JPS6357378B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a fired cement product having excellent mechanical strength. [Prior Art and its Problems] Conventionally, so-called prestressed concrete members using prestressing have been widely known as cement products with excellent mechanical strength. The prestressed concrete member is obtained by holding a steel wire or steel rod in a state where a high tensile stress occurs, embedding it in concrete, and curing the concrete part until it hardens. The prestressed concrete member obtained in this way is
Since compressive stress is applied to the central portion in the longitudinal direction, there are advantages such as an increase in apparent tensile strength and an increase in bending strength. However, extensive equipment is required to hold the buried steel wire or rod under tension until the concrete section has completely set. Moreover, the adhesion between the concrete part and the steel wire or steel rod must rely exclusively on drying and hardening of the concrete part, and the adhesion strength cannot be said to be sufficient. To compensate for this, it was necessary to take extra measures such as forming irregularities on the surface of the steel wire or steel rod. Other prior art techniques include those described in Japanese Patent Application Laid-open No. 121019/1983 filed by the present applicant. The technology described in the publication requires the required amount of cement,
A kneaded material made of aggregate, water, etc. is molded into a predetermined shape, the cement molded product is fired at an appropriate temperature, and then hydrated and hardened. Although the cement product thus obtained had extremely superior mechanical strength compared to ordinary cement products, it was not as good as the prestressed concrete member in terms of tensile strength and bending strength. [Problem-solving means and their effects] The present invention was created with the aim of solving the above-mentioned problems of the prior art, and the means taken for that purpose are: , If necessary, aggregates, reinforcing materials, admixtures, etc. are kneaded to the extent that shape retention is possible, and a metal wire is embedded in the kneaded material to form the kneaded material into an arbitrary shape. The surface of the cement is glazed, the glazed molded product is fired, and the resulting cement kneaded and fired product is hydrated.
Through the firing treatment and hydration treatment, the forces that tend to expand and contract between the cement kneaded and fired product and the metal wire buried therein are held in a restrained state. It is in. As is clear from the above solution, the method is characterized in that a firing treatment process and a hydration treatment process are employed during the process of manufacturing a cement fired product with embedded metal wires. That is, in the firing process, the metal wire embedded in the kneaded molded product expands, while the cement kneaded molded product surrounding the metal wire contracts, and in this phenomenon, the metal wire The wire and the cement kneaded molding are strongly bonded. During the cooling period after firing, the metal wire tends to contract, and in the subsequent hydration process, the cement kneaded and fired product tends to expand. However, since the cement kneaded and fired product and the metal wire buried inside are strongly bonded and restrained, the forces that try to expand and the forces that try to contract are balanced between them. will be done. Moreover, the surface of the metal wire is roughened during firing, and the cement kneaded molded product surrounding the metal wire hardens with large shrinkage during the firing process, so the adhesion between the metal wire and the cement kneaded and fired product is difficult. Extremely powerful. Thus, the cement fired product obtained according to the present invention (hereinafter referred to as the fired product of the present invention) exhibits excellent mechanical strength. [Example] First, cement such as Portland cement, alumina cement, blast furnace slag cement, or mixed cement, and water, and if necessary, an admixture such as aggregate such as silica sand, reinforcing material such as alkali-resistant glass fiber, and water reducing agent, etc. One or more of these are kneaded to the extent that shape retention is possible. Next, a metal wire is embedded in this kneaded material, and a molded product having a shape as shown in FIGS. 1 and 2 is obtained by an extrusion molding method. For extrusion molding in this case, for example, a molding method such as that disclosed in Japanese Patent Publication No. Sho 53-22082, in which a reinforcing core material is wrapped inside the kneaded material and extruded at the same time, or a molding method is used. The molded product 1 shown in FIG. 1 is an example of a plate-shaped product having a rectangular cross section. In the plate-shaped molded product 1, metal wires 2, 2, such as mild steel wire, hard steel wire, or piano wire, are wrapped around both ends of the rectangular cross section. When wrapping the metal wire 2 in the plate-shaped molded product 1, no tension is applied to the metal wire 2. This point is completely different from the case of conventional so-called prestressed concrete members. The molded product 1 shown in FIG. 2 is an example of a product molded into a rectangular tubular shape with a through hole 3 formed in the center in the axial direction. Inside the rectangular tubular molded product 1, there are metal wires 2, 2, 2, 2 near the four corners of the rectangular cross section.
