JPH034500B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing cement products, and more particularly to a method for obtaining cement products and glazed products with improved mechanical strength. (Prior art) Conventionally, cement products with high mechanical strength have been produced using cement,
A cement mixture containing aggregate and water (also called cement mortar). Pressure molding to make a cement molded product, baking it at around 800℃ before the cement molding has hardened by hydration, and manufacturing by hydrating and hardening this fired product. As shown in Publication No. 48464, a cement kneaded material (also called cement mortar) containing cement, aggregate and water is pressurized and dehydrated to form a cement molded product with a water-solid ratio of 0.15 or less,
After preliminary hydration hardening of the cement molded product,
It is manufactured by firing at around 800°C and hydrating and hardening the fired product. In addition, to manufacture glazed cement products with high mechanical strength, glaze is applied to the surface of the cement molded product treated as described above, and the glaze is baked at around 800°C to fuse the glaze to the cement molded product. A step of hydrating and curing this is performed. (Problems to be Solved by the Invention) However, the conventional manufacturing method described above has limitations in the molding method and hydration treatment, low base material strength of the fired product immediately after firing, and For example, the bending strength of the base material is only about 130Kgf/ ^cm2 ,
There were still problems with increasing the size or thinning of cement products. Therefore, the present invention is intended to solve the above-mentioned conventional problems, and is to provide a cement product or a glazed cement product that can achieve even higher mechanical strength without being subject to any restrictions on the molding method or hydration treatment. A manufacturing method is provided. Further, the present invention provides a method for producing a cement product, which is suitable for producing large and/or thin-walled cement products or glazed cement products because the mechanical strength of the finished product can be further increased. (Means for solving the problem) In research on cement mortar, the present inventor
It has been found that a hydrated and hardened cement mixture containing clay minerals such as talc significantly increases mechanical strength. This invention was achieved by utilizing the research results obtained. This first invention relates to a method for manufacturing a cement product, and the means of the first invention is a cement comprising cement, a clay mineral that can be reacted and sintered with CaO, another aggregate, and water. The kneaded material is formed by any molding method, and the cement molded product is
The process consists of firing at a temperature of ~900°C, reacting and sintering the clay mineral with CaO in the cement or the aggregate to form a fired product, and sufficiently hydrating and hardening the fired product. be done. The second invention relates to a method for manufacturing a glazed cement product in which a predetermined portion of the surface is glazed. A cement mixture made of cement and water is formed by any molding method, a glaze is applied to a predetermined surface of the cement molded product to make a glazed molded product, and the glazed molded product is
℃, the clay mineral is reacted and sintered with CaO in the cement or the aggregate to form a glazed fired product with fused glaze, and the glazed fired product is sufficiently hydrated and hardened. It is said that it consists of causing. The cement used in the present invention may be any of Portland cement, alumina cement, and mixed Portland cement. As the clay mineral, talc (3MgO・
4SiO ₂ H ₂ O), kaolinite (kaolin), sericite, etc. The aggregate is a stable material that does not undergo rapid expansion or contraction during the firing process, such as ceramic or porcelain shamots, sand, silica sand, sea sand, andesite, basalt,
Hard sandstone, feldspar, firestone, water slag, etc. are used, but the one that is particularly effective in terms of strength recovery effect is ceramic shamotsu. The raw material composition for the cement mixture is about 20 to 60 parts by weight of cement, about 15 to 55 parts by weight of clay minerals such as talc, preferably 20 to 50 parts by weight, and about 40 parts by weight or less of other aggregates, preferably. 25 parts by weight or less. For cement mixture,
Binder, sizing agent, etc. which are usually added to cement, clay minerals, aggregates and water during the manufacturing of cement products
Mixing agents such as water reducing agents, plasticizers, fluidizers, and dispersants can be appropriately selected and kneaded. The above-mentioned "arbitrary molding method" refers to the casting method, pressure dehydration molding method, extrusion molding method, centrifugal force molding method, paper forming method, press method, vibration press method, and spraying method used in the production of ordinary cement products. This concept includes any molding method such as molding method, roll method, etc. When producing a glazed cement product by the method of the second invention, preliminary firing may be performed at 300 to 400°C for about 30 to 60 minutes before or after the step of applying glaze to the cement molded product. desirable. Since water vapor and carbon dioxide gas are generated when cement hydrate is fired, such preliminary firing is performed in order to remove these in advance. This preliminary firing may be performed separately and independently from the main firing in the preheating section of the main firing furnace, but it is possible to perform the preliminary firing and main firing in the firing section of the main firing furnace without providing a time gap between them. It is also possible to carry out continuously. In the present invention, in addition to being able to use the inexpensive frit glaze used in the production of tiles, ceramic roof tiles, novelty tiles, etc. as is, it is possible to improve the weatherability of the glazed surface by appropriately blending physiological materials such as feldspar and clay with it. It can improve durability, abrasion resistance, and chemical resistance. Furthermore, the desired color and gloss of the glazed surface can be obtained. Other glazes that can be used in the present invention include raw glaze and developed glaze. Although the firing time and firing temperature in the firing step can be determined as appropriate within the above-mentioned temperature range, firing is usually performed at 650 to 900°C for 5 to 60 minutes. According to experiments to measure the mechanical strength of cement products obtained according to the present invention, the mechanical strength changes depending on the firing temperature, and the strength increases as the firing temperature increases up to around 800°C, but up to 900°C. It has been found that when the temperature exceeds this value, the strength decreases due to the progress of sintering and the intensification of shrinkage. (Function) In the first and second inventions, the hardening mechanism of the cement and talc that harden the cement kneaded material is considered as shown in Table 1.

