JP2002363906A - Asphalt pavement with water permeability and water holding property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an asphalt pavement surface layer having fine continuous cavities in a surface layer, suppressing the cultivation and outflow of underground water by allowing rain water to be penetrated therein, holding water by capillaries of the cavities in the pavement surface layer, sucking the stored water in the cavities in the surface layer by capillary to suppress surface temperature by transport of latent heat caused by evaporation, and eliminating a filling operation at a construction site. SOLUTION: In this pavement surface layer, crushed sand, pit sand, and silica sand No.3 of 30 to 60%, No.7 crushed stone of 50 to 70%, asphalt amount of 3.0 to 4.5%, and stone dust are mixed with each other, water is allowed to penetrate thereinto at a coefficient of permeability of 1.0×10<-2> cm/s or more, and water of 10% or more is held in the cavities by the capillary force of the surface layer cavities at a water content by volume of 10% or more. In fine weather and when water is not sprayed, the held water is moved to the surface layer in the cavity capillaries while evaporating to prevent the surface of the pavement from being raised to high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to water permeability, water retention,
Asphalt pavement surface layer with water absorption and water permeability,
The present invention relates to an asphalt pavement structure having both water retention and water absorption.

[0002]

2. Description of the Related Art In recent years, as urban concrete and asphalt progress, the amount of latent heat transport decreases and the ground surface rises in temperature, while the amount of stored heat increases and heat is released from the ground surface at night. It also causes tropical nights. In addition, the incidence of heat stroke in summer is relatively high in road spaces, and there is a concern that heat stress on humans may be adversely affected. In addition, the increasing population cover has blocked rainwater from penetrating the ground, leading to lower groundwater levels and lower river flows. Against this background, there is a strong need for pavements that reduce the heat island phenomenon, which continues to deteriorate, and improve the thermal environment to create a comfortable living environment and contribute to groundwater recharge and urban-type flood control.

[0003] Conventionally, as an asphalt pavement, a permeable pavement and a water-retentive pavement have been developed and introduced to the site. However, the surface layer of the permeable pavement has the ability to penetrate rainwater into the underground, but has little water retention, and thus did not prevent high temperatures. On the other hand, most of the water-retentive pavement surface so far has extremely low permeability, and has little effect on groundwater recharge and runoff control.

By the way, there is a type in which a silt-based material is filled into asphalt pavement voids to ensure water retention.
Some of them have a high water permeability, but these have a problem that they need to be filled at an asphalt construction site.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides fine continuous voids in the surface layer of a pavement, so that rainwater can effectively penetrate during rainfall to help recharge groundwater and suppress runoff. The surface temperature can be suppressed by the latent heat transport accompanying evaporation while keeping water such as rainfall using the capillary of the gap, or sucking up the moisture stored in the surface layer void to the surface layer by the action of hair management power, It is another object of the present invention to provide an asphalt pavement structure that does not require a filling operation at an asphalt construction site.

[0006]

According to the present invention, in order to achieve the above object, the invention according to claim 1 is characterized in that crushed sand, mountain sand and quartz sand No. 3 are used as fine aggregates on a pavement surface layer. 3
0 to 60%, coarse aggregate 50 to 70% made of No. 7 crushed stone, asphalt amount of 3.0 to 4.5%, and by mixing stone powder, the water permeability coefficient by pavement water permeability test during rainfall is 1.0. Infiltrating rainwater underground with water permeability of × 10 ^-2 cm / s or more, and keeping the rainwater and water sprinkling in the voids by volume water content of 10% or more by the capillary force of the surface voids,
In fine weather, when water is not sprayed, part of the water held in the voids moves to the surface layer by the action of capillary force and evaporates, preventing the surface of the pavement from becoming hot, water retention, water permeability, It is characterized by having water absorbency.

According to a second aspect of the present invention, in the asphalt pavement structure, crushed sand is used as fine aggregate on a low permeable pavement having a water permeability of 1.0 × 10 ⁻³ cm / s or less. Mountain sand, silica sand No. 3 30-60%, coarse aggregate 50-70% made of No. 7 crushed stone, asphalt amount 3.0-
By mixing 4.5% and stone powder, the permeability in a pavement permeability test during rainfall is 1.0 × 10 ⁻² cm / s.
Rainwater penetrates underground with the above water permeability, and the volume of water content is 10% or more, and rainwater and watering are held in the space by the capillary force of the surface space, and it is held in the space at the time of fine weather and non-watering. Pavement surface layer with water retention, water permeability, and water absorption properties that prevent the surface of the pavement from becoming hot due to the movement of a part of the water that has moved to the surface layer by the action of capillary force and evaporate It is characterized by having been laid.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Three embodiments of the invention described in the first aspect of the present invention as described above (hereinafter referred to as embodiments 1, 2, and 3).
A comparison experiment was performed on the performance of a test piece composed of a comparative example (hereinafter referred to as Comparative Examples 1 and 2) composed of a typical conventional technique.
It will be described with reference to a few.

The size of the test specimens of Examples 1, 2, and 3 and Comparative Examples 1 and 2 used in this experiment is a pavement having a size of 30 cm 4 and a height of 5 cm. The structure is shown. (1) In Example 1, the No. 7 crushed stone was 50% as a coarse aggregate ratio, and the type and amount of the coarse aggregate was 47 crushed sand.
%, The type of asphalt is high viscosity modification, the amount of asphalt is 3%, and the amount of stone powder is 3%. (2) In Example 2, the coarse aggregate ratio was 60% crushed stone No. 7, the type and amount of coarse aggregate was 37% of mountain sand, the type of asphalt was high viscosity modification, and the amount of asphalt was 3.5. %, The amount of stone powder is 3%. (3)
In Example 3, the coarse aggregate ratio was No. 7 crushed stone 50%, the type and amount of coarse aggregate was 47% as crushed sand, the type of asphalt was high viscosity modification, the amount of asphalt was 3.5%, and the amount of stone powder. Is 3
%.

(4) Comparative Example 1 has a coarse aggregate ratio of 39% crushed stone 39%, 7th crushed stone 20%, and the type and amount of coarse aggregate are 13% coarse sand, 10% fine sand, 13% crushed sand, The type of asphalt is ST60-80, the amount of asphalt is 5.5%, and the amount of stone powder is 5%. (5) Comparative Example 2 has a coarse aggregate ratio of 6
No. 82 crushed stone, coarse aggregate 13% coarse sand type and amount, asphalt type ST60-80, asphalt amount 4.
3%, stone powder amount is 5%.

FIG. 2 shows Examples 1, 2 and 3 and Comparative Examples 1 and 2.
5 is a diagram showing the results of a comparative experiment performed on the time change of the surface temperature with reference to FIG. The experiment was performed in a climate chamber, which had a height of 3.4 m, a planar shape of 3.7 m x 3.6 m, and all the walls in the room were covered with reflecting mirrors. The temperature was set at 30 ° C. Then, in order to adjust the radiation amount on the specimen to a constant value, a total of 64 halogen lamps (500 w) were turned on, and four specimens were placed at a time. The surface of this specimen was at a height of 15 cm from the floor.

When the radiation amount was measured at the center point of each specimen in this way, it was 1190 W / m2 to 1250.
W / m2. Although no forced wind is generated, the air-conditioning function to keep the air temperature at a constant value makes it possible to maintain the air temperature at a height of about 10 cm (25 cm from the floor surface) from the surface of the test specimen at about 0.7 to 0.9 m / cm. The wind was always blowing. In such a state, each specimen was housed in a heat insulating container to make the bottom impermeable, and at the start of the experiment, the gap was almost completely filled with water. Then, at the point when about 4 hours have passed after the start of the experiment, Examples 1, 2, and 3 have a surface temperature of 12.9 ° C., respectively, as compared with Comparative Examples 1 and 2.
The temperature decreased by 16.8 ° C and 16.6 ° C. In addition, about 25%, 32%, and 25% of the water with respect to the initial water retention were lost by evaporation.

[0013] As shown in FIG.
In Examples 2 and 3, the continuous porosity%, the water permeability coefficient cm / s and the water retention% were larger than those of Comparative Examples 1 and 2, and it was found that the stability was secured at about 3.5 kN or more. With such characteristics, in combination with what is shown in Fig. 2, during rainfall and sprinkling, rainwater penetrates underground with the same degree of water permeability as soil, and rainfall is caused by capillary force in the surface gap. When the water is retained, the water retention moves to the surface layer surface by the action of the capillary force during fine weather and when water is not sprayed, and evaporates, thereby preventing the surface of the pavement from becoming hot.

