JPH06100855A - Cement-based muddy water and cement-based grout material - Google Patents

Abstract

(57) [Summary] [Purpose] Effective use of waste concrete generated when a concrete structure is dismantled or sludge generated in ready-mixed concrete factories and concrete product factories, which previously required labor and expense for waste treatment. At the same time, the present invention provides a cement-based muddy water that can be used even under the influence of seawater, and a cement-based grout material that is not affected by seawater and can be added in one step during use. [Composition] Waste concrete generated when concrete structures are dismantled, or sludge generated in ready-mixed concrete factories and concrete product factories are pulverized and classified to obtain a fine powder part containing a high content of cement gel. Cement-based muddy water or cement-based grout material as the main component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to muddy water for excavating oil and natural gas, and cement-based muddy water and cement-based grout material used for tunnel construction, water supply and sewerage, cable burial and the like.

[0002]

2. Description of the Related Art In recent years, the amount of waste concrete generated when a concrete structure is dismantled and the amount of sludge generated in a ready-mixed concrete factory and a concrete product factory have been rapidly increasing, and the disposal thereof has become a problem. .
As one of the effective uses of such waste concrete and sludge, it has been attempted to crush and classify these to take out the aggregate contained therein and reuse it as recycled aggregate. .

[0003]

However, the fine powder portion containing a high content of the remaining cement gel from which the aggregate has been removed is rarely used, and its disposal requires a great deal of labor and cost. Is the actual situation.

In the case of excavating oil or natural gas, by removing the debris from the bottom or near the bit and transporting it to the surface of the earth, cooling or lubricating the bit, forming a film and forming an anti-wall. Muddy water is used to prevent the water from collapsing. As such muddy water, water-based ones and oil-based ones are known, but generally water-based ones are used and are most often used. Is a suspension of water and bentonite. In the tunnel construction by the shield method, various grout materials are used for the purpose of filling the space between the excavated surface and the ground. The most common grout material is a cement material, and cement, water, bentonite, water glass and the like are mixed and used.

Bentonite, which is a fine particle of clay mineral, is used as muddy water because it absorbs water, swells, and increases in viscosity, and also prevents separation and breathing of materials such as cement, water, and aggregate. It is used for grout because it is suitable for filling gaps.
However, when bentonite comes into contact with seawater, sodium ions in bentonite undergo an exchange reaction with calcium ions contained in seawater and lose their swelling property, so they cannot be applied to mud water for drilling on the seabed. There is.

Also, when bentonite is used as a grout material, when water is simultaneously added to bentonite and cement for premixing, for example, sodium in bentonite exchanges with calcium hydroxide liberated from the cement. As a result, the swelling property of the bentonite is rapidly lost, and at the same time, the hardening ability of the cement is rapidly decreased. Therefore, in order to solve this problem, in the past, it was necessary to perform a two-step operation such as sufficiently absorbing and swelling bentonite in advance, and then adding cement, which is extremely inconvenient for on-site construction and shortens the construction period. Was one of the factors that undermine. For the same reason, bentonite-based grout materials are not generally suitable for use in the presence of seawater such as undersea tunnels.

Further, bentonite is ubiquitous in resources, has a small reserve, is expensive, and the bentonite resources in Japan tend to be exhausted, so it is expected that future demand cannot be met. Therefore, similar clay minerals such as attapulgite, sepiolite, and chrysotile-based asbestos are listed as alternatives to bentonite that are not affected by cement or seawater. However, all of these give viscosity due to the fibrous structure,
Since breathing is prevented, pumpability is inferior to that of bentonite, which makes it difficult to use in actual use.

The present invention has been made in view of the above circumstances, and an object of the present invention is to eliminate waste concrete generated when a concrete structure is dismantled or sludge generated in a ready-mixed concrete factory or a concrete product factory. Although it takes time and money to dispose of waste in the past, it aims to make effective use of it, while at the same time adding cement-based mud that can be used even under the influence of seawater and water that is not affected by seawater in one step. It is to provide a cement-based grout material that can

[0009]

In the cement-based muddy water and cement-based grout material according to claims 1 and 2 of the present invention, it is necessary to include a cement hydrate such as calcium silicate hydrate. And The cement-based muddy water and cement-based grout material according to claims 3 and 4 were obtained by crushing and classifying waste concrete generated when a concrete structure was dismantled or sludge generated in a fresh concrete factory or a concrete product factory. The means for solving the above-mentioned problems is to use a fine powder portion containing a high content of cement gel as a main component. In the cement-based grout material according to claim 5, waste concrete generated when a concrete structure is dismantled or sludge generated in a ready-mixed concrete factory or a concrete product factory is crushed or crushed.
Obtained by classification, fine powder portion containing a high content of cement gel, the powder material obtained by drying until the cement gel in the fine powder is dehydrated, the cement is added And the solution.