【table】

[Table] In other words, cement particles have a C-S-
Generates H gel and Ca(OH) ₂ to develop strength. This C-S-H gel is dehydrated and decomposed by firing, but it becomes a C-S-H gel again by rehydration after firing and regains its strength. Unreacted cement particles at the initial hydration stage form C-S-H gel during rehydration after firing.
Talc, which generates Ca(OH) ₂ and develops strength, is dehydrated and activated during firing, and the surrounding CaO [Ca
CaO produced by the decomposition of (OH) ₂ , fuller's CaO present in trace amounts in cement, and CaO produced by decomposition of gypsum added to cement] is reacted and sintered to form a low-crystalline C-M-S system. It becomes a compound. Therefore, in the present invention, the strength of the base material immediately after firing is high, and the bending strength of the base material after hydration hardening can also be extremely strong. In the first invention, (a) the C-S-H gel produced by the hydration reaction of cement particles during the initial hydration stage before kneading, shaping and firing is dehydrated and decomposed in the firing process; It is rehydrated in the hydration process after firing, and C
-S-H gel, which helps increase the mechanical strength of cement products. (b) Unreacted cement particles in the initial hydration stage are activated during the calcination process, are hydrated and hardened in the hydration process after calcination, and function to increase the mechanical strength of cement products. (c) When firing at 650 to 900°C, sintering progresses and shrinks slowly, and the unhydrated parts inside the cement particles are hydrated and hardened to a considerable extent by curing after firing, further increasing the strength of the product. It works like this.
The "curing" referred to here may be any means that can sufficiently supply the required amount of water. (d) Clay minerals such as talc contained in the cement mixture are activated during the firing process and self-sinter, or react with CaO during cement mixing and sinter.
The strength of the base material immediately after firing is high because it changes into a low crystallinity compound such as M-S, and this substance does not change even during rehydration (hydration hardening) after firing, so it is important to improve the mechanical strength of cement products. Contribute to increase. In the second invention, (e) the glazed molded product is fired at 650 to 900°C, so that the glaze is reliably fused. (f) The other functions are basically the same as those of the first invention. (Example) According to the raw material composition shown in Table 2 below, this example No. 1
- No. 10, 10 formulations, and Comparative Examples No. 11 to No. 15, 5 formulations were each prepared.

