KR101379095B1 - Method of manufacturing artificial stone - Google Patents

Abstract

The present invention provides a method for stably producing an artificial stone having a strength of quasi-pumice or more by using a large amount of ITO such as dredged soil. When the mixed material containing Ito and the binder is hydrated to produce an artificial stone, the mixed material satisfies the following conditions (a) to (c). (a) Ito is contained 40 volume% or more with respect to 100 volume% of mixed materials. (b) The binder consists of at least one selected from blast furnace slag powder, blast furnace slag powder with an alkali stimulant, blast furnace cement and ordinary portland cement. (c) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and (mass of blast furnace slag + mass of lime + mass of slag + mass of ordinary portland cement x 2) / (mixed material) In the case of satisfying <2.0 of mass in water) and further mixing fly ash as part of the binder, (mass of blast furnace slag + mass of lime + mass of slaked + mass of portland cement x 2 + mass of fly ash X 0.35) / (mass of water in the mixed material) ≤ 1.5 is satisfied.

Description

Method of manufacturing artificial stone {METHOD OF MANUFACTURING ARTIFICIAL STONE}

TECHNICAL FIELD This invention relates to the method of manufacturing an artificial stone by solidifying Ito, such as dredged soil, with a binder.

Fragile Ito, represented by dredged soil, occurs along the route dredging and various civil works. Among them, those useful as civil engineering materials such as sand can be used as they are in shallow composition, backfilling, or the like. However, Ito, which has a high proportion of silt, is often in a water-containing state, and since the strength as soil is hardly expected, it is often used as waste.

In order to effectively use Ito, various techniques have been proposed and implemented conventionally. The most representative of them is a technique for improving the characteristics as soil and using it with high quality soil. For example, various techniques for improving the characteristics of the ground by adding cement and lime to Ito are described in the "Kashima Publishing Society" by the Japan Lime Association.

In addition, Patent Literature 1 discloses a technique for improving strength by mixing steel slag with dredged soil. In this technique, the strength of dredged soil is mainly modified by pozzolanic reaction with CaO powder of steel slag and Si, Al of dredged soil. In addition, Patent Literature 2 discloses a technique in which a converter slag containing free CaaO and blast furnace cement are added to the soft soil to perform solidification treatment (improving strength). .

However, such a method is a property improvement as a soil material, and although the intensity | strength of the soil material level is expressed, it is limited to the use as soil only.

On the other hand, Patent Document 3 discloses a method of mixing a solidified material such as cement with dredged soil and solidifying it to obtain a block material (solidified body).

Japanese Patent Publication No. 2009-121167 Japanese Patent Laid-Open No. 2006-231208 Japanese Patent Publication No. 2008-182898

However, the block material strength obtained by the method of Patent Document 3 is a 6N / mm ² to about average, maximum, even a mere degree 8N / mm ^2. Here, in order to use it as a substitute for a stone or concrete material, the strength (9.8 N / mm ² or more) of quasi-hard stone or more prescribed in JIS-A-5006: 1995 (rubble) is required. The strength of the block material obtained by patent document 3 is the level of curbstone (lower than 9.8 N / mm <^2> ) of the lowest quality. Although the level of the curb is quite high compared to the level of improvement of the soil material, it is not sufficient strength to be used for various purposes in place of stone or concrete. In addition, when using a large amount of ITO having a high proportion of the sedimentary soil powder (less than 75 µm), which is often seen in soft dredged soil, it is easily expected that the securing of strength will be more difficult.

Accordingly, the object of the present invention is to solve the problems of the prior art as described above, and use quasi-pumice ore in large amounts, and in particular, considering the safety factor (+3 N / mm ² ) of quasi-pumice or more, the properties of the semi-pumice It is to provide a manufacturing method capable of stably producing an artificial stone that satisfies the above.

Background Art Conventionally, a technique for producing a steel slag hydrated solidified body using steel slag as a main raw material is known (for example, "Steel Slag Hydrated Solidified Body Technical Manual", (Foundation) Coastal Technology Research Center). This technique manufactures a hydrated solidified body using steelmaking slag for aggregate, and blast furnace slag fine powder and alkali stimulant, respectively, for a binder. The present inventors carried out the manufacturing experiment of the solidified body which substituted the material of the steel slag hydrated solidified body with dredged soil based on the manufacturing technique of the steel slag hydrated solidified body.

