JPS5826058A - Manufacture of construction board - 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 The present invention relates to a method for manufacturing a construction board with excellent frost damage resistance,
A method of making raw boards by making a slurry containing ordinary Portland cement, blast furnace scraps, gypsum, and inorganic fibers, then curing the raw boards under heat, immersing them in water, and then naturally curing them indoors. *Regarding the manufacturing method of architectural board using mold.

Conventionally, various studies have been made to produce construction materials with excellent frost damage resistance, such as roof tiles for snow-covered areas. One method is to make paper from a slurry containing cement and inorganic fibers, then press the green board at a high pressure of 50 CIP/cd or higher to compress the internal structure to a high density and improve frost resistance. However, this method suffers from the drawbacks of low productivity due to high-pressure pressing and increased cost. The first and other methods include pressure-forming with an extremely small amount of water needed to hydrate the cement components when forming green boards, and then curing them in an autoclave to replenish water and harden them. This method has the disadvantage that when the architectural boards are subjected to freezing and thawing action, their mechanical strength is significantly reduced.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for manufacturing a construction board that has excellent frost damage resistance, high mechanical strength, and excellent productivity. I'll go.

Below is the original Fi4f! -Explain in detail. The slurry is usually formed by dispersing Portland cement, blast furnace slag powder, gypsum, and inorganic fibers in water, and the blended blast furnace slurry powder has a fineness of plain 4000 to soo.

It is preferable to use The mixing ratio of ordinary Portland cement and blast furnace slurry powder is 30 to 801 parts of ordinary Portland cement to 2 parts of blast furnace slurry powder.
It is preferable that the proportion of 0 to 1 liter is preferably 0 to 70 parts by weight, and the blast furnace slurry powder 1001 is preferably made of dihydrate.
[2 to 5] 1 part by weight is added to ili part. Asbestos or the like can be used as the inorganic fiber, and the above-mentioned mixture of ordinary Portland cement, blast furnace slag powder, and gypsum 1
It is preferable to mix 10 to 30 parts by weight based on 00311. A green board is prepared by dispersing the above-mentioned composition in water and forming a slurry according to a conventional method. Next, a pressure of 5'0 to 100 KP/- is applied to this raw board to compress and dehydrate it, and then the raw board is left for 6 to 12 hours in an atmosphere of 40 to 70 degrees Celsius and 90 degrees RH for moist heat curing. Do this. Next, 10
After immersing in VC water at ~25°C for 10 to 30 minutes, the specimens are left indoors for 21 to 28 days for natural curing. After curing, the hydration reaction of ordinary Portland cement is hindered when the surface and edges are painted to obtain a building board, but by adding gypsum to this, ordinary Portland cement The hydration of gold is something that can be easily done. However, by blending blast furnace slurry powder, the mechanical strength of the resulting construction board can be increased, and the construction board can be used in cold areas and undergo freezing and thawing. This increases the resistance to expansion pressure when water that permeates inside the board turns into ice. In addition, a similar effect can be obtained when manufacturing boards for construction by immersing them in water, and the diameter of the pores inside the boards become smaller due to immersion in water, increasing the frost damage resistance of the boards. It is something that can be done.

In accordance with the above 1, the present invention involves making a green board by making a slurry containing ordinary Portland cement, blast furnace slurry powder, gypsum, and inorganic fibers, then curing the green board with moist heat, then immersing it in water, and then indoors. Because of natural curing, the mechanical strength of the building board can be increased by adding blast furnace slurry powder, and the resistance to expansion pressure when water that permeates into the building board turns into ice can be increased. It can improve the frost damage resistance of construction boards, and at the same time, the addition of gypsum prevents the hydration of ordinary Portland cement from being hindered by the distribution of blast furnace slurry powder, and allows high-pressure pressing without any problems. Architectural boards with excellent frost damage resistance can be produced without the need for using this method.

The present invention will be explained below in detail based on Examples (Example) Green board made by blending 40 parts by weight of blast furnace slag powder with 60 parts by weight of ordinary Portland cement, and blending asbestos and stone f. It was cured under moist heat, then immersed in water, and then naturally cured indoors to obtain an asbestos cement board.

Comparative Example 1 An asbestos cement board was obtained in the same manner as in Example, except that ordinary Portland cement was used instead of blast furnace slag powder.

Comparative Example 2> Nine green boards were cured without being immersed in water, and nine asbestos cement boards were obtained in the same manner as in the example.

<Comparative Example 3> Pressurize the raw board with extremely less water required for hydration,
The nine pieces were cured in an autoclave while replenishing moisture, and the asbestos cement plates were made into asbestos cement plates in the same manner as in the example.

The bending strength of the asbestos cement boards of Example and Comparative Example 1 was measured by changing the material age of the asbestos cement boards, and the results are shown in Table 1.

In addition, the bending strength in the longitudinal direction was measured by adding the bending strength in a direction perpendicular to the papermaking direction, and the bending strength in the lateral direction was measured by adding the bending strength parallel to the papermaking direction. In this case, there is no difference in bending strength depending on the presence or absence of blast furnace sludge powder, but as the age of the material increases, the bending strength of the asbestos cement of Example, which is a blended product of blast furnace sludge powder, increases.

Next, the age of the asbestos cement boards of Example and Comparative Example 2 was varied, and each asbestos cement board was immersed in water for 611 hours, and the bending strength of the asbestos cement board when saturated with water was measured. The results are shown in Table 2. Table 2 Asbestos cement boards obtained by immersing green boards in water have a faster increase in strength and are more resistant to frost damage.

Examples and Comparative Examples 1 to 30 Asbestos cement board tASTM
The results of the frost damage resistance test according to the C666A method are shown in Table 3.

Table 3 As shown in the above table, the asbestos cement board of the example was tested for frost damage resistance test 3.
No change in appearance was observed even in 00 cycle flk,
There was no decrease in strength.

Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] (1) Making green boards by paper-making a slurry containing ordinary Portland cement, blast furnace slurry powder, gypsum, and inorganic fibers, then curing the green boards under heat, immersing them in water, and then naturally curing them indoors. *Method for manufacturing fine architectural boards.