JP2015034396A - Water-repellent material composition for suppressing freezing of pavement surface, freezing suppression pavement body, and method for suppressing freezing of pavement surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-repellent material composition for suppressing freezing of a pavement surface, which facilitates construction and which suppresses cut-back of the pavement surface after the construction, a freezing suppression pavement body, and a method for suppressing the freezing of the pavement surface.SOLUTION: A water-repellent material composition for suppressing freezing of a pavement surface includes a water-repellent component containing water-repellent particles and a binder resin for dispersing the water-repellent particles, and an application liquid component of an organic compound to which the water-repellent material component is added. The application liquid component content in the whole quantity is in a range of 20 mass% to 45 mass%.

Description

  The present invention relates to a water repellent composition for inhibiting freezing of a paved road surface that can be applied to the surface of a paved road surface, and a freezing coated with a water repellent composition for inhibiting freezing of the paved road surface. The present invention relates to a method for inhibiting freezing of a paved road surface using the water repellent composition for inhibiting freezing of the restrained pavement and the paved road surface.

  As a method for managing a paved road surface in winter, various techniques for suppressing freezing of the paved road surface have been studied. The pavement road surface freezing suppression technology is a technology for delaying and preventing the freezing of the pavement road surface, and has effects such as improvement of traveling safety and efficiency of snow removal work. Moreover, based on these effects, it can contribute to reduction of the running cost regarding road surface management in winter.

As one of such anti-freezing technologies for paved road surfaces, an asphalt material containing a water-repellent polymer has been proposed (see Patent Document 1). Asphalt paved road surface that has improved water repellency using this asphalt material, it is easy to peel off ice plates, compressed snow, and ice burn generated on the road surface from the paved road surface, which can contribute to delaying and preventing freezing of the paved road surface. .
However, since these methods using special asphalt materials cannot be applied to existing pavements as they are, it is necessary to renovate existing pavements and newly lay asphalt pavements using this asphalt material. However, there is a problem that requires a lot of labor and cost.

  For these reasons, in recent years, a freeze prevention method of a type in which a water repellent material is coated on a paved road surface has been proposed (see Patent Document 2). According to this method, construction can be performed on an existing pavement, and the construction is easy. Therefore, the management of a pavement road surface in winter can be greatly improved.

JP 2005-325536 A JP 2007-291827 A

However, it has been found that the liquid material used when applying the water repellent material causes the problem of cutback, which reduces the bond between the asphalt material and the aggregate constituting the paved road surface.
In response to such a problem, the present inventors have conducted various experiments to adjust the liquid material contained in the coating water-repellent material composition to suppress cutback and to prevent pavement surface freezing. It came to know.

  This invention is based on the said knowledge, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention provides a water repellent composition for anti-freezing of a paved road surface that is easy to construct and suppresses cutback of the paved road surface after construction, a freeze-inhibited pavement, and a method for suppressing freezing of the paved road surface. For the purpose.

