JPH0475180B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to hydraulic materials such as cement mortar, particularly hydraulic molding materials such as cement and concrete having high bending strength, and mold-hardened solid members. (Prior Art) Many structures and molded products using hydraulic materials such as cement mortar and concrete are known. These molded products usually have relatively high compressive strength, as typified by concrete blocks, but their bending strength is low, so in order to manufacture flat objects or structures that are subject to bending stress, it is necessary to use reinforcing steel or other materials. Reinforcement shall be used. However, molded products made of hydraulic materials containing these reinforcing materials have a considerable thickness. For this reason, the weight becomes large, and its uses are limited. Another problem with hydraulic compositions containing cement as a main component is that the corners of molded products are easily damaged due to their low impact resistance. Another problem is that it has relatively high water permeability. Several proposals have been made in the past to improve these drawbacks, but they all have their advantages and disadvantages, and no method has yet been found to improve all of the above-mentioned drawbacks at the same time. For example, it has been proposed that a high-strength hydraulic composition has cement as its main component and that it is mixed with silica hume, which is produced as a by-product during the production of ferroalloy or metal silicon. There are large variations in the strength, and sufficient strength cannot be obtained.
Furthermore, impurities such as carbon and heavy metals are unavoidably mixed in, resulting in a dark coloration, making it particularly unsuitable for color products, and requiring careful handling to prevent heavy metals from leaching out. . Furthermore, from an industrial standpoint, raw materials are dependent on industries such as ferroalloys, so there is also a problem in terms of ensuring a stable supply of raw materials. Also known is a so-called silica cement, which is a mixture of cement and white clay or fine silica. In this case, the water permeability can generally be prevented to a considerable extent, but the strength, especially the bending strength,
This is only a slight improvement. (Problems to be Solved by the Invention) An object of the present invention is to provide a hydraulic composition that solves all of the above-mentioned drawbacks, and in particular has a bending strength several times higher than that of conventional cement mortar or concrete moldings. It is an object of the present invention to provide a hydraulic composition which is twice as large and can be used as a substitute for metal members such as aluminum and iron members in some cases. (Structure of the Invention) The present invention consists of 100 parts by weight of hydraulic cement, 5 to 15 parts by weight of fine particles of cristobalite-containing minerals with an average particle size of 2 μm or less, and 5 parts by weight of silica sol (as silica content).
~15 parts by weight, 3 parts by weight or less of high performance water reducer and 25 parts by weight of water
~60 parts by weight of the hydraulic composition. Furthermore, the present invention includes 100 parts by weight of hydraulic cement, 5 to 15 parts by weight of fine particles of cristobalite-containing minerals with an average particle size of 2 μm or less, 5 to 15 parts by weight of silica sol (as silica content), 3 parts by weight or less of a high-performance water reducing agent, It is a hydraulic composition containing 10 parts by weight or less of fibers and 25 to 60 parts by weight of water. The hydraulic cement used in the present invention is usually Portland cement, but is not particularly limited as long as it is a material that hardens when mixed with water, such as white cement, magnesia cement, blast furnace cement, flyash cement, sulfate-resistant cement, etc. Cement such as cement is used. The cristobalite-containing mineral used in the present invention is not limited to cristobalite, but may be any mineral containing 50% or more of cristobalite-type SiO ₂ , with white clay and the like being particularly preferred as natural minerals.
These usually have a specific surface area of several tens to hundreds of m ² /g.
The main component is porous silica. In the present invention, the particle size of the cristobalite-containing mineral has an important meaning. i.e. average particle size
It is 2 μm or less, preferably in the range of 0.1 to 0.8 μm. If the average particle size is larger than 2 μm, the water permeability of the molded product will increase and the bending strength will decrease. In addition, the particle size distribution may generally be close to a normal distribution, but
It is preferable that the proportion of particles exceeding four times the average particle size is 5% or less. Conventionally, it has been extremely difficult to obtain fine particles of naturally occurring cristobalite-containing minerals with an average particle size of 2 μm or less using conventional crushing methods. Furthermore, when mixing with hydraulic cements, it was necessary to obtain a pulverized product in a dry state, which further increased the difficulty.
