JPH03285878A - Production of lightweight concrete board - Google Patents

Abstract

PURPOSE:To stably produce a lightweight inorg. material having internal cavities by blending a cement-based binder with granules of a foamed thermoplastic resin, hardening the blend in a molding flask and shrinking or subliming the resin by heating. CONSTITUTION:A cement-based binder is blended with a prescribed amt. of granules or chips of a foamed thermoplastic resin such as styrene foam and this blend is poured into a shallow tray-shaped molding flask and taken out of the molding flask in a hardened or semihardened state. Heat treatment is then carried out at a temp. at which the resin melts, shrinks or sublimes and the cement-based binder hardens properly and cavities are formed in the resulting concrete to obtain a lightweight concrete board. Since this board is not produced by foaming, the surface can be made smooth without any more treatment.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing lightweight concrete plates, particularly for use as construction materials such as various building materials such as ceiling materials, wall materials, and floor materials, or road materials. The present invention relates to a method for manufacturing lightweight concrete plates suitable for

[Conventional technology]

ALC is generally used for exterior walls and flooring of condominiums and houses.
The outline of the manufacturing method of aerated concrete, which is marketed under the name of , is as follows. That is, silica stone, quicklime, aluminum powder, water, and chemicals such as water reducing agents and retardants are blended and mixed as necessary, and then poured into a mold and foamed. Next, after demolding, it is sliced into appropriate sizes and cured with high temperature and high pressure steam in an autoclave. This ALC is already on the market from many manufacturers.

Another method for reducing the weight of concrete is to mix styrene foam into cement, an example of which is disclosed in Japanese Patent Laid-Open No. 53-9825. This method is effective for cast-in-place concrete. In addition, as a manufacturing method for lightweight concrete blocks, Japanese Patent Application Laid-Open No. 62-4178
There is number 2.

[Problem to be solved by the invention]

Conventional lightweight concrete is produced using the above-mentioned manufacturing method, so there are many air bubbles on the surface, the surface is not smooth, and when the surface is painted, paint absorption becomes a problem. When using a foaming agent to reduce weight, experience is required to control the foam, and modifications must be made for molding after curing or semi-curing. In ALC, since autoclaving is performed after processing into a predetermined shape, it may take time and effort to finish the final product. Furthermore, since such a manufacturing process is followed, it is difficult to produce a multilayered plate material that aims to improve the strength and finish of the product. When manufacturing multilayer board materials, when a foaming agent is used, the material is multi-layered after foaming, resulting in a difference in the curing stage and a decrease in the strength of the interface between a layer with bubbles and a relatively dense layer without bubbles. It will be done.

Various studies have been conducted to solve these problems, but no clear effective means have been found. Therefore,
An object of the present invention is to provide an effective alternative means for producing lightweight inorganic materials having voids.

[Means to solve the problem]

The present inventors conducted research to solve the above-mentioned problems and discovered a method for producing a stable lightweight inorganic material more effectively without using a foaming agent such as aluminum powder.

That is, in the production of lightweight concrete boards, the present invention involves filling a cement-based binder with granules or pieces of foamed thermoplastic resin having a volume smaller than the total volume of the board, pouring into a shallow tray-shaped formwork, and adding cement to the concrete. In the curing process, the granules or pieces are allowed to float freely without restraint, and after hardening or semi-hardening, the resin is melted, shrunk or sublimated by heating, and cavities are formed inside the concrete. Regarding the method for producing a lightweight concrete plate, the method uses a heating method involving dry air, water vapor, a solvent vapor for dissolving a foamed thermoplastic resin, or a mixed vapor thereof as a heating method. be. The present invention will be explained in detail below.

First, the lightweight concrete board of the present invention has a thickness of 5 to 5.
The thickness is in the range of 20 mm, preferably 8 to 15 mm. A combination of cement-based binding materials is used to manufacture the boards.
For example, combinations such as cement and water, silica sand, quicklime, and water are prepared. A predetermined amount of foamed thermoplastic resin that melts at a constant temperature is added to this. A typical example of foamed thermoplastic resin is styrene foam. If expanded polystyrene is used, it preferably has a specific gravity of about 0.02 or more. The amount of granules to be added is determined depending on the degree of weight reduction required and the intended strength of the product.
．． It is preferable to add about 5 to 3%.

