JPH0520378B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a gypsum-based sink flooring composition and its construction method, and particularly to a composition containing molded anhydrite, Portland cement, and fly ash as essential components, and additives commonly used in the composition. The present invention relates to a method of carrying out distribution construction by mixing aggregate and water. (Prior art) Conventionally, a so-called "self-leveling floor" is used, in which a hydraulic mixture with good fluidity is spread on a concrete slab surface, etc., and a horizontal floor surface is formed by natural flow due to the mixture's own weight. construction method (floor or self-leveling floor) is popular. The advantage of this construction method is that it can be performed with very high efficiency without requiring any skill. Various cement-based and gypsum-based compositions are known as compositions for cast flooring, and these have the characteristics necessary for cast flooring: (1) fluidity, (2) curing speed, (3) workability, and (4) surface condition. Efforts have been made to improve dimensional accuracy, water resistance, etc. And flooring made of plaster was developed in Japanese Patent Application Publication No. 59.
It is known from Japanese Patent Publication No. 58-2188 and Japanese Patent Application Laid-open No. 58-35052, etc., and among them, those using molded anhydrite are
It is known from the publication No. 217455. (Problems to be Solved by the Invention) Mold anhydrous gypsum is generally used as a raw material for building materials, and in particular, as mentioned above, it is used in combination with blast furnace slag or blast furnace cement for cast flooring materials. However, in the conventional technology using the molded anhydrous gypsum, (1) cracks occur due to expansion and contraction of the construction material, (2) unevenness (small waves) occur during repainting,
(3) The finish of the construction was inadequate in terms of bubbles, wrinkles, etc. For this reason, there are problems in that careful attention is required during construction, various post-treatments, etc. must be carried out, and it is difficult to obtain a high-quality construction product. (Means for Solving the Problems) The present inventor has completed the present invention as a result of intensive research to solve the problems of the prior art. That is, in the present invention, in a gypsum-based cast flooring composition, a mixture consisting of 150 parts by weight of cast anhydrite, 65 to 80 parts by weight of Portland cement, and 20 to 40 parts by weight of fly ash is blended. A gypsum-based cast-rolled flooring composition characterized in that it has a molded anhydrous gypsum composition in terms of weight ratio.
150 parts by weight to 65 to 80 parts by weight of Portland cement
A gypsum-based pouring method characterized by mixing commonly used additives, aggregate, and water with a mixture consisting of 20 to 40 parts by weight of fly ash and spreading the mixture over the subfloor and then hardening it. This is a construction method for flooring materials. One of the features of the composition of the present invention is that it contains flyash, which has not been used in conventional cast flooring compositions using molded anhydrite. The present inventor has discovered that when flyash is mixed with molded anhydrite in a certain range of ratios, it is possible to significantly reduce the occurrence of cracks in the cured product and the occurrence of unevenness on its surface during the aging process. It is. A particularly suitable composition of the present invention is one comprising approximately 70 parts by weight of Portland cement and approximately 30 parts by weight of fly ash per 150 parts by weight of molded anhydrite. By the way, the high-quality conventionally constructed product has a surface strength of 7 kg/cm ² at 7 days old and a compressive strength of 200 kg/cm 2 at 28 days old.
Kg/cm ² and water resistance of about 150 Kg/cm ² or higher.Of course, the product of the present invention possesses such performance and is ranked as a high-class product as a construction product. Furthermore, another feature of the present invention is that compared to the conventional one,
The difference between expansion and contraction (absolute value of expansion and contraction) during the curing process is small, which prevents cracks from occurring in the construction product. In other words, the construction work is generally completed on the third day after construction (Material Order 3).
It takes a maximum expansion value around 14 days, and then shrinks and becomes almost stable on the 14th day. However, if the absolute value of the difference between the maximum expansion value and the contraction value on the 14th day is large, Cracks will occur. Figure 2 is a diagram to explain this, and shows that the composition of (a) has a difference in expansion and contraction (this is the absolute value of the volume change) between 3 days and 14 days of age. This means that the size is considerably larger than that of 3, but the absolute value of the expansion and contraction is reduced in the case of the present invention. Type anhydrite is mainly orthorhombic anhydrous calcium sulfate obtained as a by-product during the production of hydrofluoric acid, but its strength is high, and Portland cement is mainly composed of tricalcium silicate and dicalcium silicate. Although it is hydraulic in itself, it reacts with pozzolans such as fly ash to form solids with high long-term strength. Fly ash is a byproduct of pulverized coal combustion in thermal power plants.
It is not hydraulic in itself, but when mixed with cement, the siliceous substance therein gradually reacts with calcium hydroxide produced by the hydration reaction of cement, producing stable insoluble calcium silicate. Fly ash is a compound that increases strength over a long period of time, and improves watertightness and durability.However, fly ash is a roughly spherical particle with a diameter of about 20 to 30 microns and has a smooth surface, so it acts like a ball bearing in concrete. It works to improve fluidity. In the present invention, the blending composition is limited to a certain range of numerical values as described above, and the reason for this is that the inventor's experimental results revealed the following. That is, (1) 3 which is a problem considering the finished condition as a floor.
Characteristics: Cracks, wrinkles, bubbles were visually observed and evaluated by multiple people.