The present inventors have discovered that the object of the present invention can be achieved by performing wet pulverization instead of dry pulverization and mixing it with cement as it is without any drying process. The means for pulverizing the cristobalite-containing mineral in the present invention is not particularly limited, but a preferred method is a pulverizing means using frictional force, such as a stirring type pulverizer. Apparatuses suitable for such grinding include, for example, the "K&M Ultrafine Grinding Mill" (trade name) manufactured by Matsuter+Partner, Germany, the "Kobor Mill" (trade name) manufactured by Swiss Fryma, and the Mitsui Miike Kakoki Co., Ltd. Company-made “Atlighter” (product name)
etc. can be mentioned. Of course, fine particles produced by a vibrating mill, a colloid mill, a kneader, etc. may also be used. Silica sol, which is an essential component in the present invention, is
It may be manufactured by a known method and sold on the market. This is usually made by passing an aqueous alkali metal silicate solution through an ion exchange resin packed bed to remove alkali metal ions.The silica particles are extremely fine particles, for example, about 0.005 to 0.05 μm, and generally prevent gelation and form a sol. It is used as a suspension of about 30% by weight, containing surfactants and auxiliary agents to stabilize it. In the present invention, since the presence of a surfactant may cause a decrease in the strength of the molded product obtained, it is preferable to reduce the amount of the surfactant as much as possible. It is also a preferred embodiment to produce the sol nearby and use it immediately after neutralization with ammonia or the like, for example within 10 hours. Furthermore, the aqueous medium constituting the silica sol can also be used as it is as a component of the composition of the present invention. Furthermore, the use of superplasticizers is also not possible in the present invention. High-performance water reducing agents are admixtures that have a large water reduction effect when mixed with concrete, etc., such as those with a water reduction rate of 10% or more, especially around 20 to 30%, and include naphthalene sulfonate formalin condensates,
Cocondensates of naphthalene sulfonic acid and lignin sulfonic acid, melamine sulfonic acid complexes, cocondensates of naphthalene sulfonic acid and oxycarboxylic acids, alkylaryl sulfonates, aromatic hydrocarbons,
These are melamine-based and other drugs, such as Mighty (manufactured by Kao Soap Co., Ltd.), Polefain, Hyfluid (both manufactured by Takemoto Yushi Co., Ltd.), Sunflow (manufactured by Sanyo Kokusaku Pulp Co., Ltd.), NP-10, and NP-20 (all manufactured by Nisso Co., Ltd.). (manufactured by Master Builders), Paritsuku (manufactured by Fujisawa Pharmaceutical Co., Ltd.), Sicament (manufactured by Nihon Sika Co., Ltd.), Denka
FT (manufactured by Denki Kagaku Kogyo Co., Ltd.) (all above are product names)
It is a cement admixture well known in the industry. In the present invention, by using a high performance water reducing agent, the viscosity of the composition can be adjusted and uniform mixing can be achieved. In the present invention, the cristobalite-containing mineral having an average particle size of 2 μm or less is used in an amount of 5 to 15 parts by weight, preferably 10 to 14 parts by weight, based on 100 parts by weight of hydraulic cement. If the amount is less than this, sufficient strength will not be developed and water permeability will also increase. Furthermore, if the amount exceeds the above range, the development of hardness will be delayed and high strength will not be obtained in the end. Next, the use of silica sol is also one of the features of the present invention.
It is an essential component for achieving bending strength of up to 700 kg/cm ² . The amount of silica sol used is 5 to 15 parts by weight of silica present in the silica sol, preferably 10 to 14 parts by weight, per 100 parts by weight of hydraulic cement.
Parts by weight. If the amount of silica sol is less than 5 parts by weight, the desired strength of the present invention cannot be achieved. In addition, when using a large amount of silica sol exceeding 15 parts by weight,
The strength is also reduced due to the accompanying water. In the present invention, by further using a high-performance water reducing agent, it is possible to obtain a homogeneous mixture of the above-mentioned compositions, and it is possible to significantly improve the strength.
However, since using too much will actually reduce the strength, it should not be used in an amount of 3 parts by weight or more. It is common to use a substantially effective amount or more, and generally 0.5 part by weight or more is preferred. The amount of water used in the present invention is also important. The amount of water used is 25 parts by weight per 100 parts by weight of hydraulic cement.
~60 parts by weight, preferably 35-45 parts by weight. If it is less than this, sufficient kneading cannot be obtained, and if it exceeds 60 parts by weight, the strength will decrease. Table 1 shows particularly preferred formulation examples for each component of the present invention explained above.

