JPS5811379B2 - Manufacturing method of inorganic wall material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a water-resistant inorganic wall material using β-type hemihydrate gypsum, granulated blast furnace slag (hereinafter referred to as slag), and Portland cement as main raw materials.

A wide variety of inorganic, noncombustible wall materials have been proposed, including those based on Portland cement, gypsum, and calcium silicate, but the ones that are actually mass-produced are: Many are made of Portland cement.

There has never been an industrial production of a water-resistant wall material that can be used for exterior walls using inexpensive slag or gypsum as a by-product of steel and chemical factories.

This is because the hardening speed of the well-known slag-based hardening material, which is simply a mixture of slag and slaked lime or Portland cement, is extremely slow (it does not develop enough initial strength to be demoldable until more than two days have passed after being cast in the mold). The main reasons are thought to be that mass production is difficult and products are prone to warping and cracking, and products made mainly of gypsum usually have poor water resistance and cannot be used for exterior walls.

It is also known to use a mixture of slag and gypsum (trihydrate gypsum or anhydrous gypsum) to which Portland cement is added for slaked lime, and to produce water-insoluble ettringite through a hydration reaction. It also has the disadvantage of slow curing speed.

As a result of various studies, the present inventor found that in a three-component hardening material consisting of slag, gypsum and Portland cement, when β-type hemihydrate gypsum is used as the gypsum, the initial strength development is significantly faster. Based on this knowledge, we have come to invent a method for manufacturing high-performance wall materials efficiently and at low cost, as detailed below.

First, to give an overview of the inorganic wall material manufacturing method of the present invention, β-type hemihydrate gypsum is 30 to 80% (weight%, the same applies hereinafter).
A hardening material prepared by adding 10 to 20 parts by weight of Portland cement to 100 parts by weight of a mixture consisting of This method is characterized by forming the obtained slurry into a plate shape and then curing it.

The β-type hemihydrate gypsum used in the production method of the present invention is produced by heating and dehydrating trihydrate gypsum in a vacuum, and is generally used as a general molding material that hardens simply by adding water. Although it is cheaper than the commonly used α-type earth water gypsum, it has poor crystallinity, and because it requires a large amount of water to provide the plasticity necessary for molding when preparing the slurry, the strength of the hardened molded product is low. have.

However, in a mixed system with slag and Portland cement, those using β-type hemihydrate gypsum not only harden significantly faster than those using α-type, but the properties of the cured moldings are also different from those using α-type. There is nothing like it in comparison.

However, even if β-type hemihydrate gypsum is used, it is necessary to keep the blending ratio with other materials within the above range in order to obtain good results.

The other raw materials used in the present invention, namely slag and Portland cement, do not require anything particularly special.

As the slag, granulated blast furnace slag powder obtained by rapidly cooling, drying, and pulverizing molten blast furnace slag, which is a by-product of blast furnaces, can be used, and it can also be used as Portland cement. Ordinary Portland cement can be used.

However, since early-strength cement and ultra-early strength cement are effective in accelerating the hardening of molded products, and white cement is effective in increasing the whiteness of products, it is desirable to use them as appropriate.

The blending ratio of these raw materials in the present invention is as described above, but when β-type hemihydrate gypsum is used beyond the above range, the wet strength of the product decreases and the water resistance deteriorates.

- Excessive use of 10,000 slag not only delays curing, but also causes a decrease in the strength of the product, an increase in water permeation, and the occurrence of cracks and warping.

If too much cement is used, undesirable deformations such as warping and cracking of the product will become significant.

A particularly preferable composition of the curable material specified in the present invention is 75 to 45% β-type hemihydrate gypsum, 2 slag
5-55%, Portland cement 12-17%.

The curable materials described above set rapidly when slurried with water and then harden.

In particular, those with a high gypsum mixing ratio set and harden quickly, and the slurry can be molded in about 20 to 30 minutes after molding.

