JP7821767B2 - bamboo paving - Google Patents

Description

We will disclose paving technology using bamboo.

Wood-based paving, such as that used on park walkways, is constructed by spreading a surface layer of wood approximately 3 to 5 cm thick evenly over an asphalt or concrete pavement. Patent Document 1 discloses an example of such wood-based paving, in which a bamboo surface layer is formed on top of a newly laid concrete pavement, with the bamboo surface layer being a mixture of only bamboo chips, fiber, or powder, mixed with a binder.

When wood-based paving is constructed using a leveling method, resulting in a surface layer of wood material approximately 5 cm thick, the nature of wood makes it susceptible to cracking and warping, primarily due to drying shrinkage, unless the underlying asphalt or concrete paving is new and strong. Therefore, for example, Patent Document 1 discloses a wood-based paving method in which a concrete paving made from a specified mixture of materials is newly constructed for bamboo paving, and then a surface layer of bamboo is formed on top of that paving.

Patent No. 3383246

In light of the prior art, this invention proposes a bamboo pavement and its construction method that is less likely to crack or warp after construction, and can be constructed on both newly constructed pavements such as asphalt or concrete, as well as existing pavements.

One aspect of the present invention is a bamboo pavement that includes a thin crushed bamboo surface layer formed on the pavement, and is characterized in that the crushed bamboo surface layer is made from a mixed material that contains at least a binder, crushed bamboo, and a separation inhibitor.

Another aspect of the bamboo pavement is characterized in that it includes a primer formed on the pavement and a thin crushed bamboo surface layer formed on the primer, with the crushed bamboo surface layer being composed of a mixed material containing at least a binder, crushed bamboo, and a separation inhibitor.

In these bamboo paving styles, pigments can also be mixed into the mixed material of the crushed bamboo surface layer. A thin layer refers to a layer with a thickness of 10 mm or less, and the crushed bamboo surface layer in the bamboo paving described above is preferably 3 mm or less in thickness. The crushed bamboo used in this thin layer is preferably made up of crushed pieces with a maximum length of 2 mm or less.

One aspect of the present invention, a method for constructing the above-described bamboo pavement, includes the steps of mixing at least a binder, crushed bamboo, and a separation inhibitor to create a mixed material, and spraying the mixed material onto the pavement to form a crushed bamboo surface layer. The spraying of the mixed material can be carried out in at least two spraying steps: a first spraying step in which the mixed material is sprayed onto the pavement and allowed to dry, and a second spraying step in which the mixed material is further sprayed onto the pavement after the first spraying step and allowed to dry.

Another aspect of the bamboo paving construction method includes the steps of mixing at least a binder, crushed bamboo, and a separation inhibitor to create a mixed material, applying a primer to the pavement, and spraying the mixed material onto the applied primer to form a crushed bamboo surface layer. The mixed material can be sprayed in at least two spraying operations: a first spraying operation in which the mixed material is sprayed onto the primer and allowed to dry, and a second spraying operation in which the mixed material is sprayed after the first spraying and allowed to dry.

In these application methods, pigments can be added to the mixed material. The thickness of the pulverized bamboo surface layer formed by spraying is preferably 3 mm or less. The pulverized bamboo is made by pulverizing and sieving bamboo, preferably into pulverized pieces with a maximum length of 2 mm or less.

The crushed bamboo surface layer of the present invention uses crushed bamboo consisting of finely crushed pieces of 2 mm or less, for example. This crushed bamboo is mixed with at least a binder and a separation inhibitor to form a mixed material, which can be sprayed to form a thin layer of, for example, 3 mm or less. Because it is a thin layer, it is less likely to develop problems such as cracking or warping, and as a result, it can be easily applied as a surface layer to both new and existing pavements. Furthermore, this sprayable mixed material can be applied without sagging not only on horizontal surfaces such as road surfaces, but also on inclined and vertical surfaces.

Schematic cross-sectional view showing an example of bamboo paving in the case of asphalt paving. Schematic cross-sectional view showing an example of bamboo paving in the case of concrete paving. 1 is a process diagram illustrating an example of a bamboo paving construction method.

The following describes specific examples of how the present invention can be implemented.

Figure 1 shows a cross-sectional view of an example of bamboo pavement, where a crushed bamboo surface layer is applied over a newly constructed or existing asphalt pavement. As shown in the figure, a thin crushed bamboo surface layer is formed on the surface of the asphalt pavement. The thickness of the thin crushed bamboo surface layer is 3 mm or less, and optimally 2 mm or less.

Figure 2 shows a schematic cross-sectional view of an example of bamboo paving, where a crushed bamboo surface layer is applied over a newly constructed or existing concrete pavement. As shown in the figure, a primer is applied to the surface of the concrete pavement, and a thin crushed bamboo surface layer is formed on top of this primer. In this example, the primer is applied to the concrete pavement surface as an adhesion promoter to improve the adhesion of the crushed bamboo surface layer. The thickness of the thin crushed bamboo surface layer is 3 mm or less, as in the example of Figure 1, and optimally 2 mm or less.

Figure 3 shows an example process diagram for constructing these bamboo paving projects.

Step 1 is the preparation stage, in which the area to be paved with asphalt, concrete, or other mortar is cleaned with water, etc., and masked as necessary.

In step 2, the materials required for the surface layer of the crushed bamboo are mixed to create a mixture. The components of the mixture are binder (and water), crushed bamboo, and a separation inhibitor, with pigments added as needed. The optimal weight ratio of each material is as follows:
・Binding material: 30-50%
・Water: 20-40%
・Crushed bamboo material: 10-40%
Separation inhibitor: 2 to 10%
・Pigment: 0-5%

Water-based acrylic resin is used as the binding material (binder). Other water-based resins such as water-based urethane resin and water-based epoxy resin can also be used, but water-based acrylic resin was found to be the best in terms of uniformity of the finish, prevention of sagging, light resistance, ease of application with a spray gun, environmental considerations, and ease of handling.

Crushed bamboo is made by crushing felled bamboo, sieving it, and then preparing a collection of crushed pieces below a certain size. Crushed bamboo can be fibrous, rectangular (angular), circular, or oval in shape, but in any case, by sieving the bamboo, the maximum length of each crushed piece (i.e., the longest side, diameter, or major axis of the crushed piece) is reduced to 2 mm or less. Crushed pieces longer than 2 mm are not suitable for forming thin layers, nor are they suitable for spray application using a simple spray gun.

An anti-segregation agent (also known as a thickener) is used to improve the mixing of the crushed bamboo with the binder, ensuring that the crushed bamboo is evenly distributed throughout the layer. If an anti-segregation agent is not added, the lighter crushed bamboo may float in the binder, causing the two to separate and not mix properly. A suitable anti-segregation agent is a powdered mineral.

Pigments are used as needed to adjust the color of the finished bamboo paving (lighter/dark, blackish/white, etc.).

Put the above ingredients in a bucket or other container and mix using a hand mixer to create a slurry-like mixture.

Step 3 is a primer application step that can be applied when working on concrete pavement. Step 3 is not necessary for asphalt pavement (hence the dotted line). Commercially available resin-based primers can be used as an adhesion promoter for concrete pavement. For example, the primer is applied to the work area at 0.1 to 0.2 kg/ ^m² .

Step 4 is the first spraying of the mixed material. An appropriate amount of the mixed material prepared in step 2 is placed in a hopper spray gun and sprayed onto the application area. As an example, the mixed material is sprayed at 1.5 kg/ ^m2 in the first spraying operation. After the spraying operation is completed, the material is allowed to dry for approximately 30 minutes in step 5.

Step 6 is the second spraying of the mixed material. The remaining mixed material is placed in a hopper spray gun and sprayed onto the area where the first spraying and drying has been completed. As an example, the second spraying operation also involves spraying 1.5 kg/ ^m2 of mixed material. After the spraying operation is completed, the area is dried for approximately 30 minutes in step 7 and then cured. Curing is required to completely harden the resin, and is recommended for at least 12 hours in summer and at least 24 hours in winter.

In the construction method of this example, the mixed material was sprayed in two separate steps. To illustrate this with specific numerical values, the total amount of mixed material sprayed was 1.0 to 3.0 kg/ ^m² , with 0.5 to 1.5 kg/ ^m² sprayed in the first spraying step and 0.5 to 1.5 kg/ ^m² sprayed in the second spraying step. To prevent insufficient hardening, it is appropriate to spray 0.5 to 1.5 kg/ ^m² twice. These two spraying steps form a thin, crushed bamboo surface layer with a thickness of 3 mm or less, preferably 1 to 2 mm.

The mixed material may be sprayed three or more times. For example, three sprays of 1.0 kg/m² ^each may be performed for a total spray amount of 3.0 kg/ ^m² . The more sprays performed, the more natural the texture and depth of color will be in the surface layer.

Performance evaluation tests were conducted on specimens prepared according to the above construction method. The test results are shown below.

