JPH0216263B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] This invention relates to architectural panels having excellent physical properties. [Background technology] Currently, prefabricated building panels aimed mainly at steel frame construction are being developed for the purpose of reducing weight.
There are ALC (Autoclaved Light Concrete) products and lightweight aggregate concrete products. ALC products are currently the most widely used components in steel-framed buildings, stores, houses, etc. in Japan, and have excellent overall properties such as light weight, heat insulation, and fire resistance. It also has the disadvantages of high water absorption (60 to 70 wt%), insufficient durability such as frost resistance, poor surface strength, and dent resistance. Lightweight aggregates used in lightweight aggregate-based concrete products are broadly classified into structural lightweight aggregates and heat insulation lightweight aggregates. Structural lightweight aggregates are artificial lightweight aggregates obtained by firing shale, flyash, clay, etc. in a rotary kiln, or natural volcanic rubble, etc. Lightweight aggregates for insulation purposes include expanded nacre, expanded obsidian, etc. , expanded pine rock, expanded vermiculite, synthetic resin foam particles, etc. Lightweight aggregate-based concrete products also vary depending on the type of lightweight aggregate used, and have advantages and disadvantages. For example, in concrete products based on artificial lightweight aggregate, the aggregate is relatively heavy and hard, so there is no damage to the aggregate during kneading or shaping. Therefore, strength, durability, and water resistance are good. Therefore, it is suitable as structural concrete. However, the product specific gravity is at least 1.6, which limits the weight reduction. In order to improve this point,
A foaming agent may be used in combination as in Japanese Patent Publication No. 53-7447 and Japanese Patent Application Laid-Open No. 52-140532. Even with this,
The specific gravity is only around 1.2 at most, and moreover, it is limited to injection products that contain foaming agents. Also, JP-A-53
There are also examples of using obsidian pearlite for insulation, such as No. 80419. The main component of this product is artificial lightweight aggregate, so there is a limit to how much weight it can reduce. Due to the nature of aggregate, it is difficult to use molding that requires external mechanical force. Concrete products made from volcanic rubble are relatively hard and heavy, but because they are naturally produced, it is difficult to obtain products of consistent quality, and their water absorption is high compared to their specific gravity, making them generally insufficiently durable. There's a problem. Lightweight aggregate-based concrete products for insulation are extremely lightweight. However, it has the disadvantages of high water absorption, low strength, and insufficient frost resistance, so it is not used mainly in harsh conditions such as insulation applications and outdoor applications.
In order to improve this drawback, there is an example of coating perlite and vermiculite concrete with high-density mortar, as in JP-A-54-66518. However, although this product considerably suppresses the rate of water permeation from the surface, there are concerns about its long-term durability. that's all,
Table 1 summarizes the advantages and disadvantages of the main lightweight aggregates and concrete products using them. In the table, the underlined items are defects.

[Purpose of the invention]