The present invention will be described in detail below. Cement contains calcium silicate as a main component, and when it comes into contact with water, it forms a cement gel mainly composed of calcium silicate hydrate and hardens. Therefore, a large amount of cement gel is contained in the sludge suspension generated in the ready-mixed concrete factory and the concrete product factory. This cement gel is flat, fibrous,
The solid has a specific surface area of 220 m 2 / g and has a very large surface area, and contains a large amount of water such as capillary water and gel water. Therefore, the cement gel and the one obtained by dehydrating the cement gel can absorb a very large amount of water and have a high swelling property.

The present inventor pays attention to the action that such a cement gel and the one obtained by dehydrating the cement gel absorb a large amount of water at the time of contact with water and swell, and the waste generated when the concrete structure is dismantled. The fine powder part containing a high content of cement gel, which is obtained by crushing and classifying concrete or sludge generated in ready-mixed concrete factories and concrete product factories, muddy water when excavating oil and natural gas, tunnels. The inventors have found that they can be used as grout materials for construction, water supply and sewerage, cable burial, etc., and have completed the present invention.

Regarding the crushing of the waste concrete generated when the concrete structure is dismantled and the sludge generated in the ready-mixed concrete factory and the concrete product factory,
A conventionally known crusher such as a jaw crusher is used. A commonly used sieve is used for classification, and the fine powder obtained is 1.0 mm or less, particularly 0.3 mm.
The following is preferable. Because most of the waste concrete generated when the concrete structure is dismantled, or the sludge generated in the ready-mixed concrete factory and concrete product factory is composed of aggregate and cement hydrate, it was crushed and sieved. In this case, since the cement hydrate has a lower strength than the aggregate, the cement hydrate is naturally more easily crushed. Therefore,
In the powder obtained after crushing and classifying, a large amount of cement hydrate is contained in the fine powder part having a small particle size, so that the fine powder part having a particle size of 1.0 mm or less has a high content of cement gel. This makes it possible to absorb a large amount of water and swell easily.

The fine powder portion containing a high content of cement gel obtained after pulverization / classification is added to water in this state and further added with a known appropriate material to obtain the muddy water or grout material of the present invention. Although it may be used, it is preferable to use it after further drying treatment. As a drying method, known methods such as vacuum drying, drying with a desiccant, drying with dry air, and heating drying can be adopted. However, when it is desired to carry out a large-scale continuous treatment, heating drying is adopted. In that case, it is desirable to dry at a temperature of 60 ° C. to 900 ° C. under normal pressure. This is because the cement hydrate contained in the fine powder does not dehydrate even if dried below 60 ° C, and a sufficient drying effect cannot be obtained, while above 900 ° C, the dehydrated cement hydrate. Is sintered, the surface area is reduced, and the action of water absorption and swelling is reduced. Further, when a grout material is obtained using a powder material obtained by drying the fine powder portion in this manner, it is preferable to add an appropriate amount of cement to enhance its curability and the like. Although the sludge containing a large amount of cement gel has been described, the sludge may not be contained as long as it contains the cement hydrate. Examples of the cement hydrate include calcium silicate hydrate, calcium aluminate hydrate, calcium sulfaluminate hydrate, calcium aluminosilicate hydrate, calcium hydroxide and the like. This cement hydrate is hydrated by adding water to a commercially available cement or a known special cement, and then,
It is dried and crushed before use.

