JPH0364464B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to anhydrous gypsum compositions suitable for use as various building materials, particularly as plaster for poured floors. Specifically, it is obtained by mixing a mixture of portland cement and slag in a specific proportion with a mixture of type anhydrite, potassium sulfate, an alkaline substance, and α-hemihydrate gypsum in a specific proportion. The present invention relates to anhydrite compositions. The present inventors previously published Japanese Patent Application No. 54-15496 (Japanese Unexamined Patent Publication No. 55-109252) as a composition suitable for cast flooring.
(Japanese Patent Application No. 1982-162858)
(No. Publication), Patent Application No. 1983-41709, Patent Application No. 56-51862
In Japanese Patent Application No. 56-51863, Japanese Patent Application No. 56-56971 and Japanese Patent Application No. 56-56972, compositions based on type anhydrite or a mixture of type anhydrite and Portland cement were proposed. The present invention provides a gypsum plaster composition that has even better performance than the above compositions. Gypsum-based cast flooring materials such as molded anhydrite, α-hemihydrate gypsum, and β-hemihydrate gypsum have a relatively high hardening rate when hydrated and condensed at temperatures below 30°C, and
The initial strength of the resulting cured product is also relatively high, but 30
Hydration and coagulation at temperatures higher than 0.degree. C. have the disadvantage that the curing speed is slow and the initial strength of the cured product is poor. On the other hand, such defects are not observed in cast flooring materials made from a mixture of molded anhydrite and Portland cement. However, this flooring material has the disadvantage that when a small amount of slurry is dropped onto a smooth surface formed by pouring the slurry onto the construction surface, convex portions are formed on the smooth surface. The present inventors have improved these problems and have achieved 30
Even when hydrated and condensed at temperatures exceeding ℃, the curing speed is high and the initial strength of the cured product is quickly developed.
In addition, various studies were conducted to develop an anhydrite-based cast flooring material that would not form protrusions even when slurry drops fall on the smooth floor surface formed after construction, and the present invention was completed. The present invention is based on ``per 100 parts by weight of type anhydrite, 0.2 to 5.0 parts by weight of potassium sulfate, 0.5 to 0.5 parts by weight of alkaline substances.
Per 100 parts by weight of a mixture consisting of 10.0 parts by weight and 2 to 15 parts by weight of α-hemihydrate gypsum (hereinafter referred to as base material-A), the mixing ratio of Portland cement and slag is 20 to 80 to 80 by weight. 20 is blended with 30 to 150 parts by weight of a Portland cement-slag mixture,
If necessary, known setting regulators, antifoaming agents, dispersants,
Anhydrous gypsum composition containing appropriate amounts of viscosity modifier, aggregate, etc. The type anhydrite used in the anhydrite composition of the present invention (hereinafter simply referred to as the composition of the present invention) may be any type of type anhydrite that can set and harden upon hydration, and any suitable type thereof may be used. For example, phosphoric acid byproduct gypsum, natural gypsum, wet flue gas desulfurization gypsum, alpha hemihydrate gypsum, beta hemihydrate gypsum, etc.
In addition to molded anhydrite obtained by firing at a temperature of 500℃ or higher, examples include those obtained by calcining fluoric acid by-product anhydrite and natural anhydrite, pulverizing it to an appropriate particle size, and classifying it. . There is no problem in using raw material anhydrite with different crystal shapes, crystal porosity, etc., and there is no need for special pulverization, and normally, if the particle size is 1 mm or less, it can be used. Therefore, commercially available powders can be used as they are, but particularly preferred are those having the particle size proposed by the present inventors in Japanese Patent Application No. 56-87417 and Japanese Patent Application No. 56-87418. The composition of the present invention contains hydration and hydration of type anhydrite.