In view of the above-mentioned conventional circumstances, an object of the present invention is to provide a cement-concrete building panel having the physical properties listed below. 1. Low water absorption 2. Excellent durability (freezing damage resistance) 3. Light weight 4. High insulation properties 5. Fire resistance 6. Strong surface strength, less chipping and denting 7. Easy construction In other words, using cement concrete as a base material, it is comparable to ALC. The aim is to eliminate the disadvantages of ALC, such as high water absorption, lack of durability, and low strength, by reducing the weight of ALC. [Disclosure of the Invention] In order to achieve such an object, a building panel according to the present invention is a building panel made of cement concrete, in which the planar projected shape of the panel is substantially rectangular, and the interior of the panel is substantially rectangular. Cement concrete has a hollow part that is continuous from end to end along the length direction and/or width direction, and the cement concrete has an apparent specific gravity of 0.3 to 1.2, a water absorption rate of 40% by weight or less after 24 hours, and a crushing strength. contains 50 to 95% by volume of lightweight aggregate of 2 kg or more, and the above lightweight aggregate is
A combination of coarse aggregate with a particle size of 3 mm or more and 25 mm or less and an apparent specific gravity of 0.34 to 0.8, and fine aggregate with a particle size of 5 mm or less and an apparent specific gravity of 0.5 to 1.2 and a smaller particle size and higher specific gravity than the coarse aggregate. It is characterized by the specific gravity of the concrete itself being set to be between 0.5 and 1.2. This will be explained in detail below. The building panel according to the invention is made of cement concrete containing lightweight aggregate. Here, the term "cement" refers to hydraulic cement in general, and is not particularly limited. Examples include Portland cement, various mixed Portland cements, granulated blast furnace slag, alumina cement, gypsum, and those containing silica and lime components that produce crystalline calcium silicate such as tobermorite when cured in an autoclave. It is preferable to use a combination of Portland cement and slag in such a way that the slag accounts for 50% or more of the total weight of both, as this further improves the strength. In this invention, the lightweight aggregate must have the following physical properties. a) The apparent specific gravity is 0.3 to 1.2. Beyond this, the lightweight effect as a lightweight body,
The heat insulation properties will be insufficient, and if it is less than this, the aggregate strength, water absorption, and frost damage resistance will be insufficient. b The water absorption rate of the aggregate after 24 hours of water absorption is 40% by weight or less. If it exceeds this, the product will have insufficient frost damage resistance and water absorption. c The crushing strength of the aggregate (the crushing strength when a static load is applied to a unit aggregate grain) is 2 kg or more. If it is less than this, when densely packed during kneading and semi-dry blow molding, it is difficult to obtain a satisfactory molded product because the aggregate tends to decrease in volume and strength due to destruction or crushing. Although there are no limitations on the type as long as it has the above-mentioned physical properties, it is preferable to use the following types. In other words, it is a porous lightweight aggregate obtained by firing and foaming materials whose main components are inorganic oxides such as silica and alumina. It is something. The amount of lightweight aggregate mixed is set so that it becomes 50 to 95% by volume in the lightweight concrete after hardening. If it exceeds this range, it will be difficult to obtain a cured product with sufficient strength, and the surface appearance will also deteriorate. This is because if it is less than this, it is difficult to expect a lightweight effect. Lightweight aggregates include coarse aggregate with a particle size of 3 mm or more and 25 mm or less and an apparent specific gravity of 0.3 to 0.8, and coarse aggregate with a particle size of 5 mm or less and an apparent specific gravity.
0.5 to 1.2 and is used in combination with fine aggregate, which has a smaller particle size and a larger apparent specific gravity than the coarse aggregate. The coarse aggregate has a large particle size and a low specific gravity, so it reduces the specific gravity of the entire cement concrete.
In other words, building panels can be made lighter. Since the fine aggregate has a small particle size and a high specific gravity, it has high strength and can improve the strength of cement concrete, that is, building panels. By combining these coarse aggregates and fine aggregates in an appropriate ratio, the specific gravity of the entire cement concrete is set to fall within the above range. If the cement is a combination of Portland cement and slag, or a combination thereof as the main component, with a small amount of gypsum added as necessary,
In cement concrete, ettringite crystals are generated in a state where they are entangled with cement hydrate particles or with each other, so that the strength of cement concrete is improved. However, ettringite tends to shrink when heated and dried, and expands when rehydrated. Therefore, this type of cement concrete has some problems in terms of dimensional stability. In this case, the kneaded material has a specific surface area (Blaine value) of 10,000 cm ² /g or more (preferably 20,000 cm ^{2 /} g).
If you add a fine inorganic filler (g or more),