【table】

[Table] Cement products were obtained by processing.

[Table] The bending strength was as shown in Table 4.

【table】

[Table] For preliminary hydration, the cement molded product is cured in humid air, and for firing, the temperature is raised at 10℃/min in a rapid firing furnace, and after the sample surface temperature reaches the specified temperature, it is fired for a specified period of time. did. Full-scale hydration was achieved through steam curing. The bending strength was measured using an autograph manufactured by Shimadzu Corporation, and the test conditions were a span interval of 90 mm, a loading rate of 2 mm/min, and a test piece size of 100 x 50 x 10 mm. As is clear from the bending strength results in Table 4,
It can be seen that samples No. 1 to No. 10 of this example are superior to those of the comparative example in terms of bending strength immediately after firing and bending strength after full-scale hydration treatment. (Effects of the Invention) According to the first invention, since the cement mixture contains clay minerals such as talc that can be reacted and sintered with CaO, the mechanical strength is improved, for example, compared to the conventional case in which clay minerals are not contained. It is possible to obtain a cement product that is approximately twice as high. In addition, in the present invention, the strength of the base material does not deteriorate at all during the firing process, so unlike conventional methods, there are no restrictions on the molding method or hydration treatment conditions. In the second invention, the cement mixture contains clay minerals that can be reacted and sintered with CaO, and is glazed during the manufacturing process, thereby obtaining a glazed cement product that has high functional strength as in the first invention. be able to. In addition, both of the present inventions can increase the base material strength of the fired product immediately after firing and also increase the base material bending strength after hydration hardening, so it is possible to improve the base material strength of the fired product immediately after firing, and also to increase the base material bending strength after hydration hardening. This is a preferable manufacturing method.

Claims (1)

[Claims] 1. A cement mixture consisting of cement, a clay mineral that can be reacted and sintered with CaO, other aggregates, and water is formed by any molding method, and the cement molded product is A cement characterized in that it is fired at a temperature of ~900°C, the clay mineral is reacted and sintered with CaO in the cement or the aggregate to form a fired product, and the fired product is sufficiently hydrated and hardened. How the product is manufactured. 2. The method for producing a cement product according to claim 1, wherein the clay mineral is talc powder consisting of 3MgO.4SiO ₂ .H ₂ O. 3. The other aggregate is ceramic siyamoto, porcelain ash, river sand, silica sand, sea sand, andesite, basalt,
The method for producing a cement product according to claim 1, wherein the cement product is at least one selected from the group consisting of hard sandstone, feldspar, flintstone, slag, and the like. 4. A cement mixture consisting of cement, clay minerals that can be reacted and sintered with CaO, other aggregates, and water is formed by any molding method, and a predetermined surface of the cement molded product is glazed. The glazed molded product is made into a glazed molded product, and the glazed molded product is fired at a temperature of 650 to 900°C, and the clay mineral is reacted and sintered with CaO in the cement or the aggregate to form a glazed product to which the glaze is fused. A method for producing a glazed cement product, which comprises producing a fired product and sufficiently hydrating and hardening the glazed fired product. 5. The method for producing a glazed cement product according to claim 4, wherein the clay mineral is talc powder consisting of 3MgO.4SiO ₂ .H ₂ O. 6. The other aggregates are ceramic siyamoto, porcelain ash, river sand, silica sand, sea sand, andesite, basalt,
The method for producing a glazed cement product according to claim 4, wherein the glazed cement product is at least one selected from the group consisting of hard sandstone, feldspar, anti-flint stone, slag, and the like. 7. The method for producing a glazed cement product according to claim 4, wherein the glaze is a fritted glaze alone or a fritted glaze mixed with raw materials such as feldspar.