is embedded. Both the one shown in FIG. 1 and the one shown in FIG. 2 are formed thin.
This is to ensure good penetration of the hydration reaction in the subsequent hydration treatment step. Here, thin means that it is thinner or thinner than conventional concrete blocks used for horizontal construction of walls, for example. Such a thin wall contributes to the expression of the effects brought about by the firing treatment and the hydration treatment, and also contributes to reducing the weight of the fired product of the present invention. The shape of the molded product 1 is not limited to that shown in Figures 1 and 2, and for example, the cross section is 12 x 25 (mm).
It may be a rod-shaped molded product with a thickness of . Of course,
The cross-sectional shape may be any shape such as circular, square, rectangular, or other polygonal shape. As for the metal wire 2 to be buried, since there is no need to apply tension at the time of burying, it does not matter whether it is straight or curved, and the surface should be roughened during firing or not particularly uneven. There is no need to form the same, and furthermore, it can be applied regardless of the size of the product. Next, the molded article 1 is glazed. For plate-shaped molded products 1 shown in FIG. 1 that do not have through-holes 3, glaze is applied only to the parts that are visible when the fired product of the present invention is used, or glazed and unglazed parts are separated. Arrange them alternately.
Regarding the one provided with the through hole 3 shown in Fig. 2,
The glaze 4 is applied to substantially the entire surface of the through hole 3 except for the inner surface thereof. The types of glazes used are raw glaze,
Any glaze such as fritted glaze or volatile glaze may be used. The glazing method may be any method that allows the glaze to adhere to the surface of the molded product, such as a wet method such as spraying, dipping, or painting, or a dry method, or a gas method. In addition, as a special glazing method, we carry out a self-glazing method in which soluble salts and glaze are added to the cement mixture in advance, the mixture is molded, and the additives are oozed out onto the surface of the fired product during the next firing process. You may. Next, the glazed molded product is fired.
The firing temperature and firing time when firing a glazed molded product are determined depending on the applied glaze 4 and the type of buried metal wire 2, but are usually 650°C to 650°C.
Bake at 900°C for 5 to 180 minutes. Note that the metal wire 2 is preferably made of hard steel wire or piano wire in terms of heat resistance and strength. Furthermore, this fired product is hardened by hydration treatment. When hydrating a fired product that has through holes 3 and is glazed on almost the entire surface other than the through holes 3 (for example, the shape shown in FIG. 2), the inner surface of the unglazed through holes 3 The water necessary for hydration curing is supplied from the part. Therefore, even if the glazed surface is covered with a glassy film that has almost no water permeability due to firing, there is no problem in hydrating and hardening the fired product, and sufficient strength can be developed. It is. Note that when hydrating a fired product that does not have through-holes 3 (for example, one having the shape shown in FIG. 1), water for hydration and hardening is supplied from the non-glazed surface. [Effects of the Invention] The fired product of the present invention produced as described above is significantly superior in mechanical strength to conventional cement products. In order to clarify this, a comparative test of bending strength was conducted on various types of conventional products and fired products of the present invention. The test conditions and results are shown below. () Test piece A, which is a fired product of the present invention, was manufactured under the conditions shown below. Portland cement (OPC): Silica sand:
Water reducing agent:water ratio 1:0.667:0.015:0.35
