JPS58130181A - Manufacture of lightweight foamed concrete - 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 producing lightweight cellular concrete, more specifically, lightweight cellular concrete (hereinafter abbreviated as ALC) produced by high temperature and high pressure steam curing (autoclave! raw).
The present invention relates to a method for improving water resistance without impairing strength development.

Conventionally, concrete is prepared by mixing A'LC [main materials such as cement or lime and silica powder] with lightweight aggregate as desired, and mixing air bubbles with metal powder, foaming agent, etc. It is manufactured by molding and curing in an autoclave. Although ALC has the advantages of being lightweight, insulating, and easy to install, it has high water absorption and poor freeze-thaw resistance, and has many pores and is brittle. The steel layer had the disadvantage of being weak in strength, easily chipping, and having low impact resistance.

To improve this 1. Methods have been proposed in which a water repellent containing silicone as a main component is added to a concrete mixture as a raw material, or it is applied to a molded body after being cured in an autoclave. However, with the former method, it is not possible to sufficiently strengthen the pores and the paste layer, and moreover, a large amount of mixture is required to obtain a waterproof effect, resulting in unstable air bubbles and poor strength development. . On the other hand, according to the latter,
Although the former drawback can be alleviated, there are difficulties in integrating the water repellent agent with the ALO body, and it can peel off even with the slightest impact or deteriorate outdoors, impairing its waterproof performance. There's a problem.

As a result of intensive research to solve these problems associated with the use of water repellents, the present inventor found that if a mortar layer containing all silicone resin is formed in advance on the surface of a concrete molded body to be cured in an autoclave, the surface The present invention has been completed by discovering that it is possible to produce ALC with high strength and excellent water resistance. Namely, the present invention involves curing a foam-containing concrete molded body with high-temperature, high-pressure steam to produce lightweight foamed concrete. In the manufacturing method, a special feature is to form a mortar layer containing a silicone resin on the surface of the foam-containing concrete molding, and then to perform high-temperature and high-pressure steam curing.

The present invention will be explained in detail below.

In the present invention, a concrete molded body containing air bubbles is a molded body that has not yet begun to harden, such as when a concrete mixture containing air bubbles is poured into a formwork, or a molded body that has already begun to set and harden. The metal is then cut into the desired shape using piano wire, etc., if necessary. Such aerated concrete formulations are conventionally prepared by adding foam to an aqueous slurry containing a calcareous material consisting of cement and/or lime and a siliceous powder that reacts with the lime content by autoclave curing. It can be manufactured by mixing air bubbles by a method such as a mixing foam method, a mix foam method, or a preform method. This aerated concrete formulation may have some or all of the air bubbles as lightweight aggregate.

This mixture is shaped into a desired shape, and after the foam-containing concrete molding is sealed, a mortar layer containing a silicone resin is formed on the surface of the molded concrete.

As a method for forming a mortar layer containing silicone resin, for foam-containing concrete moldings that have not yet begun to harden, a method can be adopted in which silicone resin is applied and defoamed; For concrete moldings, commonly used methods include applying cement mortar containing silicone resin with a trowel or spray painting, or applying silicone resin to the surface of the foam molding in advance and then painting the surface. A method such as crushing with a roller or the like to form a mortar layer is employed, and there are no particular restrictions on these methods.

In the latter case, when a mortar layer is formed on a molded product that has begun to set and harden, the molded product has shape retention properties.
Specifically (ri, compressive strength 1 to 3 to 4f/
It is desirable to form a mortar layer containing a silicone resin after developing a temperature of about m''.

In addition, when using cement mortar to which silicone resin has been added, an example of its formulation is: 30 to 300 parts by weight of silica powder, 50 to 2 parts by weight of water, and 100 parts by weight of cement.
1 to 20 parts by weight of silicone resin is applied to 100 parts of cement mortar made of 0.00 parts by weight, and in the method of applying silicone resin, a mortar layer consisting of approximately such a ratio is formed. You can apply silicone resin to it.

The mortar layer containing silicone resin is formed by filling and smoothing the Japanese boat-like surface of the foam-containing concrete molding, and carefully applying the silicone resin to a thickness that spreads over the entire surface. It is about 0.3 to 10 wins.

As the silicone resin, general silicone oils are sufficient, and specific examples include dimethylsiloxane oil, methylphenylsiloxane oil, methylhydrogensiloxane oil, methylsilicone varnish, phenylmethylsilicone varnish, or these varnishes. These include metamorphosed substances and their emulsions. As modified silicone resins, copolymers and blends with monomers and polymers such as epoxy, acrylic, melamine, and phenol can be used.

Next, autoclave curing can use general conditions, usually at a pressure of 10 Kg/crn2 and a temperature of 180°.
Saturated vapor of C is used, but is not particularly limited.

The ALC produced according to the present invention has the following effects: very little water permeation, excellent water resistance and freeze-thaw resistance, and significantly improved surface strength, making it difficult to see any defects.

The present invention will be explained in more detail by referring to examples below.Example-1 60 parts by weight of water was mixed with 45 weight - 1 tt43 ordinary portlancia cement and 55 parts by weight of silica powder and stirred to form a slurry. The product name [[
:: Bubbles were mixed into the mixture using Toohmix cllJ (manufactured by Hamano Kogyo ■) to give a volume weight of 0-7 g/cc, which was poured into a 10×10×40 crn mold, and after one day, the mold was removed to obtain a foam-containing concrete molded body. On the surface of the molded body, pre-manufactured ordinary poldraceite cement 10
0 parts by weight, silica powder 3 [) 0 parts by weight, silicone oil Product name [Toreshi'I]: J-N B H2O0-15
0fs: Mortar consisting of a mounting part and 10,000 weight of water was coated to a thickness of 1 light phase to form a smooth surface, then transferred to an autoclave, heated to 4 c'c/hT・, maximum pressure 10
After that, steam curing was performed for 8 hours at a temperature of 180°C.

obtained; the waterproof performance of fi ALC (8, 10
The total weight of the specimen of ×10×ΔOm was immersed in water to a depth of 2 m below the water surface and left for 24 hours.The weight increase due to moisture absorption was measured and found to be 0.9% by weight.

For comparison, ALC was manufactured by forming a mortar layer containing silicone oil, and 200% of the mortar layer was formed on the surface of the ALC. /l
N2 silicone oil? When the coating was applied and a similar test was conducted, the weight increase was 10% by weight. In addition, the weight increase of products not treated with silicone oil is 20% by weight.
It is.

Next, freeze-thaw resistance was tested in accordance with ASTM-C-666 by freezing in water and thawing in water (2 cycles of -18°C to +5°C on the 21st).
In the comparison product, the silicone oil layer peeled off from the ALO body after 50 cycles, and the chips fell off and cracks appeared.
The appearance of the ALC according to the invention was almost unchanged and had a very hard surface.

Example-2 After applying silicone oil (trade name: Toray Silicone S H200J t 350 N/m2) to the surface of a foam-containing concrete molded body produced in the same manner as in Example-1,
After crushing this surface with a roller to form a mortar layer, the same autoclave curing is performed and the ALC
was manufactured. When we conducted a water absorption test, it was 1.1%.
However, no abnormality was observed in the 50-cycle freeze-thaw test.

Patent applicant: Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] A method of curing a foam-containing concrete molding with high-temperature, high-pressure steam to produce a lightweight foamed concrete molding, which includes forming a mortar layer containing a silicone resin on the surface of the foam-containing concrete molding, and then curing with high-temperature, high-pressure steam. A manufacturing method for lightweight aerated concrete with excellent water resistance.