JP3377831B2 - Cement-based muddy water and cement-based grout material and methods for producing them - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[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 it is an object of the present invention that the conventional waste treatment requires time and money such as waste concrete generated when a concrete structure is dismantled. Cement-based muddy water that can be used effectively under the influence of seawater at the same time as effective utilization, and cement-based grout material that is not affected by seawater and can be added in one step during use, and a manufacturing method thereof To provide.

[0009]

[Means for Solving the Problems] Claim 1 in the present invention
With the described cement-based mud, demolish concrete structures
The waste concrete generated when is crushed and classified
The fine powder part containing a high content of cement gel obtained by
The main component, and the fine powder portion has a temperature of 60 ° C to 900 ° C.
The method of solving the above-mentioned problems was obtained by drying in.
A cement-based grout material according to claim 2 of the present invention
Is the waste generated when demolishing a concrete structure
Cement gel obtained by crushing and classifying concrete
The fine powder part containing a high content rate of 60% to 900 ° C.
Dry until the cement gel in the fine powder part is dehydrated
Add cement to the powder material obtained by
Was used as a means for solving the above problems. Claim 3 in the present invention
In the described cement-based mud production method, the concrete structure is
Crushing waste concrete generated when dismantling structures
・ Fine powder containing a high content of classified cement gel
The portion is dried at a temperature of 60 ° C to 900 ° C, and the obtained dryness is obtained.
The addition of water to the dried product was used as a means for solving the above problems.
The cement-based grout material according to claim 4 of the present invention.
In the manufacturing method, when the concrete structure is demolished
Cement obtained by crushing and classifying raw waste concrete
60 ° C to 900 ° C for fine powder containing high content of gel
Dry at the temperature of, and add cement to the dried product.
This is the means for solving the above problems.

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. Concrete is crushed and classified
The present invention found that the fine powder portion containing the cement gel at a high content obtained as described above can be used as a grout material for muddy water when excavating oil or natural gas, tunnel construction, water supply and sewerage, cable burying, etc. Was completed.

For crushing the waste concrete generated when the concrete structure is dismantled, a conventionally known crusher such as a jaw crusher is used. For classification, a commonly used sieve is used, and the fine powder to be obtained is preferably 1.0 mm or less, particularly preferably 0.3 mm or less. Because most of the waste concrete generated when the concrete structure is dismantled consists of aggregate and cement hydrate, when crushing and sieving this, the cement hydrate is better than the aggregate. Since the strength is low, naturally the cement hydrate is more easily crushed. Therefore, in the powder obtained after pulverization / classification, 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 cement gel content. This is because, as a result, a large amount of water is absorbed and swelling is facilitated.

Further, the fine powder portion containing a high content of cement gel obtained after pulverization and classification is further subjected to a drying treatment.
You As the drying method, vacuum drying, drying with a desiccant,
Known methods such as drying with dry air and heating drying can be adopted. However, heating drying is preferably used when particularly large-scale continuous treatment is desired.
It is desirable to dry at a temperature of 0 ° C to 900 ° C. 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. It contains a high content of cement gel
I explained the fine powder part , but this fine powder part is
It suffices if it contains 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 used by adding water to a commercially available cement or a known special cement to hydrate it, and then drying and crushing it.

[0014]

The cement-based muddy water of the present invention contains a cement hydrate, and thus 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. Therefore, 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 the cement hydrate and cement, improving work efficiency and making management easier. Become. Since the cement-based grout material of the present invention contains the cement hydrate, the strength is improved. In other words, in a suspension containing cement hydrate, there is a large amount of calcium ions released by hydration of cement, so the calcium ion concentration in water rises faster than when water is added to 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 the present invention,
Disposable waste generated when dismantling a concrete structure
Cement gel obtained by crushing and classifying cleats
The main component is a fine powder portion containing a high content and the fine powder portion
Is dried at a temperature of 60 ° C to 900 ° C,
It is not affected by seawater and therefore can be used as mud in seabed drilling. Further, the cement system of the present invention
According to the grout material, the concrete structure was demolished
The waste concrete generated during
The main component is a fine powder portion containing a high content of cement gel.
And, the fine powder portion is dried at a temperature of 60 ° C to 900 ° C.
By being dried, it becomes possible to premix with materials such as cement and aggregate, and therefore adjustment in use is one step unlike bentonite.

[0016]

Example ( Reference Example 1 ) Cement hydrate was prepared by mixing cement and water.
This cement hydrate was prepared by curing a paste prepared by mixing 1000 g of early-strength cement and 1000 g of water at 20 ° C. for 24 hours, drying at 120 ° C. for 24 hours, and pulverizing to adjust the particle size to 50 μm or less. 200 g of this hydrate and 100 g of ordinary cement were thoroughly mixed in advance, and then water 874 was added.
g 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 is 100 for the sample liquid.
The breathing rate measured after being placed in a 0 ml volumetric flask for one hour is shown.