As an index indicating the degree of strength development of the steel slag hydrated solid, strength index = [(mass of blast furnace slag + slag of flour + 2 × mass of portland cement + 0.35 × mass of fly ash) / water Mass] is used. In the production of the steel slag hydrated solid, in order to express stable strength, the strength index is kneaded at a point of more than two. Since it was considered important to secure the strength even when the dredged soil was used as in the present invention, the kneading was performed by setting the ratio of water and the binder included in the dredged soil so as to satisfy the above-described strength index. By the way, in this test, the fluidity | liquidity of the kneaded material fell rapidly, As a result, it turned out that a cavity is formed at the time of pouring, and a hydrated solid is broken or strength is not fully expressed. That is, since it was thought that strength was difficult to be expressed by mixing dredged soil, the ratio of the binder and water was maintained at a known level (a technique for producing a steel slag hydrated solidified body), but proper kneading and pouring could not be performed. In the manufacturing technique according to the above, it has been found that it is difficult to manufacture artificial stones and blocks using dredged soil as raw materials.

Therefore, in order to improve the fluidity of the kneaded material, the present inventors examine the conditions under which the water can be kneaded while adding water to the dredged soil which originally holds water, and lowering the ratio of the binder and water to some extent. It was. As a result, although the intensity | strength may be expressed depending on conditions, it also turned out that sufficient strength may not come out even if it is comparatively close to it. As a result of further investigation, as a result, Ito represented by dredged soil may inhibit the pozzolanic reaction due to surface adsorption of soil particles, and when using a large amount of dredged soil, pozzolan by surface adsorption of soil particles It was found that inhibition of the response had a significant effect on intensity expression.

Dredged include, depending on the type of soil degree is different, Ca ^{2 +} and OH ^- It was found that the effect of the adsorption. 1 (a) and (b) show examples of changes in solution Ca concentration and pH when a calcium hydroxide solution is permeated through dredged soil collected from the Tama River and dredged soil collected from Tokyo Bay. It is shown. In this test, 2 g of dredged soil was filled in a permeation tube with a filter paper on the bottom surface, and an aqueous calcium hydroxide solution adjusted to pH 12 was added dropwise at 1 mL / min to recover a leaching solution. Ca concentration and OH ^- concentration were measured. According to FIG. 1, it turns out that Ca density | concentration of a solution and OH ^- concentration (pH) are changing large only by penetrating dredged soil. Ca ^{2 +} and OH ^- are the main constituents of the reaction product (CaO-SiO ₂ -H ₂ O gels) upon hydration solidification represented by cement. Ca ^{2 +} or OH ^- is adsorbed by the soil particles of the dredged since the concentration is decreased is believed that solidifies is inhibited. The Ca ^{2 +} and OH ^- adsorption of are those of the distinctive appearing when using the ITO, such as dredged, in the normal steel slag hydrated solidified that does not include ITO as the material, was not at all consciousness. As a result of extensive studies to solve these problems, the mass ratio between the binder and the soil particles in the soil is set to a predetermined value or more, and the water and the binder ratio are optimized in a range different from that of the conventional steel slag hydrated solidifying technique. It was found that a solidified body (stone) having a large amount of Ito, such as dredged soil, and having a stable strength can be obtained.

This invention is made | formed based on this knowledge, and makes the following a summary.

[1] A method for producing an artificial stone by hydrating and curing a mixed material containing an ITO and a binder, wherein the mixed material satisfies the following conditions (a) to (c). .

(a) It contains at least 40% by volume of earth.

(b) For 100% by volume of the mixed material, the binder comprises at least one selected from blast furnace slag fine powder, blast furnace slag fine powder added with an alkali stimulant, blast furnace cement and ordinary portland cement.

(c) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and the following formula is satisfied.

(Mass of blast furnace slag powder + mass of lime + mass of lime + mass of ordinary Portland cement x 2) / (mass of water in the mixed material) <2.0

[2] The production method of the above [1], wherein the binder contains 80 to 95 mass% of blast furnace slag fine powder, and the balance is usually at least one selected from portland cement, lime powder, slaked lime and blast furnace cement. The manufacturing method of the artificial stone to make.

[3] A method for producing an artificial stone by hydrating and curing a mixed material containing Ito and a binder, wherein the mixed material satisfies the following conditions (d) to (f).

(d) It contains 40 volume% or more of ITO with respect to 100 volume% of mixed materials.