Potassium sulfate is included as a component to accelerate the setting rate. Conventionally, water-soluble sulfates such as potassium alum and aluminum sulfate have been generally used as setting accelerators for molded anhydrite. However, these sulfates make the gypsum slurry acidic and corrode the metals that come into contact with the slurry and its hardened material, so when these sulfates are used, a rust preventive agent must be applied to prevent metals from corroding. must be used in conjunction with alkaline substances to neutralize the gypsum slurry. On the other hand, when potassium sulfate is used as a setting accelerator, the gypsum slurry is usually neutral or alkaline, so in this case no alkaline substances or rust preventives are required to neutralize the slurry. Economical. Furthermore, when potassium alum, aluminum sulfate, etc. are added to molded anhydrous gypsum together with an alkaline substance, hydroxides such as aluminum hydroxide precipitate in the gypsum slurry, worsening the fluidity of the slurry and causing a hardened product. Workability during manufacturing deteriorates. On the other hand, when potassium sulfate is used,
Not only when used alone, but also when used in combination with an alkaline substance, hydroxide does not precipitate in the gypsum slurry, resulting in good workability. The amount of potassium sulfate used in the composition of the present invention is 0.2 to 5.0 parts by weight based on 100 parts by weight of type anhydrite. When the amount of potassium sulfate used is less than 0.2 parts by weight, the setting rate of molded anhydrite is low; on the other hand, even if more than 5.0 parts by weight is used, the setting rate of molded anhydrite does not increase so much and is uneconomical. . Merely adding potassium sulfate to molded anhydrite is insufficient to shorten the setting time of molded anhydrite, and the initial strength of the hardened product is slow to develop.In order to improve this point, the composition of the present invention is to contain an alkaline substance. Examples of the alkaline substance used in the composition of the present invention include, but are not limited to, slaked lime, quicklime, dolomite, caustic potash, and calcium carbonate. These alkaline substances can be used not only individually, but also in combination of two or more. The amount of alkaline substance used in the composition of the present invention is 0.5 to 10.0 parts by weight per 100 parts by weight of type anhydrite. If the amount used is less than 0.5 part by weight, it cannot be expected to shorten the setting rate of molded anhydrite or accelerate the development of initial strength of the hardened product. On the other hand, if more than 10.0 parts by weight is used, the strength of the cured product will not improve much, and the strength may even decrease. When potassium sulfate and an alkaline substance are added to molded anhydrite to cause hydration and coagulation, the gypsum slurry may cause breathing or the strength of the cured product may decrease. In order to prevent this phenomenon from occurring, α-hemihydrate gypsum is included in the composition of the present invention. The α-hemihydrate gypsum used in the composition of the present invention may have different crystal shapes, crystal vacancies, etc., and there is no need for special pulverization. Surface area is 2000～
It may be of the order of 3000 cm ² /g, but of course, a finer powder may also be used. In the composition of the present invention, depending on the setting rate of the type anhydrite used, alpha hemihydrate is usually used in the range of 2 to 15 parts by weight per 100 parts by weight of type anhydrite. If the amount of α-hemihydrate gypsum is less than 2 parts by weight, the effect will be small. On the other hand, if it exceeds 15 parts by weight, the curing speed of the molded anhydrite becomes too high, making it difficult to handle the gypsum slurry, and the strength of the cured product also decreases. In addition, the manufacturing conditions when producing molded anhydrite by firing α-hemihydrate gypsum, such as the firing time, the content of impurities in the raw materials, the type of inorganic compound roasting agent used to lower the firing temperature, etc. Depending on the amount, the amount ratio α specified in the present invention may be added to the obtained molded anhydrite.
