 15 ° C for 24 hours.
It was a method of curing for hours. The uniaxial compressive strength is more specifically 27.3 when only S-13 is used as single-grain crushed stone.
kg / cm ^2, when the S-20 to 38 parts by weight, and S-13 as a single particle lithotripsy using 37 parts by weight 24.4 kg / cm ²
Met. And, in Table 5, as a water permeability test JIS A 1218 (constant water level) for examining the water permeability, 4140 g of base course material of the upper layer roadbed has an inner diameter of 10.0 cm, a length of 12.7 cm and a volume of 100.
Put in a 0 cm ³ container and tamper (2.5 kgh, 30 cm 25
(3 times / three layers) to prepare a test piece, and the test piece was immersed in tap water from above and below. Further, the water permeability test was carried out for each of the test specimens embedded in the soil for 14 days or one year after preparation. In more detail, the hydraulic conductivity is 14 days when only S-13 is used as crushed single grain.
9.16 × 10 ^-2 cm / sec, 1.08 × 10 for 1 year
It was ^-1 cm / sec. Moreover, S-20 is used as a single-grain crushed stone.
When 8 parts by weight and 37 parts by weight of S-13 are used, it is 1.38 × 10 ⁻¹ in 14 days and 1.41 × 1 in 1 year.
It was 0 ^-1 , and all had a hydraulic conductivity of 10 ^-2 or more.

As the material of the lower layer roadbed 3 immediately below the upper layer roadbed 2, a roadbed material was used in which the materials shown in Table 6 were mixed in respective compounding amounts in a pagmill type mixing plant. Table 7 shows the characteristic values of this roadbed material.

[0021]

[Table 6]

[0022]

[Table 7]

For each item in Table 7, the same tests as those in Table 5 were conducted.

Immediately below the lower roadbed 3 and directly above the roadbed 5, a roadbed improvement portion 4 is provided, and granulated blast furnace slag is used as this material, and this material is permeable to water as shown in Table 3. The coefficient is 10 ^-2 cm / sec or more.

According to the asphalt pavement summary, the equivalent conversion factor of crusher run used for the lower roadbed is 0.25, and the bitumen stabilization treatment used for the upper roadbed is 0.80. Comparing the equivalent conversion factors in Tables 5 and 7, the equivalent conversion factor of the lower layer roadbed 3 in this example is 0.35, and the equivalent conversion factor of the upper layer roadbed 2 is 0.85. Therefore, it can be seen that the roadbed material used in the construction method of the water-permeable pavement of this example is superior in strength to the conventional roadbed material even in a normal state (a state where water does not penetrate into the roadbed). On the other hand, the target value that has the permeability function by the asphalt paving guideline is that the permeability coefficient K ₁₅ is 10 ^-2.
It is more than cm / sec. Therefore, it can be judged from the values in Tables 5 and 7 that this material also has a water permeation function.

The lower layer roadbed 3 was able to have a prescribed strength with a smaller rolling force than the upper layer roadbed 2. Therefore roadbed 5
Even when the road is weak, the lower roadbed 3 is a stronger layer on the roadbed 5.
Can be provided by applying a small rolling pressure, and it is possible to provide the upper layer roadbed 2 which is compacted with a larger rolling pressure on the stronger lower layer roadbed 3.

In the roadbed improvement portion 4, the mud of the roadbed 5 is the lower roadbed 3
It also plays a role as a barrier layer so that it does not get mixed in. By using the granulated blast furnace slag as the material of the roadbed improving portion 4, the hydraulic conductivity is made constant, and the strength is increased due to the hydraulic property over time. For example, when sand is used, the permeability coefficient is also non-uniform depending on the type, but when granulated blast furnace slag is used as the material, a certain level of water permeability is obtained, and due to its hydraulic property, strength gradually increases over time. And this example 1
The water permeability of each layer 1 to 4 of the water permeable pavement structure is 1
It is 0 ^-2 cm / sec or more. This is 36 per hour
In other words, it is a pavement that has the function of permeating 0 mm of rainwater. According to the guidelines for road earthworks and drainage, "standard rainfall intensity used for road surface drainage facilities" is 60 mm / h.
(Hokkaido) to 130 mm / h (Okinawa, Ogasawara Islands). It will have a permeation capacity of about 3 to 6 times the expected rainfall. Further, as shown in Tables 3, 5, and 7, each of the layers 1 to 4 of the water-permeable pavement structure of this example has large voids. Therefore, it can be seen that the water-permeable pavement structure of Example 1 has an excellent water storage capacity. That is, if the porosity of each of the layers 1 to 4 is effective and the natural water content is assumed to be 10%, calculation shows that the pavement structure of this example has an ability to store 234 mm of water per 1 m ^2. .