Dimensional stability can be improved. This is believed to be because the fine inorganic filler enters into the gaps between the cement hydrate particles and the ettringite crystals and fills the gaps in whole or in part to prevent dimensional changes. Such fine inorganic fillers include calcium carbonate, silica flour,
Fly atsushi, white clay, etc. are used. When using a fine inorganic filler that causes a Ponzolan reaction,
Since it bonds with cement, it also contributes to improving the strength of the hardened product. The fine inorganic filler is preferably added in an amount of 3 to 30% by weight based on the solid content of the kneaded product. This is because if it is less than this, the effect will be weak, and if it exceeds this, other physical properties will be adversely affected. Depending on the required product quality, heavy aggregates such as silica sand and other lightweight aggregates may be added within acceptable limits. In the production of cement concrete, various known additives and admixtures (water reducing agents, AE agents, hardening accelerators, waterproofing agents, etc.) are added as necessary. Reinforcing materials such as reinforcing bars, wire mesh, and pipes are treated with anti-rust treatment as necessary, as well as pulp, glass fiber, carbon fiber, and various organic fibers (polypropylene, vinylon,
(polyvinyl chloride, polyester, etc.), asbestos, mica, and other reinforcing fibers are used alone or in combination. The mixing water is preferably added in an amount of 25 to 100% by weight based on the cement. Of course, the amount varies depending on the type and amount of aggregate mixed, but if it is within the above range, it will be a semi-dry mortar with virtually no slump value and low fluidity, making it suitable for molding. It is from. If it is less than the above range, it will generally be insufficient for developing strength, and if it exceeds this,
Semi-dry molding becomes difficult, and physical properties such as strength, durability, and efflorescence resistance tend to deteriorate. Preferred formulation examples are as follows. The essential components are Portland cement and slag, and the weight ratio of inorganic binder of 50% or more of the total slag is 30% to 60%, and the inorganic filler with a specific surface area of 10,000 cm ² /g or more is 3% to 30%. , foamed inorganic lightweight aggregate with a bulk specific gravity of 1.2 or less
These are mixed at a ratio of 10% to 70%, and water is added to the inorganic binder at a weight ratio of 15%.
be mixed at a ratio of 30%. A kneaded product obtained by kneading a predetermined compound is molded into a predetermined shape, and then cured to obtain a cured product. The shape of the molded body is not limited as long as it has a hollow portion inside. However, it is generally made into a square or rectangular thick plate. This plate-like body may be curved or bent into a chevron shape. That is, it suffices if the planar projection shape is substantially rectangular. In this case, the hollow portion is preferably continuous from end to end along the length direction and/or width direction. On the sides of the opposite sides of the plate-shaped body,
Irregularities (such as protrusions and grooves) for tongue and groove joints may be formed. The hollowness ratio is preferably 5 to 40%, and it is preferable that even the thinnest part of the wall surrounding the hollow part has a thickness of 10 mm or more. When the thickness of the thinnest part is less than 10 mm and the hollowness ratio is over 40%, it is difficult to obtain the necessary strength such as impact resistance. Hollow rate 5
If it is less than %, it becomes difficult to achieve the necessary weight reduction. When a molded body is obtained by semi-dry molding, mechanical force is used to apply vibration, pressure, tapping, etc. to the material to make it dense. Therefore, at this time, if a core having the required hollow shape is inserted into the molded body, the hollow part can be molded at the same time. According to this molding method, it is possible to obtain fillability in the berries, and there is no damage to the aggregate. The design of the hollow part not only reduces weight, but also provides favorable physical properties in terms of heat insulation, sound insulation, ventilation, etc., and in combination with the fact that the concrete that forms the grain is lighter, it is possible to improve the performance of ALC etc. Achieves a weight reduction equal to or greater than that of an extremely lightweight panel. The hollow setting is also a prerequisite for obtaining a high degree of durability (freeze resistance) and high resistance to chipping and denting. By providing a hollow part, you can use this hollow part to conduct electrical wiring, piping, etc. during construction.
It becomes possible to easily pass cables, etc., and it can also be used for connecting panels and fixing them to the base. Examples will be described below along with comparative examples. The kneaded material obtained with the formulation shown in Table 1 was molded into the shape shown in FIG. 1 or the shape shown in FIG. 2 (the hollow ratio is as shown in the table). The physical properties of the lightweight concrete and the physical properties of the panel itself in the architectural panels obtained by curing and curing each molded body are as shown in Table 1, and all of the Examples were superior to the Comparative Examples. In the table, shape 1 shows FIG. 1, and shape 2 shows FIG. 2. In the figure, 1 is a lightweight concrete shell, 2 is a hollow part, 3 is a reinforcing material (reinforced steel),
4 is the male part, and 5 is the female part.

