JPH0761849A - Asbestos-free cement composition for extrusion molding of building material and production of extrusion molded cement building material - Google Patents

Abstract

PURPOSE:To obtain an asbestos-free extrusion-molded cement building material exhibiting excellent extrusion moldability and strength under a prescribed kneading water ratio. CONSTITUTION:This cement composition for asbestos-free extrusion-molded building material is produced by adding 5-30wt.% (in terms of solid) of peridotite fine powder to a cement composition containing 0.2-1.0 pts. (based on 1 pt. of cement) of fine silica powder, inorganic additive, natural organic fiber, fine aggregate and thickener. This asbestos-free extrusion-molded cement building material can be produced by adding and kneading a thickener to the above cement composition, adding 5-30wt.% (in terms of solid) of peridotite fine powder to the kneaded mixture, thoroughly kneading the mixture and extrusion molding the product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition for asbestos-free extrusion molding building materials and a method for producing extrusion-molding cement building materials. TECHNICAL FIELD The present invention relates to a cement composition for extruded asbestos-free building materials capable of obtaining a strong extruded building material and a method for producing the extruded cement building material.

[0002]

2. Description of the Related Art One of concrete products is an extruded cement board or an extruded cement building material, which is conventionally used as an outer wall or an inner wall of a building. In the production of this extrusion-molded cement building material, when the kneading water amount ratio is usually reduced in order to increase the matrix strength, the plasticity and lubricity of the base material of the extrusion-molding material remarkably deteriorates and the extrusion-moldability deteriorates. On the other hand, if the kneading water amount ratio is increased in order to improve the extrusion moldability, not only the shape retention during extrusion molding is impaired but also the specific gravity of the product decreases, resulting in a decrease in product strength.

Therefore, asbestos is mixed in order to prevent deterioration in performance due to such a change in the kneading water amount ratio and to obtain good extrusion moldability and strength. In recent years, asbestos has been weathered for a long period of time. Negative impact on the human body becomes a problem,
The emergence of alternative substances is desired. Inorganic fibers such as wollastonite, natural organic fibers such as pulp, and synthetic fibers have been attempted to be examined as the asbestos substitute materials.

[0004]

However, each of these fibers has another problem in terms of water retention, extrusion moldability and imparting a reinforcing effect, and an alternative substance having performance comparable to asbestos has not yet been obtained. The current situation is that there are none. Therefore,
The present inventor, as a result of various examinations of substances having excellent performance in place of asbestos at a constant kneading water content ratio, as a result, selected peridotite from many inorganic substances, which has a performance comparable to that of asbestos. It has now been found that it is suitable as an alternative to having and has achieved the present invention. Therefore, the problem to be solved by the present invention, under a constant kneading water amount ratio,
An object of the present invention is to provide a cement composition for asbestos-free extruded building materials having excellent extrudability and strength, and a method for producing the extruded cement building materials.

[0005]

The problems to be solved by the present invention are achieved by the following inventions.

(1) A cement composition containing 0.2 to 1.0 times the amount of silica fine powder, an inorganic additive, a natural organic fiber, a fine aggregate and a thickening agent in terms of solid content. In 5
A cement composition for extruding asbestos-free building materials, characterized by containing peritone fine powder in an amount of 30% by weight to 30% by weight.

(2) In cement, 0.
2 to 1.0 times the amount of silica fine powder, inorganic additive, natural organic fiber, and fine aggregate are added and mixed to obtain a cementitious composition, and then the obtained cementitious composition is thickened. Add a kneading agent and knead. Add 5% to 30% by weight of peridotite fine powder in terms of solid content to the obtained kneaded product, thoroughly knead, and then extrude A method for manufacturing an asbestos-free extrusion-molded cement building material.

The present invention will be described in more detail below. The cement composition of the present invention contains 5% by weight in terms of solid content.
By adding ~ 30% by weight of peridotite fine powder, under a constant kneading water amount ratio, extruded cement building materials of asbestos-free extruded cement building material with good extrusion moldability, no surface roughness and high strength The obtained cement composition can be obtained. Further, according to the production method of the present invention, an extrusion-molded cement building material having good extrusion moldability and good surface condition can be obtained under a constant kneading water content ratio.

The cement used in the present invention is not particularly limited, and any one of ordinary Portland cement, mixed cement such as blast furnace cement, silica cement, fly ash cement, and alumina cement can be used. Examples of the inorganic additive include wollastonite, mica, clay and the like. Part of this inorganic additive may be replaced with peridotite. Further, the natural organic fibers include pulp, wood powder, sawdust, cork powder, various fibers, and the like, and the fine aggregate includes river sand, sea sand, crushed stone, etc. which are generally known in this technical field.

Examples of the thickener used in the present invention include methyl cellulose, ethyl cellulose, C.I. M. C. Etc. In the present invention, the order of the fine silica powder, the inorganic additive, the natural organic fiber and the fine aggregate added to the cementitious composition may be either this order, simultaneous or non-ordered order. In the present invention, the amount of the silica fine powder added to the cement is preferably 0.2 to 1.0 times, and if the amount is outside this range, the strength development of the binder matrix is impaired.

