JPH01320241A - Cement composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having high strength and impact resistance and capable of being used for decking and flooring without using asbestos by mixing cement, a spherical aggregate, an inorg. aggregate consisting of superfine particles, a reinforcing fiber, and a cellulosic admixture. CONSTITUTION:(A) one hundred pts.wt. of cement, (B) 5-100pts.wt. of the inorg. aggregate (granular aggregate such as fly ash having 1-100mum particle diameter and 1-20wt.% superfine-particle aggregate such as micro silica having 0.01-1mum particle diameter), (C) 0.2-10pts.wt. of the reinforcing fiber (the org. fibers, pulp, fibrous wollastonite, etc., having 1-100mum diameter and 3-20mm length), and (D) 0.1-10pts.wt., preferably 0.5-5pts.wt., cellulosic admixture (methylcellulose, hydroxyethylcellulose, etc.) are mixed to obtain the cement composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a cement composition suitable for manufacturing a cement composition, particularly a floor material used for decking materials for verandas and balconies, hallway materials for apartment buildings, etc. and a method for manufacturing a cement molded body using the same.

(Prior Art) Asbestos-cement molded boards, which have relatively high strength and fire-retardant properties, are used as flooring materials such as decking materials for verandas and balconies and hallway materials for apartment complexes. This molded plate is manufactured by extrusion using a cement composition containing diasbestos. In the manufacturing process, asbestos increases the fluidity of the slurry cement composition and improves the shape retention of the extruded uncured molded body. Furthermore, it improves the strength of the final product obtained. However, the resulting molded product has the disadvantage of being weak against impact. Furthermore, the asbestos contained in it is designated as a specified chemical substance, and its carcinogenicity has become a problem. Although usage standards are established when manufacturing asbestos cement molded bodies, molded bodies using asbestos-free cement compositions are currently desired due to the problem of dust generation during manufacturing and use. .

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, and its purpose is to provide a cement molded product that has high strength and impact resistance and does not contain harmful asbestos. The object of the present invention is to provide a method for manufacturing with good moldability.

(Means for Solving the Problems) The cement composition of the present invention contains cement, inorganic aggregate, reinforcing fibers, and a cellulose-based admixture.

The inorganic aggregate mainly contains spherical aggregate with a particle size of 1 to 100 μm and contains ultrafine particle aggregate with a particle size of 0.01 to 1 μm, 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, and alumina cement may be used.

The inorganic aggregate contained in the cement composition has a particle size of 1 to 10
The main component is 0μm spherical aggregate, and the particle size is 0.01~
Contains 1 μm ultrafine particle aggregate. Among inorganic aggregates, spherical aggregates include: fly ash (pulverized coal combustion ash collected in dust collectors of coal-fired power plants), 1 spherical calcium silicate (silicon metal);

(a by-product during the production of ferrosilicon, etc.) is suitable. As the ultrafine aggregate, used are inorganic particles having the above-mentioned particle size, which can form a close-packed structure in the forming process described below, and which can cause a pozzolanic reaction in the curing process. Such ultrafine particle aggregates include microsilica, silica hume (both produced as by-products during the production of ferrosilicon), natural pozzolan, and diatomaceous earth.

Silica flour, Aerosil, etc. are suitable.

The inorganic aggregate is contained in the cement composition at a ratio of 5 to 100 parts by weight per 100 parts by weight of the cement.

The above-mentioned ultrafine particle aggregate is contained in the inorganic aggregate in a proportion of 1 to 20% by weight. 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. Furthermore, if the amount of the ultrafine aggregate is too small, the voids in the resulting molded product will become large, resulting in a decrease in strength. On the other hand, if it is excessive, the amount of mixed water increases to ensure fluidity suitable for extrusion molding, resulting in a decrease in strength.

Reinforcing fibers are used to improve the bending strength and impact strength of the resulting molded product. For example, organic fibers, pulp, fibrous wallasnite, etc. can be used. As an organic fiber material.

