JP2001181068A - Composite building material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite building material having lightness, heat insulating, sound absorbing, moisture absorbing, air cleaning properties, or the like and friendly to the environment by using natural fibrous material (chaffs, chips, or the like). SOLUTION: This composite building material is formed by adding a material containing an inorganic binder 2 to a natural fibrous material (chaffs). Subsequently, the obtained formed body is baked to obtain the composite building material 1 comprising ash 3 derived from the natural fibrous material (chaffs) and/or a carbonized product 6 and the inorganic binder and having a large number of voids 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite building material derived from an organic material and an inorganic material, which is suitably used as a floor member or a wall member of a house.

[0002]

2. Description of the Related Art Conventionally, rice husks generated during the rice harvesting season are mainly incinerated as organic wastes because they have low nutrients and have little value as fertilizers. However, the incineration and the subsequent treatment require time and money, and when incinerated as it is outdoors, it may cause smoke damage and inconvenience surrounding residents. Also, since demand for straw, bark, and the like as fertilizers is limited, it is desired to diversify ways of effective utilization.

[0003] Under such circumstances, several methods have been proposed for effectively utilizing rice hulls and the like as building materials. For example, Japanese Patent Application Laid-Open No. 50-46731 discloses a technique in which rice husk and straw are put into a cement paste, mixed with stirring, and then compression molded to obtain a lightweight cement substrate. In addition, a technique has been proposed in which chaff carbide or chaff ash obtained by burning chaff is used as a building material. For example, Japanese Unexamined Patent Publication (Kokai) No. 59-78969 discloses an inorganic hardened material containing rice hull carbide together with cement and aggregate. JP-A-60-36360 discloses a technique for producing hydraulic cement by mixing rice husk ash obtained by fluidized bed combustion with a lime raw material.

[0004]

In the above prior art, the building material is prepared by mixing a natural fiber material such as rice hulls with other materials (cement or the like) as it is or after burning it beforehand. It is obtained by curing. However, because natural fiber materials are not the main material, or because the molded body is not particularly treated after curing, natural fiber materials or their carbides, etc. There is no space around, that is, the surroundings are filled with another material (such as cement).

Therefore, even when a material derived from a natural fibrous material such as charcoal and having excellent adsorbability is included in a molded product, the fibrous material-derived material may come into contact with external air. It is difficult to sufficiently exhibit functions such as adsorptivity. Therefore, an object of the present invention is to effectively utilize a natural fiber material and sufficiently exhibit excellent functions (adsorption, deodorization, etc.) of a substance (ash and / or carbide) derived from the natural fiber material. An object of the present invention is to provide an environmentally friendly composite building material having excellent lightness, heat insulation, sound absorption, moisture absorption, etc.

[0006]

The inventor of the present invention adds a material containing an inorganic binder such as cement to a natural fibrous material such as rice hulls to obtain a molded body, and then fires the molded body (including dry distillation). )), And if the natural fibrous material in the molded body is incinerated or carbonized, the volume of the natural fibrous material is reduced due to firing, or the inside of the natural fibrous material or As a result, voids are generated in the surroundings, and as a result, the material (ash and / or carbide) derived from the natural fiber material, which is a fired product, is easily exposed to air, and the excellent properties of the material derived from the natural fiber material (air Cleaning action) and the increase in the voids inside the molded body,
The present inventors have completed the present invention by assuming that lightness, heat insulation, sound absorption, moisture absorption, and the like can be improved.