[0014]

According to the cement-based mud water of the first aspect, since it contains cement hydrate, it can be premixed with cement. That is, bentonite, which is the most commonly used viscosity mineral for grout materials, when premixed with cement, sodium ions in bentonite undergo an exchange reaction with calcium ions precipitated by hydration of cement, but do not swell, Cement hydrate does not have this concern at all. For this reason, the two-step process of adding water to bentonite, swelling and then adding cement and mixing becomes a one-step process of adding water to cement hydrate and cement, improving work efficiency and making management easy. Become. According to the cement-based grout material of claim 2, since the cement hydrate is contained, the strength is improved. That is, in the suspension containing the cement hydrate, there is a large amount of calcium ions released by hydration of the cement, so the calcium ion concentration in water rises faster than when water is added to the cement. , The reaction with water glass, which is most commonly used in grout materials, is fast and the initial strength is large. Further, since the cement hydrate is used, the entire grout is only the hardened cement, so that the long-term strength is also increased.

According to the cement-based mud of claim 3,
High content of cement gel obtained by crushing and classifying waste concrete generated when dismantling a concrete structure without using bentonite as a main component, or sludge generated in a fresh concrete factory or concrete product factory. By including the fine powder portion included in the ratio as the main component, it is not affected by seawater, and thus can be used as muddy water in drilling on the seabed. According to the cement-based grout material according to claim 4, premixing with materials such as cement and aggregate is possible, and therefore adjustment in use is one step unlike bentonite.

[0016]

【Example】

(Example 1) Cement and water were mixed to prepare a cement hydrate. This cement hydrate is a high-strength cement 10
A paste prepared by mixing 00 g and 1000 g of water at 20 ° C.
Aged for 24 hours, dried at 120 ° C. for 24 hours and pulverized to adjust the particle size to 50 μm or less. 200 g of this hydrate and 100 g of ordinary cement were sufficiently mixed in advance, and then 874 g of water was added and mixed for 1 minute to obtain a liquid of Sample 1. The results of measuring the breathing rate of Sample 1 are shown in Table 1. Here, the breathing rate indicates the breathing rate measured after one hour after placing the sample liquid in a 1000 ml volumetric flask.

[Table 1] From Table 1, the breathing rate was 0%.

As a comparative example, samples 2 and 3 were prepared using bentonite instead of cement hydrate. Sample 2 was prepared by thoroughly mixing 40 g of bentonite and 260 g of ordinary cement, and then adding water 879 to the mixture.
It was adjusted by adding g and mixing for 1 minute. Sample 3 was prepared by adding 879 g of water to 40 g of bentonite and mixing for 1 minute to sufficiently swell, and then 260 g of ordinary cement was added thereto and mixed for 1 minute. The breathing rates of the samples 2 and 3 thus obtained were measured, and the measurement results are shown in Table 2.

[Table 2] From Table 2, the breathing rate of Sample 2 was 50%, and the breathing rate of Sample 3 was 0%.

From the results shown in Table 2, it is understood that when bentonite is mixed with normal cement at the same time, the breathing rate is so large that they cannot be mixed at the same time. Also,
If bentonite and ordinary cement are mixed separately, these mixing operations become two stages and the mixing time is doubled. In addition, comparing the results of Table 1 and Table 2, the one using cement hydrate is comparable in breathing performance to bentonite.

With respect to Samples 1 and 3, 1000 ml of the liquid of each sample was mixed with 40 ml of water glass, and the gelation time at that time and the compressive strength after 1 hour and 28 days were measured, and the measurement results are shown in Table 3. Shown in.

[Table 3] From Table 3, Sample 1 using the cement hydrate showed higher initial strength and long-term strength than Sample 3 using bentonite. Then, the sample 1 showed a gelation time with no problem in practical use.

(Example 2) Concrete waste was crushed with a jaw crusher, and the obtained crushed product had an opening of 44.
The aggregate in the waste concrete was removed by sieving with a sieve of μm to obtain a fine powder portion having a particle size of 44 μm or less. 20 parts by weight of this fine powder portion was suspended in 80 parts by weight of water to prepare muddy water, and the apparent viscosity (AV), yield value (YV), and gel strength (GEL) of the muddy water were measured. Furthermore, for suspension that is muddy water,
The same measurement is performed for the case where 1.0% of 1 is added,
The effect of salt pollution was investigated. For comparison, the same measurement was carried out on mud water in which 4 parts by weight of bentonite was suspended in 96 parts by weight of water. The results obtained are shown in Table 4.