Although hemihydrate gypsum may remain, if such type anhydrite is used in the composition of the present invention, it is not necessary to add alpha hemihydrate gypsum or the amount added may be reduced. I can do it. When the mixture consisting of type anhydrite, potassium sulfate, an alkaline substance, and α-hemihydrate gypsum described above is hydrated and set at a temperature of 2 to 28°C, the initial strength of the hardened product is developed quickly; When hydrated and coagulated at a temperature higher than 30°C, the curing speed decreases rapidly and the initial strength of the cured product deteriorates. In order to improve these points, the present invention includes a mixture of Portland cement and slag (in the present invention, slag includes slag cement) in the composition of the present invention. Examples of the Portland cement used in the composition of the present invention include ordinary Portland cement, early strength cement, ultra early strength cement, and blast furnace cement. Further, the slag used in the composition of the present invention includes blast furnace slag, granulated blast furnace slag, blast furnace pig slag, ferromanganese slag, ferronitkel slag, granulated ferronitkel slag, rinsing slag,
Examples include iron sand electric pig iron slag, and particularly preferred ones include blast furnace slag, granulated blast furnace slag, ferronitkel slag, and granulated ferronitkel slag. These slags are used in powder form, and those having an average particle size of several μm to 200 μm and a Blaine specific surface area of about 2000 to 6000 cm ² /g are preferably used. In addition, as slag cement, commercially available "Cerament" (trade name, product of Daiichi Cement Co., Ltd.),
Examples include "Esment" (trade name, manufactured by Nippon Steel Chemical Co., Ltd.). The mixing ratio of Portland cement and slag in the Portland cement-slag mixture (hereinafter referred to as mixture PC-S) used in the composition of the present invention is preferably in the range of 20 to 80 to 80 to 20 by weight. . If the mixing ratio of Portland cement in the mixture PC-S is less than 20, the initial strength of the cured product will be delayed when the gypsum-cement composition slurry is cured at a temperature higher than 30°C. on the other hand,
When the mixing ratio of Portland cement exceeds 80, convex portions are formed on the smooth floor surface formed by pouring the gypsum-cement composition slurry, deteriorating the level accuracy of the finished surface and its surface quality. In the composition of the present invention, the admixture PC-S is
It is used in an amount of 30 to 150 parts by weight based on 100 parts by weight of the base material A. When the amount used is less than 30 parts by weight, the strength of the cured product obtained when the gypsum-cement composition slurry is hydrated and coagulated at a temperature higher than 30°C is low; on the other hand, when the amount used is more than 150 parts by weight In this case, the fluidity of the gypsum-cement composition slurry deteriorates. The composition of the present invention can be applied to a type of anhydrite as described above;
A slurry of the composition is obtained by blending a mixture of portland cement and slag in a specific proportion into a mixture of potassium sulfate, an alkaline substance, and α-hemihydrate gypsum in a specific proportion. It has the characteristics of a high curing speed even when cured at a temperature higher than 30°C, and the initial strength of the cured product is quickly developed.Furthermore, it does not cause any breathing, and because this breathing does not occur, The fluidity of the slurry is improved, and the curing speed is accelerated, and the initial strength of the cured product is promoted. Furthermore, due to the action specific to the Portland cement-slag mixture, the composition of the present invention exhibits the excellent effect of preventing the formation of convex portions on a smooth floor surface formed by pouring the slurry. In addition to the above-mentioned components, the composition of the present invention may contain, if necessary, known components conventionally used in this type of composition, in order to improve workability during production of a cured product and performance of the cured product. Appropriate amounts of arbitrary additives, such as setting regulators, antifoaming agents, dispersants, viscosity regulators, aggregates, etc., can be blended. Examples of setting retarders that are usually suitably used include citric acid, sodium tripolyphosphate, and polypeptone. In particular, when using polypeptone, there is less decrease in strength of the cured product compared to when using other setting retarders, and it is possible to arbitrarily control the setting time of the anhydrite composition even if only a small amount is used. Therefore, it is advantageous. Examples of setting accelerators that are usually suitably used include sodium iodide, sodium chloride, sodium sulfate, and sodium hydroxide, and the amount used is 0.1 to 100 parts by weight of type anhydrite.
It is appropriately selected within the range of 5.0 parts by weight. When a slurry is prepared by adding water to the composition of the present invention, if the amount of mixed water is small, the viscosity of the slurry increases, and depending on the stirring state, air bubbles enter the slurry, which causes a decrease in the strength of the cured product. or pinholes may occur. In order to prevent this, it is preferable to add an antifoaming agent to the composition of the present invention. As the antifoaming agent, alcohol-based, polyol-based, fatty acid ester-based, or silicone-based ones can be used. The fluidity of gypsum slurry is an important operational factor when producing a gypsum molded body, and it is preferable from the viewpoint of workability that the gypsum slurry exhibits good fluidity depending on the intended use. Due to differences in type and manufacturing conditions, the standard amount of mixed water for molded anhydrite is 25%.