(weight ratio), and further add an appropriate amount of glass fiber and knead. This kneaded material was molded using a die-pressing method to obtain a shape as shown in Fig. 1 (k ₁ = 120 mm, k ₂ = 50 mm, k ₃
= 10 mm), and two metal wires (piano wires) 2 with a diameter of 2 mm are k ₄ = 10 mm from the left and right end surfaces 1a and 1b, respectively, and k ₅ from the top surface 1c and bottom surface 1d, respectively. The plate was buried parallel to the longitudinal direction of the plate at a distance of 5 mm, and was left to stand for 2 days before being removed from the mold. This demolded molded product is baked at 850°C for 20 minutes. This fired product is cured in water for 28 days. () Conditions for conventional test piece B Kneading conditions are the same as test piece A Molding conditions are the same as test piece A except that the piano wire is not buried Baking is not performed Underwater curing conditions are the same as test piece A () Conventional Conditions for test piece C: Kneading conditions are the same as test piece A. Molding conditions are the same as test piece A, except that the piano wire is not buried. Firing conditions are the same as test piece A. Underwater curing conditions are the same as test piece A. () Conventional Conditions for test piece D: Kneading conditions are the same as test piece A. Molding conditions are the same as test piece A. No baking. Underwater curing conditions are the same as test piece A. Bending of these test pieces A, B, C, and D. strength,
The bending strength was measured using a Tensilon UTM-1-2500 testing machine under test conditions of a span interval of 100 mm and a loading rate of 1 mm/min. The results are shown in the table.

[Table] As shown above, test piece A is a fired product of the present invention.
The bending strength of the specimens was significantly improved compared to that of the conventional specimens B, C, and D, and this increase in strength far exceeded the expectations of those skilled in the art. Examining the test results in the table above from the perspective of whether piano wire was buried or not, the bending strength of test specimen D with piano wire buried was 161 kg/cm ² ,
The bending strength of test specimen B without piano wire buried is 90
Kg/cm ² , the increase in bending strength due to burying the piano is 71 Kg/cm ² . Furthermore, when considering whether or not firing treatment was performed, the bending strength of test piece C that was fired was 123 kg/ ^cm2 , and the bending strength of test piece B that was not fired was 90 kg/ ^cm2 . Therefore, the increase in bending strength due to firing treatment is 33Kg/
^cm2 . Therefore, if the burying of the piano wire and the firing treatment are carried out together, the expected increase in bending strength will be about 104 Kg/cm ² , which corresponds to the sum of the above-mentioned 71 Kg/cm ^{2 and 33 Kg/cm 2 .} This is common. However, in relation to test piece B, the bending strength of test piece A, which is different in that the piano wire was buried and the firing process was performed, is 28 kg/ ^cm2 , so the difference from the bending strength of test piece B is In fact, it is 193Kg/cm ² . Comparing this value with the above-mentioned predicted increase of 104 Kg/cm ² , it reaches about 1.9 times. This shows that the fired product of the present invention shows a surprising improvement in strength. The reason why the fired product of the present invention exhibits the excellent high strength as described above is due to the synergistic effect of the embedding of the metal wire, the firing treatment, and the hydration treatment, and the mechanism is thought to be as follows. That is, when the firing treatment is carried out, the surface of the metal wire is roughened and activated, and the metal wire is firmly bonded to the cement mixture. Furthermore, since the firing treatment is carried out in a state where the cement kneaded material after molding has not yet completely hardened, the cement kneaded material at that time shrinks significantly. However, the metal wire stretches during the firing process.
