JPH01320242A - Lightweight cement composition - Google Patents

Abstract

PURPOSE:To obtain the title composition capable of preparing a lightweight formed product having high strength as the exterior and interior building materials without using asbestos by mixing cement, an inorg. aggregate consisting essentially of spherical grains, a lightweight aggregate, and a cellulosic admixture. CONSTITUTION:(A) one hundred pts.wt. of cement (portland cement, blast-furnace cement, etc.), (B) 5-100pts.wt., preferably 5-50pts.wt., lightweight aggregate [inorg. hollow (porous) grains such as fly ash having <=2mm, preferably 0.1-2mm, diameter and <=0.5, preferably 0.1-0.4, bulk density], (C) 5-100pts.wt. inorg. aggregate (consisting essentially of a spherical aggregate having 0.1-500mum grain diameter such as fly ash), (D) 0.1-10pts.wt., preferably 0.5-5pts.wt., cellulosic admixture (methycellulose, etc.), and (E) 3-50pts.wt. preferably 5-30pts.wt., sepiolite (added, as required, wherein an alpha-type is appropriately used, and having about 0.15mum fiber diameter and 100mum fiber length) are mixed to obtain the lightweight cement composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cement composition, particularly a cement composition suitable for producing a lightweight building material used for interior or exterior building materials.

(Conventional technology) As interior and exterior building materials such as wall and ceiling materials.

A lightweight cement molded body is used. Methods for producing lightweight cement molded bodies include a method in which air bubbles are generated when water is added to each component of the cement composition and mixed;
There is also a method of preparing a molded body using a cement composition containing lightweight aggregate. Among these methods, bubbles can be generated by mixing a foaming agent such as an air-entraining agent or a surfactant and foaming by stirring; by mixing a substance that generates gas such as hydrogen peroxide when decomposed; ,
There is a method of foaming using gas generated by decomposition of the substance. However, when the slurry cement composition containing microscopic air bubbles generated in this manner is vacuum extruded, most of the air bubbles disappear due to degassing in the vacuum zone of one extruder. Therefore, a cement molded body with low density cannot be obtained.

In the method using lightweight aggregate, relatively fine-grained and low specific gravity aggregates such as perlite, shirasu balloons, and volcanic lapilli are used as the lightweight aggregate. However, when a cement composition material containing these materials is pressurized and kneaded in an extruder, the aggregate is easily crushed, and therefore a lightweight cement molded body cannot be obtained. JP-A-56-17965 and JP-A-56-1.7967 disclose that, in addition to the above pearlite shirasu balloons and volcanic lapilli, they contain alkali-resistant glass (cRc) jW fibers, charcoal and pulp. A cement composition is disclosed. The above GRC fibers are added as reinforcing fibers, and the charcoal and pulp are used to crush lightweight aggregate and GRC fibers when kneading each material of the composition.
This is added to prevent damage to the RC fibers [The above-mentioned crushing and damage during kneading are caused by strong mixing under low moisture conditions (necessary to maintain the shape of the uncured molded product)] Cheap]. but.

Charcoal and pulp contain lignin and resin, which adversely affect the hardening reaction of cement. In other words, if the molded product is cured at room temperature or in a steam atmosphere, the strength of the resulting molded product is insufficient, so treatment under high temperature and pressure using an autoclave is required. becomes.

When producing the above-mentioned lightweight cement molded body, particularly when molding is carried out by extrusion molding, it is also required that the moldability and shape retention of the resulting uncured molded body be good. Conventionally, when a cement molded body is manufactured by extrusion molding, moldability and shape retention have been ensured by adding 9 asbestos fibers. The strength of the molded product obtained by adding asbestos fibers is also improved. However, asbestos is designated as a specified chemical substance, and its carcinogenicity has become a problem. Although usage standards are established when producing asbestos cement molded bodies, molded bodies using cement compositions that do not contain asbestos are currently desired due to the problem of dust generation during manufacture and use.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, and its purpose is to prepare a high-strength and lightweight seven-piece molded product that can be used as an exterior or interior building material. A cement composition that can be used.

Another object of the present invention is to provide a lightweight cement composition that does not contain toxic asbestos.

(Means for solving the problems) The lightweight cement composition of the present invention comprises cement, lightweight aggregate,
It contains an inorganic aggregate and a cellulose-based admixture, and the average particle size of the lightweight aggregate is 2 mm or less.

The inorganic aggregate contains spherical particles as a main component, thereby achieving the above object.

The lightweight cement composition of the present invention further contains Seviolite, thereby achieving the above object.

As the cement contained in the cement composition used in the present invention, any known cement such as Portland cement, blast furnace cement, or alumina cement may be used.