Means for solving the problems are as follows. That is,
<1> A water repellent component containing water repellent particles, a binder resin that disperses the water repellent particles, and a coating liquid component of an organic compound to which the water repellent component is added, and the coating liquid component in the total amount The water repellent composition for inhibiting freezing of a paved road surface, characterized in that the content of is 20 mass% to 45 mass%.
<2> A freeze-inhibited pavement, wherein the water-repellent composition for anti-freezing of a paved road surface according to <1> is coated on the paved road surface.
<3> The paved road surface is composed of a dense pavement having a porosity of 0% or more and less than 8%, and the coating amount of the water repellent composition for inhibiting freezing on the paved road surface is 50 g / m ^{2 to} 300 g / m ^2. The anti-freezing pavement according to the above <2>.
<4> The pavement road surface is composed of a rough pavement having a porosity of 8% or more and 30% or less, and the coating amount of the water repellent composition for inhibiting freezing of the pavement road surface is 25 g / m ^{2 to} 200 g / m ^2. The anti-freezing pavement according to the above <2>.
<5> The water-repellent composition for inhibiting freezing of a paved road surface is applied in at least a part of the paved road surface in any of a vertical stripe pattern and a checkered pattern in which the width direction of the paved road surface is the vertical direction. The anti-freezing pavement according to any one of <2> to <4>.
<6> The water repellent composition for inhibiting freezing of a paved road surface is coated on the paved road surface coated with an undercoat material selected from either an epoxy resin or a urethane prepolymer <2> to <5 > Freezing suppression pavement according to any one of the above.
<7> The anti-freezing pavement according to <6>, wherein the coating amount of the undercoat material with respect to the coating amount of the anti-freezing water repellent composition on the paved road surface is 0.9 to 1.1 times in terms of mass ratio. .
<8> A method for inhibiting freezing of a paved road surface, comprising applying the water repellent composition for freezing inhibition of a paved road surface according to the above <1> on the paved road surface.
<9> the porosity of the pavement surface of dense-graded pavement less than 8% 0% or more, coating the anti-freezing for water repellent material composition pavement at a coverage of from ^50g / ^{m 2 ~300g} / m 2 The method for inhibiting freezing of a paved road surface according to <8>.
<10> the porosity of the pavement surface 8% to 30% or less rough pavement, coating freeze suppression water repellent material composition pavement at a coverage of from ^25g / ^{m 2 ~200g} / m 2 The method for inhibiting freezing of a paved road surface according to <8>.
<11> A water repellent composition for inhibiting freezing of a paved road surface is applied in at least a part of the paved road surface with a vertical stripe pattern or a checkered pattern in which the width direction of the paved road surface is the vertical direction. The method for inhibiting freezing of a paved road surface according to any one of <8> to <10>.
<12> Before applying the water repellent composition for inhibiting freezing of a paved road surface, an undercoat material selected from either an epoxy resin or a urethane prepolymer is applied on the paved road surface from <8> to <11 > The method for inhibiting freezing of a paved road surface according to any one of the above.
<13> Freezing of the paved road surface according to <12>, wherein the coating amount of the primer is 0.9 times to 1.1 times in terms of mass ratio with respect to the coating amount of the water repellent composition for inhibiting freezing of the paved road surface. Suppression method.

  According to the present invention, the above-mentioned problems in the prior art can be solved, the construction is easy, and the water-repellent composition for inhibiting freezing of a paved road surface that suppresses cutback of the paved road surface after construction, freezing It is possible to provide a method for suppressing freezing of a suppressed pavement and a paved road surface.

It is a figure which shows the measurement result of an ice adhesion tension test.

(Water repellent composition for inhibiting freezing of paved road surface)
The water repellent composition for inhibiting freezing of a paved road surface of the present invention includes a water repellent component and a coating solution component, and optionally includes other components.

<Water repellent component>
The water repellent component includes water repellent particles and a binder resin that disperses the water repellent particles. In this specification, water repellent means that when a water droplet having a volume of 50 mm ³ is dropped on a coating film obtained by applying and drying the anti-freezing water repellent composition on the paved road surface on a flat substrate, It shows that the contact angle of the water droplet with respect to the coating film is 90 ° or more.

The water-repellent particles are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include known fluororesin particles and inorganic compound particles.
The fluororesin is not particularly limited as long as it has water repellency. For example, a tetrafluoroethylene resin, a tetrafluoroethylene-hexafluoropropylene copolymer resin, a vinyl fluoride resin, or the like is preferably used. it can.
As the inorganic compound, SiO ₂ , Al ₂ O ₃ or the like whose surface is hydrophobized with dimethylene silicone oil or the like can be suitably used.
In addition, these may be used individually by 1 type and may use 2 or more types together.
Although there is no restriction | limiting in particular as an average particle diameter of the said water repellent particle, From a viewpoint of obtaining a uniform coating film, 0.05 micrometer-20 micrometers are preferable, and 0.1 micrometer-10 micrometers are more preferable.

  There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, well-known silicone resin, a fluororesin, an acrylic silicone resin, an acrylic resin etc. are mentioned.

  The composition ratio of the water-repellent particles and the binder resin in the water-repellent component is not particularly limited. From the viewpoint of obtaining a uniform coating film, the binder resin is 20% by mass in 100 parts by mass of the water-repellent component. It is preferable that the water-repellent particles are the remaining 80% by mass to 45% by mass.

