JPH0930850A - Judgment of admixture and admixture by the same judgment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for previously, simply and accurately judging whether mineral powder is suitable as an admixture. SOLUTION: This method comprises preparing mineral powder in slurry having 10-50wt.% concentration and leaving the mineral powder slurry to stand and judging whether the mineral powder is suitable as an admixture by the volume of the resultant suspension. Concretely, the method comprises suspending mineral powder slurry prepared in 10-50wt.% concentration and judging the mineral powder in which volume of suspension after leaving to stand is half amount or above based on total amount of slurry as a suitable admixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an admixture and a method for determining the admixture, and more specifically, a foam mortar widely used for various backfill materials, such as tunnels, abutments,
The present invention relates to an admixture used for a foamed mortar suitable for a backfill injection material such as a retaining wall and a sewer pipe, and a determination method thereof and an admixture selected by the method.

[0002]

2. Description of the Related Art In tunnel construction, sewage pipe burying construction, etc., a backfill material is injected to fill a space around a shield and a pipe. Usually, cement milk or cement mortar is used as the backfill material, but recently, foamed mortar containing a large amount of air due to the action of the foaming agent is often used. The reason for this is that bubble mortar has a lower material cost than ordinary mortar,
In addition, it has advantages such as high fluidity and low-pressure injection, high filling ability and large construction capacity, and low strength even when re-excavating, so that work similar to ordinary earth and sand excavation can be performed. is there.

However, since adiabatic temperature rise of aerated mortar is significantly higher than that of ordinary mortar, for example,
When applied to buried backfilling of an FRP pipe having a low heat resistant temperature, the FRP pipe may be thermally deteriorated during filling.
Therefore, a method of suppressing an increase in adiabatic temperature by mixing fly ash or the like as an admixture in bubble mortar has been studied.

[0004]

However, when fly ash or the like is mixed with cellular mortar and used, it is difficult to determine in advance whether or not it is suitable as an admixture. Conventionally, individual admixtures were actually added to the mortar. Since the evaluation is performed after kneading and curing, it takes a long time to obtain the evaluation result, and there is a problem that it is too expensive and troublesome. The present invention
It solves the conventional problems in the use of such admixtures, and when using various natural rock powders and recycled resource powders as admixtures, not limited to fly ash, the suitability as admixtures It is an object to provide a method for making a quick and accurate determination in advance and an admixture selected by the method.

[0005]

According to the present invention, when natural rock powder such as limestone or recycled resource powder such as fly ash is used as a cement admixture, suitability as an admixture is determined based on the sedimentation volume of the slurry. To do. That is,
According to the present invention, a determination method having the following configuration is provided. (1) Concentration of mineral powder 10 to 50% by weight (hereinafter%)
After preparing the slurry of the mineral substance powder,
A method for determining the suitability of a mineral powder as an admixture based on the volume of the suspension. (2) Suspending the mineral powder slurry prepared to have a concentration of 10 to 50%, and using the mineral powder whose suspension volume after standing for 30 minutes is half or more of the total amount of the slurry liquid as the admixture. ) The determination method described in.

Further, according to the present invention, the following admixture selected by the above determination method is provided. (3) An admixture made of mineral powder in which the mineral powder slurry prepared to have a concentration of 10 to 50% is suspended and the suspension volume after standing for 30 minutes is half or more of the total amount of the slurry liquid. (4) One or more rocks of natural rocks whose mineral powder is limestone, dolomite, silica stone, anti-firestone, obsidian, zeolite, talc, acid clay, sepiolite, diatomaceous earth, shirasu, wollastonite or shale. Above is powder
Admixture described in (3). (5) One or more of the recyclable resource powders whose mineral powder is coal ash, blast furnace slag, silica fume, chaff ash, municipal waste incineration ash, sewage sludge incineration ash, or paper sludge as described above ( Admixture described in 3). (6) The admixture according to the above (3), wherein the mineral powder is a mixed powder of natural rocks and the reused resource powder. (7) The admixture according to any one of the above (3) to (6), which is used for foamed mortar.

[0007]

[Detailed Description] The method of the present invention has a slurry concentration of 10 to 10.
A mineral powder slurry is prepared at 50%, the mineral powder slurry is allowed to stand, and the suitability of the mineral powder as an admixture is determined by the volume of the suspension. Specifically, a mineral powder slurry prepared by suspending the slurry having a slurry concentration of 10 to 50% and having a suspension volume after standing for 30 minutes is half or more of the slurry volume at the start of standing is prepared as a mineral powder. This is a method of using an admixture. In the present invention, the suspension volume means the volume occupied by the mineral powder in a state where the mineral powder and water are separated after the suspension slurry is allowed to stand, and includes a suspended state and a deposited state. .

When the slurry concentration is adjusted to 10 to 50%, if the concentration is less than 10%, a difference in the precipitation does not appear because the precipitation of the suspension is too fast. Is difficult to recognize. Preferably 20 to 3
A slurry concentration of 0% is suitable. In addition, the standing time is 30
3 minutes after the start of foaming when constructing aerated mortar
This is because it is difficult for the powder to be retained in the bubbles due to the bubbles, because most of the powder is deposited within about 0 minutes.

In order to carry out the present invention simply, 75 parts by weight of water is added to 25 parts by weight of a mineral powder and suspended, and this is put into a graduated cylinder.
The admixture may be selected so that the suspension volume becomes 50 ml or more after standing for 0 minute. This embodiment will be described with reference to FIG. 1. Samples (A) to (E) in FIG. 1 are prepared by adding a suspension sample containing 25 parts by weight of mineral powder and 75 parts by weight of water to a glass graduated cylinder. It is a schematic diagram showing a state after standing still for 30 minutes, and in the samples (A) and (B), most of the mineral powder is deposited,
The supernatant portion 10 occupies about 2/3 of the total volume of the slurry liquid, and therefore the volume of the suspension portion 20 occupied by the mineral powder is about 1/3.
It is. On the other hand, in the samples (C), (D) and (E), the volume of the supernatant portion 10 is small and the volume of the suspension portion 20 occupies about 70 to 90% of the total volume of the slurry liquid. According to this result, the mineral powders of the samples (C), (D), and (E) are suitable as the admixture.

The mineral powder whose suspension volume after standing still for 30 minutes at the above slurry concentration is more than half of the slurry volume at the start of standing is such that when the powder is added to a foam mortar as an admixture It is well encapsulated in the slurry and well retained in the slurry, and is uniformly dispersed in the cement powder.
For ordinary cement powder, slurry was prepared to the same concentration as the above-mentioned mineral powder, and when the suspension volume after standing for 30 minutes was determined, most of the cement powder had a suspension volume of 50 ml or more. ing. Therefore, when the mineral powder of the present invention obtained by the above method is added to cement powder, it suspends and uniformly disperses with the cement powder in the slurry, so that a good effect as an admixture can be obtained.

As the above-mentioned mineral powder, one or two kinds of natural rocks such as limestone, dolomite, silica stone, anti-firestone, zeolite, obsidian, talc, acid clay, sepiolite, diatomaceous earth, shirasu, wollastonite or shale. The above can be used. Or coal ash,
Blast furnace slag, silica fume, rice husk ash, municipal waste incineration ash, sewage sludge incineration ash, paper sludge, or other recyclable resource powders, or natural rocks and the above recyclable resource powders. Mixed powder may be used.

The mineral powder admixture according to the present invention is not particularly limited in its use conditions, and can be used in the same manner as a usual admixture for aerated mortar. The mineral powder is suitable as an admixture for foamed mortar, but is not limited to this and can be used for ordinary ready-mixed concrete.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the present invention will be shown below together with test examples and comparative examples. It should be noted that the present embodiment is an example and does not limit the scope of the invention.

Test Example 25 parts by weight of various cement powders shown in Table 1 had a pH of 6.5 to 7.5.
The slurry obtained by adding 75 parts by weight of ion-exchanged water was stirred and suspended in a glass graduated cylinder having a capacity of 100 ml and allowed to stand still, and the suspension volume after standing for 30 minutes and after standing for 60 minutes was measured. The results are shown in Table 1. Table 1 also shows specific gravity, average particle size, Blaine specific surface area, and pH of each of the above slurry for these cement powders. As is clear from this result, most of the cement powders have a suspension volume of 50 ml or more after standing for 30 minutes, so that the admixture should be integrated with the cement powder in order to exhibit good dispersibility in the cement slurry. The suspension volume of the admixture must also be 50 ml or more so that it can be suspended.

[0015]

[Table 1]

Example 1 Various natural rock pulverized products shown in Tables 2 and 3 were made into slurries in the same manner as in Example 1, and the suspension volume after standing for 30 minutes and after standing for 60 minutes was measured. The results are shown in Tables 2 and 3. Also, as in Example 1, the physical properties of these powders are shown in Tables 2 and 3. These rock powders were added to ordinary Portland cement according to the compounding ratio shown in Table 4, and the foaming agent (trade name OFA-2, manufactured by Chichibu Onoda Co., Ltd.)
A preform (specific gravity 0.
04) was prepared, and this was put into mortar milk that was kneaded in a Hobart mixer, and mixed for 10 minutes to produce an aerated mortar having a specific gravity of 0.8. Using this foamed mortar, a test piece with a diameter of 5 cm and a height of 10 cm is formed.
After 7 days and 28 days of humid air curing at 0 ℃, JSJS
Uniaxial compressive strength was measured according to FT 511. Furthermore, the appearance of the test piece was observed to examine the material separation and the presence or absence of cracks.
The results are shown in Tables 5 and 6.

As shown in Tables 2 and 3, the average particle size, particle shape, specific gravity, specific surface area, pH, etc. of each mineral powder are greatly changed, and these physical properties have specific tendencies. However, as shown in Table 5 and Table 6, those having a suspension volume after standing for 30 minutes within the range of the present invention have 7-day-age and 28-day-age compressive strengths other than that. It is much larger than the sample. The appearance of the specimen is also good. On the other hand, those using the mineral powder which is out of the scope of the present invention have low compressive strength, and most of the specimens are separated into the foam portion and the water and hardened material portion, and some of the specimens Had many cracks. Furthermore, there are many specimens whose specific gravity exceeds 1, which is not preferable in terms of weight reduction.

Example 2 An aerated mortar specimen was prepared under the same conditions as in Example 1 except that the cement type was changed from normal cement to early-strength and moderate-heat cement, and the raw materials were prepared according to the compounding ratios shown in Table 7. ,
The compressive strength was measured and the appearance was examined. The results are also shown in Table 7. Example 3 A foamed mortar specimen was produced in the same manner as in Example 1 except that the cement type and the water ratio were changed as shown in Table 8, the compressive strength thereof was measured, and the appearance was examined. The results are also shown in Table 8.

In any of Examples 2 and 3, those using the mineral powder within the range of the present invention have excellent compressive strength, but those outside this range have significantly low compressive strength.

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

[Table 6]

[0025]

[Table 7]

[0026]

[Table 8]

[0027]

According to the method of the present invention, when mineral powder is used as an admixture, particularly when it is used as an admixture of foamed mortar, the determination of suitability thereof can be made quickly and in a manner suitable for actual construction. Easy to do. In bubble mortar, as the particle size and weight of the material particles increase, it becomes more difficult to wrap the material particles with the bubbles, and thus the generated bubbles disappear without wrapping the material particles.
However, this defoaming not only involves the particle size and weight of the particles, but also various factors such as the specific surface area, particle shape, and pH of the particle surface. Furthermore, during actual construction, the resistance of the pipe wall during injection and Since the influence of mutual interference of particles is also large, it is extremely difficult to judge the adequacy of the admixture from the general equation of sedimentation velocity. However, according to the method of the present invention, the suitability can be promptly and easily determined in advance in a mode suitable for actual construction. Furthermore, the mineral powder according to the present invention is of good quality as an admixture, and a good cellular mortar can be easily obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a suspended state of a mineral powder.

[Explanation of symbols]

 10-supernatant portion, 20-suspension portion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G01N 33/38 G01N 33/38 (72) Inventor Kenji Nozaki 2-4-2 Daisaku Sakura City, Chiba Prefecture No. Chichibu Onoda Central Research Institute (72) Inventor Yu Shirasaka 2-4 Daisaku Sakura, Chiba Prefecture Chichibu Onoda Central Research Institute

Claims (7)

[Claims] 1. An admixture for mineral powder according to claim 1, wherein the mineral powder is prepared into a slurry having a concentration of 10 to 50% by weight (hereinafter referred to as "%"), the mineral powder slurry is allowed to stand, and then the volume of suspension thereof is used. A method to judge the suitability as. 2. A mineral powder having a concentration of 10 to 50% prepared and suspended, and the suspension volume after standing for 30 minutes is half or more of the total volume of the slurry is used as an admixture. The determination method according to Item 1. 3. An admixture comprising a mineral powder in which a mineral powder slurry prepared to have a concentration of 10 to 50% is suspended and the suspension volume after standing for 30 minutes is at least half the total amount of the slurry liquid. 4. The mineral powder is limestone, dolomite, silica stone, anti-firestone, obsidian, zeolite, talc, acid clay,
The admixture according to claim 3, which is one or more rock powders of natural rocks such as sepiolite, diatomaceous earth, shirasu, wollastonite or shale. 5. The recyclable resource powder, wherein the mineral powder is coal ash, blast furnace slag, silica fume, chaff ash, municipal waste incineration ash, sewage sludge incineration ash, or paper sludge, or two or more types thereof. The admixture according to claim 3. 6. The admixture according to claim 3, wherein the mineral powder is a mixed powder of natural rocks and the recycled resource powder. 7. The admixture according to claim 3, which is used in a foamed mortar.