It varies widely, up to 65% (relative to the weight of gypsum). usually,
If the amount of mixed water is increased, breathing will occur, the setting time will be delayed, a long curing time will be required, and the strength of the obtained molded product will be low, making it impractical. A dispersant or the like can be added to the composition of the present invention, which can improve the fluidity of the slurry obtained even when the amount of mixed water is reduced. Examples of the type of dispersant used include phosphoric acid esters, lignin sulfonates, naphthalene sulfonates, polyalkylaryl sulfonates, and melamine-formalin condensate sulfonates. Usually, it is preferable to use the melamine-formalin condensate sulfonate alone, or to use it as the main ingredient and supplementarily use a lignin sulfonate or a polyalkylaryl sulfonate. The amount of these dispersants used is usually
The amount is 0.05 to 2.0 parts by weight per 100 parts by weight. The composition of the present invention may contain methylcellulose, hydroxyethylcellulose, or polyvinyl alcohol as a viscosity modifier in order to prevent slurry breathing and aggregate sedimentation as much as possible. Conventionally, various polymer emulsions, water-soluble synthetic polymers, water-soluble natural polymers, and the like have been proposed as equivalents to methylcellulose, hydroxyethylcellulose, polyvinyl alcohol, and the like. However, many of them have drawbacks, such as not being effective unless used in large amounts, and requiring a long time to dissolve in water, and no comparable material to the above-mentioned methylcellulose etc. has been found. Methylcellulose, hydroxyethylcellulose, and polyvinyl alcohol have various molecular weights, and the viscosity of their aqueous solutions differs depending on the molecular weight, so the amount used varies depending on the type used, but if the amount used is too small, slurry fluidity will be lower. becomes worse. The usage amount of these viscosity modifiers is
The amount is usually 0.05 to 2.0 parts by weight per 100 parts by weight, and an amount such that the initial viscosity of the composition slurry of the present invention during kneading is 800 to 4,500 centipoise when measured with a B-type viscometer is particularly preferable. Examples of aggregates to be added to the composition of the present invention include, for example, wood flour, perlite, whitebait balloons, and other lightening and bulking materials, as well as silica sand, river sand, mountain sand,
Examples of sand include sea sand and standard sand. In addition, foaming agents, water retention agents, anti-wear agents, various polymeric substances, etc. may be added to the composition of the present invention as required. EXAMPLES Next, the present invention will be specifically explained using examples and comparative examples. The present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, in each of the following examples, all "parts" simply represent "parts by weight.""Cerament" is slag cement made by Daiichi Cement Co., Ltd., and "Neocerament" is Portland cement made by Daiichi Cement Co., Ltd.
It is a slag-cement mixture (Portland cement to slag-cement mixture ratio is estimated to be approximately 40:60 by weight). Examples 1 to 6 and Comparative Examples 1 to 6 To 100 parts of various types of anhydrite, potassium sulfate, an alkaline substance, and α-hemihydrate gypsum were added in the quantitative ratios shown in Table 1 to obtain base material-A. . A Portland cement-slag mixture (mixture agent PC-S) was added to the obtained base material-A at a ratio shown in Table 1 per 100 parts thereof to obtain a gypsum-cement composition. This composition contains a dispersant and a viscosity modifier in the amount ratio shown in Table 1 per 100 parts of the type anhydrite used.
A setting control agent and 0.05 part of an antifoaming agent "San Nopco 14 HP" (manufactured by San Nopco) were added to the composition thus obtained, and bone was added in the amount ratio shown in Table 1 per 100 parts of the composition. To the composition obtained by adding the material and the aggregate, water was added in an amount shown in Table 1 per 100 parts, and the mixture was kneaded. Note that the symbols listed in Table 1 represent the following additives, respectively. ● Dispersant column: MF... "Melment-F10" (melamine formalin condensate sulfonate, manufactured by Showa Denko K.K.), MG... "Maginone-100" (polyalkylaryl sulfonate, Yamasou Chemical Co., Ltd.) ), PS…“Pozolith No. 8” (lignin sulfonate, manufactured by Nisso Master Builders Co., Ltd.), Viscosity modifier column; MC…Methyl cellulose, HC…Hydroxyethyl cellulose, PVA…Polyvinyl alcohol, This Regarding the gypsum-cement composition slurry obtained in this way, the viscosity and flow values immediately after kneading and after 60 minutes of standing, the presence or absence of breathing due to standing, and the slurry droplets on the smooth surface formed by pouring the slurry. Whether or not a convex portion is formed when dropped;
The compressive strength of the cured product and the presence or absence of level reduction of the cured surface were tested at coagulation temperatures of 3°C and 32°C. Note that the viscosity of the slurry was measured using a B-type viscometer. The flow value was determined by flowing the slurry down onto a horizontal glass plate using a glass funnel (distance between glass plate surface and funnel leg end: 25 mm, inner diameter of funnel leg:
8mm, slurry amount: 100ml), indicated by its spread width. The larger this value is, the better the fluidity is. The presence or absence of convex formation by slurry droplets can be determined by measuring the flow value of the slurry as described above, and then determining whether convexities are formed directly below the funnel (at or near the center of the slurry where the flow has almost stopped). Judgment was made by visual observation. In addition, the compressive strength of the hardened body is 40 mm (height) x 40 mm (width) x 160 mm.