<Coating liquid component>
The coating liquid component is an organic compound to which the water repellent component is added, and the content ratio of the coating liquid component in the total amount of the water repellent composition for freezing suppression on the paved road surface is 20% by mass to 45% by mass. It is characterized by being. By suppressing the content of the coating liquid component to 45% by mass or less, cutback of the paved road surface on which the water repellent composition for freezing suppression of the paved road surface is applied can be suppressed. Moreover, the workability with respect to the said pavement surface of the water repellent composition for the freezing suppression of the said pavement surface can be ensured by making the content rate of the said coating liquid component into 20 mass% or more.

The coating liquid component is a component that is generally used as an organic solvent, and the organic compound is not particularly limited and may be appropriately selected depending on the purpose. More specifically, organic compounds that are liquid at room temperature (25 ° C.) such as butyl acetate, heptane, toluene, isooctane, ethylene alcohol, and the like can be given.
When the fluororesin is used as the binder resin, the organic compound is preferably butyl acetate, and when the silicone resin is used, heptane, toluene, isooctane, or the like is preferable.
In addition, these may be used individually by 1 type and may use 2 or more types together.

<Other ingredients>
The other components are not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately selected depending on the purpose. For example, sodium chloride, chloride, which is sprayed on a paved road surface for the purpose of inhibiting freezing. Examples thereof include chemical freeze inhibitors such as calcium, physical freeze inhibitors such as rubber, and photocatalysts (titanium oxide) used for antifouling purposes.

(Freezing suppression pavement)
The anti-freezing paving body of the present invention is characterized in that the anti-freezing water repellent composition for the paved road surface is coated on the paved road surface. Thereby, the cutback after coating is suppressed, and construction can be performed simply by coating, and the construction is facilitated. Moreover, the said freeze suppression paving body can be constructed | assembled by apply | coating the water-repellent material composition for freeze suppression of the said paved road surface with respect to the existing pavement, and can be constructed | assembled at low cost. In particular, by selecting a place such as a sharp curve or a slope where anti-freezing is expected and constructing the anti-freezing pavement, it is possible to reduce the cost required for winter road surface management of the pavement. Moreover, since the construction is easy, it is possible to cope with the pavement road surface where the freezing problem occurs in a short construction period.

As the pavement constituting the anti-freezing pavement, all general pavements made of asphalt material and aggregate are applicable, and the existing pavement surfaces throughout the country are also applicable as described above.
The coating method is not particularly limited and may be appropriately selected depending on the purpose.For example, the water repellent composition for inhibiting freezing of the paved road surface may be selected by a general application means such as a roller brush. The method of drying after apply | coating on the said paved road surface is mentioned.

The amount of application of the water repellent composition for inhibiting freezing of the paved road surface to the paved road surface will be described.
First, as the coating amount in the case of coating on the pavement surface of dense-graded pavement, are not particularly ^{limited, 50g / m 2 ~300g / m} 2 is preferred. When the coating amount is less than 50 g / m ² , the coating film becomes uneven and water repellency may be uneven. Even when the coating amount exceeds 300 g / m ² , the water repellency is further improved. May not be expected and may be costly.
In the present specification, the dense-grain pavement refers to a pavement having a porosity of 0 to 8% in the surface layer having a depth of 5 cm from the surface.

Then, as the coating amount in the case of coating on the pavement surface of the rough surface pavement, is not particularly ^{limited, 25g / m 2 ~200g / m} 2 is preferred. When the coating amount is less than 25 g / m ² , the coating film becomes non-uniform and water repellency may be uneven. When the coating amount exceeds 200 g / m ² , the gap is formed between the rough surface structures. The water repellent composition for inhibiting freezing of the paved road surface is drooped, and further improvement in water repellency cannot be expected, resulting in high costs.
In the present specification, the rough surface pavement refers to a pavement having a porosity of 8% to 30% in the surface layer having a depth of 5 cm from the surface.

As a coating area | region with respect to the said pavement road surface of the water repellent composition for anti-freezing of the said pavement road surface, it can be set as the whole or a part of pavement division which should perform freezing suppression.
In the case of coating on a part of the paved road surface, there is no particular limitation, but it is preferable that the coating is performed in any one of a vertical stripe pattern and a checkered pattern in which the width direction of the paved road surface is vertical.
By coating in such a manner, it is possible to reduce the cost required for the construction while securing the slip resistance necessary for the safe passage of the traveling vehicle based on the freezing suppression as the entire paved section.