(e) The binder is composed of at least one selected from blast furnace slag powder, blast furnace slag powder with an alkali stimulant, blast furnace cement and ordinary portland cement and fly ash.

(f) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and the following formula is satisfied.

(Mass of blast furnace slag + mass of lime + mass of lime + mass of ordinary Portland cement × 2 + mass of fly ash × 0.35) / (mass of water in the mixed material) ≤ 1.5

[4] In the production method of [3], the binder contains 70 to 85% by mass of blast furnace slag fine powder, and contains 10 to 30% by mass of fly ash in a ratio with respect to the mass of blast furnace slag fine powder. The method for producing an artificial stone, characterized in that the addition is usually at least one selected from Portland cement, lime powder, slaked lime, blast furnace cement.

[5] The method for producing artificial stone according to any one of the above [1] to [4], wherein the mixed material further includes aggregate.

[6] The method for producing an artificial stone, wherein the aggregate is steelmaking slag in the production method of the above [5].

[7] The method for producing artificial stone according to the production method of [6], wherein a compounding amount of the steelmaking slag per unit volume in the mixed material is 700 kg / m ³ or more.

[8] The method for producing an artificial stone according to any one of the above [1] to [7], in which Ito contains 65 vol% or more of particles having a particle size of 0.075 mm or less.

[9] The manufacturing method of any one of the above [1] to [8], wherein Ito is dredged soil generated from dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is used using the dredged soil stored in the dredged soil dump. Method of producing an artificial stone, characterized in that for producing.

According to the present invention, it is possible to stably produce an artificial stone having a strength of quasi-pumice or more by using a large amount of ITO such as dredged soil.

BRIEF DESCRIPTION OF THE DRAWINGS It is a graph which shows the example of the change of the solution Ca concentration and pH, when the calcium hydroxide solution permeated through dredged soil.
Fig. 2 is a graph showing the relationship between the mass ratio (bonding material / soil in ITO) of the binder mixed in the mixed material and the soil particles (solid content) in the soil and the strength (uniaxial compressive strength after 28 days of curing) of the solid.
Fig. 3 shows the strength index B / water (= [mass of blast furnace slag fine powder + mass of lime + mass of slag + mass of ordinary portland cement x 2 + mass of fly ash x 0.35) ] / [Mass of water in the mixed material]) and a slump value.
4 is a graph showing the relationship between the curing period and the strength (uniaxial compressive strength) of a solid.
It is a figure explaining one Embodiment of this invention using the dredged soil dump.

The present invention is a method for producing an artificial stone by kneading a mixed material containing Ito and a binder, more preferably an aggregate, and hydrating-curing (solidifying by a hydration reaction of the binder), wherein the mixed material has the following conditions ( a) to (c) are satisfied.

(a) It contains at least 40% by volume of earth.

(b) The binder consists of at least one selected from blast furnace slag powder, blast furnace slag powder with an alkali stimulant, blast furnace cement and ordinary portland cement.

(c) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and the following formula is satisfied.

(Mass of blast furnace slag powder + mass of lime + mass of lime + mass of ordinary Portland cement x 2) / (mass of water in the mixed material) <2.0

Moreover, a fly ash can be mix | blended further as a binder, In this case, a mixed material satisfy | fills the following conditions (d)-(f).

(d) contain at least 40% by volume of earth.

(e) The binder is composed of at least one selected from blast furnace slag powder, blast furnace slag powder with an alkali stimulant, blast furnace cement and ordinary portland cement and fly ash.

(f) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and the following formula is satisfied.

(Mass of blast furnace slag + mass of lime + mass of lime + mass of ordinary Portland cement × 2 + mass of fly ash × 0.35) / (mass of water in the mixed material) ≤ 1.5

Dredged soil is typical of the soil used in the present invention, but in addition, for example, mud generated from excavation work, construction sludge and the like can be mentioned. Here, itato generally means the thing which cannot carry out a bandit and shows the fluidity which a person cannot walk on it. As a rough strength, the cone index prescribed | regulated by JIS-A-1228: 2009 (a cone index test method of hardened soil) is 200 N / mm <^2> or less.

Ito represented by dredged soil is more effective in the adsorption of ions as the deposited soil powder increases, and in the prior art, it is difficult to obtain a solid having a suitable strength, and thus the production method according to the present invention is particularly useful. Specifically, the present invention can be said to be particularly useful when targeting the soil containing 65 vol% or more of soil particles (sedimentary soil powder) having a particle diameter of 0.075 mm or less.

