JP2005290172A - Self-collapse type solidified product and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-collapse type solidified product which is a soil-solidified product, enabling it to self-collapse after being used, and to control the time of being collapsed. <P>SOLUTION: The self-collapse type solidified product is characterized by containing a delay type expandable material having a mildly expanding property in the solidified product obtained by solidifying soil with a solidifying material composed mainly of light burned magnesia. A raw material containing the solidifying material composed mainly of light burned magnesia, soil, the delay type expandable material having the mildly expanding property, and optionally compounded aggregates and an admixture, is mixed with water followed by solidifying the resultant mixture, Wherein calcined magnesia baked at a high temperature of 1,200°C or higher, is contained as the delay type expandable material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a self-disintegrating solid material obtained by solidifying soil and its use. More specifically, the soil solid material is formed by a self-disintegrating solid material and a self-disintegrating solid material that can be self-disintegrated after the period of use by containing a delayed-type expansive material and the disintegration timing can be controlled. Related to the underwater structure.

  Recently, the needs for concrete products are diversifying. For example, for natural type environmental products such as revetment blocks, there is a demand for a product that maintains strength until the roots of the plants are stretched, and after the vegetation has flourished, the concrete may decrease in strength and naturally collapse. Examples of such self-destructing concrete products include self-degrading concrete products using biodegradable polymers, self-destructing concrete products using an alkali-aggregate reaction (Patent Document 1), A self-destructive concrete product (Patent Document 2) using an internal expansion force generated by corrosion has been proposed. However, all of these concrete products have a problem that the collapse time cannot be controlled freely because the collapse action depends on natural decomposition and corrosion.

On the other hand, a technique for solidifying soil using light-burned magnesia is known, and this soil-hardened molded product is known to be able to produce a high-strength molded product by performing press molding or extrusion molding. (Patent Document 3). This molded product is widely used for road pavement materials, earth retaining materials, landscape materials, etc., but it is exclusively intended to obtain a high-strength hardened soil, and is expected to self-collapse after use. It does not include that means.
Open 2002-291359 JP 52-81280 A Japanese Patent Laid-Open No. 2001-200252

  The present invention solves the above-mentioned conventional problems, and by using a delayed expansion material having a slower reaction rate than conventional expansion materials for soil solids, it can self-collapse after a period of use. Another object of the present invention is to provide a self-disintegrating solid that can control the disintegration time by controlling the reaction rate of the expansion material.

According to the present invention, the following self-disintegrating solids and the like are provided.
(1) A self-disintegrating solid material characterized in that a solid material obtained by solidifying soil with a solidifying material contains a delayed expansion material having a slow expansion effect.
(2) Mixing water with a solidified material mainly composed of light-burned magnesia, soil, a delayed expansion material having a slow expansion effect, and a raw material containing an aggregate and an admixture blended as necessary. The self-disintegrating solid material according to (1), which is solidified as described above.
(3) The self-disintegrating solid material according to the above (1) or (2), wherein the delay-type expansion material having a slow expansion effect is a magnesia-based delay-type expansion material.
(4) The self-disintegrating solid material according to any one of the above (1) to (3), wherein the delayed-type expansion material having a gradual expansion action is heavy-burned magnesia fired at a high temperature of 1200 ° C. or higher.
(5) A solid material according to any one of (1) to (4) above, which has continuous pores and is filled with a medium in the continuous pores, and is a self-disintegrating solid material for planting.
(6) For solid planting according to any one of (1) to (4) above, having a pot-shaped recess that opens on the surface, and filling the pot-shaped recess with a medium. Self-disintegrating solids.
(7) A self-disintegrating submerged structure or ground which is installed in water formed by the solid material described in any one of (1) to (6) above or buried in a wet ground Medium structure.

[Specific description]
The self-disintegrating solid material of the present invention is a self-disintegrating solid material characterized in that a solid material obtained by solidifying soil with a solidifying material contains a delayed-type expansion material having a slow expansion effect, for example, Mixing water into a solidified material mainly composed of light-burned magnesia, soil, a delayed expansion material having a slow expansion action, and a raw material containing an aggregate and an admixture blended as necessary. It is a self-disintegrating solid that is solidified.

  Conventionally, lime-based materials mainly composed of quick lime and CSA-based expanded materials mainly composed of calcium sulfoaluminate (CSA) are known as concrete expanded materials. However, since both the conventional lime-based expandable material and CSA-based expandable material are almost completely expanded at an age of about 7 days, they cannot be used as delayed-type expandable materials that exert an expansion action after a long period of time. As a method of delaying the reaction time of this conventional expanding material, (a) a method of decreasing the chemical activity by raising the firing temperature of the expanding material and tightening, (b) increasing the particles of the expanding material, Examples thereof include a method of delaying the hydration reaction by reducing the surface area, and (c) a method of coding a substance that gradually dissolves in water on the surface of the expansion material.