The lightweight aggregate contained in the composition has a particle size of 2 m.
m or less, and has a bulk specific gravity of 0.5 or less, preferably a particle size of 0.1 to 2 mm, and a bulk specific gravity of 0.1 to 0.4. As such hollow particles, it is preferable to use fly ash (pulverized coal combustion ash collected in a precipitator of a coal-fired power plant) that has been subjected to specific gravity conversion, that is, hollow particles that have been suspended by water droplet beneficiation of fly ash. It is. Such lightweight aggregate is contained in the composition in a proportion of 5 to 100 parts by weight, preferably 5 to 50 parts by weight, based on oo parts by weight of cement. If the amount is too small, the obtained cement molded body will have a high specific gravity, and if it is too small, the strength of the obtained molded product will be poor.

The inorganic aggregate contained in the cement composition has a particle size of 0.1~
The main component is 500μm spherical aggregate. Fly ash and micro silica are used as spherical aggregates.

Silica hume, spherical calcium silicate (a by-product during the production of silicon metal, ferrosilicon, etc.) are suitable. When the particle size of inorganic aggregate is less than 0.1 μm,
In order to ensure appropriate fluidity in the kneading and extrusion steps of each component of the cement composition, it is necessary to use a large amount of water, which reduces the strength of the resulting molded product.

When the particle size exceeds 500 μm, the surface of the molded product obtained becomes rough.

Moreover, the strength also decreases. The inorganic aggregate is contained in a proportion of 5 to 100 parts by weight per 100 parts by weight of cement.

If the proportion of the inorganic aggregate in the entire composition is low, moldability will be poor, and if it is excessive, the strength of the molded product obtained will be reduced.

The cellulose-based admixture imparts water retention and viscosity to the kneaded product when the components of the 2Mi product are mixed and extruded. Therefore, water is prevented from separating during extrusion molding under pressure, and appropriate fluidity can be obtained. Due to the thickening effect of the cellulose admixture, the obtained uncured molded product has excellent shape retention until hardening. As the cellulose-based admixture, methylcellulose, hydroxyethylcellulose, etc. are preferably used. This cellulose-based admixture is 0.1 to 10 parts by weight per 100 parts by weight of cement.
It is contained in the composition in an amount of parts by weight, preferably 0.5 to 5 parts by weight. If the amount is too small, the viscosity when mixed with the composition will be low, resulting in poor moldability and poor shape retention after molding. If it is in excess, the viscosity will be high and the moldability will be poor.

The cement composition of the present invention further contains sepiolite as necessary. This sepiolite is 9 e.g. (
OHz) 4 (Oll) 4MgeSj 120:1
It is a magnesium silicate compound represented by 0.6 to 811zO. This sepiolite is a clay mineral with a double-chain structure.

It exists in the form of fibers, powder, particles, plates, etc.

Sepiolite exists in either an α-type or a β-type crystal structure, and α-type sepiolite (α-sepiolite), which naturally exists in a fibrous form, is preferably used. The fiber diameter of this fibrous sepiolite is 0.01~0.
30 p m, preferably about 0.15 p m; and the fiber length is 1 μm or more, preferably 100 μm or more. Sepiolite is added in the cement composition, preferably 3 to 50 parts by weight, preferably 5 to 3 parts by weight, per 100 parts by weight of cement.
It is contained in a proportion of 0 parts by weight.

If the amount is too low, the resulting hardened cement molded body will have a high density, resulting in an increase in overall weight. Impact resistance is also reduced, and workability such as cutting and nailing is also poor. If it is in excess, the strength of the molded article will decrease.

In the cement composition, further optionally.

Contains reinforcing fibers. Reinforcing fibers are used to improve the bending strength and impact strength of the resulting molded product.

It includes, for example, the machine fibers, valves.

Metal fibers and the like may be used. Organic fiber materials include vinylon, polypropylene, polyethylene, acrylic resin, aramid, and polyester.

An alkali-resistant material such as carbon is suitable.

Materials for metal fibers include steel fibers and stainless steel fibers. The type of valve is not particularly limited, but waste paper pulp is more suitable as it does not have a negative effect on the solidification and hardening of cement. The diameter and fiber length of the reinforcing fibers vary depending on the material, but usually the diameter is 1 to 100 μm.
A fiber length is 3 to 20 mm. This reinforcing fiber is 10 parts by weight or less, preferably 0.2 parts by weight per 100 parts by weight of cement.
It is contained in the composition in a proportion of ~10 parts by weight. If it is in excess, the dispersibility when mixing the ingredients of the composition will be poor, resulting in a decrease in the strength of the molded product obtained.

In order to produce a cement molded body by the method of the present invention, a process similar to conventional cement extrusion molding can be adopted. For example, first of all, the above-mentioned cement and light aggregate.

Tri-blend the inorganic aggregate, cellulosic admixture, and optionally sepiolite and reinforcing fibers. An appropriate amount of water is added to the mixture for wet blending, and then thorough kneading is performed using a kneader.