In such a state, the metal wire and the cement mixture are firmly bonded. Thereafter, when the firing is finished and the cooling period begins, the metal wire shrinks, and during the hydration treatment, the cement kneaded and fired product tends to expand. but,
Since the cement kneaded and fired product and the metal wire buried therein are bonded to each other in a dry and solid manner, the forces that tend to expand and the forces that tend to contract between them are balanced and held in a restrained state. Through this series of actions, the strength of the fired product of the present invention is unexpectedly improved. Moreover, the above-mentioned competing restraint conditions prevent penetration from occurring on the glaze surface applied to the fired product of the present invention. Since the fired product of the present invention has excellent mechanical strength as described above, it can be used in applications unimaginable with conventional cement fired products. That is, to give one example, it can be used as a constituent member of fences installed inside and outside parks and gardens, around houses, and other areas. 3 and 4 show a fence assembled from members made of the fired product of the present invention. The members constituting the fence include the second
As shown in the figure, a thin-walled cement fired product body 5 (see Figure 2) in the shape of a rod, plate, etc. is used, which is provided with a through hole 3 and has a glaze 4 on almost the entire surface other than the through hole 3. . The metal wire 2 as described above is embedded in the thin cement fired product body 5.
For example, as shown in FIG. 2, it is assumed that four metal wires 2 are equally distributed and buried in positions corresponding to the four corners of the through hole 3. However, the number is arbitrary. The fence in the illustrated example has a large number of vertical beam members 6 made of such a fired cement body 5.
They are assembled by arranging and fixing them with a frame member 7 or the like at an appropriate distance l, m, or n from each other. The fence shown in FIG. 4 is an example in which a relatively large frame member 7 with a roof-shaped cross section and a rectangular cross section is used as the frame member 7, and a vertical bar member 6 is used as a strip-shaped plate, which are assembled. The effects of the present invention can be summarized as follows. That is, since the fired product of the present invention can be provided with through holes or formed into a thin wall shape, it can be used as a lightweight and inexpensive construction member. Furthermore, the surface is glazed and the glazed surface is prevented from penetrating, making it beautiful and highly weather resistant. Furthermore, the cement kneaded and fired product and the metal wire buried inside are strongly bonded, and the expansion force and contraction force between them are maintained in a restrained state that is balanced against each other. Demonstrates outstanding strength not found in other products. The fired product of the present invention can be used, for example, to divide the inside and outside of a park or garden, or as a component of a fence that surrounds the exterior of a mansion. Since the arrangement can be fixed at appropriate intervals, ventilation is also good. Also, there are disadvantages of conventional products, such as unsightly appearance in concrete block walls, poor ventilation, danger during earthquakes, etc., difficulty in maintaining the aesthetic appearance over a long period of time in spritzstone blocks and pseudostones, and large weight. Disadvantages such as difficulty in handling with ceramic blocks, disadvantages such as drying time during construction, poor dimensional accuracy, high price and weight of ceramic blocks, and disadvantages such as poor weather resistance and easy rusting of painted metal fences. , poor color tone in aluminum fence,
All of the drawbacks such as high cost have been eliminated. In this way, the present invention has an excellent effect in that it can provide a member that can be used for assembling fences, etc., which could not be expected with conventional fired products.

[Brief explanation of the drawing]

The drawings are for explaining embodiments of the present invention, and FIG. 1 is a perspective view of a plate-shaped molded product with a rectangular cross section, and FIG. 2 is a perspective view of a tubular molded product with a rectangular cross section provided with a through hole. 3 and 4 are partially cutaway perspective views of a fence assembled using members that become the fired product of the present invention. 1...Molded product, 2...Metal wire, 3...Through hole,
4... Glaze, 5... Thin cement fired product body, 6
... Vertical beam member, 7... Frame member.

Claims (1)

[Claims] 1. Knead the required amount of cement and water, as well as aggregates, reinforcing materials, admixtures, etc. to the extent that shape retention is possible.
A metal wire is embedded in this kneaded product, the kneaded product is formed into an arbitrary shape, the surface of this molded product is glazed, the glazed molded product is fired, and the obtained cement kneaded and fired product is hydrated. By going through the firing treatment and hydration treatment, the forces that tend to expand and the forces that tend to contract between the cement kneaded fired product and the metal wire buried therein are held in a restrained state. A method for producing a fired cement product, characterized by: