JP2515767B2 - Extruded building materials with excellent explosion resistance - Google Patents

Description

TECHNICAL FIELD The present invention relates to an extruded building material having a hollow portion with high strength and high elastic modulus, which is excellent in explosion resistance.

(Prior Art) Conventionally, in an extruded building material having a high-density and solid matrix, water existing inside the product when heated becomes steam and expands rapidly to generate internal stress, which causes cracking,
There was a problem in fire resistance due to phenomena such as explosion. In particular,
Since the explosion blast phenomenon is likely to occur in proportion to the density of the product matrix, it is a troublesome phenomenon that the denser the internal structure and the higher the strength and the higher the strength of the extruded building material, the more likely it is to occur.

Therefore, by adding natural organic fibers such as cotton, pulp, hemp, etc. or semi-synthetic fibers such as acetate fibers, rayon fibers, etc. to the raw materials to reduce the weight and make an escape route for water vapor to the outside (JP-A-60-108354). No. JP-A-51-19016), a method of adding lightweight aggregate such as diatomaceous earth to reduce the weight to improve explosion blast resistance (JP-B-55-23786), water / cement ratio A method of preparing a soft asbestos-cement kneaded product having a large size, allowing it to stand for a while, and reducing the weight by forming a cement hydrate, and improving explosion resistance (JP-A-51-19017), The method of such was proposed.

(Problems to be solved by the invention) However, in the improvement of fire resistance by the conventional weight reduction, the excellent characteristics of the high-density matrix are sacrificed, and therefore, the characteristics of high strength and high elastic modulus are obtained. However, in the case of an extrusion molded building material having a hollow portion, a large thermal temperature difference occurs between the heating side plate (top plate) and the back side plate (base plate) during heating (ie, When the top plate side is directly heated by the flame, it expands first, and then contracts as the temperature rises, while the bottom plate side
At the time when the top plate side begins to contract, the temperature rises slowly compared to the top plate, causing expansion. In such an extruded building material having a hollow portion, the behavior largely differs in the panel thickness direction during the fire resistance test, and when one shrinks, one shrinks, so a strain stress due to deformation occurs in the extruded panel having a hollow portion. Therefore, there has been a problem that an extruded building material having a hollow portion is more likely to cause an explosion phenomenon than a flat plate.

The present invention is intended to provide an extruded building material having a hollow portion excellent in explosion resistance while maintaining the high strength and high elastic modulus of the matrix.

(Means for Solving the Problem) In the present invention, the density of the matrix mainly composed of the hydraulic binder and the reinforcing fiber is 1.65 to 2.0 g / cm ³ , and the heating linear shrinkage rate up to 900 ° C. is 3 to 8. %, Which is an extruded building material having a hollow portion with excellent explosion resistance.

Conventionally, as a method for obtaining a molded article such as a building material, a press molding method that has been adopted when manufacturing a fireproof coating material, a casting method that is used for manufacturing an autoclave curing lightweight cellular concrete, and an asbestos cement board. In addition to the paper-making method and the like used in the production of etc., there are the extrusion-molding method and the like used in the present invention.

It is desirable that the reinforcing fibers are oriented and homogeneous in order to mix and use the reinforcing fibers in the raw material and to obtain the sufficient reinforcing effect. Therefore, those obtained by the press molding method and the casting method are not preferable. Although the one obtained by the paper-making method can obtain the orientation of the reinforcing fibers, it is excellent in productivity for forming a thin plate-like product having a thickness of about 4 to 15 mm, but it has a thickness exceeding that. It is not suitable for obtaining a product. Further, although the product obtained by the papermaking method has a heating linear shrinkage ratio of 2% or less which will be described later, it causes a cracking phenomenon depending on the constitution of the matrix according to the manufacturing method, and there is a problem in fire resistance performance. On the other hand, the extrusion molding method not only provides sufficient orientation of the reinforcing fibers, but it is not only a thin solid sheet, but also a hollow section is provided in a cross section that is difficult to obtain with other manufacturing methods with good productivity. Product, that is,
An extruded building material having a hollow portion can also be obtained. The extruded building material having this hollow portion can have a thicker plate thickness because the hollow portion exists even if the matrix portion is made of the same material, but as described above, it is more likely to explode than a solid flat plate. However, when the conditions of the present invention are satisfied, the product has a high strength and high elastic modulus matrix and is excellent in fire resistance.