In addition, in the following description, when it refers to the "sedimentary soil powder" of Ito, it shall refer to the particle | grains of particle size 0.075mm or less.

Since the present invention aims to effectively use ITO represented by dredged soil, it is preferable that the ratio of ITO in the mixed material is as large as possible, and therefore, the ratio of ITO in the mixed material (containing water contained in the original ITO). Ratio) to 40% by volume or more. In addition, although the upper limit of the ratio of the soil is not specifically limited, If the ratio of dredging soil is 60 volume% or less, the relative quantity of steelmaking slag will become an appropriate quantity, and the specific gravity of solidified body will not fall significantly below 2.0. If the specific gravity does not fall significantly below 2.0, it has utility as a stone substitute. Therefore, as for the ratio of the earth in a mixed material, 60 volume% or less is preferable.

Examples of the binder include blast furnace slag fine powder, blast furnace slag fine powder to which an alkali stimulant is added, blast furnace cement, and ordinary portland cement. One or more of these may be used.

In addition, from the viewpoint of reducing the environmental load without using natural materials as much as possible, and also from the viewpoint of securing the strength of the artificial stone (hereinafter sometimes referred to as "solidified body") and the manufacturing cost, as a binder, the blast furnace slag powder is alkali. Preference is given to the addition of stimulants. By using an alkali stimulant together with the blast furnace slag fine powder as a binder, an alkaline environment can be created, whereby the hydraulic properties of the blast furnace slag fine powder can be exhibited. That is, the hydration reaction of blast furnace slag fine powder can be accelerated | stimulated, and the intensity | strength of a solidified body can be ensured.

As the alkali stimulant, for example, one or more kinds of lime powder, slaked lime, ordinary portland cement, blast furnace cement and the like can be used. In this case, it is preferable that 80-95 mass% of fine blast furnace slag powders are contained, and remainder is 1 or more types chosen from lime powder, slaked lime, ordinary portland cement, and blast furnace cement. When using an alkali stimulant together with blast furnace slag fine powder as a binder, when the ratio of blast furnace slag fine powder is 80 mass% or more, an excess alkali component will not remain in a solidified body. For this reason, when the solid is used in the sea or the like, the load of alkali on the seawater environment is small. It is also economically advantageous. On the other hand, even if the ratio of blast furnace slag fine powder exceeds 95 mass%, it can knead | mix and solidify. However, when it is 95 mass% or less, since it is easy to disperse stably and the effect of a stimulant becomes small because of the alkali inhibitory effect of dredged soil, the effect of adding blast furnace slag powder is high, and it is not necessary to use various raw materials, Since there is no load on equipment, it has economic feasibility.

Since the suction action of the amount of the soil particles Ca ^{2 +} or OH ^{- -} Dredged such as ITO is Ca ^{2 +} and OH, as shown in Figure 1 and the potential to significantly impact the amount of adsorption of, and cement In the case of solidification by gelation, it was considered important to form a network of gels. Therefore, the factors involved in strength development were examined while changing the balance between the dredged soil and the binder. As a result, it was found that the amount of binder and the proportion of soil particles contained in dredged soil had a great influence on the strength.

Fig. 2 shows the results of examining the relationship between the mass ratio of the binder mixed in the mixed material and the soil particles (solid content) in the soil (bonding material / soil in the soil) and the strength of the solid (uniaxial compressive strength after 28 days of curing). In this test, 90 vol% of dredged soil was used as ITO, blast furnace slag fine powder was mainly used as a binder, and slaked lime and ordinary Portland cement were used as alkali stimulants. In addition, the ratio of the amount of binder in the mixed material and water was set to (mass of blast furnace slag + mass of lime + mass of slaked lime + ordinary portland cement x 2) / (mass of water in the mixed material) <2.0.

According to Figure 2, in order to secure the strength of the solidified body, it can be seen that a certain amount or more of the binder is required for the amount of soil particles of the soil. As the strength of the solid, there is no inherent problem as long as 9.8 N / mm ² or more, which is the required strength level of the semi-hard pumice, can be secured. However, when considering the dredged soil unevenness or manufacturing unevenness, it is necessary to ensure the quality of the target strength, such as raw concrete, having a strength margin of about 3N / mm ² . Specifically, if [the soil particles in the binder / ITO] ≥ 1.7, the uniaxial compressive strength after 28 days of curing can be about 15 N / mm ² having a strength margin. For this reason, the quantity of the binder in a mixed material shall be 1.7 times or more by mass ratio with respect to the soil particle (solid content) in soil. Moreover, since the mass ratio is 2.2 times or more, since stable intensity | strength expression can be expected even if there is a non-uniformity of dredged soil, it is more preferable.

