JPH08226101A - Construction method for upper subgrade and upper subgrade material - Google Patents

Abstract

PURPOSE: To improve reliability for executing a construction work and restrain the occurrence of dust during the work by increasing compressive strength and reducing the dispersion thereof. CONSTITUTION: Water is added to crushed asphalt wastes having a grain size equal to or less than 40mm, and cement to such an extent as not causing the scatter of the cement. Thereafter, an upper subgrade material and the crushed asphalt wastes mixed in a ready-mixed concrete plant, cement and water, after further mixed in the plant, are carried to a construction site and placed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road construction method and road constituent materials, and more particularly to a construction method for an upper layer roadbed using waste asphalt and the like and an upper layer roadbed material.

[0002]

2. Description of the Related Art Conventionally, when constructing an upper layer roadbed, it is customary to mix aggregates such as crushed stone, cement, asphalt emulsifiers, etc. at the construction site.

[0003]

However, in the conventional construction method, a material that easily scatters, such as cement, is mixed at the construction site, so dust is accumulated on the entire surface, especially in private houses and shops. There is a possibility of causing a kind of pollution in the vicinity of, and the working environment is also poor for workers, and from these points, there is a problem that the above-mentioned upper roadbed is very difficult to construct. There are similar problems when using crushed materials of asphalt waste as the above aggregate, and since the strength is also insufficient, it is necessary to increase the thickness of the upper roadbed to supplement the strength. Therefore, since the earth and sand at the construction site must be dug deeply and removed, there is a problem that the construction cost becomes high. The present invention has been made against the background of such circumstances, the object of the present invention, no dust occurs during construction,
Moreover, it is an object of the present invention to provide an upper layer roadbed construction method and an upper layer roadbed material using waste asphalt material that can improve the strength of the roadbed. While the inventors of the present application are conducting various researches to solve the above-mentioned problems, the strength of the upper layer roadbed using waste asphalt is low, because the mixing of various materials is not sufficient, the original property is exhibited. The inventor of the present invention has come to the present invention by discovering that it has not been completed.

[0004]

The present invention has been made to achieve the above object, and the present invention is configured as follows. A Upper-layer roadbed for crushing asphalt waste material with a particle size of 40 mm or less, cement, and water added to the extent that cement does not scatter in a ready-mixed plant, and then transporting the mixture to a construction site for construction Construction method. B In the method for constructing an upper layer roadbed according to the item A, the cement has a weight ratio of 5 to 6% to the crushed material of the asphalt waste material, and the water has a weight ratio of 3 to the total amount of the crushed material and the cement. 7% construction method of upper roadbed. C An upper layer roadbed material containing at least a crushed material of asphalt waste material having a particle size of 40 mm or less, and cement and water to the extent that the cement does not scatter, and mixing them in a raw plant. D In the upper layer roadbed material according to the item C, the cement has a weight ratio of the asphalt waste material to the crushed material of 5 to 6
%, The water has a weight ratio of 3 to 7% with respect to the total amount of the crushed material and cement. Here, "crushed material with a particle size of 40 mm or less" means 4
It means a crushed product that is small enough to fall from a 0 mm square sieve mesh.

[0005]

EXAMPLES Examples of the present invention will be described in detail below. [Example 1] Crushed material of asphalt waste material whose particle size was adjusted in advance, and the weight ratio to the crushed material was 2%, 4%, 6%
After mixing well the cement which is equivalent to the cement and the water to the extent that the cement powder does not scatter, in the asphalt pavement summary of the Japan Road Association, a diameter of 10c
It was prepared by compacting the test piece of m. The number of test specimens was 3 for each cement addition amount of 2, 4, and 6%, for a total of 9 specimens. A water content of 3 to 7% by weight relative to the total amount of crushed material and cement was used as the amount of water such that the cement powder did not scatter.
The type of cement used is blast furnace cement type B (made by Aso Cement).

Table 1 shows the results of testing the relationship between the amount of cement added and the compressive strength using the above specimens.

[Table 1] Based on Table 1, the compressive strength (uniaxial compressive strength) with respect to the amount of cement added is plotted and connected by a line, as shown in FIG. According to FIG. 1, when the amount of cement added is 5 to 6%, the uniaxial compressive strength is 28 to 32.8 (kgf / cm ² ). Since the uniaxial compressive strength of the upper layer roadbed subjected to cement stabilization treatment by adding 30 is 30 (kgf / cm ² ), the upper layer roadbed material of the present example has substantially the same strength. That is, according to this embodiment, the strength is improved to the same extent as that of the ready-mixed concrete for road.

The equivalent conversion factor α, which indicates how many centimeters of the hot asphalt mixture for the surface layer / base layer, corresponds to the uniaxial compressive strength of 30 (kgf / cm ² ) when the cement stabilization treatment is applied to the crushed stone of the particle size control in the upper layer roadbed. Is α = 0.55 (this is the same in the case of the present embodiment), while α = 0.35 is used in the case of the crushed particle size control. When the cement is mixed with the crushed material of asphalt waste material at the construction site to form the upper layer roadbed, it is almost the same as the case of the above-mentioned crushed stone of particle size adjustment. Therefore, the ratio is 0.55 / 0.35 = 1.57. In other words, if the required thickness of the upper layer roadbed is, for example, 20 cm when using conventional crushed stones with a controlled particle size or when mixing and adjusting asphalt waste materials and cement at the construction site, this embodiment 20 / if using the above-mentioned upper layer roadbed material
A thickness of 1.57 = 12.7 cm will suffice. Therefore, the depth of digging the road surface for road construction is reduced to about 60% (12.7 / 20 = 0.64) of the conventional one, and
Since the amount of earth and sand to be dug and transported is reduced to the same extent, there are advantages that road construction costs can be reduced and construction period can be shortened. According to the asphalt pavement guideline, the upper layer roadbed has a thickness of up to 15 cm per layer, so if the conventional roadbed requires a thickness of 20 cm as in the above example, divide it into two times. Although the construction must be performed in two layers, in the case of this embodiment, the thickness of the upper layer roadbed is 1
Since it only needs to be 2.7 cm, only one layer of construction is required, and the cost can be significantly reduced and the construction period can be shortened.

[Embodiment 2] Same as in Embodiment 1 with the same kind of material, blending ratio and particle size adjustment and different particle size adjusting method (several kinds with maximum particle size of 40 mm or less are set and particle size composition is set). The upper layer roadbed materials, which were mixed with each other in the ready-mixed plant, were transported to the road construction site, and the upper layer roadbeds were constructed according to the usual method. Since 3 to 7% of the total amount of water is added to the upper layer roadbed material, the cement powder does not scatter during construction, and therefore dust pollution does not occur.
In addition, it was possible to improve the working environment of the conventional construction site where dust was intense. The crushed asphalt waste may have a particle size of about 40 mm, but the maximum particle size is preferably 30 mm or less in consideration of workability during construction.

[Test Example 1] A soil compaction test (JIS A1210) was carried out on the upper layer roadbed material obtained by mixing 4% by weight of cement with a crushed material of asphalt waste having a maximum particle diameter of 25 mm. The test is a test method:
1.4b, tamping method: 1st method, mold inner diameter: 10
cm. The test results are shown in Table 2 and FIG. Moisture content 9.
At 0%, the maximum dry density was 2.041 g / cm ³ , and sufficient results were obtained for the upper layer roadbed.

[Table 2] Although some embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. Is.

[0010]

Since the present invention is configured as described above, it has the following effects. According to the construction method of the upper layer roadbed and the upper layer roadbed material according to claims 1 to 4,
Compared to the case of using conventional particle size controlled crushed stone or mixing crushed material of asphalt waste material with cement at the construction site, the strength is significantly improved by about 60% and the variation in strength Can be reduced and reliability can be increased. (It is considered that the cause is mixing by the ready-mixed plant, but the degree of strength improvement is far beyond the common sense of those skilled in the art.) If the strength of the upper layer roadbed is improved, the thickness of the upper layer roadbed will be inversely proportional to it. As the material of the upper roadbed is reduced, the depth to be dug at the road construction site and the amount of earth and sand to be transported and removed are also reduced in inverse proportion to the strength of the upper roadbed. It is possible to significantly reduce the cost and shorten the construction period. Further, according to the method for constructing the upper layer roadbed and the material for the upper layer roadbed according to claims 1 to 4, since water is added to the extent that the cement does not scatter, the cement powder cannot enter during the construction, and dust pollution is avoided. This will prevent the outbreak and improve the working environment at the construction site.
As a result, it is possible to improve work efficiency during construction.

[Brief description of drawings]

FIG. 1 is a graph showing experimental results in an example of the present invention.

FIG. 2 is a graph showing test results relating to the present invention.

Claims (4)

[Claims] 1. A crushed product of asphalt waste material having a particle size of 40 mm or less, cement and water added to the extent that the cement does not scatter are mixed in a ready-mixed plant, and then the mixture is transported to a construction site for construction. Construction method of the upper roadbed. 2. The method for constructing an upper layer roadbed according to claim 1, wherein the cement has a weight ratio of the asphalt waste material to a crushed material of 5 to 6%, and the water has a weight to a total amount of the crushed material and the cement. Construction method for upper roadbed with a ratio of 3 to 7%. 3. An upper layer roadbed material containing at least a crushed material of asphalt waste material having a particle size of 40 mm or less, cement and water to the extent that the cement does not scatter, and mixing these by a raw concrete plant. 4. The upper layer roadbed material according to claim 3,
An upper layer roadbed material, wherein the cement has a weight ratio of 5 to 6% to the crushed material of asphalt waste, and the water has a weight ratio of 3 to 7% to the total amount of the crushed material and cement.