JPH09316807A - Semi-flexible paving structural body, manufacture thereof, and cement injection material used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement injection material in which high fluidity can be maintained for a long time, and of a low material separation property, and a semi-flexure paving structural body of excellent durability and low cost using the injection material by preventing deterioration of fluidity of the injection material, and preventing deterioration of strength achievement performance while maintaining low material separation property. SOLUTION: A semi-flexure paving structural body is obtained by injecting cement injection material including cement fine powder of 8μm or less on a base comprising asphalt and aggregates. The cement injection material comprises cement in which cement fine powder including grain of 8μm or less at a volume ratio of 70% or more is blended by 10wt.% or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement injection material that retains high fluidity for a long time and has low material separation property, and a pavement structure using the injection material.

[0002]

2. Description of the Related Art Generally, an injection material used for semi-flexible pavement needs to have an increased viscosity to prevent material separation, and an organic thickener such as methyl cellulose is added and mixed. .

[0003]

However, increasing the viscosity of the injection material by adding and mixing an organic thickening agent such as methylcellulose has some effect in reducing the material separability. There is a possibility that the fluidity of the material may be reduced and the strength development may be reduced.

The present invention has been made in order to solve the above problems, and while maintaining the low material separability, it prevents deterioration of the fluidity of the injection material, deterioration of strength development, etc., and durability. An object of the present invention is to provide a semi-flexible pavement structure that is excellent in performance and is inexpensive.

[0005]

In order to solve the above problems, the present invention has been made as a semi-flexible pavement structure, a method for producing the same, and a cement injection material used for the semi-flexible pavement structure. A feature of the structure is that it is obtained by injecting a cement injection material containing fine cement powder of 8 μm or less into a roadbed on which asphalt and aggregate are laid.

A characteristic of the method for manufacturing the semi-flexible pavement structure is that it is manufactured by injecting a cement injection material containing cement fine powder of 8 μm or less into a roadbed on which asphalt and aggregate are laid. .

This semi-flexible pavement structure is an open-grain asphalt concrete laid by premixing asphalt with aggregate having a porosity of 20 to 25%, which is generally used in the conventional semi-flexible pavement. Then, the above-mentioned injection material is injected, cured, and integrated.

Further, the characteristics of the cement injection material are as follows:
The cement fine powder is composed of 10% by weight or more of cement fine powder having a volume ratio of particles of 8 μm or less of 70% or more.

That is, it is characterized in that a known cement is prepared by adding and mixing cement fine powder having a prescribed particle size range in a predetermined ratio.

The publicly known cement referred to here is a publicly known cement such as normal Portland cement, early-strength Portland cement, moderate heat Portland cement, sulfate resistant Portland cement, etc. according to JIS standard, and super fast cement. Further, mixed cement obtained by mixing one kind or two or more kinds of admixtures such as blast furnace slag powder, fly ash, silica stone powder, silica fume and gypsum with these known cements is also included.

The cement fine powder added here is the above-mentioned known cement produced by using, for example, a centrifugal force air classifier, and the volume ratio of particles having a particle size range of 8 μm or less is 70% or more. And the addition amount was 10% or more. This is because, when it is outside the above range, the material separation resistance cannot be sufficiently improved and the strength development is not sufficient when it is used as a semi-flexible pavement injection material.

That is, the cement fine powder has a very high fineness and contains a lot of cement minerals such as tricalcium silicate, dicalcium silicate, tricalcium aluminate and ferric aluminate, and gypsum. It is a powder of high cement content and causes a decrease in fluidity when used as a cement for ordinary mortar and concrete, but when used at a relatively high water / cement ratio, the fineness and high activity of the cement fine powder are used. Separation of solids (cement, sand) and water in grouting material (bleeding)
It also contributes to prevent the settling of coarse particles in the cement. In addition, the cement fine powder is a powder having extremely high hydration activity as described above, and improves the strength development of the above-mentioned injection material from the early age.

Further, in order to obtain high fluidity, a high-performance water reducing agent is usually used, and there are various types such as delayed type, standard type, accelerated type, etc., as in the case of using for ordinary concrete or mortar. You can use the type that suits your purpose, and the amount used is the same as for normal concrete and mortar.
It may be added in any amount as long as the desired fluidity can be obtained.

[0014]

Embodiments of the present invention will be described below.

Example 1 In this example, a mixture ratio of 65% by weight of cement and 35% by weight of cement fine powder was used, and the cement and the cement fine powder contained 30% by weight of No. 7 silica sand as a premixed mixture. Injection mortar was used.

0.75% by weight of a high-condensation product of naphthalenesulfonic acid (trade name: Mighty 100, manufactured by Kao Corporation) as a high-performance water-reducing agent, based on 100 parts by weight of this premixed injection mortar, commercially available ethylene vinyl acetate. An injectable material was prepared by adding 2% by weight of the re-emulsified powder resin and thoroughly kneading with a hand mixer at a water / injection mortar ratio = 40%. Further, the obtained pouring material was poured into open-grained asphalt concrete having a porosity of 23% to obtain a semi-flexible pavement structure.

The cement used here is ordinary Portland cement (volume ratio of particles of 8 μm or less is 38%, fineness is
3200 cm ² / g), and the cement fine powder is produced by classifying the ordinary Portland cement with a centrifugal force air classifier, and the volume ratio of particles with a particle size of 8 μm or less is 92 μm.
%, And the degree of fineness was 10600 cm ² / g.

Example 2 In this example, cement 85 was used as an already mixed mortar.
The mixture was composed of 15% by weight of cement fine powder and 15% by weight of cement powder, and contained 30% by weight of No. 7 silica sand. The other components and the like are the same as those in Example 1 described above, and thus the description thereof is omitted.

Example 3 In this example, cement 90 was used as the premixed mortar.
The mixture was composed of 10% by weight of cement fine powder and 10% by weight of cement fine powder, and contained 30% by weight of No. 7 silica sand. The other components and the like are the same as those in Example 1 described above, and thus the description thereof is omitted.

Example 4 In this example, the premixed mortar having the same composition ratio as in Example 3 was used. However, the volume ratio of particles of the cement fine powder having a particle size of 8 μm or less was 70%. The other components and the like are the same as those in Example 1 described above, and thus the description thereof is omitted.

Comparative Example 1 As Comparative Example 1, the volume ratio of particles having a particle size of 8 μm or less is 50%.
A mixed injection mortar containing 10% by weight of cement fine powder and 90% by weight of cement and containing 30% by weight of No. 7 silica sand was prepared.

Comparative Example 2 As Comparative Example 2, the volume ratio of particles having a particle size of 8 μm or less is 70%.
A mixed injection mortar containing 5% by weight of cement fine powder and 95% by weight of cement and containing 30% by weight of No. 7 silica sand was prepared.

Comparative Example 3 As Comparative Example 3, the cement fine powder was not blended and the cement
A mixed injection mortar containing 100% by weight, 30% by weight of No. 7 silica sand and 0.2% by weight of a thickener was prepared.

Comparative Example 4 As Comparative Example 4, the cement fine powder was not mixed and the cement
A mixed injection mortar containing 100 wt% of No. 7 silica sand and 30 wt% of the whole was prepared.

Test Example Fluidity of the above Examples 1 to 4 and Comparative Examples 1 to 4,
Bleeding rate, compressive strength, and bending strength were tested.

The test results are shown in Table 1 below.

[0027]

[Table 1]

Since such an injection material is required to be injected into open-grained asphalt concrete as a semi-flexible pavement injection material and filled without any gaps to be integrated with the open-grained asphalt concrete, the fluidity of the injection material is high. It is desirable that the P funnel flow time is between 9 and 15 seconds.
The bleeding rate in time is preferably 3% or less, and the strength of the injected material is 7 days old and the compressive strength is 150 kgf / cm ²
Or more, or bending strength of 21 kgf / cm ² or more, or age
The flexural strength after 28 days is preferably 40 kgf / cm ² or more.

As the semi-flexible pavement structure, it is desirable that its bending strength is 30 kgf / cm ² or more after 28 days of age.

In this respect, all of Examples 1 to 4 satisfy these conditions.

On the other hand, in Comparative Example 3 containing 0.2% of the thickener, the P funnel flow-down time was significantly increased to 22.7 seconds, and a decrease in fluidity was observed as compared with Examples 1 to 4.

Further, the bleeding rates are comparative examples 1, 2, and
In No. 4, all exceeded 3%.

[0033] Other embodiments In the above embodiment, although the addition of superplasticizer, ethylene vinyl acetate redispersible powdered resin, it is not a condition in the present invention the addition of these.

In the above embodiment, ordinary portland cement was used as the cement. However, the type of cement is not limited to this, and high-strength portland cement, moderate heat portland cement, sulfate resistant portland cement, or portland cement is used. Other than that, it is also possible to use super rapid hardening cement, mixed cement such as blast furnace cement or fly ash cement.

[0035]

As described above, according to the present invention, since the known cement is mixed with 10% by weight or more of cement fine powder in which the volume ratio of particles of 8 μm or less is 70% or more, the material separation is small, Moreover, the effect of being able to provide a low-separation, high-fluidity cement injection material with high fluidity was obtained.

Further, by using the material low-separation and high-fluidity cement injecting material of the present invention, there is a practical advantage that it is possible to provide a semi-flexible pavement structure which is simple in construction and excellent in durability.

Front page continuation (72) Inventor Kiyohiko Uchida 7-55, Minami Enkajima, Taisho-ku, Osaka Sumitomo Osaka Cement Co., Ltd.

Claims (3)

[Claims] 1. A semi-flexible pavement structure obtained by injecting a cement injection material containing cement fine powder of 8 μm or less into a roadbed on which asphalt and aggregate are laid. 2. A cement injection material, characterized in that cement is mixed with 10% by weight or more of fine cement powder having a volume ratio of particles of 8 μm or less of 70% or more. 3. A method for producing a semi-flexible pavement structure, which comprises injecting a cement injection material containing cement fine powder of 8 μm or less into a roadbed on which asphalt and aggregate are laid.