That is, the composite building material of the present invention is obtained by adding a material containing an inorganic binder to a natural fiber material, molding the resultant, and then sintering the obtained molded body. It comprises ash and / or carbide and an inorganic binder (claim 1). Examples of the natural fiber material include those made of at least one selected from chaff, straw, and wood chips (Claim 2). Another example of the natural fiber material is a wood piece (claim 3). The wood piece is bulky as compared with rice hulls or the like, but can be formed into a predetermined shape by bonding with an inorganic binder. As the inorganic binder, for example, a material (composition) containing cement is preferably used (claim 4).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a natural fibrous material used in the present invention, chaff, straw, wood chips, wood chips and the like are used. Rice husk is a by-product of rice hulling after rice harvest. Rice hulls are covered with lignin or oil-based organic matter, so when mixed in an inorganic binder such as cement,
Non-uniform distribution is likely. Therefore, in order to uniformly disperse the rice hulls in the inorganic binder, at the time of mixing the rice husks and the inorganic binder, or adding a surfactant, or
It is desirable to treat the surface of the rice husk with a surfactant in advance.

[0009] If the untreated straw is too long, it is appropriately cut as necessary, and preferably, for example, 50
Adjust so that the length is about mm or less. In the present specification, a wood chip refers to a relatively non-bulky wood having a maximum dimension (length) of about 50 mm or less, such as crushed material such as shavings and pulp chips. In the present specification, a piece of wood refers to a lump-shaped piece of wood having a maximum dimension (length) of about 300 mm or less, preferably about 200 mm or less, and specifically, crushed material such as thinned wood, bark, and bamboo. is there.

The inorganic binder is preferably one which is cured by adding water at normal temperature. Specifically, a cement-based inorganic binder or another inorganic binder capable of forming a hydraulically cured product (for example, water glass) , Castable binder, etc.) or a mixture thereof.
The amount of water for curing may be appropriately determined according to the type of the inorganic binder. Cement-based inorganic binders are cement compositions consisting of cement and one or more other materials that are optionally incorporated.

As the cement, Portland cement such as early-strength Portland cement, ultra-high-strength Portland cement, ordinary Portland cement, eco-cement,
Blast furnace cement, fly ash cement, ultra-rapid hardening cement, alumina cement, silica cement and the like are used. Among them, a cement having heat resistance that does not significantly deteriorate due to a high temperature at the time of firing, and a cement having a large initial strength that can secure a certain initial strength or more even by blending a natural fiber material are preferably used.

Here, examples of the cement composition having heat resistance include an alumina cement composition that can be used even in a high temperature range of 800 ° C. or higher, a cement composition containing a high content of blast furnace slag, and the like. Specific examples of alumina cement compositions, the CaO ₂ · 2Al ₂ O ₃ as a main material, 12
Calcium aluminate such as _{CaO · 7Al 2 O 3, CaO} · Al 2 O 3, high purity alumina powder, surfactants, and the like retarders appropriately added, Al ₂ O ₃ content is 70 wt% or more High alumina cement and the like. Specific examples of the cement composition containing a high content of blast furnace slag include, for example, alumina cement 15 to 60% by weight, blast furnace slag 25 to 75% by weight,
5-15% by weight of siliceous substance, 0.1-5% by weight of boron compound
(However, B ₂ O ₃ basis), alkali metal compound 1.5-4 wt% (R ₂ O reference; R is K and / or Na) include those made of. Examples of the cement having a large initial strength development include ultra-rapid hardening cement, early-strength Portland cement, ultra-high-strength Portland cement, and ecocement.

[0013] Other materials to be blended with the cement as required include admixtures such as fly ash, silica fume, blast furnace slag fine powder, calcium aluminate powder, AE agent, AE water reducing agent, high performance water reducing agent. Agent, high performance A
E Examples of the agent include a water reducing agent, a retarder, and a hardening agent. The mixing ratio (total amount) of other materials to be added as needed together with the cement is usually 30 parts per 100 parts by weight of the cement.
Not more than parts by weight.