On the other hand, if the amount of the binder is simply increased, the binder will be in an excessively large amount with respect to water, whereby a decrease in strength or a poor filling tends to occur. Regarding the ratio of water to the binder in the mixed material, the strength index based on the strength index used for the steel slag hydrated solid, that is, (mass of blast furnace slag + mass of lime + mass of slaked lime + mass of ordinary portland cement × 2) / (mass of water in the mixed material). In addition, since the blast furnace cement is a mixture of blast furnace slag fine powder and ordinary portland cement, the mass according to the mixing ratio of the blast furnace slag fine powder of the blast furnace cement is referred to as "mass of the blast furnace slag fine powder", and the mass according to the mixing ratio of the ordinary portland cement of the blast furnace cement. The above formula is applied as "usually the mass of portland cement."

In the case of the steel slag hydrated solid, the mixing ratio of the binder and the water is designed so that the strength index is 1.5 or more, and the condition exceeding 2.0 is common (refer to the "steel slag hydrated solidified body technical manual"). On the other hand, when dredged soil is used, it turns out that completely different conditions are needed. Water content ratio of dredged soil 220% (water ratio = ([water content (mass%) of dredged soil) / [solid amount (mass%) of dredged soil)]) * 100), and there is comparatively enough water such as 50% of dredged soil Table 1 shows the relationship between the strength index of the mixed material kneaded under the conditions and the strength (uniaxial compressive strength after 28 days of curing) of the obtained solid. According to this, the higher the strength index (i.e., the higher the ratio of binder to water), the higher the strength, but the limit is reached at about 1.95, resulting in poor kneading at a condition exceeding 2.3. From the above results, the amount of the binder is (mass of blast furnace slag + mass of lime + mass of slaked lime + ordinary portland cement x 2) / (mass of water in the mixed material) of less than 2.0, preferably 1.95 or less.

As a binder, a fly ash can be mix | blended further. For example, when steelmaking slag is mix | blended with an aggregate material as an aggregate as mentioned later, since a large amount of Ca is contained in steelmaking slag, alkali content may become excess. Since dredged soil is a main component, SiO ₂ can be stabilized by hydration reaction with excess alkali. However, since the mineral phase constituting the solid particles of the dredged soil varies depending on the dredging area and the history of occurrence, the reactivity may not be stable. In such cases, fly ash is blended as part of the binder. That is, it is preferable to use fly ash together with 1 or more types chosen from blast furnace slag fine powder, the blast furnace slag fine powder which added the alkali stimulator, blast furnace cement, and a normal portland cement.

Since the composition of the fly ash is the center of amorphous SiO ₂ and Al ₂ O ₃ , it can be expected that the pozzolanic reaction occurs more quickly than the crystalline material when excessive alkali is generated. However, when the fly ash is excessively blended, the amount of Ca in the binder is too small, which may impair the stability of the original reaction. From this point of view, when the fly ash is blended, the upper limit is about 40% by mass based on the ratio of at least one selected from blast furnace slag fine powder, blast furnace slag fine powder added with an alkali stimulant, blast furnace cement and ordinary portland cement. It is desirable to.

In addition, as described above, as the binder to be blended into the mixed material, it is particularly preferable to add an alkali stimulant to the blast furnace slag fine powder. When fly ash is used in combination with such a binder, 70 to 85% by mass of blast furnace slag powder is contained, and 10 to 30% by mass of fly ash is contained in the ratio of the mass of blast furnace slag fine powder, and the balance is usually Portland. It is preferable that it is at least 1 type chosen from cement, lime powder, slaked lime, and blast furnace cement. The reason for blending the blast furnace slag powder in the above range is basically the same as the reason described above. However, since fly ash is used in combination, the blending ratio of blast furnace slag fine powder is relatively small. In addition, as described above, when the fly ash is excessively blended, the amount of Ca in the binder is too small, which may impair the stability of the original reaction. Therefore, as for the compounding quantity of a fly ash, it is preferable to make an upper limit about 30 mass% as a ratio with respect to the mass of blast furnace slag fine powder. On the other hand, in order to acquire the effect by mix | blending a fly ash, it is preferable to make about 10 mass% as a minimum with respect to the mass of blast furnace slag fine powder.