However, if the gypsum content is low, the curing will be somewhat slow, so it is recommended to add a small amount of curing accelerator as necessary, such as when performing continuous molding.

Effective curing accelerators include aluminum sulfate, alum, and potassium sulfate.

The amount of curing accelerator added is at most 3% based on the curable material.
degree.

In addition, in order to give the product toughness and increase resistance to deflection, impact, etc., reinforcing fibers with a content of less than 5% of the hardenable material, such as alkali-resistant glass fibers, inorganic fibers such as rock wool, vinylon, Organic fibers such as nylon may be mixed and uniformly dispersed.

In addition, by blending lightweight aggregates such as perlite, shirasu, and kansuishite to approximately 10% of the hardenable material,
The weight of the product can be reduced without significantly impairing its test characteristics, and processing such as sawing and nailing can be made easier.

It is desirable that the total amount of these auxiliary ingredients does not exceed 15%.

The appropriate amount of water used to slurry the raw material mixture varies depending on the composition of the raw material and the molding method, but usually requires 55 to 65% of the total solid raw material.

Although the method for forming the slurry raw material is arbitrary, it is advantageous to take advantage of its rapid hardening properties and adopt a continuous forming method similar to that used for manufacturing gypsum plates.

In other words, the slurry prepared in the raw material mixing tank is continuously sent to the molding frame on the conveyor belt, and while moving along with the belt, the slurry is molded, defoamed, and initial hardened, and then cut into appropriate dimensions and demolded. (If the raw materials are properly mixed as described above, the molded product can be demolded within 60 minutes, making such continuous molding possible.

). The demolded board is placed in a high humidity room with a humidity of 98-100%, or polyvinylidene chloride latex is applied to the surface to form a curing film (it may be packed in a curing sheet).
, and cure for 2 to 7 days.

Finally, drying is performed at 40 to 60°C.

The wall materials obtained in this way have excellent physical properties such as bending strength and compressive strength, as well as water resistance, and are free from warping and minute surface cracks.Of course, they also have excellent fire resistance, making them highly suitable for use as exterior wall materials. It's about performance.

The present invention will be explained below with reference to Examples.

The methods for measuring the physical properties of the products shown in the Examples are as follows.

Coagulation test: Conducted using a Vigor needle device based on JISR9122.

Demoldable time: A slurry mixed uniformly using a mixing machine specified by JISR5201 was cast into a similarly specified molding mold, and the time required for demolding was measured.

Bending strength/compressive strength: According to JISR5201.

However, the wet strength is the value in the wet state after immersing the cured specimen in water for 24 hours.

Water permeability: 0.0 using a JISA1404 water permeability test device.
The amount of water permeation is measured when a water pressure of 5 kg/cm2 is applied for 1 hour.

Running water elution rate: 400 per minute with a test specimen according to JISR5201 placed in a 30cm x 50cm, 15cm deep vat.
Inject ~500cc of water.

When this is continued for 7 days, the weight loss due to elution is expressed as a percentage of the original amount.

Example 1 Slag, β-type hemihydrate gypsum, Portland cement, and other auxiliary materials were molded and cured according to JISR5201.

Table 1 shows the changes in the curing properties and properties of the cured product when the raw material composition was variously changed.

Claims (1)

[Claims] 1. A hardenable material made by adding 10 to 20 parts by weight of Portland cement to 100 parts by weight of a mixture consisting of 30 to 80% by weight of β-type hemihydrate gypsum and 20 to 70% by weight of granulated blast furnace slag. A method for producing an inorganic wall material, characterized in that the slurry is mixed with water together with 90 to 15% by weight of auxiliary components to form a slurry, the resulting slurry is formed into a plate shape, and then cured. 2 Reinforcing fibers, lightweight aggregates or (and) auxiliary ingredients
The manufacturing method according to claim 1, wherein sclerosing-promoting diarrhea is added.