JPS6096555A - Fiber reinforced cement cured body and manufacture - 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 [Technical Field] The present invention relates to a hardened fiber-reinforced cement body used as a building material, etc., and a method for producing the same.

[Background technology]

Among the many cement-based building materials, fiber-reinforced hardened cement mixed with asbestos has been widely used since it has high quality and high strength. However, recently, the carcinogenicity of asbestos has been brought up as a social issue, and a trend towards asbestos removal has become desirable. Therefore, bulbs, organic fibers, and inorganic fibers have come to be used as substitutes for asbestos, but they have lower strength than hardened fiber-reinforced cement containing asbestos, and are particularly susceptible to strength loss when water is absorbed. The current situation is remarkable.

[Purpose of the invention]

In view of the above-mentioned current situation, the present invention provides a fiber-reinforced cement cured body that does not contain asbestos at all, has excellent strength, especially strength and dimensional stability when absorbing water, and can be manufactured at low cost, and a method for manufacturing the same. The purpose is to

[Disclosure of the Invention] In order to achieve the above object, the inventors have made extensive studies and have finally completed the following invention.

The first invention is a fiber-reinforced cement hardened body produced by mixing organic fibers other than asbestos and/or inorganic fine fibers as reinforcing fibers with hydraulic cement, and a silica fume which is produced as a by-product during the production of ferrosilicon. , silica hume with an average particle size of 1 micron or less and a 5iOz composition of 40% or more per total solid weight.
The gist of the second invention is a cured body of fiber reinforced cement containing 30% of carbon dioxide, and in order to produce such a cured body,
Silica hume, which is a by-product during the production of ferrosilicon, is added to the nurary made of fibers and water obtained by disintegrating wood bulbs with a large amount of water.
Add 5 to 30 parts of silica hume having an n2 content of 40 parts by weight or more based on the total solid weight, mix and disperse thoroughly, then add hydraulic cement, immediately form a plate-like body by a paper-making method, and cure it. The gist of this paper is a method for producing a cured fiber-reinforced cement product. These will be explained in detail below.

The inventors focused their attention on pozzolan, which is mixed in during the production of silica cement. Pozzolan is a siliceous mixture of volcanic ash and tuff, and has physical properties that allow it to easily combine with lime. By the way, during the production of ferrosilicon, an ultrafine powder siliceous material called silica fume, which has a substantially spherical form and has a particle size of 0.1 micron to 1 micron, is produced as a by-product. Silica hume contains amorphous 5i(h) and reacts well with Ca(OH)z generated during cement hardening. For this reason, the inventors decided to mix silica hume into cement as an ultrafine pozzolanic material. In this way, we have come to believe that it is possible to obtain a high-quality, high-strength inorganic cured product.

Therefore, the above-mentioned silica fume is added to a composition for a fiber-reinforced cement hardening body, which consists of only mortar mixed with various water-cement ratios and sand-cement ratios, or which includes reinforcing fibers such as bulbs and synthetic fibers. The strength was measured after mixing.

As a result, regarding the fiber-reinforced cement hardened specimens,
When 15% of silica fume is mixed in, the strength is improved by 50% when left under normal conditions (at room temperature of 25°C) compared to the product without the addition, and when left in saturated water for 24 hours, the strength increases by 40%.
It was found that the strength was improved by 0. On the other hand, for mortar specimens without fibers mixed in, the strength was only improved by a factor of 5, both when left under normal conditions and when left in water for 24 hours. In other words, when silica fume is mixed into a fiber-reinforced hardened cement product, especially a fiber-reinforced hardened cement material mixed with wood pulp and/or organic synthetic fibers, its strength is significantly improved regardless of whether it is normal or saturated with water. It is.

The relationship between the amount of silica hume mixed and the bending strength is shown in Figure 1. Below 5 weight ratio, the bending of the fiber-reinforced cement cured product does not significantly improve the strength, and up to 20 weight ratio, the added amount almost changes. The strength increases proportionally, and the strength does not change even if it exceeds 30 degrees.

Therefore, the amount of silica hume mixed is 5% of the total solid weight.
~30%.

Silica fumes with a SiO2 composition of less than 40% have too much carbon and Al 203 as other components, so the performance of the cured fiber-reinforced cement tends to be poor. Therefore, the Sio2 composition of silica hume is 40 or more, preferably 80 or more.

In producing the fiber-reinforced cement hardened body according to the present invention, a hydraulic cement such as ordinary Portland cement, slurry cement mixed with blast furnace slurry, or alumina cement is used as a binder, and the above-mentioned silica hume is added to this in the above-mentioned range, Synthetic fibers such as wood pulp, vinylon, polypropylene, nylon, and acrylic are added as reinforcing fibers, and if necessary, inorganic fibers such as wollastonite, rock wool, glass a-fiber, and mica are added, and these are mixed with water. Ru. Thereafter, this is appropriately shaped by an extrusion molding method, a casting method, a paper making method, etc., and is then cured and hardened.

In this invention, the strength is improved by incorporating silica hume, which is particularly remarkable in papermaking methods that require a large amount of water during shaping.

Moreover, the following can be said about the m-method move 1vL. In other words, if silica hume is added to a slurry consisting of fibers and water and hydraulic cement is added after sufficient mixing, the strength is higher than when silica hume is mixed with hydraulic cement into the slurry. . This is presumed to be because silica hume is an ultrafine particle, which causes secondary agglomeration, and requires a large amount of water to uniformly disperse the final particles.