Once again, in other words, the extruded building material having a hollow portion of the present invention has a density of a matrix mainly composed of a hard water-based binder and reinforcing fibers of 1.65 to
2.0 g / cm ³ and a heating linear shrinkage rate up to 900 ° C of 3 to
It is characterized by being 8%.

As the hydraulic binder in the present invention, in addition to cements such as ordinary Portland cement and alumina cement, siliceous raw materials such as silica stone powder and silica sand may be used together up to 100% with respect to the weight of cement. You can also

As the reinforcing fibers, asbestos, which is an endless fiber that has been conventionally used for reinforcing cementitious materials, alkali resistant glass fibers, carbon fibers, and various natural fibers and synthetic fibers as organic fibers can be used.

The amount used depends on the type of hydraulic binder, but is generally 3 to 30% relative to the hydraulic binder,
The density of the matrix can also be changed by the amount of fiber added.

The matrix of the present invention is mainly composed of a hydraulic binder material and reinforcing fibers, but a thickener may be used for improving the fluidity of the mortar if necessary. Examples of the thickener include water-soluble polymers such as methyl cellulose and polyvinyl alcohol.

Next, describing the range of the density of the matrix, when using a panel with a thickness of 60 mm and a hollow ratio of 40% or more, which is a standard for general extruded building materials with hollow parts, as a member for fire-resistant structure outer walls, the Building Standards Act Considering the allowable wind load, etc., elastic modulus 20 × 104kg / cm ² or more, bending strength 250kg / c
High strength and high elastic modulus of m ² or more are required, but it is difficult to secure this performance when the density of the matrix is 1.65 g / cm ³ or less.

If the matrix density exceeds 2.0 g / cm ³ , it is difficult to prevent the explosion phenomenon, which is not preferable.

Also, the matrix density a 1.65~2.0g / cm ³
Explosion does not occur when the heating linear shrinkage up to 900 ° C is less than 3%, but the elastic modulus is 20 × 104k.
g / cm ² or more and bending strength of 250 kg / cm ² or more cannot be obtained, which is not preferable.

Moreover, even the matrix density a 1.65~2.0g / cm ³
If the heating linear shrinkage rate up to 900 ° C exceeds 8%, the above-mentioned elastic modulus of 20 × 104 kg / cm ² or more and bending strength of 250 kg / cm 2 or more are achieved, but the explosion phenomenon cannot be prevented. Not preferable.

Thus, the density of the product matrix in the extrusion molding material having a hollow portion is 1.65 ~ 2.0 g / cm ³ , and
Since the heating linear shrinkage rate up to 900 ° C is 3 to 8%, it has high fire resistance that does not cause an explosion phenomenon that passes the fire resistance test according to JIS-A1304, and has a high strength, for example, a bending strength of 250 kg. / cm ² or more, high elastic modulus, for example 20 × 1
It is a building material with a hollow part of 04 kg / cm ² or more.

(Examples) Hereinafter, the present invention will be described in detail with reference to Examples. In addition,
The various test methods in the examples were as follows.

・ Test method for heating wire shrinkage up to 900 ° C Thermomechanical analyzer TM manufactured by Rigaku Denki Co., Ltd.
A standard type was used. The conditions are as follows.

Differential expansion method Standard sample: Alumina Sample shape: 5mmφ × 20mml Heating rate: 20 ° C / min (room temperature to 1000 ° C) Sampling method: Sampling was performed so that the direction parallel to the extrusion direction during extrusion was the longitudinal direction of the sample. .

Three samples were measured, and the average value of the heat shrinkage at 900 ° C. was taken as the heat shrinkage of the sample.

-Fire resistance test method In measuring, according to JIS-A1304 "Fire resistance test method for building structural members", a heating test was carried out by the following method, and the presence or absence of an explosion phenomenon was evaluated.

Heating grade: Fireproof 1 hour (outer wall specifications) Sample: Thickness 60mm, width 59 for extrusion molded building material with hollow part
A plate with a total length of 2 m, which has a cross-sectional shape of 2 mm and a hollow ratio of 45.1% (illustrated in Fig. 1), is fixed to the mounting angle with Z clips at the two upper and lower parts so that the mounting span is 1.8 m, and heated. The test was conducted.

-Bending strength and elastic modulus test method, so that the orientation direction of the reinforcing fiber and the longitudinal direction are the same.
Take out a solid sample of width 40mm and length 500mm and use it with an effective span of 4
Bending strength was calculated from fracture strength by loading with a centralized point load of 00 mm. The elastic modulus was obtained from the bending at the time of 1/3 of the breaking load. The measurement was carried out on three test pieces, and the bending strength and elastic modulus were taken as the average values thereof.