[Table 4] From Table 4, in the muddy water using bentonite, AV, YV and GEL are remarkably increased by the addition of NaCl, whereas in the muddy water using fine powder obtained from the waste concrete of the present invention, there is almost no change. Therefore, it was confirmed that the product of the present invention has no problem in use in seawater.

(Example 3) Concrete waste was crushed with a jaw crusher, and the obtained crushed product had an opening of 0.
The aggregate in the waste concrete was removed by sieving with a 3 mm sieve to obtain a fine powder portion having a particle size of 0.3 mm or less. Then, put this fine powder portion in a dryer and
Dried for hours. Next, the obtained dried fine powder parts 150, 2
00 and 250 parts by weight are prepared respectively, and these and 100 parts by weight of early strength Portland cement are simultaneously added to water 450
The mixture was put in a mixer containing parts by weight and mixed. Then, 50 parts by weight of No. 3 water glass was put into each of these mixers and kneaded to obtain three kinds of grout materials (Nos. 1 to 3). Table 5 shows the composition of these grout materials. Regarding the obtained grout material, the standards of the Japan Society of Civil Engineers "Method of fluidity test of injection mortar of prepacked concrete", "Testing method of breathing rate and expansion coefficient of injection mortar of prepacked concrete", "Compression of injection mortar of prepacked concrete The flow value, breathing rate, and compressive strength were measured according to the “Strength Test Method”, and the results are shown in Table 6.

Example 4 Concrete waste was crushed with a jaw crusher, and the obtained crushed product had an opening of 44.
μm, 90 μm, 0.15 mm, 1.0 mm, 2.0 m
The aggregate in the waste concrete is removed by sieving with a 3.0 m sieve and a particle size of 44 μm or less, 44 μm to 9 μm.
0 μm, 90 μm to 0.15 mm, 0.15 mm to 1.0
mm, 1.0 mm-2.0 mm, 2.0 mm-3.0 mm, and 6 types of fine powder parts were obtained. Further, these fine powder portions were put into a dryer and dried at 120 ° C. for 6 hours. Next, 200 parts by weight of each of the obtained dry fine powder portions were prepared, and these and 100 parts by weight of early strength Portland cement were simultaneously treated with water 4 times.
The mixture was put into a mixer containing 50 parts by weight and mixed. Then, add 50 parts by weight of No. 3 water glass to each of these mixers and knead them to form 6 kinds of grout materials (No.
9). Table 5 shows the composition of these grout materials. Flow value of the obtained grout material in the same manner as in Example 3,
The breathing rate and compression strength were measured, and the results are shown in Table 6.

(Example 5) Concrete waste was crushed with a jaw crusher, and the obtained crushed product had an opening of 0.
The aggregate in the waste concrete was removed by sieving with a 3 mm sieve to obtain a fine powder portion having a particle size of 0.3 mm or less. Further, the obtained fine powder portion was put in a drying oven at temperatures of 400, 700 and 950 ° C. for 6 hours to obtain three kinds of dried products. Next, 200 parts by weight of the obtained three kinds of dry fine powder portions were prepared, respectively, and these and 100 parts by weight of early-strength Portland cement were simultaneously placed in a mixer containing 450 parts by weight of water and mixed. Then, 50 parts by weight of No. 3 water glass was put into these mixers and kneaded to obtain three kinds of grout materials (No. 10 to 12). Table 5 shows the composition of these grout materials. With respect to the obtained grout material, the flow value, the breathing rate and the compression strength were measured in the same manner as in Example 3,
The results are shown in Table 6.

(Comparative Example 2) Bentonite (50 parts by weight) and water (450 parts by weight) were placed in a mixer, respectively, and mixed sufficiently to allow bentonite to absorb water. Thereafter, 100 parts by weight of early-strength Portland cement was added thereto and mixed, and further 50 parts by weight of No. 3 water glass was added and kneaded to obtain a conventional grout material (No. 13). The composition of this grout material is shown in Table 5. With respect to the obtained grout material, the flow value, breathing rate and compressive strength were measured in the same manner as in Example 3, and the results are shown in Table 6.

