JPS6047233B2 - Cellular concrete and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cellular concrete, and more particularly to a method for producing cellular concrete with low drying shrinkage.

Aerated concrete is widely used as a building material for walls, floors, roofs, etc., as well as various heat insulating materials. Conventionally, this aerated concrete is made by mixing metal aluminum powder into a slurry of a finely pulverized mixture of silicic acid raw materials such as silica and calcareous raw materials such as quicklime, slaked lime, and cement, and foaming the resulting reaction product. After that, it was cut into a suitable shape and further heated in an autoclave at 91 dG, about 18
It is obtained by performing high-temperature, high-pressure steam curing at 0°C to cause a hydrothermal reaction between the silicic acid raw material and the calcareous raw material. The resulting product becomes porous, just like natural pumice, due to the foaming action of the metallic aluminum powder, and its structure is that of tobermolite, which is extremely stable mineralogically and is obtained through the reaction of silica and lime. It has a cell structure with crystals as the main bond and material. The cell walls of this cell structure are usually less than a few times thick and have weak resistance to external forces, and the drying shrinkage of the product at room temperature is about 1/2 of that of concrete. There is a demand for the appearance of large aerated concrete structures. As a result of research aimed at providing such aerated concrete, the present inventor found that when alumina-containing minerals such as kaolinite and halloysite are heat-treated at high temperatures, their activity becomes high, and that they are combined with calcareous raw materials 5 and silicic acid raw materials. The present invention was completed based on the knowledge that aluminum tobermolite is produced in the reaction product by reacting it with a slurry made of aluminum under high temperature and pressure, and the drying shrinkage of the resulting aerated concrete is reduced.

The gist of the present invention is to add clay minerals or activated high alumina minerals activated by heat treatment at high temperatures to a mixture of silicic acid raw materials, calcareous raw materials, metal aluminum powder and water, There is a method for producing aerated concrete, which is characterized by its ability to produce concrete.

Clay minerals include kaolinite, halloysite, birophyllite, montmorillonite, and allofene, and hyaluminous minerals include bauxite.

Activation of this clay mineral or high alumina mineral is obtained by calcining it at 500-800° C. for 1-5 hours.

Silicate raw materials include silica stone, ores containing large amounts of silicic acid, and fly ash, and calcareous raw materials include quicklime, slaked lime, cement, etc., as shown in JLSA54L6R autoclave-cured lightweight aerated concrete products. Raw materials are used.

The blending ratio of silicic acid raw materials with calcareous raw materials should be such that the molar ratio of silica in all charged raw materials to calcium oxide components in all charged raw materials is approximately 2:1 to 1:1. be done. The amount of calcined clay mineral or calcined high alumina mineral is 1% to 2% based on the charged silicic acid raw material, preferably 1% to 2% based on various properties such as compressive strength and bending strength of the product.
Preferably, it is l call volume%.

High temperature and high pressure steam curing is carried out in an autoclave.
At that time, the temperature is at least 160°C and the pressure is 7k9.
It is IcIiG. According to the present invention, Si in calcium silicate hydrate produced by a hydrothermal reaction is partially substituted with N and dissolved as a solid solution, and as a result, aluminum tobermolite with good crystallinity is produced. Therefore, the drying shrinkage of the product is reduced, and in practical use, various properties such as bending strength and compressive strength are not impaired.

Therefore, since the aerated concrete obtained by the method of the present invention has greatly improved drying shrinkage at room temperature,
The occurrence of cracks due to drying shrinkage after construction is suppressed, and the durability of the construction material can be improved. Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Examples 1 to 4, Comparative Example 1 Pyrofluorite (Al, O
82l. 6%, SlO272.6%) and 60
It was calcined at 0°C for 3 hours.

This calcined pyrofluorite, silica stone (Ig・10ss1
．． 9%, SlO292. O%, MgOO. 3%, Al,
O3 4.2%, Fe2O3l. 2%) and quicklime (Ig
・IOSSI. 34%, SiO, l. 48%, CaO9
5.33%, R2O3O. 66%, MgOl. OO%)
and metal aluminum powder in the proportions shown in Table 1, and the resulting mixed compositions were steam-cured in an autoclave at 8k91dG at 175°C for 10 hours. The drying shrinkage of the obtained product was measured and the results were
Shown in the table. Examples 5 to 8, Comparative Example 2 A120345.1%, SlO25l. 1%, Fe2O
3l. 9%, MgOl. Halloysite having a composition of 9% was calcined at 700''C for 5 hours, and the calcined body obtained was mixed with silica, quicklime, and metallic aluminum powder in the proportions shown in Table 2, and the resulting mixture was mixed. 8k91 each
dG1175°C and steam curing for 1 hour.

The drying shrinkage of the obtained products was measured according to Examples 1 to 4, and the results are shown in Table 2. Examples 9-13. Comparative Example 3 Hawksite (Al2O377.3%, SlO2l6.
6%, Fe2O3 2.7%) was calcined at 800°C for 3 hours.

This calcined body was mixed with silica stone, quicklime, and metallic aluminum powder in the proportions shown in Table 3, and the resulting mixture was:
(8 kgIcItG each in an autoclave)
Steam curing was performed at 1175°C for an hour. The drying shrinkage of each of the obtained products was measured according to Examples 1 to 4, and the results are shown in Table 3. As is clear from Tables 1, 2, and 3, when producing aerated concrete by adding foaming agents such as silicic acid raw materials, calcareous raw materials, and metal aluminum powder and performing high-temperature and high-pressure steam curing, It was found that when clay minerals or high alumina minerals activated by calcining were added to raw material No. 5, the drying shrinkage of the resulting aerated concrete was reduced.

Claims (1)

[Claims] 1. 500 to 80% in the mixture of silicic acid raw material and calcareous raw material
A method for producing cellular concrete, which comprises adding clay minerals or activated high alumina minerals activated by heat treatment at 0°C, further adding metallic aluminum powder as a foaming agent, and curing with steam. 2. The method for producing aerated concrete according to claim 1, wherein clay minerals or high alumina minerals are activated by calcining for 1 to 5 hours. 3. Cells according to claims 1 and 2, which contain activated clay minerals or activated high alumina minerals in an amount of 1 to 20% by weight, preferably 1 to 10% by weight, based on the silicic acid raw material. Concrete manufacturing method. 4 High temperature and high pressure steam curing at least 160℃, 7kg
Claim 1: Conducting in saturated steam of /cm^2
A method for producing aerated concrete according to items 3 to 3. 5 Aerated concrete consisting of foamed hydrated calcium silicate containing aluminum tobermolat.