When fly ash is blended as part of the binder, the ratio of water to the binder in the mixed material is a strength index corresponding to the strength index used for the steel slag hydrated solid, that is, (mass of blast furnace slag powder + mass of lime + It was found that the mass of calcined lime + mass of ordinary Portland cement x 2 + mass of fly ash x 0.35) / (mass of water in the mixed material). In addition, since the blast furnace cement is a mixture of blast furnace slag fine powder and ordinary portland cement, the mass according to the mixing ratio of the blast furnace slag fine powder of the blast furnace cement is referred to as "mass of the blast furnace slag fine powder", and the mass according to the mixing ratio of the ordinary portland cement of the blast furnace cement. The above formula is applied as "usually the mass of portland cement."

As described above, the strength of the solidified body when the fly ash is not blended as a binder reaches a critical point at the strength index of 1.95 and becomes poor in kneading at 2.3. However, when the fly ash is blended, the amount of powder in the mixed material is further increased. Therefore, it becomes easy to become kneading defect more. On the other hand, the result of having investigated the relationship between the said strength index and the slump value of a mixed material on the conditions which mix | blended 25 mass% of fly ash by the ratio with respect to the mass of blast furnace slag fine powder is shown in FIG. In this test, fly ash was further formulated by using blast furnace slag fine powder as a binder as a binder using 92 vol% of dredged soil as sediment, and using slaked lime as an alkali stimulant and ordinary portland cement.

According to FIG. 3, when the strength index is 1.5, the slump value is secured by 3 cm or more, and an appropriate kneading state is obtained. However, when the strength index exceeds 1.5, the slump value is greatly reduced, and the kneading starts to be poor even with the naked eye. The tendency to do was confirmed. For this reason, when the strength index exceeds 1.5, the strength itself reaches a limit that can be obtained, and when the strength index becomes larger, the strength decreases. Therefore, when fly ash is mix | blended as a part of binder, it is preferable that intensity index shall be 1.5 or less.

The amount of water in the mixed material is determined by the water content, volume fraction and strength index of the dredged soil. Generally, it is about 30 to 50% by volume ratio in the mixed material.

Aggregate can be mix | blended with a mixed material like concrete etc., and it is preferable to mix | blend aggregate from a characteristic point, such as volume stability. As aggregate, although natural sand and natural crushed stone can be used similarly to normal concrete, it is preferable to use steelmaking slag from a viewpoint of obtaining a high strength thing without including a natural resource as much as possible. In addition, since steelmaking slag is heavier (larger specific gravity) than natural crushed stone, by using this as aggregate, the weight (high specific gravity) of the solid can be secured.

Examples of the steelmaking slag include molten iron preliminary slag (talin slag, desulfurization slag, desulfurization slag, and the like), converter decarburization slag, and furnace slag. One or more of these may be used. The steelmaking slag is preferably one having a particle size of 25 mm or less.

As a volume ratio in the mixed material, about 15 to 50% of the aggregate is appropriate. In addition, when using steelmaking slag as an aggregate, it is preferable that the quantity of steelmaking slag in a mixed material is 700 kg / m <^3> or more from a viewpoint of the weight security and volume stability as a solidified body.

In the production method of the present invention, Ito, a binder, more preferably aggregate is blended, and a mixed material to which water is added is kneaded as necessary, and the kneaded material is solidified by a hydration reaction of the binder to obtain an artificial stone.

Ito, such as dredged soil, removes foreign matter by a sieve or the like as necessary. As a kneading means for the mixed material, for example, a kneading facility for fresh concrete may be used, but it may be carried out in a yard such as outdoors using a heavy machinery for civil engineering such as a shovel.

In order to solidify the kneaded material, for example, it may be poured into a suitable mold to solidify and cure (hydration hardening), or may be cast in a layered form such as outdoors to solidify and cure (hydration hardening). In particular, when producing a large amount of stone, it is preferable to pour a layer in the yard.

The result of having examined the relationship between the curing period and the intensity | strength (uniaxial compressive strength after 28 days of curing) of a solid body is shown in FIG. In this test, 60 vol% of dredged soil was used as distilled soil, blast furnace slag fine powder was mainly used as a binder, and slaked lime and ordinary portland cement were used as alkali stimulants. In addition, the ratio of the amount of binder in the mixed material and water was set to (mass of blast furnace slag + mass of lime + mass of slaked lime + ordinary portland cement x 2) / (mass of water in the mixed material) <2.0. The curing period is a period until the target compressive strength can be obtained, and as shown in FIG. 4, generally about 7 days or more is appropriate.