The thickness of each layer of the pavement structure of Example 1 was determined by the T _A method. The design conditions are as follows. Roadbed condition: Design CBR 1.5% Design traffic: D traffic T _A target value: 45.3 cm (when roadbed design CBR = 3%) The following calculation is used to determine each layer thickness that satisfies this condition. . Surface layer 1 (drainage pavement-like asphalt mixture) layer thickness T ₁
= Equivalent thickness T _{A1 of} 5 cm = 5 x 1.00 = 5.00 cm Equivalent thickness T _{A2 of the} upper roadbed ₂ = 35 cm T _A2 = 35 x
0.85 = 29.75cm Layer thickness of lower layer roadbed 3 T ₃ = 35cm equivalent thickness T _A3 = 35 ×
0.35 = 12.25 cm Total pavement thickness T = T ₁ + T ₂ + T ₃ = 5 cm + 35 cm = 75 cm Equivalent conversion thickness T _A = T _A1 + T _A2 + T _A3 = 5.0 cm + 29.75c
m ＋ 12.25cm ＝ 47cm ＞ 45.3cm Subgrade improvement part 4 to improve subgrade CBR to 3% or more
(Granulated blast furnace slag) CBR = {(80 × 1.5 ^1/3 ＋ 20 × 20 ^1/3 ÷ 100} ³ = 3.1 when the thickness is 20 cm
%> 3.0% Cross section calculation of conventional drainage pavement under the same design conditions is as follows. Surface layer (diffusion pavement asphalt mixture) layer thickness T ₁ =
Equivalent thickness of 5 cm T _A1 = 5 × 1.00 = 5.00 cm Layer thickness of base layer (coarse asphalt mixture) T ₂ = Equivalent thickness of 10 cm T _A1 = 10 × 1.00 = 10.00 cm Upper layer roadbed (stabilizing bitumen) Layer thickness T ₃ = 10 cm, equivalent thickness T _A3 = 10 × 0.80 = 8.00 cm Layer thickness of upper layer roadbed (grain size adjusted crushed stone) T ₄ = 35 cm, equivalent thickness T _A4 = 35 × 0.35 = 12.25 cm Lower layer Layer thickness of roadbed (crusher run) T ₅ = 40cm equivalent thickness T _A5 = 45 × 0.25 = 11.25cm Total pavement thickness T = T ₁ + T ₂ + T ₃ + T ₄ + T ₅ = 5cm +10
cm + 10cm + 35cm + 45cm = 105cm Equivalent conversion thickness T _A = T _A1 + T _A2 + T _A3 + T _A4 + T _A5 = 5.
0cm ＋ 10cm ＋ 8cm ＋ 12.25cm ＋ 11.25cm ＝ 46.5cm ＞ 45.3
From the calculation of cm or more, the permeable pavement structure of Example 1 has the same design conditions (roadbed CBR = 1.5 as compared with the conventional drainage pavement structure).
%, D traffic), the total layer thickness is reduced by 30 cm, and the number of layers is reduced by 2 layers. This is because all the roadbed materials used in the pavement structure of Example 1 have high strength.

According to the water-permeable pavement structure of Example 1, the subgrade 5 (20 cm) is provided immediately above the subgrade 5.
Granulated blast furnace slag is used as the material of the subgrade for improving the subgrade. As a result, even if the CBR of the roadbed 5 is low, the CBR of the roadbed 5 can be improved to 3% or more.

In this Example 1, the roadbed improvement portion 4 was provided on the assumption that the CBR of the roadbed 5 was small.
When the value is large, the roadbed improvement portion 4 can be omitted. The thickness of each layer also varies depending on the design conditions.

Example 2 Next, when the design condition is B traffic and roadbed CBR 3% or more
The same T as in Example 1 _AThickness of each layer of pavement structure by method
It was determined. In this case, the water-permeable pavement structure of Example 2 is shown in FIG.
As shown in Fig. 1, from the pavement surface to the bottom, surface layer 1 (5 cm) upper layer road
3 layers of board 2 (25 cm) and lower roadbed 3 (25 cm)
The lower roadbed 3 is installed just above the roadbed 4 (about 1 m).
You. Each material of each layer 1 to 3 is the same as each layer of Example 1.
You. In this case, the permeability coefficient and storage capacity of each layer 1 to 3 are shown.
8 shows.

[0032]

[Table 8]