(Examples) Examples 1 to 3 and Comparative Examples 1 to 4 In Table 1, the thickness of the sectional shape shown in FIG.
The compounding conditions for obtaining an extruded building material with a length of 2 mm and a hollowness of 45.1% are shown.

In addition, a flexible board manufactured by Asahi Asbestos Industry Co., Ltd. manufactured by the papermaking method is shown as Comparative Example 4.

The raw materials and extrusion molding equipment used in each example are as follows.

-Raw material Cement: Union Cement Co., Ltd. Ordinary Portland cement Silica powder: Ukusu silica stone Finely pulverized product (weight average 20 to 30μ
m) Asbestos: Canadian carry 6D methyl cellulose: Shin-Etsu Chemical Co., Ltd. “Metroses 90SH 150”
00 ”Light weight aggregate: Fuyolite No. 2 manufactured by Fuyolite Industrial Co., Ltd. Extrusion molding apparatus:“ MV-FM-200-1 type ”manufactured by Miyazaki Tekko Co., Ltd. In addition, according to Table 1, each raw material was thoroughly mixed with powder by stirring. , And water was added and kneaded. After passing this through a kneader,
It was molded by an extruder. After subjecting this molded body to primary curing for 6 hours at 60 ° C. under saturated vapor pressure, it was subjected to high temperature and high pressure steam curing under the conditions shown in Table 2 to obtain a product.

 The results are shown in Table 3.

Comparative Example 1 has the same composition as Examples 1 and 2, but
Since the curing conditions are only primary curing and no high temperature and high pressure curing, the density is 1.75 g / cm ³ , but the heating linear shrinkage rate up to 900 ° C is 1.3%, which is less than 3%.

Therefore, although the fire resistance is good, the flexural strength and elastic modulus are higher than 250 kg / cm ^2, which is an index of high strength and high elastic modulus, 2
It is less than 0 × 104 kg / cm ² , which is not preferable.

Comparative Example 2 is different from Example 1 in that the heating rate, the maximum saturated steam temperature, and the cooling rate are the same among the mixing and curing conditions, but the holding time is different from 4 hours. Therefore, the density
Although it is 1.72 g / cm ³ , the heating wire shrinkage rate up to 900 ° C is 9.3.
% And 8%. Therefore, although the flexural strength and elastic modulus are above the index, it is 9
The explosion occurred in minutes. There is a problem in fire resistance.

In Comparative Example 3, 20% of lightweight aggregate is used, so 900 ° C
Although the heating linear shrinkage rate is up to 4.2%, the density is 1.47 g / c
Below m ³ and 1.65 g / cm ³ . For this reason, the bending strength and elastic modulus are below the index values, although the explosion phenomenon is not defeated, which is not preferable.

Comparative Example 4 is a flexible board having a thickness of 12 mm made by the papermaking method. The density is within the desired range, and the flexural strength and elastic modulus both exceed the index values. Moreover,
Despite the low heating linear shrinkage (1.2%) that does not cause the explosion phenomenon in extruded building materials, the matrix structure based on the manufacturing method causes a cracking phenomenon 6 minutes after the start of heating during the fire resistance test, and the fire resistance performance. There is an upper problem.

(Effect of the Invention) Compared with the above Comparative Examples 1 to 4, in Examples 1 to 3, the density is all 1.65 g / cm ^{3 to} 2.0 kg / cm ³ , and the heating linear shrinkage rate up to 900 ° C. It is in the range of 3 to 8%. As a result, not only the flexural strength and elastic modulus exceeded the high strength / high elastic modulus index of 250 kg / cm ² or more, 20 × 104 kg / cm ² , but also cracks and explosions occurred during the fire resistance test. It can be seen that the extruded building material having a hollow portion according to the present invention has excellent fire resistance and has high strength and high elastic modulus.

[Brief description of drawings]

FIG. 1 shows the cross-sectional shape of the product of the present invention and at the same time the cross-sectional shape of the products obtained in Comparative Examples 1 to 3.

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Claims (1)

(57) [Claims] 1. A matrix comprising a hydraulic binder and reinforcing fibers as a main component, which has a density of 1.65 to 2.0 g / cm ³ and a heating linear shrinkage rate up to 900 ° C. of 3 to 8%. Extruded building material with a hollow part with excellent explosion resistance.