Examples of the inorganic binder other than the cement-based inorganic binder capable of forming a hydraulic hardened body include water glass and a binder mainly composed of slag. Here, the water glass is obtained, for example, by heating and melting silicon dioxide and sodium carbonate, and heating and melting the melt in an autoclave, and can form a fire-resistant cured body, and can be used alone. Or a mixture with a cement composition. As a binder mainly composed of slag, for example, a binder containing 100 parts by weight of granulated blast furnace slag and 0.5 to 20 parts by weight of an alkali metal hydroxide such as sodium hydroxide, or a by-product during the production of an alloy such as stainless steel. After mixing the alkali metal compound, boron compound, and fluorite into the slag,
Cooled and crushed modified slag powder (main mineral is 11
CaO ・ 7Al ₂ O ₃・ CaF ₂ , 3CaO ・ 2SiO ・ CaF ₂ , CaF ₂ etc.)
Examples of the binder include a silica flower and a binder obtained by mixing a phosphate as needed. Since water glass and binders mainly composed of slag have high heat resistance, they are suitably used as the material of the composite building material of the present invention.

The mixing ratio of the natural fiber material is not particularly limited, but is preferably 30 to 200 parts by weight based on 100 parts by weight of the inorganic binder. If the compounding ratio is less than 30 parts by weight, it is not possible to obtain a sufficient effect (light weight, sound absorbing property, etc.) by compounding the natural fiber material, and it is generated at the time of carbonization inside the molded article. Since a continuous gap for removing gas is not sufficiently formed, the hardened body may be crushed due to an increase in internal pressure due to the gas. Conversely, if the compounding amount exceeds 200 parts by weight, the strength of the molded article may be too low, the deformation of the building material may be too large, and the necessary strength and shape may not be secured.

[0016] In addition to the natural fiber material and the inorganic binder, an aggregate and various additives (colorant, extender, etc.) can be blended as required. Here, the aggregate has a particle size of 2.
A refractory fine aggregate such as vermiculite of 5 mm or less, silica sand, or the like is preferably used to secure a certain strength or more. When compounding aggregate, the amount
The amount is 0 to 200 parts by weight, preferably 0 to 150 parts by weight, particularly preferably 0 to 100 parts by weight based on 100 parts by weight.

Next, an example of a method for producing a composite building material according to the present invention will be described. First, when using rice hulls, straw, wood chips, etc. as a natural fiber material, a natural fiber material, an inorganic binder,
Then, a predetermined amount of water is added to the aggregate and the admixture added as needed, and the mixture is lightly kneaded until the natural fiber material is distributed to some extent uniformly in the mixture. The amount of water may be appropriately determined depending on the composition of the inorganic binder so as to obtain an appropriate water cement ratio or the like. As a kneading means, for example, a conventional mixer such as a pan-type mixer or a twin-screw mixer is used. In addition, as a method of charging each material at the time of kneading, all the materials may be simultaneously charged at once, or a natural fiber material, an inorganic binder, and an aggregate added as necessary. After the admixture is charged and kneaded, other materials such as water, a surfactant, a high-performance water reducing agent, and a retarder may be charged. As a natural fibrous material, when using a piece of wood having a large volume so that it is difficult to knead it with an inorganic binder, or a piece of straw having a long length, for example, water is previously poured between the pieces of wood stacked in a formwork. The paste or slurry containing the added inorganic binder is poured to bond the pieces of wood. At this time, if necessary, excess water may be removed by suction as in a papermaking method. The molding may be press molding. The obtained mixture is put into a predetermined mold, covered with a curing sheet, and cured for a predetermined time to obtain a molded body.

The molded body is subjected to a heat treatment for a predetermined time in a high-temperature furnace adjusted to have a temperature condition within a certain range, and is fired. The heating temperature varies depending on the type of the natural fiber material, but is preferably about 200 to 800 ° C. By performing the treatment within this temperature range, the natural fibrous material contained in the molded body is at least carbonized, the vaporized components are removed, and the carbonaceous material is further changed to ash. If the heating temperature is less than 200 ° C., carbonization is difficult, and if it exceeds 800 ° C., there is a possibility that the inorganic binder may have an unrecoverable adverse effect on strength. However, when an inorganic binder having high heat resistance is used, the temperature condition may be increased to a temperature exceeding 800 ° C. (for example, 800 to 1,000 ° C.). The carbonization may be incomplete in some cases. When a wood piece is used as a natural fiber material, it is preferable that the wood piece be kept in a carbonized state (a state of charcoal) and not incinerated in order to obtain excellent adsorptivity and the like. After firing, the strength reduced by firing may be recovered by water curing or steam curing as necessary.