The obtained plastic kneaded material is introduced into an extrusion molding machine having a desired mold, and extrusion molding is performed under pressure. The extruded molded product having the desired shape is produced under predetermined conditions (for example, at a temperature of 4
It is cured by being allowed to stand (curing) for 4 to 48 hours at 0 to 60° C. and 90 to 100% humidity. General-purpose equipment may be used for all of the above blending step, kneading step, and extrusion molding step.

(Function) When the above cement composition is extruded by the method of the present invention, the kneaded material has sufficient fluidity in the extruder, the flow rate becomes uniform, and the extruded uncured compact remains until hardening progresses. It has sufficient shape retention. These good properties are due to the fact that the inorganic aggregates in the cement composition are mainly spherical particles, and the lightweight aggregates mentioned above are also often spherical particles5. ■ After extrusion, shape retention is imparted by the action of the above inorganic aggregate and lightweight aggregate, as well as the cellulose admixture; ■ In addition, if sepiolite is contained, the sepiolite is This is thought to be mainly due to the fact that the kneaded material contained has thixotropy, so it has good fluidity under pressure and has sufficient shape retention after extrusion.

Since the kneaded material contains a cellulose-based admixture, an appropriate viscosity is imparted to the kneaded material. Even when molding is performed using a mold having a complex irregular cross-sectional shape, the five dehydration steps are not required and the molding can be performed easily. The extruded uncured molded product has good shape retention and does not deform before it hardens. Since the obtained cured molded body contains lightweight aggregate, the molded body has a low specific gravity. It also has sufficient strength and impact resistance.

In particular, when reinforcing fibers are contained, the strength and impact resistance are even better. Such molded bodies are suitably used for wall materials, ceiling materials, etc. of houses.

According to the present invention, a lightweight and high-strength cement molded body suitable for interior and exterior building materials such as wall materials and ceiling materials can be easily manufactured without using conventional asbestos fibers. As asbestos fibers are not used, there is no risk of cancer caused by asbestos dust during the manufacturing process or during use.

(Margin below) (Example) The invention will be explained below with reference to examples.

(A) Preparation of plastic kneaded product: Bortland cement 100
Fly ash (spherical particles with an average particle size of 50 μm) 30 Methyl cellulose (90511-30,000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 water
40 Mixer (Eirich mixer) each component of the above-mentioned cement composition.
RVO2 type; manufactured by Nihon Eirinhi Co., Ltd.) and 11000r
Mixed for 2 minutes at p.

Water was added thereto, and after further mixing for about 1 minute, the mixture was thoroughly kneaded using an auger kneader (MP-100 model; manufactured by Miyazaki Iron Works Co., Ltd.) to obtain a plastic kneaded product.

([3) Preparation of flat cement molded product: The kneaded product obtained in section (A) was vacuum extrusion molded with a flat trial mold (250 mm inside opening x 15 mm thick) (MV
-FM-A-1; manufactured by Miyazaki Iron Works Co., Ltd.) hopper,
A flat sample having a width of 250 mm, a thickness of 15 mm, and a length of 50 cm was prepared by extrusion molding. The extrusion pressure and extrusion amount per unit time at this time were measured. The extrusion pressure was measured by measuring the pressure in the resistance section from the barrel of the extruder to the mold using a Bourdon tube pressure gauge. The amount of extrusion per unit time is 60% of the flat sample extruded from the die tip.
The length (cm/m1n) discharged per second was measured and calculated using a quintic equation.

T: Extrusion per unit time ff1 (p, /hr) α: Cross-sectional area of the mold exit (afl) β: Length of the extruded flat sample (c+++/min) The above uncured molded body was heated for 5 hours. After being left at room temperature (preliminary), it was held for 12 hours in an atmosphere of 50°C and RH 95% or more (first curing), and then immersed in water at 20°C for about 4 weeks.

(C) Performance evaluation of molded product = Cut the sample obtained in section (B) after immersion into a width of 25+ um and a length of 240 mm (cut perpendicular to the extrusion direction) and place it in a gear oven at 105°C. After drying for about 48 hours, it was allowed to cool to room temperature.

This sample was supported at an interval of 200 mm, and an autograph (manufactured by Shimadzu Corporation) was used in the center of the sample.
The bending strength was measured by applying force at a bending speed of 10 minutes (bending strength test). Separately, the sample after soaking was cut into 200 mm width and 200 mm length, and after drying at 105°C for 2 days, the specific gravity of the molded body was measured using the following equation: Specific gravity - weight of plate/thickness x width x length (Weight was measured in grams to the second decimal place. Dimensions were measured in cm to the second decimal place.) The results of each test are shown in Table 1.