  The delayed expansion material used in the present invention may have a delayed reaction time by any of the methods (a), (b), and (c), but is different from conventional lime-based expansion materials and CSA-based expansion materials. A remarkable effect can be obtained by using an expansion material (referred to as a magnesia-based expansion material) containing as a main component.

  In general, magnesia is mainly light-burned magnesia obtained by baking magnesium carbonate at 800 ° C. to 900 ° C., and heavy-burned magnesia obtained by baking at a higher temperature, for example, 1500 ° C. or higher (generally over-burned magnesia or dead magnesia). It is also called baked magnesia). Light-burned magnesia is suitable for a relatively early reaction because of its relatively high activity, and heavy-burned magnesia is suitable for the delayed expansion material of the present invention because of its low activity and therefore slow reaction. According to the test example of the present invention, if the magnesia firing temperature is 1200 ° C. or higher, a sufficiently slow expansibility (this is referred to as a slow-expanding action) can be obtained. If the firing temperature exceeds 1650 ° C., the slow-acting expansion action is not very different, and rather the firing cost increases. Therefore, heavy firing magnesia fired at 1200 ° C. to 1650 ° C. is preferred in practice.

  In the present invention, the chemical activity, that is, the expansion timing can be controlled by adjusting the firing temperature of magnesia, which is the main component of the expansion material, or the particle size at the time of pulverization. Further, the amount of expansion, that is, the self-disintegration power can be controlled by adjusting the content of the expansion material in the solid.

  The self-disintegrating solid material of the present invention is a solid material obtained by solidifying a soil with a solidifying material, for example, a solidified material containing light-burned magnesia as a main component, and containing the delayed expansion material. Specifically, for example, the delayed expansion material is mixed with a solidified material mainly composed of light-burned magnesia, soil, and an aggregate and an admixture mixed as necessary, and water is added. It is a solid substance formed by mixing and solidifying.

  As the solidifying material used in the present invention, ordinary cement, blast furnace cement, fly ash cement, colloidal cement, super fast hardening cement and other cement, cement-based solidified material based on cement, lime, lime based lime based material There are solidification materials, cement-lime composite solidification materials combining the functions of cement-based solidification materials and lime-based solidification materials, and water glass.

Further, as a solidifying material mainly composed of light-burned magnesia, magnesia cement, light-burned magnesia, light-burned magnesia, and magnesia chloride and / or gypsum and other auxiliary agents are added. The solidified material mainly composed of light-burned magnesia refers to a material containing 20% by weight or more of light-burned magnesia in the solidified material. Among these, those containing 50% or more of light-burned magnesia are preferable. The mixing amount of the solidifying material varies depending on the properties of the soil and the like, but may be about 100 to 800 kg with respect to 1 m ^{3 of} solid matter. Aggregates are mixed as needed. As the type of aggregate, either fine aggregate or coarse aggregate can be used. The admixture is an admixture generally used for solidifying soil and a general admixture for concrete. The amount of these soil, solidified material, aggregate and the like is not limited.

  The self-disintegrating solid material of the present invention having continuous pores can be used as a solid material for planting by filling the continuous pores with a medium such as soil or fertilizer. Moreover, the self-disintegrating solid material of the present invention, which has a pot-shaped recess opening on the surface, is filled as a solid material for planting by filling the pot-shaped recess with a medium such as soil or fertilizer. Can be used. Any of these solid materials can be easily adapted to the surrounding environment because they are cracked by the action of the delay-type expansion material after a predetermined period of time and self-collapse.

  In addition, since the underwater structure formed by the self-disintegrating solid material of the present invention is self-disintegrating due to the action of the delay-type expansion material after a predetermined period of time after being installed in water, This is useful for temporary structures underwater. The same applies when buried in wet ground.

  In the self-disintegrating solid material of the present invention, the use of a solidified material mainly composed of light-burned magnesia and soil has a lower alkalinity than a commercially available Portland cement-based solidified material, and is suitable for plants and organisms. Since it returns to the soil after several years, it is particularly advantageous when applied to concrete products that require consideration for the environment.

  The self-disintegrating solid material of the present invention is characterized in that it contains a delay-type expansion material having a gradual expansion action as described above, preferably a delay-type expansion material mainly composed of heavy burned magnesia. After a long period of time, it slowly cracks in the solid substance due to its slow expansion action and self-collapses. This expansion time depends on the natural environment, such as corrosion of iron materials and biodegradation of polymer compounds. Unlike conventional self-destructive action, for example, the firing temperature of magnesia, which is the main component of the expansion material, and during grinding Since it depends on the particle size, the amount of the expanding material, etc., the decay time can be controlled by adjusting these.

  Hereinafter, the present invention will be specifically described by way of examples.

Using a mortar with the composition shown in Table 1, a test specimen (dimension 40 × 40 × 160 mm) was prepared in accordance with JIS R 5201 (cement physical test method), and a 60 ° C. hot water curing test was performed on this test specimen. It was. About each test body, length was measured based on JIS A 1129 (the mortar and concrete length change test method), and the external appearance was observed. The results for the test specimens having different firing temperatures are shown in Tables 2 to 4. Table 2 shows the results of immersion in hot water at 60 ° C. for 14 days using magnesia at each firing temperature, and Table 3 shows the cracks and collapsed state. Table 4 shows the results of immersion for 7 to 28 days for test specimens (5% powder, 5% granules, 10% powder, and 10% granules) using magnesia calcined at 1450 ° C. In addition, the particle size of magnesia used two types, powder (brane specific surface area 2000 ± 200 cm ² / g) and granules (diameter 0.3 to 0.6 mm).

  As shown in Table 2, almost no expansion was observed in the test body in which magnesia fired at 800 to 1000 ° C. was mixed in cement mortar. It is considered that this does not affect the change in the length of the mortar after curing because all the MgO components have reacted before the cement mortar is cured.

  On the other hand, as for the test body using magnesia baked at 1200-1500 ° C., the amount of expansion increases as the calcination temperature increases, the one baked at 1450 ° C. has the maximum expansion, and the one baked at 1500 ° C. has the expansion amount. Somewhat lower. Therefore, as shown in Table 3, cracks are seen from the mixture containing 10% of the magnesia powder baked at 1200 ° C., and collapse is observed from the mixture containing 10% of the magnesia powder baked at 1400 ° C.

  The amount of expansion differs depending on the firing temperature. As the firing temperature becomes higher than 1200 ° C., the tightening proceeds, the chemical activity gradually decreases, and the amount of highly active components that can react in room temperature water decreases, while the room temperature water The amount of the component that does not react in the reaction is extremely low and the unreacted component gradually reacts and expands as a result of accelerated curing. In addition, since a component with very low activity will start to increase when a calcination temperature exceeds 1500 degreeC, what does not react even if accelerated curing will remain, and the amount of expansion will reach a peak. Therefore, a preferable baking temperature is 1200-1600 degreeC, and the most desirable baking temperature is 1400-1500 degreeC. When the firing temperature exceeds 1600 ° C., the number of components having extremely low activity increases, the refractory material of the firing furnace becomes expensive, and the cost of firing energy increases, which is not suitable.

As shown in Table 2, when magnesia is powder (brane specific surface area 2000 ± 200 cm ² / g) and granule (diameter 0.3-0.6 mm), the granule has a larger expansion amount than the powder, and is 1400 ° C. or more. Those using calcined magnesia tend to collapse. Table 4 shows similar results. Since the expansion force concentrates and the destructive force increases, it collapses early, and when the particle size is reduced, the reaction with water increases, but since the expansion force is dispersed, the destructive force becomes smaller and the disintegration time is delayed. Because.

  From the above, it can be seen that the decay time is determined based on the three factors of magnesia firing temperature, particle size, and mixing amount, and that the decay time can be arbitrarily controlled by adjusting these three factors. In addition, although Table 1-Table 4 are the test examples using cement, the same result is obtained also about the solid substance which solidified soil using light-burned magnesia as a solidification material.

Claims (7)

A self-disintegrating solid material, characterized in that a solid material obtained by solidifying soil with a solidifying material contains a delayed expansion material having a slow expansion effect.
Solidified by mixing water with solidified material mainly composed of light-burned magnesia, soil, delayed expansion material with slow expansion, and aggregate and admixture blended as necessary. The self-disintegrating solid material according to claim 1.
The self-disintegrating solid material according to claim 1 or 2, wherein the delay-type expansion material having a slow expansion effect is a magnesia-based delay-type expansion material.
The self-disintegrating solid material according to any one of claims 1 to 3, wherein the delayed-type expansion material having a slow expansion function is heavy-burned magnesia fired at a high temperature of 1200 ° C or higher.
The solid material according to any one of claims 1 to 4, wherein the solid material has continuous pores and is filled with a medium in the continuous pores for planting.
The solid material according to any one of claims 1 to 4, wherein the solid material has a pot-like recess that opens on the surface, and is filled with a medium in the pot-like recess. .
A self-disintegrating underwater structure or an underground structure, which is installed in water formed by the solid material according to any one of claims 1 to 6 or embedded in a wet ground.