The obtained stone is crushed to an appropriate size as necessary. This crushing treatment may be performed using a crusher, or when the kneaded product is poured into the yard in the form of a layer as described above, the solids of the yard may be roughly crushed by a breaker, and then crushed by a crusher. . In addition, a crushed solidified body (mass) is usually classified by a sieve to obtain a mass of a predetermined size. For example, when used as a submerged breakwater material or the like, a mass of about 150 to 500 mm is obtained.

The stone preferably has a strength of 9.8 N / mm ² (hardness of semi-hard pumice prescribed in JIS-A-5006: 1995) of uniaxial compressive strength after 28 days of curing, and preferably of 15 N / mm ² or more of the present invention. According to the manufacturing method of this, the stone of such strength can be manufactured easily. In particular, solids produced using steelmaking slag as aggregates, in particular steelmaking slag as aggregates, and also solids produced using blast furnace slag fine powder and alkali stimulants (for example, ordinary Portland cement) as binders have sufficient strength and strength. Weight (high specific gravity) can be secured.

Next, the method of manufacturing the artificial stone by storing the dredged soil produced by the dredging work once in the dredged soil dump, and using the dredged soil stored in the dredged soil dump as the soil.

Dredged soils generated by dredging work have errors in water content depending on the location of dredging. In the case of farming marine products (seaweed, oysters, etc.) in the vicinity of dredging construction, there is a risk that fouling of seawater by dredging construction may affect marine products. It is not possible to carry out through), and there is a limit in the construction time (that is, seasonality). When carrying out this invention in such a situation, it is preferable to store the dredged soil which generate | occur | produced in dredging construction once in a dredged soil dump, and to manufacture solidified body using the dredged soil stored in this dredged soil dump. Thereby, even if there is an error in the dredged soil water content according to (i) the dredging place, the water content of the dredged soil can be averaged once by storing it in the dredged soil dump, and (ii) the construction time of dredging is limited, Even when there is a time when the dredged soil cannot be collected, it can be stored in the dredged dump to provide a stable supply of dredged soil to the solidified manufacturing process. (iii) By storing the dredged soil in the dredged soil dump, it is possible to easily perform the evaluation management and adjustment of the water content.

It is explanatory drawing which shows one Embodiment of this invention using the dredged soil dump. Dredged soil generated by dredging work is stored in dredged soil dump once. The shape and structure of the dredged dump may be arbitrary. For example, earth and sand may be piled up in the yard to form an annular embankment, and the dredged soil may be stored inside. Dredged soil generated by dredging construction is transferred to and stored in dredged soil dump regardless of its water content and other properties and conditions. The dredged soil supplied from this dredged soil dump is mix | blended with the binder mentioned above, More preferably, an aggregate, the mixing material which added water as needed is kneaded, and this kneaded material is solidified by the hydration reaction of a binder, and an artificial stone is produced. Get

[Example]

[Example 1]

The materials are blended and kneaded (mixed for 5 minutes in a 0.75 m ³ mixing plant and discharged after a predetermined time) under the mixing conditions shown in Tables 2 and 3, and the kneaded material of the mixed material is 100 mm in diameter x 200 mm in height. It was molded into a mold of a size and solidified to prepare a solid (artificial stone). The dredged soil was made up of 90% by volume of sedimentary soil collected from the water of Tokyo Bay, and water was added to adjust the water as needed. In addition, converter slag (particle size: 0-25 mm) was used as steelmaking slag which is an aggregate. The uniaxial compressive strength of the solid after 28 days of curing was measured by a compression test (JIS-A-1108: 2006). The results are shown in Tables 2 and 3 together.

According to Tables 2 and 3, in the examples of the present invention, solidified bodies (stones) of stable strength sufficiently satisfying the properties of the semi-hard stone are obtained even when the safety coefficient (+ 3N / mm ² ) is taken into consideration. On the other hand, in the comparative example, it becomes 9.8 N / mm <^2> or more, and has high intensity | strength compared with patent document 3, but considering the said safety coefficient, the solidified body of sufficient strength is not obtained.