Alkali-resistant materials such as vinylon, polypropylene, polyethylene, acrylic resin, aramid, polyester, and carbon are suitable. The diameter of the reinforcing fiber is 1 to 100
The suitable fiber length is 3 to 20 μm. The reinforcing fibers are contained in the composition in an amount of 0.2 to 10 parts by weight per 100 parts by weight of cement.

If the amount of reinforcing fibers is too small, the strength of the resulting molded product will decrease. 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 resulting molded product.

The cellulose-based admixture is used for the purpose of imparting a certain degree of viscosity and improving fluidity when extruding the composition. As the cellulose-based admixture, methylcellulose, hydroxyethylcellulose, etc. are preferably used. The cellulose-based admixture is contained in the composition in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of cement. If the amount is too small, the viscosity of the composition will be low, while if it is too large, the viscosity will be high, resulting in poor moldability.

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 cement and inorganic aggregate.

Tri-blend the reinforcing fibers and cellulosic admixture. 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. (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 flowability in the extruder,
The flow rate becomes uniform and the extruded uncured molded product has sufficient shape retention until curing progresses. These good properties are due to the fact that: - Among the inorganic aggregates in the cement composition, spherical aggregates exhibit a bearing effect under pressure; This is thought to be mainly due to the fact that the material 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 molding can be easily performed without requiring a dehydration step.

The extruded uncured molded product has good shape retention and does not deform before it hardens. Since the obtained cured molded product contains reinforcing fibers, the molded product has sufficient strength and impact resistance. Such molded bodies are suitably used as flooring materials for houses.

According to the present invention, a high-strength cement molded body suitable for flooring 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.

(Example) The present invention will be explained below using examples.

(8) Preparation of a plastic kneaded product: The components of the cement composition of the above formulation other than water were placed in a mixer (Eirich Mixer; Japan Eirich Co., Ltd. eA) and mixed for 2 minutes at 11,000 rpm. Add water to this,
After mixing at 800 rpm for about 1 minute, the mixture was sufficiently kneaded using an auger kneader (MP-100 model; manufactured by Miyazaki Iron Works Co., Ltd.) to obtain a plastic kneaded product.

(B)-1 Preparation of flat cement molded product: The kneaded material obtained in section (8) was processed using a vacuum extrusion molding machine ( MV-F
M-A-1; manufactured by Miyazaki Tekko Co., Ltd.) hopper.

A flat sample having a width of 250 mm, a thickness of 15 mm, and a length of 50 crn 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 6
The length (cm/m1n) discharged in 0 seconds was measured and calculated using a quadratic formula.

T: Extrusion amount per unit time (f/l+r) α: Cross-sectional area of mold exit (cffl) β: Length of extruded flat sample (cm/min) The above uncured molded body was kept at room temperature for 5 hours. After leaving it (preface) at
It was held in an atmosphere of 50'C and R1195% or more for 12 hours (first curing), and then immersed in water at 20°C for about 4 weeks.

(B)-2 Preparation of a molded body having an Ω-shaped cross section; As shown in FIG. A mold having an outer mold 12 in which a recessed groove 12a into which the upper portion fits was disposed along the longitudinal direction was prepared. The widthwise dimension of the top surface of the protrusion of this inner mold 11 is 7 cm, the widthwise dimension of the bottom surface is 9cm, and the height is 5cm. The width direction dimension of the opening of the concave groove part of the outer mold 12 is 115 cm, the width direction dimension of the inner deep part is 9.5 cm,
And the depth is 5cm. Separately, (B)- was extrusion molded in the same manner as in Section 2.
5cm x 1.5cm x 35cm) was obtained. As shown in FIG. 1(a), this uncured long plate-shaped cement molded body 3 is placed on a pair of support plates 21 and 22 facing each other across the protrusion of the inner mold 11 in the width direction. Each side is placed s12, and as shown in FIG. 1(b), press (
(pressure 10 kg/cJ, 10 seconds), an uncured molded body 30 having an Ω-shaped cross section as shown in FIG. 1(C) was obtained.