As one embodiment of the freeze-suppressed pavement, a water-repellent material for suppressing freezing of the pavement road surface is coated on the pavement road surface by first applying a primer to the pavement road surface. An antifreezing pavement coated with the composition may be mentioned.
The undercoat material is selected from either an epoxy resin or a urethane prepolymer, and by curing them, the effect of suppressing the cutback on the coating liquid component can be enhanced.

  The epoxy resin and the urethane prepolymer are not particularly limited as long as they strengthen the asphalt structure of the pavement by curing after coating, and can be appropriately selected according to the purpose. A commercially available prepolymer can be used as the composition.

  The application amount of the paved road surface of the undercoat material is not particularly limited, but is preferably about the same as the application amount of the water repellent composition for freezing suppression of the paved road surface, specifically, the freezing of the paved road surface. It is preferable that the coating amount of the undercoat material with respect to the water repellent composition for suppression is 0.9 to 1.1 times. With such a coating amount, the coating film can be applied without any unevenness, and the cutback suppressing effect can be enhanced.

(Method for inhibiting freezing of paved road surface)
The method for inhibiting freezing of a paved road surface according to the present invention is characterized in that the water repellent composition for inhibiting freezing of the paved road surface is coated on the paved road surface. Thereby, the cutback after coating is suppressed, and construction can be performed simply by coating, and the construction is facilitated. In addition, the method for suppressing freezing of the paved road surface can be implemented by applying the water-repellent material composition for suppressing freezing of the paved road surface to an existing pavement, and can be applied at low cost. . In particular, it is possible to reduce the cost required for winter road surface management of the paved road surface by selecting a place such as a sharp curve or a slope where anti-freezing is expected and performing the anti-freezing paved surface control method for the paved road surface. it can. Moreover, since the construction is easy, it is possible to cope with the pavement road surface where the freezing problem occurs in a short construction period.

In addition, as the method of coating the paved road surface with the anti-freezing water repellent composition for the paved road surface, the matters described with respect to the anti-freezing paved body can be applied, and redundant description is omitted. .
In addition, as described for the freeze-inhibited pavement, the method of applying the primer to the pavement surface can be cited as one of the embodiments, and the specific construction method is also described above. The matter explained about the freeze prevention pavement can be applied.

(Examples 1 to 3 and Comparative Examples 1 and 2 / Preparation of a water-repellent composition for inhibiting freezing of paved road surfaces)
As a water repellent component, a water repellent material (NTT Advanced Technology) having a silicone resin content of 50% by mass and a tetrafluoroethylene resin particle (average particle diameter of 1 μm) content of 50% by mass Manufactured by the same company).
55 parts by mass of this water-repellent component is added to 45 parts by mass of a mixed solution containing heptane, toluene, and isooctane as main components as a coating liquid component, and then stirred to produce a water-repellent material for inhibiting freezing of a paved road surface according to Example 1. A composition was prepared.

  In addition, Examples 2 and 3 and the comparison were made in the same manner as in Example 1 except that the blending amounts of the water repellent component and the coating liquid component were changed to the content of the coating liquid component shown in Table 1 below. A water repellent composition for inhibiting freezing of each paved road surface according to Examples 1 and 2 was prepared.

Using the water-repellent material composition for suppressing freezing of each paved road surface according to Examples 1 to 3 and Comparative Examples 1 and 2, a cutback suppression test of the paved road surface was performed.
That is, the anti-freezing water repellent composition for each pavement surface according to Examples 1 to 3 and Comparative Examples 1 and 2 is a dense pavement (asphalt) having a porosity of 4% in the surface layer from the surface to a depth of 5 cm. Using a roller brush on the surface of the test piece of the (paved) body, it was applied at a coating amount of 200 g / m ² , and the degree of adhesion (discoloration) of the dissolved asphalt to the roller brush was judged visually, and the cutback suppression effect was achieved. evaluated. In addition, this evaluation was objectively performed by the comprehensive judgment of five contractors with normal vision.
The evaluation criteria for the cutback suppression evaluation were as follows. The evaluation results are shown in Table 1 below.
○: Almost no discoloration of the roller brush is observed.
X: A clear discoloration is seen in the roller brush.

