JPS6186480A - Manufacture of explosive crack-resistant cement product - 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 applications The present invention relates to a method for manufacturing blast-resistant cement products.

Problems with the Prior Art Seventh: When a ment product is heated rapidly, the moisture contained in the base material evaporates, resulting in a significant increase in volume. in this case,
Without an escape route for the water vapor, the internal pressure would rise rapidly, reaching a pressure of, for example, 90 ka/ci at 300° C., which would cause the cement product to explode. This explosion is not only extremely dangerous, but also unfavorable from a fire safety perspective.

This explosion is caused by the ease with which water vapor can be removed from cement products, i.e.
It is known that there is a close relationship with the diameter of pores formed within the structure of a cement product, and that the resistance to passage of water vapor is inversely proportional to the square of the pore diameter.

Therefore, as a means to prevent the explosion of cement products, methods include roughening the internal structure of cement products to create pores, or mixing combustible substances into the structure to make it easier for water vapor to escape when heated. is considered. However, the former method has problems such as sacrificing the bonding strength of the tissue, resulting in a decrease in product strength and poor waterproofness.
In the latter case, the flame retardance of the cement product was sacrificed, and no matter how much the explosion resistance was improved, it was meaningless.

Problems to be Solved by the Invention In view of the above-mentioned problems, the present invention aims to provide a means for manufacturing explosion-resistant cement products that can exhibit sufficient flame retardancy without sacrificing product strength and waterproofness. It was made for the purpose of

The technology that led to solving the problem The method for producing a blast-resistant cement product of the present invention is to add at least 1% by weight or more to a cement mixture consisting of cement, fine aggregate, reinforcing fibers, etc. based on the cement mixture. The method is characterized in that particles of an inert substance reactive with cement are added in an amount that does not impair the strength of the molded product made of the cement mixture, and after homogeneous mixing, water is added and a cement product is molded by appropriate means. .

In the above, the seven-mention mixture consisting of cement, fine aggregate, reinforcing fibers, etc. means a conventionally commonly employed cement mixture, and there are no particular limitations on the thickness phase and amount of each of these.

Particles of substances that are inert to react with cement refer to particles that are made of substances that have little or no reaction with the cement matrix, such as calcium carbonate particles, zeolite particles, etc., as well as expanded shale,
Mention may be made of calcined particles of expanded shale or particles of anti-flinder foam. It should be noted that the particles are not limited to those mentioned above, and may be other particles as long as they are particles of a substance that is inactive to react with cement. For example, the particle surface may be coated with a substance that is inactive to react with cement.

In addition, the blending amount of the above particles is based on the entire cement mixture.
The content is at least 1% by weight.

This is because if the amount is less than 1% by weight, sufficient explosion resistance cannot be obtained.

In addition, it is natural that the upper limit of the amount of the above-mentioned particles is set at an amount that does not impair the strength of the molded product, but the specific numerical value is related to the particle size of the particles, the expansion rate of the particles, etc. Although it cannot be said for certain, it is generally about 5% by weight based on the total amount of the cement mixture.

However, regarding particle size, manufacturing method, particle morphology,
In relation to specific gravity, - although it cannot be said generally, the particle size is approximately 4.7.
For example, in the case of calcium carbonate particles, the average particle size should be 2.4 m or less, in the case of zeolite particles, it should be 4.7 m or less, and for other foamed particles, the average particle size should be 4.7 m or less, similar to zeolite particles. is suitable.

The molding process for the cement product in the present invention is not particularly limited and may be any conventionally known dry method, paper forming method, casting method, or the like.

Function Generally, in order to prevent the explosion of cement products, the pores that serve as a means for removing the necessary water vapor are required to be 1μ or more.
It is said that if the pores are smaller, almost no water vapor can move. Therefore, it is important to increase the number of pores of 1 μ or more in the cement structure.

In the present invention, the reactive inert particles added to the cement mixture have little or no reaction with the cement matrix I-1,1, so that the interface between the inert particles and the cement matrix is almost nonexistent. They do not adhere closely, and gaps are formed around the particles. This gap provides a way for water vapor to escape, which helps prevent explosions.

Furthermore, in order to reduce the adhesion between reactive inert material particles and the cement matrix, when autoclave curing is used to cure cement molded products, the temperature and pressure conditions are set low to reduce the reactivity with the cement matrix. It is also preferable to make it low.

Example Next, embodiments of this invention will be described.

From the cement mixture of the following composition, the thickness is 5. The length and width are both 5.
Five plate-shaped products of 00 city were formed by press molding, and autoclave curing was performed under the conditions shown in the table. Note that A in the table below is a blank, and the reaction inert material particles are completely small (Q).

A (blank) B Cl)
E F silicon sand 40M
jlk'? o 40', A amount OO4n weight% 4
0 weight% 40 weight% 40 weight% cement 40I40
I+ 40# 40# 40# 40# Asbestos 5# 5n 5#
5# 5++ 5*Valve 5# 5#
5# 5# 5# 5y perlite 10++1
0 〆+ 10# lo# lOn
Lo# Five plates of each of the above A NF were placed above a flame in a horizontal furnace with temperature conditions set at 925° C. - A seat tear test was conducted.

The results were as shown in the table below.

A (Plankun BCDEF 5 H splits x & OOO.

Part of the surface is cracked 0 2 modified 2 pieces 0
0 3 sheets different None 0 2 sheets 3 sheets 5th 5 sheets 2 sheets As is clear from the results in the table above, the explosion resistance of cement products containing particles that are inert to cement, such as calcium carbonate particles and zeolite particles, is It turned out to be very good.

Effects As explained above, this invention can significantly improve the explosion resistance of cement products by simply adding an inert substance that reacts with cement, so that explosion-resistant cement products can be easily and , can be manufactured at low cost, requires the addition of reactive inert material particles, and has the advantage of being highly versatile since it does not require any means of molding the cement product.

Claims (2)

[Claims] (1) A cement mixture consisting of cement, fine aggregate, reinforcing fibers, etc., is added to the cement mixture in an amount of at least 1% by weight or more based on the cement mixture, in an amount that does not impair the strength of the molded product made of the cement mixture. A method for producing an explosion-resistant cement product, which comprises adding particles of a reactive inert substance, uniformly mixing them, adding water, and then forming the cement product by an appropriate means. (2) Manufacture of explosion-resistant cement products in which the inert material particles are calcium carbonate particles, zeolite particles, expanded shale, fired particles of expanded shale, particles made of anti-firestone foam, or mixed particles of two or more of these. Method.