【table】

【table】

[Table] Examples 7, 8, 9, and 10 have a specific surface area of 10000 cm ² /g
Since the above fine inorganic filler was added, Example 4, which did not contain such a filler,
As shown in Table 3, the dimensional shrinkage upon heating is smaller than that of Sample No. 5. For reference, the Blaine value of blast furnace slag was 4000 cm ² /g, the Blaine value of ordinary Portland cement was 3000 cm ² /g, and the Blaine value of white Portland cement was 4000 cm ² /g.

〔Effect of the invention〕

Since the construction panel according to the present invention has the above configuration, it has a light weight equivalent to or more than that of ALC,
It has heat insulation, sound insulation, fire resistance, etc., as well as high durability, frost resistance, and surface strength (resistant to chips and dents) comparable to ordinary cement concrete. That is, as will be explained in detail below, in this invention, the shape or structural requirements of the building panel, and the requirement to select and use cement concrete or lightweight aggregate as the material of the building panel under specific conditions. By combining these, the performance described above can be achieved. First, as for the structure of the architectural panel, the planar projection shape of the panel is substantially rectangular, and the interior of the panel is provided with a hollow part that is continuous from end to end along the length direction and/or width direction. Therefore, the building panel becomes lighter by the amount of the hollow part, and at the same time, the hollow part improves the heat insulation and sound insulation properties between both sides of the building panel, and moreover, the hollow part becomes an air flow path when the building panel is installed. This makes it possible to improve ventilation and to run wiring and piping through the hollow space. Next, by selecting and using a lightweight aggregate that satisfies the above-mentioned property conditions as the lightweight aggregate to be included in cement concrete, the specific gravity of the cement concrete, that is, the building panel, can be significantly reduced. , in combination with the formation of the hollow portion described above, can greatly contribute to the weight reduction of lightweight aggregate-based concrete construction panels, which have conventionally been inferior in light weight, and can be made as light as ALC products. Moreover, the architectural panel according to this invention is
Since the water absorption rate is extremely low compared to ALC products, it can eliminate the weak point of ALC products such as high water absorption, and also has excellent frost damage resistance and surface strength.
We can offer something superior to ALC products. In particular, coarse aggregate with a large particle size and low apparent specific gravity is used as a lightweight aggregate that improves the performance of cement concrete, that is, construction panels as described above.
By using it in combination with fine aggregate, which has a small grain size and a large apparent specific gravity, it is possible to set the balance between the overall weight of cement concrete and performance such as strength in the most favorable range, making it suitable for use as a building panel. In practical terms, it becomes possible to demonstrate optimal performance.

[Brief explanation of drawings]

FIG. 1 is a partially sectional plan view showing one embodiment of a building panel according to the present invention, and FIG. 2 is a front sectional view thereof. FIG. 3 is a plan view showing another embodiment, and FIG. 4 is a front view thereof. 1... Shell (lightweight concrete part), 2...
Hollow part, 3...Reinforcement material.

Claims (1)

[Scope of Claims] 1. An architectural panel made of cement concrete, wherein the planar projection shape of the panel is substantially rectangular, and the inside of the panel is provided with a wall extending from end to end along the length direction and/or width direction. Cement concrete has a hollow part that continues up to
Lightweight aggregate with an apparent specific gravity of 0.3 to 1.2, a water absorption rate of 40% by weight or less after 24 hours, and a crushing strength of 2 kg or more, 50 to 95
Including volume%, the above lightweight aggregate has a particle size of 3 mm or more and 25 mm.
Coarse aggregate with an apparent specific gravity of 0.34 to 0.8 and a particle size of 5
It is made of a combination of fine aggregate with an apparent specific gravity of 0.5 to 1.2 mm or less and a particle size smaller than the above-mentioned coarse aggregate and a higher specific gravity, and the specific gravity of the concrete itself is
An architectural panel characterized by being set to be 0.5 to 1.2. 2. The building panel according to claim 1, wherein unevenness for tongue and groove jointing is formed on the side surfaces of opposite sides of the panel. 3. The building panel according to claim 1 or 2, wherein the hollow portion of the panel has a hollowness ratio of 5 to 40%, and the wall surrounding the hollow portion has a thickness of 10 mm or more even at its thinnest portion. 4. The building panel according to any one of claims 1 to 3, wherein a reinforcing material is embedded in the cement concrete layer.