After pouring into a mold having dimensions of (length 5) and setting and hardening, measurements were taken 24 hours later. The results obtained are shown in Table 1. In each of the examples shown, neither breathing of the slurry nor reduction in the level of the cured surface due to standing was observed. Comparative Example 1 When the mixture agent PC-S was not used at all, the compressive strength of the obtained cured product was greatly affected by the coagulation temperature, and was large when the coagulation temperature was low (3°C), but When the condensation temperature was high (32°C), it decreased significantly (Experiments No. 1 and 2). Portland cement (hereinafter referred to as a) was used as a mixing agent.
The compressive strength of the resulting cured product was almost unaffected by the condensation temperature when only the following components were used: Convex portions were formed (Experiment Nos. 3 and 4). On the other hand, when only slag (hereinafter referred to as component b) was used as a mixture, the compressive strength of the resulting cured product was significantly reduced when the coagulation temperature was high (Experiments Nos. 5 and 6). In addition, the a component in the mixture PC-S is small, and the a/
When the value of (a+b) was less than 0.2, the compressive strength of the obtained cured product decreased significantly when the coagulation temperature was high (Experiment Nos. 7 and 8). Comparative Example 2 The a component in the mixture SC-S was large and a/(a
When the value of +b) exceeded 0.8, convex portions were formed when slurry drops were dropped on the smooth surface formed by pouring the slurry (Experiments Nos. 19 and 20). Example 1 Mixture agent PC-S having the composition specified in the present invention
When using the composition of the present invention obtained by blending the following in a predetermined ratio, the compressive strength of the resulting cured product is almost unaffected by the coagulation temperature, and even at high coagulation temperatures, the cured product's compressive strength remains unchanged. No significant decrease in compressive strength was observed. Further, when slurry droplets were dropped onto the smooth surface formed by pouring the slurry, no convex portions were formed (Experiments Nos. 9 to 18). Examples 2 to 6 Even when the types of materials used are changed, when the composition of the present invention is used, the compressive strength of the obtained cured product is hardly affected by the coagulation temperature, and even at high coagulation temperatures, No significant decrease in compressive strength of the cured product was observed. Furthermore, when slurry droplets were dropped onto a smooth surface formed by pouring slurry, no convex portions were formed (Experiments Nos. 27 to 36;
41, 42; 45, 46; 49-52). Comparative Examples 3 to 6 On the other hand, when compositions outside the range of the compositions of the present invention were used, no satisfactory results were obtained. Comparative Examples 4 to 6 When the mixture agent PC-S was not used at all, the compressive strength of the cured products obtained when the coagulation temperature was high was observed to be significantly reduced (experimental
No. 39, 40; 43, 44; 47, 48). Comparative Examples 3 to 4 When a composition outside the range of the composition of the present invention was used, convex portions were formed when a slurry droplet was dropped on a smooth surface formed by pouring the slurry (Experiment No. 21-26; 37, 38), and a decrease in compressive strength was observed in the cured products obtained when the coagulation temperature was high (Experiments Nos. 23-26).

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Claims (1)

[Claims] Per 100 parts by weight of type 1 anhydrite, per 100 parts by weight of a mixture consisting of 0.2 to 5.0 parts by weight of potassium sulfate, 0.5 to 10.0 parts by weight of an alkaline substance, and 2 to 15 parts by weight of alpha hemihydrate, portland cement and slag. 30 to 150 parts by weight of a Portland cement-slag mixture with a mixing ratio of 20 to 80 to 80 to 20 by weight, and if necessary, known setting regulators, antifoaming agents, dispersants, viscosity regulators, and aggregates. An anhydrite composition comprising appropriate amounts of the following.