``Those containing an appropriate amount of fly ash have an improvement effect compared to conventional ones. (2) Concerning the unevenness that occurs at the joints of paint during construction, ``products containing an appropriate amount of fly ash will be reduced by a ball-bearing-like action compared to conventional products. ” (3) Expansion;
The difference in shrinkage (absolute value of expansion and contraction) is smaller when a suitable amount of fly ash is blended than with conventional products. In other words, ``It is effective in preventing cracks. ' If the amount of Portland cement is less than 65 parts by weight for 150 parts by weight of molded anhydrite, a hardened product with high strength cannot be obtained, and if it exceeds 80 parts by weight, cracks are observed and the fluidity is not sufficient. Not only will construction not be carried out smoothly, but it will also generate small waves due to unevenness. In addition, if the fly ash is less than 20 parts by weight, the fluidity will decrease, the degree of shrinkage will increase and cracks will occur, and the long-term strength will not increase, and if it exceeds 40 parts by weight, the viscosity will increase and the fluidity will not be sufficient. , the strength of the cured product also decreases. It goes without saying that in the present invention, conventional additives may be added in conventional amounts. Commonly used additives include alkaline agents such as slaked lime and quicklime, water reducing agents such as melamine formalin condensed sulfonates, water retaining agents such as methyl cellulose and hydroxyethyl cellulose, and antifoaming agents such as silicone surfactants. It is used by adding it as needed. During construction, aggregate and water are further added, and silica sand, river sand, etc. are used as the aggregate. In construction, the composition of the present invention is mixed with aggregate, additives, and water to form a slurry, which is spread on the concrete slab floor to promote self-leveling, and then wait for hardening. The composition of the present invention, aggregate, additives, and water have a flow value of 220 ± 15 mm, preferably 220 ± 10 mm.
mm, especially preferably 220±5 mm. As an additive, alkaline agent type anhydrite
9 to 18 parts by weight per 150 parts by weight, water reducing agent 1 to 4 parts by weight per 150 parts by weight of molded anhydrite, water retention agent 0.12 to 0.25 parts by weight per 150 parts by weight of molded anhydrite
The antifoaming agent is preferably added in an amount of 0.065 to 0.125 parts by weight per 150 parts by weight of molded anhydrite. The aggregate is preferably blended in an amount of 50 to 100 parts by weight based on 150 parts by weight of the molded anhydrite. Next, the results of a comparative test using a composition within the scope of the present invention and another composition will be explained. The following various tests were conducted on test specimens of each formulation listed in Table 1. The measurement method for each test is as follows. [Flow value] A polyvinyl chloride cylinder (capacity 100ml) with an inner diameter of 5cm and a height of 5.1cm is filled with slurry, and when the cylinder is quickly pulled up, the diameter of the spread of the slurry in two orthogonal directions is measured after 2 minutes. do. [Surface strength] Pour the slurry into a frame with a height of 30 mm and a side of 500 mm on a PC plate (500 x 500 x 50 mm) and heat it at room temperature.
After being allowed to stand for 1 day, it is left to stand for an additional 25 days at room temperature. Measurements are made using a Sakuma surface strength tester 7 and 28 days after pouring, respectively. That is, steel attachment 3 with a diameter of 100 mm.
Alternatively, adhere five pieces with epoxy resin and measure the stress required to peel each piece off. [Bending strength and compressive strength] JISR5201 with internal length 160 mm, width 40 mm, and depth 40 mm
The slurry was poured into a triple mold, left to stand at room temperature for 3 days, and then the solidified composition was taken out and measured as a test piece after 7 days, and further left to stand at room temperature for 25 days before being measured as a test piece. Bending strength was measured using a Michaelis testing machine. The span between two rolls (diameter 8mm) is 100
mm, place the test specimen vertically on top of it, and calculate the maximum load by applying a load to the center of the span using one roll (8 m in diameter). Bending strength (Kg/cm ² ) = 0.234 x maximum load (Kg) After measuring the bending strength, the compressive strength is determined by applying pressure from the top of the folded piece of the specimen placed on a horizontal surface with a square pressure plate of 40 mm on a side. Using a compressive strength testing machine with a maximum capacity of 20 tons, the material is crushed at an average pressurizing speed of 80 kg/sec, and the maximum load is measured. Compressive strength (Kg/cm ² ) = Maximum load (Kg) / 16 (cm ² ) [Water resistance] After leaving the specimen indoors for 21 days, it was immersed in water for 7 days, and the bending strength and compressive strength of the specimen were determined. It was measured. [Maximum expansion/contraction amount] Pour the test sample slurry (flow value: 220-230) into a mold to make a 4 x 4 x 16 cm test piece, and hold it at room temperature for 14 hours.
The amount of expansion and contraction in the long axis direction was measured using a contact gauge over a period of days. [Small wave height] Several joint rods (diameter 10 mm) were placed horizontally on a 550 mm square PC board to form a formwork, and the test sample slurry was thoroughly poured into it. After leaving it for 30 minutes, one Remove the joint bar. Next, by pouring another fresh specimen slurry to the same thickness so that the one joint rod was in contact with the side of the removed part,
After the coating was applied and left to cure for one day, the height of the surface irregularities (waves) of the cured product that occurred along the area of the coating was measured with a dial gauge with an accuracy of 1/100 mm. A schematic diagram is shown in Fig. 3. Of the additives added to all of the above test specimen numbers, the water retention agent was methylcellulose (Metrose 90SH30000 manufactured by Shin-Etsu Chemical Co., Ltd.), the water reducing agent was melamine formalin condensation sulfonate (Melment F10 manufactured by Showa Denko), And the antifoaming agent is a silicone antifoaming agent (SN Defoamer 14-HP manufactured by San Nobuco)
However, silica sand (No. 5) was used as the aggregate.