Same as Example 1 except that the amount of lightweight aggregate was 15 parts by weight and the amount of water was 45 parts by weight.

The results are shown in Table 1. The results of Examples 3 and 4 and Comparative Examples 1 and 2 are also shown in Table 1 below.

Punishment Piece 1 The same as Example 1 except that the lightweight aggregate star was 30 parts by weight, the amount of methylcellulose was 1.5 parts by weight, and the amount of water was 45 parts by weight.

The same as Example 1 except that the amount of lightweight aggregate was 5 parts by weight.

The amount of lightweight aggregate is 30 parts by weight, and the amount of methyl cellulose is 1 part by weight.
．． Same as Example 1 except that 5 parts were used, the amount of water was 45 parts by weight, and no reinforcing fibers were used.

Example 1 was the same as Example 1 except that no flammable lightweight aggregate was used and the amount of water was 30 parts by weight.

Extrusion molding was attempted in the same manner as in Example 1, except that spherical aggregate was not used and the amount of lightweight aggregate was 100 parts by weight. However, molding was defective and a molded article with a satisfactory shape could not be obtained.

(Left below) Exposed portland cement 100
Fly ash (spherical particles with an average particle size of 50 μm) 50 vinylon fibers (RM182 x 6; manufactured by Kuraray Co., Ltd.) 1
Polypropylene fiber (PZL182' x 10; manufactured by Daiwabo Co., Ltd.) 1 methylcellulose (903+1-30,00
0, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 Water
50 Using the cement composition of the above formulation, a molded body was prepared in the same manner as in Example 1, and its performance was evaluated. The results are shown in Table 2. The results of Examples 7 to 9 and Comparative Examples 3 to 4, which will be described later, are also shown in Table 2.

It is the same as Example 6 except that the amount of light weight aggregate was 10 parts by weight and the amount of water was 45 parts by weight.

Actual drawing 1 No polypropylene fibers were used, the amount of lightweight aggregate was 10 parts by weight, and the amount of spherical aggregate was 40 parts by weight.

The amount of water was 40 parts by weight, and Seviolite was tea (trade name, Toyota Tsusho ■, average fiber diameter 0.15 μm).

The procedure was the same as in Example 6 except that 5 parts by weight of the fiber (fiber length: 5 μm; manufactured in Turkey) was used.

No polypropylene fiber was used, the amount of lightweight aggregate was 15 parts by weight, and the amount of spherical aggregate was 40 parts by weight.

The same as Example 6 except that the amount of Seviolite was 15 parts by weight, the amount of methylcellulose was 1 part by weight, and the amount of water was 45 parts by weight.

North rescue±l Without lightweight aggregates and polypropylene fibers.

The amount of spherical aggregate was 40 parts by weight, and the world of Seviolite was 5 parts by weight.
The procedure was the same as in Example 6, except that the amount of methyl cellulose was 1 part by weight, and the amount of water was 40 parts by weight.

The star of the light weight aggregate is 100 parts by weight, and the amount of spherical aggregate is 40 parts by weight.
Extrusion molding was attempted in the same manner as in Example 6 except that the amount of water was 45 parts by weight.

However, molding was defective and a satisfactory molded product could not be obtained.

(Margin below) Tables 1 and 2 to 9 using the compositions of the present invention.

It can be seen that a cement molded body can be obtained with good moldability by extrusion molding. The obtained uncured molded product has excellent shape retention and does not deform even when immersed in water for a long period of time due to hydration. The molded product obtained by curing is lightweight and has good strength.

(Effects of the Invention) According to the present invention, a lightweight and high-strength cement molded body can be obtained by extrusion molding with good moldability and high efficiency. Such a cement molded body is suitably used as an interior/exterior material for, for example, wall materials and ceiling materials of houses. Since it does not contain asbestos, there is no risk of cancer caused by asbestos dust either during the manufacturing process or during use.

that's all

Claims (1)

[Scope of Claims] 1. A cement composition containing cement, lightweight aggregate, inorganic aggregate, and a cellulose admixture, wherein the lightweight aggregate has an average particle size of 2 mm or less, and the inorganic bone A cement composition whose main component is spherical particles. 2. Claim 1 further containing sepiolite
The cement composition described in Section. 3. 5 to 5 parts of lightweight aggregate per 100 parts by weight of the cement
100 parts by weight, and the composition according to claim 1, containing the inorganic aggregate in a proportion of 5 to 100 parts by weight. 4. 5 to 5 parts of lightweight aggregate to 100 parts by weight of the cement
The composition according to claim 2, wherein the composition contains 100 parts by weight of sepiolite, 5 to 50 parts by weight of sepiolite, and 5 to 100 parts by weight of inorganic aggregate. 5. The composition according to claim 1 or 2, wherein the lightweight aggregate is fly ash having a bulk specific gravity of 0.5 or less.