[Table 5]

[Table 6]

As shown in Table 6, the grout material of Example 3 (Nos. 1 to 3) was obtained by adding and kneading bentonite and cement in two stages, and the grout material of Comparative Example 2 (No. 1).
It was confirmed that the breathing rate, flow value and compressive strength were comparable to those of 13). Further, in the grout material (Nos. 4 to 9) of Example 4, it was found that the breathing rate, the flow value, and the compression strength were rapidly deteriorated when the particle size of the fine powder portion was larger than 1.0 mm. In the grout material (No. 10 to 12) of Example 5, it was found that the one dried at 950 ° C. had worse breathing rate, flow value and compressive strength than those dried at 900 ° C. or less. .

[0026]

As described above, the cement-based mud water according to claim 1 and the cement-based grout material according to claim 2 of the present invention contain cement hydrate such as calcium silicate hydrate. The Japanese fine powder and cement can be premixed. Therefore, it is possible to work with two silos including a bentonite silo and a cement silo with a single silo, and a single weighing machine or the like. Then, water is added to the bentonite to swell, then a two-step process of adding cement and mixing, because cement hydrate does not react with sodium ions in bentonite, it becomes a mixture of cement hydrate and cement. This is a one-step mixing process in which water is added, the work efficiency in mixing can be improved, and the management of silos and the like becomes easier. Furthermore, since the cement hydrate is contained, the entire grout material is only the hardened cement body, so that the strength of the grout material can be improved. The cement-based muddy water according to claim 3 is obtained by crushing and classifying waste concrete generated when a concrete structure is dismantled without using bentonite as a main component, or sludge generated in a fresh concrete factory or a concrete product factory. Since the main component is the fine powder portion containing a high content of cement gel obtained by the above, it is not affected by the ions contained in seawater and therefore can be used as muddy water in seabed drilling. . The cement-based grout material according to claim 4 has sufficient performance comparable to the conventionally used two-stage-added grout material, and has a main component of a fine powder portion containing a high content of cement gel. As a result, it can be premixed with cement, aggregate and other materials without any problems, and therefore adjustment in use is different from bentonite in one step, improving workability and workability on site. be able to. In addition, since these muddy water and grout materials use waste, they can be manufactured at low cost, and the labor and cost conventionally required for waste disposal can be reduced and effective use of resources can be achieved. Can be achieved.

Front Page Continuation (72) Inventor Norio Yokota, 585 Tomimachi, Funabashi, Chiba, Sumitomo Cement Corporation Central Research Laboratory (72) Inventor Masao Sato, 585, Tomimachi, Funabashi, Chiba Sumitomo Cement, Ltd. (72) Inventor Yuji Shiota 585, Tomicho, Funabashi, Chiba Sumitomo Cement Co., Ltd. Central Research Laboratory

Claims (9)

[Claims] 1. Cement-based mud containing a hydrate of cement such as calcium silicate hydrate. 2. A cement-based grout material containing a cement hydrate such as calcium silicate hydrate. 3. A fine powder containing a high content of cement gel, obtained by crushing and classifying waste concrete generated when a concrete structure is dismantled or sludge generated in a fresh concrete factory or a concrete product factory. Cement-based muddy water that is mainly composed of parts. 4. A fine powder containing a high content of cement gel, obtained by crushing and classifying waste concrete generated when a concrete structure is dismantled, or sludge generated in a fresh concrete factory or a concrete product factory. Cement-based grout material with parts as the main component. 5. A fine powder containing a high content of cement gel, obtained by crushing and classifying waste concrete generated when a concrete structure is dismantled or sludge generated in a fresh concrete factory or a concrete product factory. A cement-based grout material obtained by adding cement to a powder material obtained by drying a portion of the fine powder until the cement gel in the fine powder is dehydrated. 6. The cement-based muddy water according to claim 3, wherein the fine powder portion containing a high content of cement gel has a particle size of 1 mm or less, which is obtained by pulverizing and classifying. 7. The cement-based grout material according to claim 4 or 5, wherein the fine powder portion containing a high content of cement gel, which is obtained by crushing and classifying, has a particle diameter of 1 mm or less. 8. The cement-based muddy water according to claim 3 or 6, wherein a fine powder portion containing a high content of cement gel, obtained by pulverizing and classifying, is further dried at a temperature of 60 ° C. to 900 ° C. Cement-based muddy water. 9. The cement-based grout material according to claim 4, 5 or 7, wherein a fine powder portion containing a high content of cement gel, obtained by pulverizing and classifying, is further 60 ° C to 90 ° C.
Cement-based grout material that has been dried at a temperature of 0 ° C.