The reason for this is that in the composition of the present invention, the binder for expressing the strength of the matrix is cement and silica fine powder, and the calcium component in this cement is the silica component in the silica fine powder and the autoclave. The hydrothermal reaction due to curing causes the formation of a calcium silicate-based crystal and contributes to the development of strength, but the ideal cement-silica ratio in this reaction is about 1: 0.3 to 0.6. Therefore, outside this range, the reactivity deteriorates and the strength developability decreases.

The peridotite (olivine) added to the cementitious composition according to the present invention is an olive-colored rock similar to serpentine, has a fat luster and is composed of olivine. Therefore, the peridotite contains a large amount of magnesia, and its fine powder is needle-like crystals and has a property of being highly lubricious.

In the present invention, the addition amount of peridotite fine powder is 5% by weight to 30% by weight in terms of solid content,
Within this range, a product having excellent extrusion moldability and strength can be obtained even with a predetermined kneading water content ratio. In the present invention, when the addition amount is less than 5% by weight, not only the strength but also the extrusion moldability is not sufficient at a predetermined kneading water amount ratio, and the surface of the obtained extrusion molded cement plate shows roughness. On the other hand, when it exceeds 30% by weight, the binder ratio (cement and silica fine powder) is relatively lowered, and the bending strength is lowered.

The peridotite used in the present invention is in the form of fine powder and has a Blaine value of 3000 cm ² / g.
It is preferably about 1000 cm ² / g.

[0015]

In the present invention, the peridotite added to the cementitious composition is a rock rich in magnesia, and its fine powder is acicular crystals and has a property of being highly lubricious.
When the peridotite fine powder is added, even if the peridotite fine powder is added in an amount of 5 wt% to 30 wt% in terms of the solid content of the cementitious composition in a state where the mixing water amount ratio is reduced, The cement matrix exhibits good extrudability, that is, suitable lubricity and plasticity, when performing extrusion. Furthermore, since it is possible to obtain lubricity and plasticity without increasing the kneading water amount ratio in this way, it is possible to maintain the shape retention during extrusion molding and increase the specific gravity of the extrusion molded cement building material, thus increasing the product strength. You can increase it.

[0016]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited thereto.

Example Cement 40% by weight, silica fine powder 40% by weight fine silica sand, inorganic additive 16% by weight wollastonite,
In a blend consisting of 3% by weight of pulp as a natural organic fiber,
1 wt% of methyl cellulose was added and mixed as a thickener to produce an asbestos-free base material for extruded cement boards, and peridotite powder (brain 2000 cm
² / g) was added at the addition amount shown in Table 1. Then, 20% by weight of water was added to the obtained base material and mixed sufficiently to produce an asbestos extrusion-molded base material for cement board.

Extrusion molding using this base material, width 70 m
An extruded cement board having m, a thickness of 15 mm and a length of 200 mm was obtained. This extruded cement board was placed at 20 ° C for 24 hours and then autoclaved at 170 ° C.
I went there for 8 hours. Table 1 shows the extrusion moldability, surface condition and physical properties of the thus obtained product which is an asbestos-free extrusion molded cement board building material.

[0019]

[Table 1]

As is clear from Table 1, the product in which the peridotite fine powder was not added had a slightly poor surface condition and a small bending strength at a kneading water content ratio of 20%. When the kneading water amount ratio is further lowered, the plasticity and lubricity of the kneaded product are lost and extrusion molding becomes impossible. Further, when the kneading water amount ratio is increased to improve the surface condition, the bending strength further decreases.

On the other hand, by adding and mixing the peridotite fine powder, both the extrusion moldability and the surface condition of the product can be satisfied without increasing the mixing water amount ratio.
Bending strength also shows a high value. That is, 5% by weight to 20% by weight
It can be seen that when the peridotite fine powder is added, the bending strength is increased, and the extrusion moldability and the surface condition are good. With the addition of 30% by weight of fine peridotite powder, the surface condition of the product is slightly inferior, but the extrusion moldability is good.

[0022]

INDUSTRIAL APPLICABILITY The present invention uses 5% by weight of fine powder of peridotite.
It is a cementitious composition containing 30 to 30% by weight of the cementitious composition, which makes it possible to obtain an extrudable cementitious composition having good extrudability and good strength under a constant kneading water content ratio without asbestos. can get. Further, according to the production method of the present invention, an extruded cement board building material having a good surface condition and excellent strength can be obtained without adding asbestos.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C04B 14:04 Z 16:02) Z

Claims (2)

[Claims] 1. A cement composition containing 0.2 to 1.0 times the amount of silica fine powder, an inorganic additive, a natural organic fiber, a fine aggregate and a thickening agent in terms of solid content in terms of solid content. A cement composition for asbestos-free extrusion molding construction material, containing 5% to 30% by weight of fine peridotite powder. 2. Cement, 0.2 to the cement.
A 1.0 times amount of silica fine powder, an inorganic additive, a natural organic fiber, and a fine aggregate are added and mixed to obtain a cementitious composition, and then a thickener is added to the obtained cementitious composition. After adding and kneading, to the resulting kneaded product, 5 wt% to 30 wt% of peridotite fine powder in terms of solid content is added to the kneaded product, and after sufficiently kneading, extrusion molding is performed. A method for producing an asbestos-free extrusion molded cement building material.