[Table] In the present invention, it is generally preferable to mix the finely ground cristobalite-containing mineral, silica sol, and high performance water reducing agent, add hydraulic cement to the suspension, and stir. . Of course, the mixing order is not limited to this. When mixing, it is preferable to use a high-speed stirring mixer. The composition of the present invention is generally molded within 30 minutes, preferably within 20 minutes after kneading. As the molding means, conventionally known methods such as filling a mold, coating the surface of a certain shape, extruding using an extruder, etc. are used. Molded articles obtained from the composition of the present invention containing the above-mentioned components in specific proportions have particularly excellent bending strength. For example, when the composition of the present invention is kept at 60°C for 24 hours and then left for 14 days, the bending strength is
A molded product of 150-400 kg/cm ² is obtained. Further, by performing autoclave curing, a molded product having a bending strength of 350 to 700 Kg/cm ² can be obtained in a short time. Furthermore, the composition of the present invention contains, in addition to the above-mentioned components,
By mixing 10 parts by weight or less of alkali-resistant glass fibers, carbon fibers, asbestos fibers, whiskers, metal fibers, and other fibers to 100 parts by weight of cement, the bending strength of the molded product can be significantly improved, and the bending strength of the molded product can be increased to 700 kg. / ^cm2 or more. The composition of the present invention includes various admixtures used in general mortar or concrete, such as AE agents,
Chemical admixtures such as hardening retarders, hardening accelerators, swelling agents, waterproofing agents, etc., and/or fine aggregates, coarse aggregates, etc. can be mixed as necessary. (Operations and Effects of the Invention) As described above, the hydraulic cement, cristobalite-containing mineral fine powder, silica sol, and high performance water reducing agent are essential components of the present invention, and even if any of these is missing, the purpose of the present invention cannot be achieved. It is not possible to obtain a composition for obtaining a molded article having a high bending strength. The mechanism of why the bending strength comparable to that of metal is developed in the present invention is not necessarily clear, but the excessive lime content of cement, the porous and fine-grained cristobalite-containing mineral, and the silica sol are extremely effective and completely effective. It seems certain that they will react and form a highly strong compound. Silica cement is conventionally known, but although this cement usually has a slow curing speed and is unlikely to crack due to heat generation, it cannot be expected to particularly improve strength. On the other hand, in the case of the composition of the present invention, the curing speed is no different from that of ordinary concrete, and moreover, due to the addition of fibers, the curing speed is 700 kg/cm ²
This amazing bending strength can be obtained. Another extremely important feature of molded articles made from the composition of the present invention is that their water permeability is almost zero. Because of this high bending strength, the molded product made from the composition of the present invention can be used, for example, as a substitute for metal sheet piles, and is also effective as a material that will not corrode at all even if it is underground.
In addition to being used for high-strength products such as press molds, it can also be used as channel materials for various buildings or construction materials, particularly structural members, L-shaped, I-shaped, and square-shaped. Example 1 A hydraulic composition having the composition shown in Table 2 was first mixed with cristobalite mineral (white clay) and silica sol (30% aqueous solution), and then a naphthalene sulfonate formalin condensate (Kao soap) was added as a high performance water reducing agent. Mighty) was added, water for adjustment was added to this, and the mixer was heated at 6000RPM using a high viscosity stirrer for approx.
After kneading for minutes, the resulting hydraulic composition was mixed at 40×
Place it in a 10 x 160 mm mold and use an autoclave.
It was cured at 10Kg/cm ² (180°C) for 5 hours. Thereafter, the sample was taken out of the autoclave and left for one day. The bending strength of the sample was measured by loading at the center with a distance between supporting points of 100 mm, and it was found to be 510 Kg/cm ² .

[Table] Example 2 Samples were molded and tested in the same manner as in Example 1. The composition used is shown in Table 3. The bending strength was 740Kg/ ^cm2 .

[Table] Comparative Examples 1 to 7 The compositions shown in Table 4 were tested in the same manner as in Example 1. The bending strength is shown in Table 4.
In each example, 14 g of a high performance water reducing agent was added.

【table】

Claims (1)

[Claims] 1 100 parts by weight of hydraulic cement, 5 to 15 parts by weight of fine particles of cristobalite-containing mineral with an average particle size of 2 μm or less, 5 to 15 parts by weight of silica sol (as silica content), 3 parts by weight of high performance water reducing agent. part or less and 25 to 60 parts by weight of water. 2 100 parts by weight of hydraulic cement, 5 to 15 parts by weight of fine particles of cristobalite-containing minerals with an average particle size of 2 μm or less, 5 to 15 parts by weight of silica sol (as silica), 3 parts by weight or less of high performance water reducer, 10 parts by weight of fibers. A hydraulic composition containing not more than 25 to 60 parts by weight of water.