JP2018172245A - Manufacturing method of solidified body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a solidified body using dredged soil as a raw material, capable of ensuring a predetermined solidified body strength even under a condition where a curing temperature is low in a production process. SOLUTION: A mixture having a volume ratio of dredged soil (including water): 55-60%, binder: 19-37%, aggregate: 4-29% is prepared by a hydration reaction with a binder. A method for producing a solidified product by solidifying to obtain a solidified product, wherein (BP+2×NP+0.35×FA)/W (however, BP: mixture when the curing temperature in the solidification step of the mixture is 5 to 10° C. Compounding amount of blast furnace slag fine powder per 1 m3 (kg), NP: compounding amount of ordinary Portland cement per 1 m3 of mixture (kg), FA: compounding amount of fly ash per 1 m3 of mixture (kg), W: per 1 m3 of mixture By setting the strength index defined by the water content (kg) of 1.8 to 1.8 or more, a solidified body having a compressive strength after curing for 28 days of 15 N/mm 2 or more is obtained. [Selection diagram] None

Description

  The present invention relates to a method for producing a solidified body using clay as a raw material, and the solidified body to be produced is particularly suitable as an alternative material for stone for civil engineering.

The dredged soil generated during dredging work such as harbor channel dredging is generally very soft and not strong, so it is difficult to effectively use it as a civil engineering material as it is. Conventionally, in order to effectively use dredged soil, many techniques have been proposed for improving characteristics as soil and making it usable in the same way as high-quality soil (for example, Patent Documents 1 to 4). .
On the other hand, Patent Documents 5 to 7 show a method in which a solidified material such as cement is mixed with clay and solidified to form a block material (solidified body).

JP 2006-334518 A JP 2006-152150 A Japanese Patent No. 3924738 Japanese Patent No. 3375929 JP 2008-182898 A JP-A-10-127201 Japanese Patent No. 5907246

In order to use the solidified body as an alternative material for civil engineering materials, particularly stone materials, a predetermined strength (for example, a compressive strength of 9.8 N / mm ² or more in the case of semi-hard stone) is required. The strength of the solidified body is affected by the temperature (curing temperature) when the hydration reaction by the binder proceeds. In general, the blending amount of the binder in the mixture is determined under the condition of a curing temperature of 20 ° C, but when the production time is winter and the curing temperature is lower than 20 ° C, a predetermined strength is obtained. I can't.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and in a method for producing a solidified body using clay as a raw material, a predetermined solidified body strength can be obtained even under conditions where the curing temperature is low in the production process. It is providing the manufacturing method of the solidified body which can be ensured.

The gist of the present invention for solving the above problems is as follows.
[1] Mixing clay, aggregate, and binder, and the blending amount thereof is a volume ratio in the mixture, and clay (including moisture): 55-60%, binder: 19-37%, bone A material: a method of producing a solidified body in which a mixture of 4 to 29% is obtained and the mixture is solidified by a hydration reaction with a binder to obtain a solidified body,
When the curing temperature is 5 to 10 ° C. in the solidification step in which the mixture is solidified by a hydration reaction with the binder using at least one selected from blast furnace slag fine powder, ordinary Portland cement, and fly ash as the binder In addition,
By making the strength index defined by the following formula (1) of the mixture 1.8 or more, a solidified product having a compressive strength after curing for 28 days of 15 N / mm ² or more is obtained. Production method.
Strength index = (BP + 2 × NP + 0.35 × FA) / W (1)
However BP: mixture 1 m ³ amount of blast furnace slag per (kg)
NP: amount of ordinary Portland cement per mixture 1 m ³ (kg)
FA: amount of fly ash per mixture 1 m ³ (kg)
W: Water content per 1 m ^{3 of} mixture (kg)
[2] The method for producing a solidified body according to [1], wherein the aggregate is steel slag.

According to the present invention, when a solidified body using kneaded clay as a raw material is produced, even under conditions where the curing temperature in the production process is low in winter or the like, a predetermined strength (compressed strength after 28 days curing 15 N / mm) ² or more) can be produced.

The method of the present invention is a method for producing a solidified body obtained by mixing clay, aggregate and binder, and solidifying the mixture by a hydration reaction with the binder to obtain a solidified body. When it becomes -10 ° C, the required solidified body strength (compressive strength after curing on the 28th, 15 N / mm ² or more) can be obtained by prescribing the specific ratio of the binder in the mixture in relation to moisture. It is intended to be obtained.
In the present invention, the blending amount of the clay, aggregate, and binder in the mixture is as follows: clay (including moisture): 55-60%, binder: 19-37%, aggregate: 4-29 %, And this mixture is solidified by a hydration reaction with a binder to obtain a solidified product.

  Making the ratio of clay (including moisture) in the mixture 55% or more (hereinafter “%” represents the volume ratio) by volume ratio is effective for effective utilization of the clay and ease of handling the mixture (including moisture). Is preferable from the viewpoint of easy handling of the mixture. On the other hand, since the clay is light with a specific gravity of about 1.3 although it depends on the water content, it is preferable that the ratio of the clay is 60% or less in order to secure the weight (high specific gravity) of the solidified body. Moreover, it is preferable to make the ratio of a binder 19% or more in order to increase the solidified body strength at a low curing temperature. On the other hand, the ratio of the binder is preferably 37% or less from the viewpoint of reducing the material cost and handling ease of the mixture (if the amount of the binder is too large, the slump value is lowered and the handling property is lowered). Moreover, it is preferable that the ratio of the aggregate is 4% or more in order to secure the weight of the solidified body. On the other hand, the ratio of the aggregate is preferably 29% or less from the viewpoint of securing the amount of the binder and increasing the strength of the solidified body.

  The dredged soil is mud excavated from the bottom of the water by dredging work. The clay used in the present invention preferably has a water content of 210% or more from the viewpoint of easy handling. In order to obtain this water content, water is added to the clay before the mixing step as necessary. If the water content of the clay is too large, it is necessary to increase the amount of binder added to ensure the strength of the solidified body. Therefore, the water content of the clay is limited to about 300% from the economical viewpoint. It is preferable to do. Here, the water content ratio of the clay is determined by the water content ratio = (A / B) × 100, where the water content contained in the clay is A (mass%) and the solid content is B (mass%). .

  Although there is no special restriction | limiting in the kind of aggregate used by this invention, It is preferable to use especially the steelmaking slag which is a by-product of steel production. Since steelmaking slag is heavier (larger specific gravity) than natural crushed stone, the weight (high specific gravity) of the solidified body can be ensured by using this as an aggregate. Examples of the steelmaking slag include hot metal pretreatment slag (such as dephosphorization slag, desiliconization slag, and desulfurization slag), converter decarburization slag, and electric furnace slag, and one or more of these can be used. The steelmaking slag preferably has a maximum particle size of 25 mm or less.

  The binder may be any material that can solidify the mixture by a hydration reaction. Examples thereof include ordinary Portland cement, blast furnace slag fine powder, fly ash (including cases where they are included as blast furnace cement and fly ash cement), and one or more of them can be used. Further, from the viewpoint of securing the strength of the solidified body and the manufacturing cost, it is preferable to use an alkali stimulating material together with the blast furnace slag fine powder as a binder. Thus, by using an alkali stimulating material together with the blast furnace slag fine powder as the binder, the hydraulic property of the blast furnace slag fine powder can be exhibited by creating an alkaline environment. That is, the hydration reaction of the blast furnace slag fine powder can be promoted, and the strength of the solidified body can be ensured. As the alkali stimulating material, for example, ordinary Portland cement (including cases where it is included as blast furnace cement or fly ash cement), lime, or the like can be used. From the viewpoint of strength development, the ratio (volume ratio) of the blast furnace slag fine powder and the alkali stimulating material (for example, ordinary Portland cement) is preferably about blast furnace slag fine powder: alkali stimulating material = 3: 1 to 6: 1.

The present invention is directed to the case where the curing temperature in the solidification step of solidifying the mixture by a hydration reaction with a binder is 5 to 10 ° C.
In the present invention, the binder (including the case where an alkali stimulating material is used) includes blast furnace slag fine powder, ordinary Portland cement, and fly ash (including cases where both are included as blast furnace cement and fly ash cement). The strength index defined by the following formula (1) is set to 1.8 or more for the mixture at the time when the raw materials are mixed using one or more selected from: When such a mixture is cured at a curing temperature of 5 to 10 ° C., a solidified body having a compressive strength of 15 N / mm ² or more after curing for 28 days can be obtained.
Strength index = (BP + 2 × NP + 0.35 × FA) / W (1)
However BP: mixture 1 m ³ amount of blast furnace slag per (kg)
NP: amount of ordinary Portland cement per mixture 1 m ³ (kg)
FA: amount of fly ash per mixture 1 m ³ (kg)
W: Water content per 1 m ^{3 of} mixture (kg)

The solidified body needs to have a compressive strength after curing for 28 days of 9.8 N / mm ² (the hardness of semi-hard stone specified in JIS-A-5006: 1995) or more. In view of the variation (mixing variation), etc., the compressive strength after curing for 28 days is preferably 15 N / mm ² or more. When the strength index defined by the above formula (1) of the mixture is less than 1.8, when the curing temperature is 5 to 10 ° C., a solidified body having a compressive strength after curing for 28 days of 15 N / mm ² or more is obtained. I can't.