In Table 8, the hydraulic conductivity and the measured values at the site are shown.
Is the Japan Road Association's edition.
It is the value measured by the method specified in "Q". In addition, the water storage capacity
Subtract the natural water content (10%) from the porosity of the field measurement value
Value obtained by calculating the water storage ratio and multiplying it by the thickness
Is. The calculation to obtain the water storage capacity of each layer is shown below.
You. Surface layer 1 (porosity 18%) water storage capacity = 50 mm x 0.18
= 9.0mm For the upper roadbed 2, the wet density γ in the normal compacted state_t= 2.15t / m3 Dry density γ_d= 1.65t / m3 Specific gravity G = 2.3t / m3_w(Unit weight of water
If the amount) = 1, the gap ratio e = (γ_w/ Γ_d) × G-1 = (G / γ_d) -1
= (2.3 / 1.65) -1 = 0.39 Pore ratio e = (water content + void ratio) (water content +% occupied by voids) n = {e / (1 + e)} × 1
00 = 28.1% Moisture content W_n= (W_w/ W_S) × 100 = 10% (However, weight
Ratio) Water content (weight) ratio = 1- {W_w/ (1 + W_n)} = 0.091 Water content V_W＝ 1.65 × 0.091 ＝ 0.151 (15.1%) Porosity V_S= N-V_W= 28.1-15.1 = 13.0% Therefore, the water storage capacity of the upper roadbed 2 = 250 mm (of the upper roadbed 2
(Thickness) × 0.13 = 32.5 mm for lower layer roadbed 3 (including barrier layer)
In the normal compacted state, the wet density γ_t= 1.56t / m3 Dry density γ_d= 1.28t / m3 Specific gravity G = 1.7t / m3_w(Unit weight of water
If the amount) = 1, the gap ratio e = (γ_w/ Γ_d) × G-1 = (G / γ_d) -1
= (1.7 / 1.28) -1 = 0.328 If the void ratio e = (water content ratio + void ratio), then (water content +% occupied by voids) n = {e / (1 + e)} * 1
00 = 24.69% Water content W_n= (W_w/ W_S) × 100 = 10% (However, weight
Ratio) Water content (weight) ratio = 1- {W_w/ (1 + W_n) = 0.091 Water content V_w= 1.28 × 0.091 = 0.116 (11.6%) Porosity V_a= N-V_w= 24.69 -11.6 = 13.1% Therefore, the water storage capacity of the lower roadbed 3 = 250 mm (of the lower roadbed 3
Thickness) x 0.131 = 32.75 mm. Table 8 Results of water storage capacity
Pavement structure of this example 2 is 1m²Stores 74.3 mm of water
Have the ability to That is 10,000 m²Pavement surface
743m when converted to product ³Can be said to have a water storage capacity of
This is a water tank of approximately 10m x 10m x 7m (height)
It is equivalent to installing it underground. The pavement of Example 1 described above
The storage capacity of the mounting structure is also the value calculated by the same calculation as above.
is there.

If the conventional standard pavement or drainage pavement (Ministry of Construction) is set under the same setting conditions, a base layer (coarse-grained asphalt mixture) is required directly under the surface layer 1 and the total layer thickness is 60 cm. . Therefore, the water-permeable pavement structure of Example 2 has a total layer thickness of 5 cm thinner and the number of layers is reduced by one layer under the same design conditions (roadbed CBR 3% or more, B traffic). This is because the roadbed material used for the pavement structure of this example has high strength.

According to the water-permeable pavement structures of Examples 1 and 2, the water-permeable pavement structure has good water permeability and has a strength capable of withstanding a heavy load of the vehicle, and therefore can be used in a roadway. And unlike the drainage pavement, the pavement structures of Examples 1 and 2 have the ability to store water, so that even when the rainfall exceeds the permeability of the roadbed 5, temporary rainwater is stored in the pavement. After that, this rainwater gradually permeates the roadbed 5 and is returned to the groundwater. Therefore, unlike the drainage pavement, it is not necessary to provide a drainage facility, and the existing sewer facility is not burdened. In addition, as with conventional drainage pavement, water does not accumulate on the pavement surface, increasing slip resistance on the roadway, preventing the hydroplane phenomenon, preventing water splashing, improving visibility at night and in the rain, reducing running noise, etc. The effect of.

[0036]

According to the water-permeable pavement structure of the present invention, since it has good water permeability, it is not necessary to provide a separate drainage facility, and since rainfall is groundwater, groundwater is recharged and roadside trees are activated. Contribute to. In addition, in the creation of new development projects,
Portions that used to be forests and fields will be transformed into factory land, residential land, roads, etc. Naturally, pavement will also be built. If this happens, the natural environment will undergo major changes and the amount of rainwater flowing into sewer facilities will also increase. The water-permeable pavement has the effect of suppressing this change. Since the water-permeable pavement structure of the present invention has the strength to withstand the heavy load of the vehicle, it can be used on the roadway.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a water-permeable pavement structure of Example 1.

FIG. 2 is a cross-sectional explanatory view of a water-permeable pavement structure of Example 2.

[Explanation of symbols]

 1 Surface layer 2 Upper layer roadbed 3 Lower layer roadbed 4 Roadbed improvement part 5 Roadbed

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taro Hanai 9-27 Kawabuchicho, Hachimanto-ku, Kitakyushu, Fukuoka Prefecture Taihei Pavement Co., Ltd. (56) References: 1-79605 (JP, U)

Claims (1)

(57) [Claims] 1. A surface layer which is a water-permeable asphalt mixture, and an upper layer roadbed below this surface layer, which comprises 70-80 parts by weight of single-grain crushed stone S-13 and / or S-20 and granulated blast furnace. 15-30 parts by weight of slag and alkaline stimulant 2
~ 4 parts by weight and 1 to 3 parts by weight of granulated granulated blast furnace slag are formed on the basis of a roadbed material, and a lower layer roadbed is provided under the upper layer roadbed, This lower layer roadbed is formed on the basis of a roadbed material obtained by mixing 90 to 97 parts by weight of granulated blast furnace slag, 1.8 to 6 parts by weight of alkaline stimulant, and 1.2 to 4 parts by weight of granulated blast furnace granulated slag. A permeable pavement structure characterized by