The amount of voids can be easily calculated from the volume of foamed thermoplastic resin added. In addition, the shape of the particles is not particularly important, but
Preferably, it has a diameter of about 2 to 5 IIIn. The size of the voids can be controlled simply by making the sizes of the particles uniform, so that voids with a stable shape can be easily managed.

During production, water reducing agents, retardants, etc. may be added for reasons of workability and strength.

Furthermore, reinforcing steel or fiber materials may be added during compounding in order to improve the overall strength.

After mixing each, pour into a shallow tray-shaped mold and take it out from the mold in a hardened or semi-hardened state, at a temperature at which the foamed thermoplastic resin melts or sublimates, and a temperature at which the cementitious binder hardens in just the right amount. heat treatment to obtain the desired product. Generally, the heating temperature is arbitrarily selected within the range of 130 to 220°C, and if pressurization is required, the heating temperature is
Apply 12 atmospheres. Heating methods include those using dry air, those involving water vapor, those involving vapor of a solvent capable of dissolving the foamed thermoplastic resin, and those using mixed vapor of water vapor and solvent vapor, and any of them may be used. The processing time is
The time is not particularly specified as long as the foamed thermoplastic resin is dissolved or sublimated and the cementitious binder is cured in just the right amount. When the granules reach their melting temperature, they melt, leaving voids where the granules were, and the resin forms a thin film around the voids or penetrates into the hardened cement material.

Since the lightweight concrete plate of the present invention is not manufactured by foaming with a foaming agent, it is easy to finish the surface smooth from the beginning.

If you want to make one side of the board smooth, pour a mixture of foamed thermoplastic resin and cementitious binder into a tray-shaped mold and let it stand. The bottom of the formwork becomes smooth and contains no air bubbles. If the fluidity of the foamed thermoplastic resin and cementitious binder mixture is controlled, the thickness of the bubble-free layer at the bottom of the formwork can be controlled, and the thickness of the foamed thermoplastic resin and cementitious binder mixture can be controlled. The hardness of smooth surfaces can be adjusted.

As an extension of the method of the invention, it is also possible to produce plates with a multilayer structure consisting of a cell-rich layer and a cell-free layer. Prepare a formulation without granules and a formulation with granules of foamed thermoplastic resin, pour the formulation without granules into the bottom of the mold, pour the formulation with granules on top, and then pour the formulation without granules into the bottom of the mold. If a particulate-free mix is poured on top, it is possible to create a three-layer lightweight cellular concrete slab with a thicker surface layer that does not contain air bubbles. Using this idea, it is also possible to create a multilayer structure.

[Example] 100 parts of Portland cement, 150 parts of sand, 90 parts of water, 1 part of water reducing agent, and 3 parts of expanded polystyrene with a diameter of 5.2 to 5 II Inn were mixed in a weight ratio of 3. After stirring, the mixture was put into a mold of 3 ocIn square and 1 degree deep. Pour. After curing, the formwork was removed and heated at 150°C for 5 hours to obtain the desired lightweight concrete board with one side smooth.

The resulting lightweight concrete board has a specific gravity of approximately 0.8, which is lighter than commercially available gypsum board's approximately 1.0, and a wall vinyl cloth was applied with an adhesive coating amount of 200g/r+ (there was no difference between the two). The agent should not be easily inhaled, and
A commercially available water-based paint was uniformly applied to a smooth surface using a spray gun at a coating amount of 300 g/rrf, and it was confirmed that no color unevenness occurred over the entire surface, proving that it is suitable as a building material.

〔Effect of the invention〕

The present invention is a manufacturing method that provides good surface smoothness, makes finishing such as painting easy, and does not require time and effort for the final finishing of the product. It has the advantage of being easy to produce multi-layered plate materials for the purpose of improving the strength and finish of products, and its practical effects are extremely significant.

Claims (2)

[Claims] (1) When manufacturing lightweight concrete boards, granules or pieces of foamed thermoplastic resin with a volume smaller than the total volume of the board are charged into a cement-based binding material, poured into a shallow tray-shaped formwork, and the cement hardens. In the process, the granules or pieces are allowed to float freely without restraint, and after hardening or semi-hardening, the resin is melted, shrunk or sublimated by heating, and cavities are formed inside the concrete. Method of manufacturing lightweight concrete plates. (2) The method for manufacturing a lightweight concrete board according to claim 1, wherein the heating method involves dry air, water vapor, a solvent vapor for dissolving the foamed thermoplastic resin, or a mixed vapor thereof.