【table】

[Table] Items marked with * are outside the scope of the present invention.
The test results are shown in Table 2. Further, changes in expansion and contraction rates over time are shown graphically in FIG. In addition, in the same figure, A1 is for specimen number 1, A2 is for specimen number 2, A
3 is specimen number 3, A4 is specimen number 4, A5 is specimen number 5, B1 is specimen number 7, and B2 is specimen number 8. As can be seen from the above test results, the absolute value of the difference between expansion and contraction was large (causing cracks) and small waves (irregularities) were formed on the surface of specimens other than specimen numbers 3 and 4 falling within the scope of the present invention. However, test specimens Nos. 3 and 4, which are within the scope of the present invention, showed "difference in expansion and contraction (material age 3).
The maximum amount of expansion and contraction (×10 ^-4 mm) for 14 days and 14 days is 6.4~
7.8, and the "wave height" was 5.7 to 8.7 mm, which is significantly lower than other test specimens. When looking at the "maximum amount of expansion and contraction" among other test specimens, there are some that have performance comparable to that of the present invention, but if one performance is good, the other is bad. (Effects of the Invention) As described above, according to the present invention, the concrete obtained through construction not only has the performance of a high-grade product, but also has a low difference in expansion and expansion and contraction depending on the age of the material, and has a smooth surface. Since the height of small waves is not large, as a result, cracks do not occur in the product, and the surface flatness is also good. and,
It has now become possible to use fly ash in a new combination as a formulation for molded anhydrite-based cast flooring. Therefore, compared to conventionally known gypsum-based cast floor compositions, the present invention exhibits much superior effects and contributes greatly to this field.

[Brief explanation of the drawing]

Figure 1 is a graph showing the expansion and contraction states of Examples and Comparative Examples according to the present invention, Figure 2 is a graph explaining the absolute value of the difference between expansion and contraction, and Figure 3 is the joint area of the test specimen. A schematic diagram of the surface unevenness (small waves) state that occurs in this figure is shown. 1... PC version, 2... joint bar, 3... test specimen,
4...Painting area.

Claims (1)

[Claims] 1. In a gypsum-based poured flooring composition, the weight ratio is 150 parts by weight of molded anhydrite, 65 to 80 parts by weight of Portland cement, and 20 to 20 parts by weight of fly ash.
40 parts by weight of a gypsum-based cast flooring composition. 2. A mixture of 150 parts by weight of molded anhydrite, 65 to 80 parts by weight of Portland cement, and 20 to 40 parts by weight of flyash is mixed with commonly used additives, aggregate, and water, and this is used as a base material. A construction method for plaster-based flooring that is characterized by being spread on the floor and then hardening.