JPS6016853A - Concrete composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a concrete composition with the addition of metal fibers, the purpose of which is to significantly improve the strength and mechanical thermal shock resistance of conventional concrete compositions with the addition of metal fibers. The purpose of the present invention is to provide a concrete composition that can be improved.

Concrete compositions include fireproof concrete using alumina cement, sodium silicate, aluminum phosphate, or the like as a binder, and concrete using portland cement as a binder.

For example, in the case of fireproof concrete, in recent years it has become possible to reduce the amount of alumina to 7 mn 1-' by combining ultrafine powder with a deflocculant, and it has become possible to pour with a low moisture content, making it possible to obtain a product equivalent in quality to fired bricks. It's here.

However, although the quality of fireproof concrete has greatly improved, the main cause of damage is often cracking and peeling caused by thermal stress, similar to the case with fired bricks.

As a solution to this problem, a method of adding metal fibers has recently been developed, which improves strength and reduces stress by adding metal fibers.
Damage caused by cracking and peeling was reduced by improving the deflection characteristics.

Regarding the shape and amount of Kincho fiber used in this type of fireproof concrete, the cross-sectional area is 0, / -” 0.
3 mm' length, 20-110 dragon-shaped /-A
Parts by weight are used.

There have been various reports on the theory of strengthening by adding metal fibers, and one example is σ-KVfT (
-! -2□(1) d σ: Maximum load: Fiber shape factor vf: Fiber addition amount τ: Fiber/matrix bond strength L: Fiber length d: Fiber diameter. i) etc.

From the point of view of reinforcement, it can be seen that the greater the amount of metal fiber added, the greater the fiber/matrix bond strength, and the greater the aspect ratio ('), the greater the effect.

However, at present, it can be said that the shape and amount of metal fibers added are mainly determined by reinforcing performance and workability during construction. For example, if it is too short or too thick, the reinforcing performance will not be sufficient, and if it is too long or thin, or if it is added in a large amount, it will form ball-shaped lumps during mixing, significantly reducing workability. From this point of view, metal fibers are suitable for use with o, i~0, . 3ms
', those with a length of 20 to 110 w are limited to 7 to 6 parts by weight, and the theory of reinforcement by metal fibers is also limited.

The concrete composition of the present invention overcomes all the drawbacks of conventional fire-resistant concrete containing metal fibers, in which the amount of metal fibers added is limited due to workability. That is, the novelty of the concrete composition of the present invention is that the workability of fireproof concrete is improved by fully specifying the particle size of fireproof concrete and the length of metal fibers, and it is possible to add a large amount of metal fibers. The point is that the reinforcement theory can be demonstrated to its fullest potential.

In general, fireproof concrete is used that has a maximum particle size of about JO-3ram in terms of workability and filling properties.

However, when metal fibers are added, the movement of coarse particles is suppressed by the metal fibers, resulting in formation of ball-shaped lumps ν and separation of fine powder from metal fibers and coarse particles, resulting in a significant deterioration in workability. The results of a detailed study of these points are shown in Figures 1 and 2. Figure 1 shows the effect of refractory concrete 1,1 on the amount of metal fiber that can be added (wt%).
- In the curve diagram showing the influence of the maximum particle size of the stainless steel fibers, the added metal fibers are stainless steel fibers of 0.3XQ and 3X/5.
It is between. Figure 2 is a curve diagram showing the influence of the length of metal fiber on the number of metal fibers that can be added. It is.

From FIG. 1 and FIG. 2, it was found that the smaller the maximum particle size of the refractory concrete IJ-t and the shorter the length of the fibers, the more metal fibers could be added. Next, Figure 3 shows the influence of the length and amount of metal fibers added on the room temperature bending strength of fireproof concrete containing metal fibers. In this case, the maximum particle size of fireproof concrete is 10vnm, the added metal fiber is stainless fiber〇,,'j X 0.3×1 city, and A is J =
5 vm, B is J == / Omm, C is f =
/! ; vnn, D is J-S 5 battle. metal fa・
As for the length of the f-bar, if it becomes too short, the reinforcing effect will be reduced. From these results, it was found that fireproof concrete with a maximum grain size of 2n or less, length,! i −/ 5 +u
It is most effective to add + metal phi, <-f10 to 0 parts by weight.

In addition to stainless steel fibers, metal fibers such as special steel, carbon steel, copper, and copper alloys can be used as the metal fibers.

Regardless of whether the cross-sectional area is small or large, the reinforcing effect is not sufficient, and from this point on, 0. /~0.3 gates is promising.

The fire-resistant concrete used in the present invention is particularly one in which a binder is added to 1 m or more of fire-resistant aggregate such as +a, alumina, silica, spinel, magnesia, chromium, zircon, silicon carbide, carbon, etc. It is not limited.

Examples of the invention are described below.

Example A predetermined amount of water is added to a fireproof concrete composition containing the ingredients listed in Table 1 and kneaded. FIG. 4 shows the room-temperature bending load strength and deflection amount characteristics at which complete failure of concrete obtained from the concrete compositions of Examples/~3 and Comparative Examples/~3 thus adjusted. From this, the concrete obtained from the concrete composition of the example has a bending load strength of x times that of the comparative example, and the amount of deflection at which fracture starts is 2 to 2 times that of the comparative example.
．． 5 times was obtained. This shows that the strength and mechanical thermal shock resistance of conventional fireproof concrete to which metal fibers have been added are significantly improved.

In addition to fireproof concrete, the concrete composition of the present invention can also produce similar effects in concrete using portland cement as a binder.

[Brief explanation of the drawing]

Figure 1 is a curve diagram showing the influence of the maximum grain size of surface j fire concrete on the amount of metal fibers that can be added, Figure 2 is a curve diagram showing the influence of the length of metal fibers on the amount of metal fibers that can be added. Figure 3 is a diagram showing the influence of the length and amount of metal fibers added on the room temperature bending strength of fireproof concrete containing metal fibers, and Figure 3 shows Examples 1 to 3.
FIG. 3 is a curve diagram showing the bending load strength at room temperature and the deflection amount at which failure completely starts for concrete obtained from the concrete compositions of Comparative Examples 1 to 3. In the figure: A... Concrete with added metal fiber length 5 mm, B... Concrete with added metal fiber length 10x, C... Length of added metal fiber/concrete with linkage, D is the length of the added metal fiber, 2
Koho concrete. Patent Applicant: Shinagawa Shiro Brick Co., Ltd. Fig. 1 Fire resistance] Largest grain size outside the sill (mm) Fig. 2 Metal fiber length strain (mm) Fig. 3 Modern fiber scrap daily amount (wt%)

Claims (1)

[Claims] For fireproof concrete with a maximum particle size of 2 mm or less, length S ~ l
A concrete composition characterized in that lθ to 0 parts by weight of S-shaped metal fibers are added.