In this invention, the fiber-reinforced cement hardened body mixed with pulp or synthetic fiber shows a remarkable improvement in strength when compared with the mixture of silica hume. The reason for this is inferred as follows from the electron micrographs compared with mortar.

This is thought to be because silica fume not only fills the voids in the cement matrix, but also disperses around the fibers sandwiched between the cement matrices, creating fine irregularities in the cement matrix and increasing the pulling force of the reinforcing fibers.

Regarding silica fume, there is no big difference in effectiveness whether it is produced as a by-product during the production of ferrosilicon in a conventional electric furnace or from a molten metal furnace. As for the sub-produced ferrosilicon, it is desirable that it be mixed in while remaining trapped in water.

Next, examples will be described together with comparative examples.

Using the raw materials shown in Table 1 and applying the manufacturing method and manufacturing conditions shown in the same table, hardened fiber reinforced cement bodies of Examples 1-10 and Comparative Examples 1-3 were made.

(F Margin) The Hachinik papermaking method was implemented as follows at a pilot plant owned by the company. First, roll up 4 layers with a making roll and press to 100kg/cd-3.5
After being cured for 2 weeks under conditions of 45° C. and 95*RH, the molded product was molded under a pressure condition of 2 seconds, and then taken out and left in air at 25° C. for another week. This was defined as the normal state, and the state of being left in water for 24 hours was defined as the state of water saturation.

The wood valves are NUKP (coniferous unexposed craft valves) and Canadian standard filtration (C5F) in the refiner.
It was used after being beaten to 250 cc.

The silica fume used in Examples 2 to 8 had a 5i02 composition produced as a by-product from an electric furnace, and only in Example 1 had a 5tOa composition produced as a by-product from a smelt furnace. 46 weight silica hume was used.

During mixing, Bulb+Vinylon+Silica Hue were first mixed and stirred for 3 minutes, then hydraulic cement was added and stirred for 3 minutes.

The physical properties of the cured products of Examples and Comparative Examples are as listed in Table 1.

Example 1 is an example in which a SiOz composition 4-position kahium, which was produced as a by-product from a smelt furnace under the same molding and compounding conditions as Example 4, is used, but there is no major difference in the physical properties of the cured product between the two.

In Examples 2 to 8 and Comparative Example 1, under the same molding conditions, the amount of silica hume mixed was increased to 30 weight MTo, and the amount of silica hume was not mixed at all. Compared to Comparative Example 1, in Examples 2 to 8, the strength was approximately proportional to the amount of mixture.

Both dimensional stability has been improved.

Example 9 and Comparative Example 2 compare changes in physical properties caused by mixing silica fume in an extrusion method, and Example 1O and Comparative Example 3 compare changes in physical properties caused by mixing silica fume in a casting method. In both manufacturing methods, when silica fume was mixed, both strength and dimensional stability improved.

[Effects of the Invention j] Since the present invention is configured as described above, it is possible to provide a fiber-reinforced cement hardened body that has high strength and a small dimensional change rate, even if it does not contain asbestos. Furthermore, since silica fume, which is produced as a by-product during the production of ferrosilicon, is used, it can be produced at low cost.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the amount of silica hume mixed and the bending strength. Each plot is shown as an average of n=10. In the figure, black circles. The black triangle indicates the case where silica fume, which is produced as a by-product from the melt furnace, is mixed. Agent: Takehiko Matsumoto, Patent Attorney ★ Welcome! Feather 0 10 20 30 Amount of silica hume mixed (weight'/.) Fig. 1

Claims (7)

[Claims] (1) In a fiber-reinforced cement hardened product produced by mixing organic fibers other than asbestos and/or inorganic fibers as reinforcing fibers with hydraulic cement, silica fume is produced as a by-product during the production of ferrosilicon, and has an average particle size. Silica hume with a diameter of 1 micron or less and a 5i02 composition of 40% by weight has a total solids weight of 5 to 30%.
Contains fiber reinforced cement hardened material. (2) The fiber-reinforced cement hardened body according to claim 1, wherein the silica hume is produced as a by-product in an electric furnace. (3) The fiber-reinforced cement hardened body according to claim 1, wherein the silica hume is produced as a by-product from a melt furnace. (4) The fiber-reinforced cement hardened body according to any one of claims 1 to 3, wherein the organic fiber is a wood bulb and/or an organic synthetic fiber. (5) Silica hume, which is produced as a by-product during the production of ferrosilicon, is added to the slurry consisting of fibers and water obtained by disintegrating wood pulp with a large amount of water, and the average particle size is 1 micron or less and the 5i02 composition is 40% by weight. After adding 5 to 30 parts of silica hume per total solid weight and thoroughly mixing and dispersing, hydraulic cement is added, and a plate-shaped body is immediately formed using a papermaking method, and cured to form a hardened fiber-reinforced cement body. The fiber-reinforced cement hardened body to be manufactured! Law. (6) The method for manufacturing a fiber-reinforced cement hardened body according to claim 5, wherein silica hume produced as a by-product from an electric furnace is mixed as the silica hume. (7) The method for manufacturing a fiber-reinforced cement cured body according to claim 5, characterized in that silica hume, which is produced as a by-product from a melt furnace, is mixed in as the silica hume while wet with water.