[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 1 ) Concrete waste was crushed with a jaw crusher, and the obtained crushed product was sieved with a sieve having an opening of 44 μm to remove aggregate in the waste concrete, and a fine powder portion having a particle size of 44 μm or less. Got 20 parts by weight of this fine powder part is mixed with 80 parts of water.
Muddy water was prepared by suspending it in parts by weight, and the apparent viscosity (AV), yield value (YV), and gel strength (GEL) of the resulting muddy water were measured. Further, the same measurement was performed for the case where NaCl was added in an amount of 1.0% to the suspension which was muddy water, and the influence of salt contamination 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 2 ) Concrete waste was crushed with a jaw crusher, and the obtained crushed product was sieved with a sieve having a mesh opening of 0.3 mm to remove aggregates from the waste concrete, and the particle size was reduced to 0.
A fine powder portion of 3 mm or less was obtained. Further, the fine powder portion was put into a dryer and dried at 120 ° C. for 6 hours. Next, the obtained dried fine powder parts 150, 200, and 250 parts by weight 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 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” . The results are shown in Table 6.

Example 3 Concrete waste was crushed with a jaw crusher, and the obtained crushed product had openings of 44 μm, 90 μm, and 0.15.
mm, 1.0 mm, 2.0 mm, 3.0 mm sieve to remove the aggregate in the waste concrete, and the particle size is 4
4 μm or less, 44 μm to 90 μm, 90 μm to 0.15
mm, 0.15 mm to 1.0 mm, 1.0 mm to 2.0 m
m, 2.0 mm-3.0 mm 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 the obtained dry fine powder portion were prepared respectively, and these were mixed with the early strength Portland cement 1
At the same time, 00 parts by weight was put into 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 6 kinds of grout materials (Nos. 4 to 9). Table 5 shows the composition of these grout materials. The actual The resulting grout material
The flow value, breathing rate, and compressive strength were set in the same manner as in Example 2.
It was measured. The results are shown in Table 6.

( Example 4 ) Concrete waste was crushed with a jaw crusher, and the obtained crushed product was sieved with a sieve having a mesh opening of 0.3 mm to remove aggregate in the waste concrete, and the particle size was 0.3 m.
A fine powder portion of m or less was obtained. 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 types of dry fine powder parts were prepared respectively, and these and 100 parts by weight of early strength Portland cement were simultaneously treated with water 450
The mixture was put in a mixer containing parts by weight. 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 compressive strength were measured in the same manner as in Example 2 . The results are shown in Table 6.

(Comparative Example 2) 50 parts by weight of bentonite and 450 parts by weight of water were placed in a mixer, respectively, and sufficiently mixed to allow the bentonite to absorb water. After that, to this, early strength Portland cement 10
0 parts by weight was added 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 2 (Nos. 1 to 3) was obtained by adding and kneading bentonite and cement in two steps, 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). Example
In the grout material of No. 3 (Nos. 4 to 9), it was found that the breathing rate, the flow value, and the compressive strength suddenly deteriorated when the particle size of the fine powder portion became larger than 1.0 mm. In the grout material (No. 10 to 12) of Example 4 , 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 security of the present invention is as follows.
Since the mento-based muddy water and the cement-based grout material contain a cement hydrate such as calcium silicate hydrate, the cement hydrate fine powder and the 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 etc. becomes easy. 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. In addition, the cement-based mud water of the present invention is a cement gel obtained by crushing and classifying waste concrete generated when a concrete structure is dismantled without using bentonite as a main component. Since the main component is the fine powder portion contained at a high content rate, it is not affected by the ions contained in seawater and therefore can be used as muddy water in drilling on the sea floor. Further, the cement of the present invention
The grout material has sufficient performance comparable to the conventionally used two-step-added grout material, and is mainly composed of a fine powder portion containing a high content of cement gel. Therefore, it can be premixed with materials such as cement and aggregate without any trouble, and therefore, the adjustment at the time of use can be improved in one step unlike bentonite, so that workability and workability at the site can be improved. 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.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Yokota 585 Tomimachi, Funabashi, Chiba Prefecture Sumitomo Cement Co., Ltd. Central Research Institute (72) Inventor Masao Sato 585 Tomimachi, Funabashi, Chiba Sumitomo Cement Co., Ltd. Central Research Laboratory (72) Inventor Yuji Shioda 585 Tomicho, Funabashi, Chiba Sumitomo Cement Co., Ltd. Central Research Laboratory (56) Reference JP-A-56-72073 (JP, A) JP-A-2-279545 (JP) , A) JP-A-1-318080 (JP, A) Patent 3312780 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 17/00-17/52 C04B 28/00- 28/36 C09K 7/00-7/08

Claims (4)

(57) [Claims] 1. When a concrete structure is dismantled
It was obtained by crushing and classifying raw waste concrete,
The main component is a fine powder portion containing a high content of cement gel,
And the fine powder portion is dried at a temperature of 60 ° C to 900 ° C.
Cement-based muddy water characterized by 2. When the concrete structure is dismantled
It was obtained by crushing and classifying raw waste concrete,
The fine powder portion containing the cement gel at a high content rate, 60 ℃ ~ 9
The cement gel in the fine powder part is dehydrated at a temperature of 00 ° C.
Cement was added to the powder material obtained by drying until
Cement-based grout material characterized by 3. When the concrete structure is dismantled
Cement obtained by crushing and classifying raw waste concrete
60 ° C to 900 ° C for fine powder containing high content of gel
Drying at the temperature of and adding water to the dried product.
And a method for producing cement-based mud water. 4. When the concrete structure is dismantled
Cement obtained by crushing and classifying raw waste concrete
60 ° C to 900 ° C for fine powder containing high content of gel
Dry at the temperature of, and add cement to the dried product.
A method for producing a cement-based grout material, which comprises: