JP2853403B2 - Mortar and concrete construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for applying a mortar, concrete, among other things, the aggregate which is formulated with mineral composition mainly composed of corundum _{(α-Al 2 O 3)} , the bone The present invention relates to a mortar / concrete construction method for improving workability by adjusting the particle size distribution of materials.

[0002]

2. Description of the Related Art In general, mortar concrete is composed of a hardening agent such as cement, an aggregate such as sand, a coarse aggregate such as gravel, a water reducing agent, and the like. When these mortar / concrete compositions are kneaded with water, the components of cement, such as calcium oxide, silicon dioxide, and magnesium oxide, react with water and gradually harden and solidify including the aggregate. . The water reducing agent has the function of improving the dispersibility of cement and reducing the amount of water for kneading mortar / concrete.

Incidentally, it is desirable that such mortar concrete has high compressive strength. Currently, high-strength mortar concrete having compressive strength of about 800 to 1000 kgf / cm ² is desired.
Concrete is actually used, but in recent years,
Ultra high strength mortar concrete having a compressive strength of 000 kgf / cm ² or more has been demanded.

Therefore, it is necessary to use an aggregate having a high hardness in order to manufacture the cemented mortar concrete, and corundum (α-Al ₂ O ₃ ) is used as such an aggregate having a high hardness. It has been proposed by the present inventors to use calcined bauxite as a main component.

[0005]

However, α-A
When using an aggregate containing l ₂ O ₃ as a main component, workability is deteriorated as compared with river sand, hill sand, and the like generally used as an aggregate, which hinders the casting of mortar and concrete. I will. For example, if the workability is poor, the amount of the high-performance AE water reducing agent added tends to increase, and as a result, the viscosity of the cement paste becomes high, and the workability is degraded.

Accordingly, an object of the present invention is to provide a mortar / concrete construction method capable of significantly improving workability during construction by adjusting the particle size distribution of aggregate.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of forming a grain shape by cutting corners of an aggregate containing corundum (α-Al ₂ O ₃ ) as a main component. Particle size of 1.2 mm and a pass rate of 69% or less.
A transmittance of 24% or less at 6mm, a transmittance of 15% or less at 0.3mm, a transmittance of 5% or less at 0.15mm ,
And it adjusts so that a coarse particle rate may be about 3.1-3.2 .

[0008]

In the mortar / concrete construction method of the present invention, since the mortar / concrete is formed of an aggregate containing corundum (α-Al ₂ O ₃ ) as a main component, the strength (hardness) of the aggregate itself is obtained.
Can be extremely high. On the other hand, corners of the aggregate having sufficient hardness as described above are cut off, and the passage ratio of the sieve of the aggregate is 1.2 mm and the passage ratio is 69% or less.
Adjust so that the transmittance is less than 24% at 6mm, less than 15% at 0.3mm, and less than 5% at 0.15mm .
And the coarse grain ratio is adjusted to about 3.1 to 3.2.
By doing so, the coarseness ratio of the aggregate can be kept within the optimum range, and the workability at the time of construction without changing the compressive strength of the ultra-high strength mortar concrete can be greatly improved.

[0009]

Embodiments of the present invention will be described below in detail. That is, in the mortar / concrete construction method of the present embodiment, first, an ultrafine powder additive having a pozzolanic activity having a weight ratio of 5 to 20% with respect to Portland cement is mixed. Then, 1 to 5% of a high-performance water reducing agent or a high-performance AE water reducing agent is mixed into these binders, and the ratio of the water binder used is 25% or less. Further, an aggregate containing corundum (α-Al ₂ O ₃ ) as a main component was added to the cement matrix prepared in this manner by using a mortar.
Mixed more than 5% by volume per the concrete 1 m ^3.

The aggregate at this time has an apparent specific gravity of 2.
A material having a compression strength of at least 9 and a compression strength of at least 2000 kgf / cm ² is used. For example, the mineral composition of the aggregate is corundum (α-Al ₂ O ₃ ) and mullite (Al ₆ Si
Using calcined bauxite mainly composed of ₂ O _13), is preferably one that does not contain Rutairu (TiO ₂₎ in the bauxite, as its chemical composition, Al ₂ O ₃ is 8
6% or more, 2.5% or less of Fe ₂ O ₃ , and 7% of SiO ₂ .
5%, which TiO ₂ has a 3.5% or less is used.

Here, in this embodiment, the corners of the above-mentioned aggregate are rounded to form a grain shape, and the particle size of this aggregate is adjusted as follows. It is desirable that the corners of the aggregate be set to an extent that the actual product ratio is 60% or more.

By the way, the particle size of the aggregate is adjusted by 1.2.
mm, 0.6 mm, 0.3 mm, 0.15 mm 4
Preparing different kinds of sieves , passing 1.2mm sieves
Rate is 69% or less, and the passing rate of 0.6 mm sieve is 24
% Or less, the passage rate of the sieve of 0.3mm is 15% or less,
The passage rate of the sieve of 0.15 mm is set to 5% or less , and
The coarse particle ratio is about 3.1 to 3.2 .

FIG. 1 is a graph showing the passage rate of the aggregate having different coarse grain ratios with respect to the size of the sieve . What is the coarse grain ratio?
An index that indicates the particle size distribution of fine aggregate, given by
available. Sotsuburitsu = (80,40,20,10,5,2.5,1.2,0.6,0. Sum of the percentage of the weight of the sample remaining in sieve 3,0.15mm) / 100 and FIG. A screen for each characteristic shown in 1
The coarse particle ratio of each characteristic obtained from the excess ratio is as follows.
You. Sieve Passage rate (%) Percentage of sample weight remaining on the sieve (%) Sieve Passage rate (%) Percentage of sample weight remaining on the sieve (%) Sieve Passage rate (%) Percentage of sample weight remaining on the sieve (%) Sieve Passage rate (%) Percentage of sample weight remaining on the sieve (%) That is, the characteristic a has a coarse particle ratio of approximately 2.4, the characteristic b has a coarse particle ratio of approximately 2.7, the characteristic c has a coarse particle ratio of approximately 3.1, and the characteristic d has a coarse particle ratio of approximately 3.2. Has become. Here, "abbreviated"
Is based on the assumption that a value of 2.5 mm is estimated.
FIG. 2 is a graph created using these coarse grain ratios on the horizontal axis.
If the fineness modulus of the aggregate was changed respectively, the figure shows <br/> Suyo concrete slump and flow values can be changed respectively. In FIG. 2, each characteristic a,
The 4-week intensities of b, c, and d are indicated by parentheses, respectively.

Therefore, from FIGS. 1 and 2, the particle size distribution is changed by adjusting the passing rate of the sieve of the aggregate as described above, and the coarse particle ratio such as the characteristics a and b is about 2.4. It is understood that the workability at the time of construction is greatly improved by improving the ratio of coarse particles, such as the characteristics c and d, to about 3.2. Those having characteristics c and d exhibiting such good fluidity have a sieve of 1.2.
mm is less than 69%, 0.6mm is less than 24%
Passage rate, Passage rate of 15% or less at 0.3mm, 0.15m
This the particle size is adjusted to be 5% or less of the pass rate in m
Is assumed. Thus, in this embodiment, by adjusting the particle size of the aggregate, the construction of the ultra-high-strength mortar / concrete can be reliably performed without increasing the amount of the water reducing agent as in the related art.

[0015]

As described above, the mortar of the present invention
In the concrete construction method, corundum (α-
Since the aggregate is mainly composed of Al ₂ O ₃ ), the strength (hardness) of the aggregate itself can be extremely increased. Also, the corners of the aggregate were cut off, and the passing rate of the sieve of the aggregate was 69% or less at 1.2 mm, and 2% at 0.6 mm.
Less than 4%, less than 15% at 0.3mm
Adjust to be 5% or less at 0.15mm
To further adjust the coarse particle ratio to about 3.1 to 3.2.
By the the, we enjoyed the optimum range of fineness modulus of the aggregate, an excellent effect that the workability at the time of construction of ultra high strength mortar and concrete can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the sieve size and the passage rate for adjusting the particle size of aggregate in the construction method of the present invention.

FIG. 2 is a graph showing a relationship between a concrete slump and a flow value with respect to a coarse particle ratio of aggregate in the construction method of the present invention.

Continuation of front page (72) Inventor Kenichi Ichinose 4-640 Shimoseito, Kiyose-shi, Tokyo Obayashi Corporation Technical Research Institute Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 28/00-28 / 36 C04B 14/00-20/12 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. Aggregate mainly composed of corundum (α-Al ₂ O ₃ ) is shaped by taking corners of the aggregate, and the particle size of this aggregate is less than 69% with a sieve of 1.2 mm. Pass rate, 0.
A transmittance of 24% or less at 6mm, a transmittance of 15% or less at 0.3mm, a transmittance of 5% or less at 0.15mm ,
A mortar / concrete construction method characterized in that the coarse particle ratio is adjusted to be about 3.1 to 3.2 .