Moreover, the ease of application | coating of the water-repellent material composition for freeze suppression of each pavement road surface which concerns on Examples 1-3 and Comparative Examples 1 and 2 in the said cutback suppression test was evaluated as workability.
The evaluation criteria for this workability evaluation were as follows. The evaluation results are shown in Table 1 below.
○: The coating can be applied uniformly without any lumps.
X: Paint lumps and the like occur and uniform application is not possible.

As shown in Table 1, in the water-repellent material composition for inhibiting freezing of a paved road surface according to Comparative Example 1, the coating liquid component is contained in a large amount, thereby binding the asphalt material and the aggregate in the asphalt pavement. The cutback suppression is insufficient.
Moreover, in the water repellent composition for suppressing freezing of the paved road surface according to Comparative Example 2, the coating liquid component is too small and the workability is insufficient.
On the other hand, in the water-repellent material composition for suppressing freezing of each paved road surface according to Examples 1 to 3, good results were obtained in both cutback suppression and workability.

(Examples 4 to 11 / Construction for dense-grain pavement)
The water repellent composition for inhibiting freezing of a pavement road surface according to Example 2 is obtained by applying a roller brush to the surface of a test piece of a dense pavement (asphalt pavement) having a porosity of 4% in the surface layer from the surface to a depth of 5 cm. Using, it apply | coated with the application quantity of 25 g / m < ² >, it was made to dry, and the freeze suppression pavement which concerns on Example 4 was constructed | assembled.

  Moreover, Example 5 was carried out similarly to Example 4 except having changed the application quantity of the water-repellent composition for freezing suppression of the paved road surface which concerns on Example 2 into the application quantity shown in Table 2 below. Each anti-freezing pavement according to No. 11 was constructed.

With respect to each of the freeze-inhibited pavements according to Examples 4 to 11, the surface properties at the time of coating were visually observed, and the coating properties were evaluated.
The evaluation criteria for this coating property evaluation were as follows. The evaluation results are shown in Table 2 below.
○: The coating can be applied uniformly without any lumps.
△: There is a place where uniform coating cannot be performed due to the occurrence of paint lumps and the like.

As shown in this Table 2, in each anti-freezing pavement according to the coating amount in Example 5-10 to ^{50 g} / m 2 to 300 g / ^{m 2,} good results regarding coating performance was obtained. At the same time, in each freeze-inhibited pavement according to Examples 5 to 10 having good coatability, the water-repellent effect of the water-repellent component is uniformly exhibited on the paved road surface, and a sufficient freezing-inhibiting effect is obtained. can get.

(Examples 12 to 18 / Construction for rough pavement)
The water repellent composition for inhibiting freezing of a paved road surface according to Example 2 is obtained by applying a roller brush to the surface of a rough pavement (asphalt pavement) having a porosity of 23% in the surface layer from the surface to a depth of 5 cm. Using it, it apply | coated with the application quantity of 10 g / m < ² >, it was made to dry and the freeze suppression pavement which concerns on Example 12 was constructed | assembled.

Moreover, except having changed the application quantity of the water repellent composition for anti-freezing of the pavement road surface which concerns on Example 2 into the application quantity shown in Table 3 of an after-mentioned, it is the same as Example 12, Example 13- Each anti-freezing pavement according to 18 was constructed.
For each of the freeze-inhibited pavements according to Examples 12 to 18, the coatability was evaluated according to the same evaluation criteria as the coatability evaluation for the dense-grained pavement. The results are shown in Table 3 below.

As shown in this Table 3, in each anti-freezing pavement according to the coating amount in Example 13-17 to ^{25g / m 2 ~200g / m 2} , good results regarding coating performance was obtained. At the same time, in each of the freeze suppression pavements according to Examples 13 to 17 having good coatability, the water repellent effect of the water repellent component is uniformly exhibited on the pavement surface, and a sufficient freeze suppression effect is achieved. can get.