This uncured molded body was cured according to Section (B)-1.

As shown in 2nd [1(a) and (b), a cured molded body 31 having a concave portion projecting upward was obtained.

Performance evaluation of (C)-1 molded product: Cut the immersed sample obtained in section (B)-1 into 25 mm width and 240 mm length (cut perpendicular to the extrusion direction) L, gear at 105°C After drying in an oven for about 48 hours, it was allowed to cool to room temperature. This sample was supported at intervals of 200 mm, and an autograph (manufactured by Shimadzu Corporation) was used in the center.

Bending strength was measured by applying force at a bending speed of 2.5 mm/min (bending strength test). Separately, put the sample after soaking into a width 2
It was cut into pieces of 50 mm and length 250 mm (cut perpendicular to the extrusion direction) and subjected to oven treatment in the same manner as above. Place this sample on flat river sand.

A 1 kg steel ball was dropped onto the center of the sample from a height of 2 m, and it was observed whether any abnormalities were observed in the sample (impact strength test). The results of each test are shown in the table below.

(Performance evaluation of CL2 molded body: (B) The cured molded body 31 obtained in Section 2 was cut into a length of 30 cm perpendicular to the longitudinal direction, and the depth of the recess was ) was measured using calipers.The results are shown in the table below.

The procedure was the same as in Example 1 except that the amount of fly ash was 30 parts by weight, the amount of microsilica was 5 parts by weight, and the amount of water was 32 parts by weight.

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

Implementation ±1 The amount of microsilica was 5 parts by weight, and the amount of water was 3 parts by weight.
5 parts by weight, and further used 1 part by weight of polypropylene fibers (diameter 43 μm, length 1Q mm) as reinforcing fibers.

The same as Example 1 except that the amount of microsilica was 2 parts by weight, the amount of water was 38 parts by weight, and 1 part by weight of polypropylene fiber was used.

, Comparison 2 Comparison - Example'' - Same as Example 1 except that no microsilica was used.

The amount of micro silica is 50% without using coal fly ash.
Extrusion molding was attempted in the same manner as in Example 1 except that the amount of water was 35 parts by weight.

However, it generated heat in the extruder and solidified, clogging the mold and making molding impossible.

(Leaving space below) From the table, it can be seen that when using the composition of the present invention, a cement molded product can be obtained by extrusion molding.The obtained uncured molded product has excellent shape retention and hardened The molded product obtained by this process has excellent bending strength and impact resistance.Because it is hydrated, it does not deform even when immersed in water for a long period of time.

(Effects of the Invention) According to the present invention, a cement molded body having high strength and excellent impact resistance can be obtained by extrusion molding with good moldability and high efficiency. Such a cement molded body is suitably used as a flooring material such as a decking material or a flooring material for an apartment complex. Since it does not contain asbestos, there is no risk of cancer caused by asbestos dust either during the manufacturing process or during use.

4. ``Simple day'' Figures 1 (a) to (C) 2 are explanations showing an example of the process of press working an uncured long plate-shaped cement molded body obtained by extrusion molding using the present invention. 2, and FIGS. 2(a) and 2(b) are a perspective view and a sectional view of a cement molded body having an Ω-shaped cross section obtained by the press working.

3... Uncured long plate-shaped cement molded body, 30... Ω-shaped cross-section cement molded body.

that's all

Claims (1)

[Scope of Claims] 1. A cement composition containing cement, inorganic aggregate, reinforcing fibers, and a cellulose admixture, wherein the inorganic aggregate is mainly composed of spherical aggregate with a particle size of 1 to 100 μm, Particle size 0
．． A cement composition containing ultrafine aggregate of 01 to 1 μm. 2. 5 to 5 parts of inorganic aggregate per 100 parts by weight of the cement
Contained in a proportion of 100 parts by weight, 1 to 20 parts of the inorganic aggregate
Claim 1, wherein the weight % is the ultrafine particle aggregate.
The composition described in Section.