When rice husk is used as a natural fibrous material, if it is sufficiently heated from a carbonized state to an incinerated state by firing, 15 to 20% by weight of ash before carbonization remains as a residue. The ash derived from rice hulls has a high content of the SiO ₂ component, and thus has the effect of promoting the hydration of cement. FIG. 1 schematically shows a composite building material after firing using rice husks. Composite building material 1 is composed of inorganic binder 2
And the voids 4 and the ash 5 generated by incineration of the rice husk 3. Since the ash 5 is covered with the voids 4, it can absorb or adsorb moisture and impurities in the air that has entered from the outside, and exhibits functions such as hygroscopicity. Moreover, since the composite building material 1 has many voids 4 inside, it is excellent in lightness, heat insulation, sound absorption, moisture absorption, heat retention, and the like.

When straw is used as the natural fibrous material, charcoal or ash is generated by firing. FIG. 2 schematically shows a composite building material after firing when straw is used as a natural fiber material. The composite building material 11 includes an inorganic binder 12, voids 14 formed by carbonizing the straw 13, and ash 15.
And fine aggregate 16. Since the composite building material 11 has many voids 14 inside, it is lightweight, heat insulating, sound absorbing,
Excellent in hygroscopicity and heat retention.

When wood (wood chips or wood chips) is used as a natural fiber material, charcoal is produced by carbonization. Since charcoal has the ability to adsorb gas and the like, it can purify air. In addition, since charcoal has a void portion inside, it is excellent in lightness, hygroscopicity and the like. FIG. 3 schematically shows a composite building material after firing in the case of using wood chips as a natural fiber material. The composite building material 21 includes an inorganic binder 22, charcoal 23 and fine aggregate 24 generated by carbonizing wood pieces.

Regardless of which type of natural fiber material is used, in a building material that does not require much strength, the inorganic binder only needs to be present to an extent bridging the natural fiber materials. .

[0023]

The composite building material of the present invention has a large number of voids therein and is light in weight, and is excellent in heat insulation, sound absorption, moisture absorption, heat retention and the like. Further, when charcoal is included in the composite building material, an air purifying action can be further expected. Therefore, the composite building material of the present invention can be suitably used as a building material such as a roof material, a partition wall, an underfloor material, and an outer wall. In addition, the composite building material of the present invention effectively utilizes plant waste materials such as rice husks, straw, waste wood and the like, which have been difficult to dispose of without prior use, and is therefore promising as an environmentally friendly building material in the future. is there. Furthermore, when a composition containing cement is used as the inorganic binder, the interaction between the silica component (SiO ₂ ) contained in the ash in the composite building material and the cement can improve the strength of the inner surface of the void. It is possible to realize a building material having sufficient strength despite having many voids.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of a composite building material of the present invention (when using rice hulls as a natural fiber material).

FIG. 2 is a view schematically showing an example of a composite building material of the present invention (when straw is used as a natural fiber material).

FIG. 3 is a diagram schematically showing an example of a composite building material of the present invention (when a wood piece is used as a natural fiber material).

[Explanation of symbols]

 1,11,21 Composite building materials 2,12,22 Inorganic binder 3 Rice hulls 4,14 Voids 5,15 Ash 13 Straw 16,24 Fine aggregate 23 Charcoal

Claims (4)

[Claims] An ash and / or carbide derived from a natural fiber material and an inorganic material obtained by adding a material containing an inorganic binder to a natural fiber material and molding the resultant, and then sintering the obtained molded body. A composite building material consisting of a binder. 2. The composite building material according to claim 1, wherein the natural fiber material is at least one selected from chaff, straw, and wood chips. 3. The composite building material according to claim 1, wherein the natural fiber material is a piece of wood. 4. The composite building material according to claim 1, wherein the inorganic binder contains cement.