[Example 2]

The materials are blended and kneaded (mixed for 5 minutes in a 0.75 m ³ mixing plant and discharged after a predetermined time) under the mixing conditions shown in Table 4, and the kneaded material of the mixed material is molded into a mold having a diameter of 100 mm x 200 mm in height. And solidified to prepare a solid (artificial stone). The dredged soil used 92 vol% of the sedimentary soil collected from the water of the Seto Inland Sea, and added water as needed to adjust the moisture. In addition, converter slag (particle size: 0-25 mm) was used as steelmaking slag which is an aggregate. The uniaxial compressive strength of the solid after 28 days of curing was measured by a compression test (JIS-A-1108: 2006). The results are shown in Table 4 together.

According to Table 4, in the example of this invention, even if the safety coefficient (+ 3N / mm <^2> ) is considered, the solidified body (stone) of the stable strength which fully satisfies the characteristic of a semi-hard pumice is obtained. On the other hand, in the comparative example, it becomes 9.8 N / mm <^2> or more, and has high intensity | strength compared with patent document 3, but considering the said safety coefficient, the solidified body of sufficient strength is not obtained.

Claims (19)

A method for producing an artificial stone by hydrating and curing a mixed material containing Ito and a binder, wherein the mixed material satisfies the following conditions (a) to (c).
(a) It contains 40 volume% or more of Ito with respect to 100 volume% of mixed materials.
(b) The binder consists of at least one selected from blast furnace slag powder, blast furnace slag powder with an alkali stimulant, blast furnace cement and ordinary portland cement.
(c) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and the following formula is satisfied.
(Mass of blast furnace slag powder + mass of lime + mass of lime + mass of ordinary Portland cement x 2) / (mass of water in the mixed material) <2.0 The method of claim 1,
The binder contains 80 to 95 mass% of blast furnace slag powder, and the balance is usually at least one selected from Portland cement, lime powder, slaked lime and blast furnace cement. A method for producing an artificial stone by hydrating and curing a mixed material containing Ito and a binder, wherein the mixed material satisfies the following conditions (d) to (f).
(d) containing at least 40% by volume of ITO based on 100% by volume of mixed material
(e) The binder consists of at least one selected from blast furnace slag powder, blast furnace slag powder with an alkali stimulant, blast furnace cement and ordinary portland cement and fly ash.
(f) The amount of binder is 1.7 times or more by mass ratio with respect to the soil particles (solid content) in the soil, and the following formula is satisfied.
(Mass of blast furnace slag + mass of lime + mass of lime + mass of ordinary Portland cement × 2 + mass of fly ash × 0.35) / (mass of water in the mixed material) ≤ 1.5 The method of claim 3,
The binder contains 70 to 85% by mass of blast furnace slag powder and 10 to 30% by mass of fly ash in proportion to the mass of the blast furnace slag powder, and the balance is usually selected from Portland cement, lime powder, slaked lime and blast furnace cement. The method for producing artificial stone, characterized in that at least one. 5. The method according to any one of claims 1 to 4,
A method for producing an artificial stone, characterized in that the mixed material further comprises aggregate. 6. The method of claim 5,
A method for producing an artificial stone, characterized in that the aggregate is steelmaking slag. The method according to claim 6,
A method for producing an artificial stone, characterized in that the compounding quantity of the steelmaking slag per unit volume in the mixed material is 700 kg / m ³ or more. 5. The method according to any one of claims 1 to 4,
A method for producing an artificial stone, characterized in that it contains 65 vol% or more of particles having a particle size of 0.075 mm or less. 6. The method of claim 5,
A method for producing an artificial stone, characterized in that it contains 65 vol% or more of particles having a particle size of 0.075 mm or less. The method according to claim 6,
A method for producing an artificial stone, characterized in that it contains 65 vol% or more of particles having a particle size of 0.075 mm or less. 8. The method of claim 7,
A method for producing an artificial stone, characterized in that it contains 65 vol% or more of particles having a particle size of 0.075 mm or less. 5. The method according to any one of claims 1 to 4,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. 6. The method of claim 5,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. The method according to claim 6,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. 8. The method of claim 7,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. 9. The method of claim 8,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. 10. The method of claim 9,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. 11. The method of claim 10,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump. 12. The method of claim 11,
A method for producing an artificial stone, in which Ito is dredged soil generated by dredging construction, and the dredged soil is stored in a dredged soil dump once, and an artificial stone is manufactured using the dredged soil stored in the dredged soil dump.

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