  In the manufacturing process of the solidified body, the slump value (measured by the slump test) of the mixture is about 2 to 10 cm in order to facilitate the handling of the mixture and thereby reduce the variation in the strength of the solidified body to be manufactured. It is desirable. Here, easy handling of the mixture means that the mixture flows properly during pumping, placement and curing, and that the mixture does not contain a large amount of air during curing. If the handling property of the mixture is inferior in these respects, not only the workability is deteriorated, but also the strength of the solidified product to be produced is varied and the product yield is also deteriorated.

A preferred production process of the present invention includes, as basic steps, a mixing step of mixing clay, aggregate and binder, and a solidification step of solidifying the mixture obtained in this mixing step by a hydration reaction with the binder. And a crushing step of crushing the solidified body obtained in this solidification step.
Moreover, you may perform the process (a) which removes the foreign material of a clay, and the process (b) which adds water to a clay and adjusts a water | moisture content as needed before a mixing process. When both steps are performed, the steps (a) and (b) are usually performed in this order. In the step (a), for example, the foreign matter is removed by sieving the clay. In step (b), water is added so that the moisture content of the clay is at a desired level.

In the mixing step, the clay, aggregate and binder are mixed and sufficiently kneaded. As the kneading means, for example, a normal fresh concrete kneading facility may be used, but it may be performed in a yard such as outdoors using a heavy machine for civil engineering work such as an excavator.
In the solidification step, the mixture (kneaded product) obtained in the mixing step may be poured into a suitable formwork and solidified and cured (hydrated and cured), for example, or layered in a yard such as outdoors. It may be set and solidified and cured (hydrated and cured). This solidification / curing period is until the target compressive strength is obtained, and is generally about 28 days. In particular, when a large amount of the solidified body is produced, it is preferable to place it in a layer on the yard.

  In the crushing step, the solidified body obtained in the solidifying step is crushed to an appropriate size according to the application. This crushing treatment may be performed using a crusher, and when the mixture is placed in layers in the yard as described above, the solidified body of the yard is roughly crushed with a breaker, and then the crusher You may crush by. Moreover, normally, the solidified body (lumps) subjected to the crushing process is classified with a sieve to obtain a chunk of a predetermined size. For example, when using it as a submerged bank material etc., the lump | aggregate of a magnitude | size about 150-500 mm is obtained.

The clay, aggregate (steel slag), and binder (blast furnace slag fine powder, ordinary Portland cement, fly ash) were mixed to produce a solidified body. The dredged material was collected from Fukuyama Port. Converter decarburization slag (particle size: 0-25 mm) was used as the steelmaking slag for the aggregate. In this example, a mixture of clay, aggregate and binder is kneaded, this kneaded material is placed on a mold, and cured for 28 days at 5 ° C., 10 ° C., and 20 ° C., and the diameter is 100 mm. X A solidified body having a height of 200 mm was produced.
The slump value of the mixture of clay, aggregate and binder was measured by a slump test (JIS-A-1101: 2005). Moreover, the compressive strength of the manufactured solidified body was measured by a compression test (JIS-A-1108: 2006). The results are shown in Table 1, together with the moisture content of the clay, the raw material blending ratio of the mixture, the strength index of the mixture defined by the formula (1), and the curing temperature.

As shown in Table 1, when the curing temperature is 20 ° C., it is compressed after 28 days curing by setting the blending amount of the binder having a strength index of 1.5 as in Reference Examples No. 7 and 8. The strength can be 15 N / mm ² or more. On the other hand, when the curing temperature is 10 ° C. or lower, the compression strength after the 28-day curing is 15 N / mm ² or more with the compounding amount of the binder having a strength index of 1.5 as in the comparative example of No. 1. I can't. On the other hand, the compression strength after curing on the 28th is 15 N / mm ² or more by setting the amount of the binder to be a strength index of 1.8 or more as in the inventive examples of Nos. ² to 5. Can do.

Claims (2)

The clay, the aggregate and the binder are mixed, and the blending amount thereof is the volume ratio in the mixture. The clay (including water): 55 to 60%, the binder: 19 to 37%, and the aggregate: 4 A method for producing a solidified body, which is a mixture of ˜29%, and this mixture is solidified by a hydration reaction with a binder to obtain a solidified body,
When the curing temperature is 5 to 10 ° C. in the solidification step in which the mixture is solidified by a hydration reaction with the binder using at least one selected from blast furnace slag fine powder, ordinary Portland cement, and fly ash as the binder In addition,
By making the strength index defined by the following formula (1) of the mixture 1.8 or more, a solidified product having a compressive strength after curing for 28 days of 15 N / mm ² or more is obtained. Production method.
Strength index = (BP + 2 × NP + 0.35 × FA) / W (1)
However BP: mixture 1 m ³ amount of blast furnace slag per (kg)
NP: amount of ordinary Portland cement per mixture 1 m ³ (kg)
FA: amount of fly ash per mixture 1 m ³ (kg)
W: Water content per 1 m ^{3 of} mixture (kg)   The method for producing a solidified body according to claim 1, wherein the aggregate is steel slag.