JPS61168558A - Formation of fiber reinforced cementitious matter - 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] (Industrial Application Field) The present invention is directed to a method for forming fiber-reinforced cementitious materials, particularly to an early forming method for alkali-resistant glass fiber-reinforced cement materials containing alumina cement as the main component. This is related.

(Prior art) When molding cement products, it takes a long time for the product to solidify and harden, making it difficult for the mold to rotate, which has a significant impact on productivity. Various studies have been conducted on whether cement products themselves can maintain their shape even if their strength is low.

On the other hand, regarding various cementitious substances, alumina cement is known as an early-strengthening cement as one of its characteristics, and it hardens and develops strength in a shorter time than other hydraulic substances such as Portland cement. It is widely used for various purposes (for example, urgent construction work).

(Problems to be solved by the invention) However, even in such alumina cement,
When molding this into a predetermined shape or continuously extruding it to obtain various and large numbers of products, early curing properties are still insufficient. Various extrusion products reinforced with alkali-resistant glass fibers are industrially useful, and the rotational speed of the mold used therein has a significant impact on productivity.

(Means for Solving the Problems) In view of the above, the present inventor conducted various studies and examinations with the aim of curing alumina cement materials containing alkali-resistant glass fibers as early as possible, and found that these raw materials It has been found that the above object can be achieved by molding under specific conditions in a mold.

Thus, the present invention uses sand and alumina cement.

To provide a method for molding a fiber-reinforced cementitious material, which comprises kneading a cementitious material containing alkali-resistant glass fiber as a main component and then molding the material under pressure in a mold heated to a temperature of 80 to 130°C. be.

In the present invention, it is important that the blended and kneaded cementitious material is molded under pressure in a mold maintained at a predetermined temperature.

In order to make alumina cement that does not contain fibers harden quickly, this purpose can be achieved by keeping it at a certain temperature.
Can develop sufficient strength.

However, when fibers are mixed into alumina cement, if the temperature is maintained at a predetermined temperature during molding and no pressure is applied, the hardening itself will progress sufficiently quickly, but the strength will not be developed sufficiently, which is not desirable in practice. It was found that there is no.

Thus, in the present invention, the pressure applied during molding is generally 5 to 100 kg/cm2 in press molding,
Preferably, it is 10 to 100 kg/cm2, and in extrusion molding, it is appropriate to use about 3 to 30 kg/cm2.

Further, the temperature during molding must be 80 to 130°C.

Alumina cement sets and hardens quickly at temperatures above 30°C, but at temperatures below 80°C, it is not possible to demold the mold within a few minutes, and metastasis occurs later, which causes a decrease in strength. On the other hand, if the temperature exceeds 130°C, especially above 150°C, the molded product may be destroyed or deformed due to instantaneous evaporation of the water contained during molding, and its strength will also decrease. Appropriate.

As for the mixing ratio used in the present invention, it is appropriate to adopt an alumina cement sand ratio of 9 = 1 to 3, preferably 3:1 to 2:1, and a water cement ratio of about 20 to 30%. .

In addition, the form of the alkali-resistant glass fiber used is as follows:
Filament, strand, roving, cut products, twisted products, aggregates, collected waste products, etc. of these can be used, and from the viewpoint of strength, strands are preferable.

Rovings and processed products thereof are preferable, and considering the productivity of the molded product and the surface properties such as fluff, etc., it is 5 to 10.
It is appropriate to use chopped strands cut to about 0.0 cm layer length. In addition, the amount used is 1 to 1 per molded product.
10% by weight, preferably 2-8% by weight is suitable.

Further, in the present invention, other components such as ordinary Portland cement and thickeners may be used as appropriate as long as they do not impede the purpose of the present invention.

(Example) In the following examples, the composition shown in the table below was used as alumina cement, and Bayer alumina and quicklime were melted by heating in an electric furnace, and then cooled and re-solidified.

Blaine value of alumina cement shown in the table above 400C■2
Mix 2 parts of 7g with 1 part of sand at W/C = 30%, then fill the mold with mortar with 5iai of alkali-resistant glass added to make it 3% of the total, heat, and press mold. The zero strength was measured after curing by heating and curing at room temperature.

It is understood that these can be immediately removed from the mold and can be handled at a sufficiently early stage, so that productivity can be increased accordingly.

Claims (1)

[Claims] 1. After kneading cementitious material containing sand, alumina cement, and alkali-resistant glass fiber as main components, the temperature is 80-1.
A method for molding a fiber-reinforced cementitious material, which comprises molding under pressure in a mold heated to 30°C.