Further, according to the invention described in claim 2 of the present invention, the first, second and third embodiments have a water permeability of 1.0 ×.
Since it is composed of an asphalt structure constructed by laying on a low permeable pavement having a water permeability of 10 ⁻³ cm / s or less, the permeability coefficient in a pavement permeability test during rainfall is 1.0 × Infiltrate rainwater into the ground with water permeability of 10 ^-2 cm / s or more, and keep the rainwater or watering in the voids by volume force of 10% or more due to the capillary force of the surface voids. The water held in the voids moves to the surface layer by the action of capillary force and evaporates, so that the surface of the pavement has water retention, water permeability, and water absorption that prevent the surface from becoming hot. I have.

[0015]

The present invention is as described above. According to the first aspect of the present invention, crushed sand, mountain sand and quartz sand No. 3 are used as fine aggregates in the pavement surface layer in an amount of 30 to 60%, crushed stone No. 7 50-70% of coarse aggregate consisting of: asphalt amount of 3.0-4.5
% And stone powder, rainwater permeates underground with a water permeability of 1.0 × 10 ^-2 cm / s or more by a pavement water permeability test during rainfall, and the volume is increased by the capillary force of the surface gap. Water content of 10% or more, keeps rainwater and water spray in the gap, and in fine weather, when not watering, water held in the gap moves to the surface layer by the action of capillary force and evaporates, Since it has water permeability and water absorption, there is an effect that the surface of the pavement can be prevented from becoming hot.

According to a second aspect of the present invention, in the asphalt pavement structure, crushed sand is used as fine aggregate on a low permeable pavement having a water permeability of 1.0 × 10 ⁻³ cm / s or less. Mountain sand, silica sand No. 3 30-60%, coarse aggregate (No. 7 crushed stone) 50-70%, asphalt amount 3.0-4.5
% And stone powder, rainwater permeates underground with a water permeability of 1.0 × 10 ^-2 cm / s or more by a pavement water permeability test during rainfall, and the volume is increased by the capillary force of the surface gap. Moisture retention of 10% or more, keeps rainwater and water spray in the gap, and in fine weather and non-water spray, part of the water held in the gap moves to the surface layer by the action of capillary force and evaporates. It has water permeability and water absorption to prevent the surface of the pavement from becoming hot, which can reduce the urban heat island phenomenon and improve the thermal environment, and contribute to groundwater recharge and runoff control in rainy weather. This has the effect of greatly contributing to the solution of urban and global environmental problems.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of Embodiments 1, 2, and 3 of the invention described in claim 1;

FIG. 2 is a comparison diagram showing a change over time of the surface temperature between Examples 1, 2, and 3 and Comparative Examples 1 and 2.

FIG. 3 is a comparison diagram of respective performances of Examples 1, 2, and 3 and Comparative Examples 1 and 2.

Claims (2)

[Claims] Crushed sand, mountain sand, quartz sand No. 3 as fine aggregate
0-60%, 50-70% coarse aggregate composed of No. 7 crushed stone,
3.0-4.5% of the amount of sphalt, and mix stone powder
As a result, during rainfall, the permeability
1.0 × 10 ^-2rainwater with a permeability of at least cm / s
Penetrates down and the capillary force of the surface voids
With a water content of 10% or more, rainwater and sprinkling are held in the voids,
When the weather is fine or when water is not sprayed, some of the water
By moving to the surface layer by the action of capillary force and evaporating,
Water retention, water permeability and absorption to prevent the surface of
Pavement surface layer characterized by being provided with water. 2. On a low permeable pavement having a water permeability of 1.0 × 10 ⁻³ cm / s or less, 30-60% of fine sand, mountain sand and silica sand 3 as fine aggregate, No. 7 crushed stone 50 ~
By mixing 70%, asphalt amount of 3.0-4.5%, and stone powder, rainwater has a permeability of 1.0 × 10 ^-2 cm / s or more during rainfall with a permeability of 1.0 × 10 ^-2 cm / s or more. In addition to allowing the water to penetrate into the pores, the capillarity of the surface pores keeps rainwater and water spray in the pores at a volumetric water content of 10% or more. Water retention that prevents the surface of the pavement from becoming hot by moving to the surface layer and evaporating by the action of
An asphalt pavement structure characterized by laying a pavement surface layer having water permeability and water absorption.