Next, in order to confirm the actual freezing suppression effect, the freezing suppression pavement according to Example 8 (dense grain pavement) and the freezing suppression pavement according to Example 15 (rough surface pavement) A tensile test was performed.
That is, in accordance with the “Paving Performance Evaluation Method Separate Volume (Japan Road Association)”, a steel sheet in which a nonwoven fabric is pasted on the coated surface of each freeze-suppressed pavement according to Examples 8 and 15 on the contact surface side with the coated surface. A tensile jig consisting of the above was installed, the tensile jig was pulled with a tensile tester in a state where the coated surface and the tensile jig were frozen, and the tensile strength (MPa) required for peeling was measured.
In addition, the freezing of the coating surface and the tension jig was performed by sprinkling water between the coating surface and the tension jig in a state where each anti-freezing pavement was cooled to a temperature of about −5 ° C. It was performed by curing for about 10 hours in the state.

The test result of the ice adhesion tensile test is shown in FIG. In addition, “shaved ice” in FIG. 1 indicates that the test was conducted after previously filling the gap of the rough pavement with shaved ice, and “normal” means that the test was performed under conditions where the shaved ice was not filled. Indicates that it has been done.
Moreover, in FIG. 1, the test result when not applying the water-repellent material composition for freezing suppression of a paved road surface for comparison is shown as “no application”.

  As shown in FIG. 1, the anti-freezing pavement (dense grain pavement) according to Example 8 and the anti-freezing pavement (rough surface pavement) according to Example 15 are “no application”. The ice adhesion tensile strength (MPa) can be suppressed to a lower level than the case of "," and the freezing suppression effect of the paved road surface can be expected by breaking the peeled ice layer when passing through the vehicle.

Claims (13)

A water repellent component comprising a water repellent particle, a binder resin that disperses the water repellent particle, and a coating liquid component of an organic compound to which the water repellent component is added,
A water repellent composition for inhibiting freezing of a paved road surface, wherein the content of the coating liquid component in the total amount is 20% by mass to 45% by mass.   A freezing-suppressed pavement, wherein the water-repellent composition for inhibiting freezing of a paved road surface according to claim 1 is coated on the paved road surface. Paved road surface, porosity consists of dense graded pavement less than 8% 0% or more, the coating amount of the anti-freezing for water repellent material composition pavement is a 50g ^/ m ² ~300g / m 2 according Item 3. The antifreezing pavement according to item 2. Paved road surface, porosity consists of rough pavement 30% or less than 8%, the coating amount of the anti-freezing for water repellent material composition pavement is a 25g ^/ m ² ~200g / m 2 according Item 3. The antifreezing pavement according to item 2.   A water repellent composition for inhibiting freezing of a paved road surface is applied in at least a part of the paved road surface by any one of a vertical stripe pattern and a checkered pattern in which the width direction of the paved road surface is the vertical direction. Item 5. The freeze suppressing pavement according to any one of Items 2 to 4.   The water repellent composition for inhibiting freezing of a paved road surface is coated on the paved road surface coated with an undercoat material selected from either an epoxy resin or a urethane prepolymer. Freezing suppression pavement.   The freezing-inhibited pavement according to claim 6, wherein the coating amount of the undercoat material with respect to the coating amount of the anti-freezing water repellent composition on the paved road surface is 0.9 to 1.1 times in terms of mass ratio.   A method for inhibiting freezing of a paved road surface, comprising applying the water-repellent composition for inhibiting freezing of a paved road surface according to claim 1 on the paved road surface. Claim porosity on pavement surface of dense-graded pavement less than 8% 0% or more, for coating the anti-freezing for water repellent material composition pavement at a coverage of from 50g / m ² ~300g / m ² The method for inhibiting freezing of a paved road surface according to 8. Claim porosity on pavement surface 8% to 30% or less rough pavement, to coating with a coating weight of 25g / m ² ~200g / m ² freeze suppression water repellent material composition pavement The method for inhibiting freezing of a paved road surface according to 8.   The water-repellent composition for inhibiting freezing of a paved road surface is applied in at least a part of the paved road surface by any one of a vertical stripe pattern and a checkered pattern in which the width direction of the paved road surface is the vertical direction. The method for inhibiting freezing of a paved road surface according to any one of 8 to 10.   The precoating material selected from either an epoxy resin or a urethane prepolymer is applied on the pavement road surface before coating the water repellent composition for inhibiting freezing of the pavement road surface. To prevent freezing of paved road surface.   The method for inhibiting freezing of a paved road surface according to claim 12, wherein the coating amount of the primer is 0.9 to 1.1 times in terms of mass ratio with respect to the coating amount of the water repellent composition for inhibiting freezing of the paved road surface.