[1] Adhesion strength Adhesion strength was measured using a Construction Research Institute type tensile tester. The results were 0.81 N/ ^mm2 for the asphalt pavement specimen and 0.53 N/ ^mm2 for the concrete pavement specimen. According to the Construction Guidelines for Outdoor Sports Facilities (Japan Sports Facilities Association, revised edition 2012), the standard physical property value of acrylic resin surface materials is 0.3 N/ ^mm2 , so it can be seen that they have sufficient adhesion strength.
[2] Skid resistance value (BPN)
The test results for the specimen showed a value of 70 when wet. According to the Pavement Design and Construction Guidelines (Japan Road Association, 2006 edition), the guideline value is 40 when wet, so it can be seen that the material has sufficient skid resistance.
[3] GB coefficient (shock absorption) and SB coefficient (rebound resilience)
The results of GB and SB tests on the specimen showed a GB coefficient (% cm) of 23 and an SB coefficient (% cm) of 5. When these results were compared with the values given in the Pavement Performance Evaluation Method Supplement - Evaluation Methods for Required Performance Indicators (Japan Road Association), they fell within the walkability range comparable to that of clay-based/asphalt elastic mixtures. It was confirmed that the pavement has better shock absorption and is easier to walk on than general asphalt and concrete pavements.
[4] Amount of infiltrated water: An on-site permeability test was conducted to examine the amount of infiltrated water when the crushed bamboo surface layer according to the present embodiment was applied to a permeable pavement. According to the Pavement Design and Construction Guidelines (Japan Road Association, 2006 edition), the guideline value for the amount of infiltrated water on a sidewalk is 300 ml/15 s. The amount of infiltrated water on the permeable pavement before spraying the mixed material was 1218 ml/15 s, and after spraying the mixed material, the amount of infiltrated water was 702 ml/15 s. Although a 45.6% decrease was observed, it was confirmed that the amount of infiltrated water was sufficient compared to the guideline value.

The embodiment described above by way of example has the following advantages.
The use of bamboo allows for a pavement surface that blends in with nature, making it ideal for use in zoos, natural parks, etc. In such cases, it can be applied to existing pavements, making construction inexpensive and easy.
The crushed bamboo surface layer uses a mixture containing the above-mentioned ingredients, and because the crushed bamboo is broken into small pieces of 2 mm or less, the mixture can be sprayed onto the surface, resulting in a thin layer. This mixture can be applied not only on large-scale projects using spraying machines, but also with simple spraying machines such as hopper spray guns and ricin guns. Because it is sprayed, it can be easily applied at low cost to both new and existing pavements. Furthermore, because it is sprayed onto a thin layer, it can be applied without sagging not only on horizontal surfaces such as road surfaces, but also on inclined and vertical surfaces, making it versatile.
Since it is a spray-on application, when it is applied to existing pavement, even if there are cracks in the pavement, it can be applied by simply repairing them with repair material.
The surface layer of the crushed bamboo is a thin layer applied by spraying, so it hardens in a short time, shortening the curing time and allowing for early release. Furthermore, even if cracks develop on the surface layer of the crushed bamboo due to aging, they can be easily repaired by spraying again on top.

A number of examples of the present invention have been shown and described above. However, in addition to these examples, various other embodiments can be conceived based on the concept of the present invention as understood from the above description.

Claims (9)

A bamboo pavement including a crushed bamboo surface layer having a thickness of 3 mm or less formed on the pavement,
Bamboo pavement, in which the surface layer of the crushed bamboo is made of a mixed material consisting of at least a binder, crushed bamboo , and a separation inhibitor, and the crushed bamboo consists of crushed pieces with a maximum length of 2 mm or less . A bamboo pavement comprising a primer formed on the pavement and a crushed bamboo surface layer having a thickness of 3 mm or less formed on the primer,
Bamboo pavement, in which the surface layer of the crushed bamboo is made of a mixed material consisting of at least a binder, crushed bamboo , and a separation inhibitor, and the crushed bamboo consists of crushed pieces with a maximum length of 2 mm or less . The bamboo paving described in claim 1 or 2, wherein a pigment is further mixed into the mixed material. A method for constructing bamboo paving, comprising:
Mixing at least a binder, crushed bamboo, and a separation inhibitor to form a mixed material;
and spraying the mixed material onto the pavement to form a crushed bamboo surface layer .
The crushed bamboo material is made by crushing and sieving bamboo into crushed pieces having a maximum length of 2 mm or less,
The application method uses either a hopper spray gun or a spray gun including a lysine gun to spray the mixed material . The spraying of the mixed material is
a first spraying operation of spraying the mixed material onto the pavement and drying it;
5. The construction method according to claim 4 , wherein the construction method comprises at least two spraying operations, that is, a second spraying operation in which the mixed material is further sprayed and dried after the first spraying operation. A method for constructing bamboo paving, comprising:
Mixing at least a binder, crushed bamboo, and a separation inhibitor to form a mixed material;
applying a primer onto the pavement;
and spraying the mixed material onto the primer to form a pulverized bamboo surface layer .
The crushed bamboo material is made by crushing and sieving bamboo into crushed pieces having a maximum length of 2 mm or less,
The application method uses either a hopper spray gun or a spray gun including a lysine gun to spray the mixed material . The spraying of the mixed material is
a first spraying operation of spraying the mixed material onto the primer and drying it;
The application method according to claim 6 , wherein the application is carried out by at least two spraying operations, that is, a second spraying operation in which the mixed material is further sprayed and dried after the first spraying operation. The application method according to any one of claims 4 to 7 , further comprising adding a pigment to the mixed material. A construction method according to any one of claims 4 to 7 , wherein the thickness of the crushed bamboo surface layer after formation is 3 mm or less.