JPH1192197A - Cement hardened body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dense cement hardened body hardened in a short time, almost free from pores and having sufficient mechanical strengths. SOLUTION: A cement compsn. consisting of cement, an aluminum compd. and a calcium compd. is mixed with water to obtain the objective cement hardened body. The volume of pores of >=10<3> Å diameter which exist after the lapse of 3 hr after the addition of water to the cement compsn. is <=0.1 cc per 1 g of the cement hardened body and the compressive strength of the hardened body is >=50 kg/cm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cured cement having a high curing speed.

[0002]

2. Description of the Related Art In the case of performing work using cement, in order to shorten the construction period, a cement which has a high setting speed and a high setting speed and is excellent in quick setting properties is required. In particular, it is important to shorten the construction period in emergency construction such as road construction, repair of railway and aeronautical equipment in urban areas. Also, in a factory that manufactures industrial products made of cement, cement having excellent quick-setting properties is desired in order to shorten the time required for shipment and simplify the curing equipment.

[0003] Therefore, in order to increase the setting speed of cement, various cement quick-setting agents have been studied.
Japanese Patent No. 1141491 discloses calcined alum, lime, alkali metal aluminate, alkali metal carbonate, gypsum,
A composition comprising a cement is disclosed. However, although the cement quick-setting agent cures in a short time, there are many pores having a relatively large diameter in the initial stage of curing, and there is a defect that sufficient mechanical strength cannot be obtained.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve such a defect, and has been made in order to harden a cement in a short time, has a small number of pores, is dense, and has a sufficient mechanical strength. The purpose is to get the body.

[0005]

The hardened cement according to the first aspect of the present invention (hereinafter referred to as the first invention) is obtained by adding water to a cement composition comprising cement, an aluminum compound and a calcium compound. In the cured product obtained by mixing, the volume of pores having a diameter of 10 ³ Å or more, which is present 3 hours after water is added to the cement composition, per 1 g of the cured cement product,
0.1 cc or less.

The invention described in claim 2 of the present application (hereinafter referred to as “second
In the first invention, the hardened cement of the invention)
The compressed strength of the cured cement body after 3 hours from the addition of water to the cement composition is 50 kg / cm ² or more.

Since the first invention and the second invention are mutually related inventions, they are collectively referred to as a cement hardened body of the present invention and will be described below.

The aluminum compound is not particularly restricted but includes, for example, aluminum hydroxide [Al (O
H) ₃ ]; clay minerals containing aluminum, such as kaolinite, montmorillonite, halosite, and pyrophyllite; and the like. Of these, aluminum hydroxide is preferably used.

The calcium compound is not particularly limited.
For example, calcium hydroxide, a common industrial material,
Um [slaked lime (Ca (OH)_Two)], Gypsum [CaSO_Four
・ 2H_TwoO], calcium nitrate [Ca (NO_Three)_Two・ 4
H_TwoO], calcium silicate hydrate [CaSiO_Three・ N
H_TwoO], calcium chloride hydrate [CaCl_Two・ 6H _Two
O] and the like. Of these, calcium hydroxide
[Slaked lime (Ca (OH)_Two)] Is preferably used.

The degree of crystallization of the crystal structure of the aluminum compound and the calcium compound varies depending on the production conditions, and the chemical reactivity differs. Usually, application of mechanical energy to these compounds causes disorder in crystallinity, increases the solubility of aluminum and calcium in water, and increases the rate of cement hardening reaction. Therefore, it is preferable that the aluminum compound and the calcium compound are activated by applying mechanical energy. However, when these are amorphous, there is no need to apply mechanical energy.

The average particle size of the aluminum compound and the calcium compound is not particularly limited, but is preferably 0.1 to 500 μm from the viewpoint that the application of the mechanical energy effectively works.
m is preferred, and more preferably 0.1 to 100 μm.

The method for applying mechanical energy is not particularly limited, and a crusher generally used for crushing is used. Examples of such a pulverizer include ball media mills such as ball mills, vibration mills, planetary mills, and media stirring mills that combine impact, friction, compression, and shear; roller mills; mortars, and the like. It is also possible to use a jet pulverizer mainly for impact and attrition. Among them, a ball-medium mill is preferable because mechanical energy can be applied mechanically and effectively.

In the pulverization, a pulverizing auxiliary usually used in pulverizing cement clinker, silica sand, limestone or the like can be used. Examples of the grinding aid include liquid-based materials such as alcohols such as methyl alcohol and ethanolamines such as triethanolamine; solid-based materials such as sodium stearate and calcium stearate; and gas-based materials such as acetone vapor. And the like.

[0014] The mechanical energy is expressed as 0.5 to 30 k / unit weight of aluminum compound or calcium compound for processing the electric power supplied to the pulverizer.
wh / kg, preferably 0.5 to
20 kwh / kg, more preferably 0.5 to 1
0 kwh / kg. If it is less than 0.5 kwh / kg, the modification of the crystal structure is insufficient, so that the reactivity with the cement is insufficient. If it exceeds 30 kwh / kg, an excessive load on the pulverizing device, a ball as a medium, Various problems such as excessive wear of the container, mixing of impurities into the treated powder, coarsening of particles due to agglomeration of the treated powder, and productivity such as cost occur.

The mixing of the aluminum compound and the calcium compound is not particularly limited, and an omni mixer, an Erich mixer or the like can be suitably used. The molar ratio of Al / Ca of the mixture of the aluminum compound and the calcium compound needs to be 0.5 to 5, and preferably 1 to 5.
~ 4. When the molar ratio of aluminum (Al) / calcium (Ca) in the above mixture is less than 0.5, the reaction rate at normal temperature is slow, and when it exceeds 5, the physical properties such as the mechanical strength of the cured cement body are reduced. Inferior. Here, Al /
The Ca molar ratio is a numerical value indicating the Al / Ca ratio of the number of aluminum atoms (Al) and the number of calcium atoms (Ca) contained in the mixture.

The cement is not particularly limited, and includes, for example, Portland cements such as ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, moderate heat Portland cement, sulfate-resistant Portland cement, etc .; blast furnace cement, silica cement, Mixed cements such as fly ash cement; special cements such as white Portland cement, cement-based solidifying material, and alumina cement. Of these, Portland cement is preferably used because it is inexpensive and has stable quality.

The mixture of the aluminum compound and the calcium compound to be added to the cement is not particularly limited.
The amount is preferably 1 to 100 parts by weight, more preferably 3 to 50 parts by weight, based on 100 parts by weight of cement. If the amount is less than 1 part by weight, there is no effect of addition, and sufficient setting speed and curing speed cannot be obtained. On the other hand, if it exceeds 100 parts by weight, the curing speed is too high, and a sufficient working time cannot be obtained.

The amount of water is preferably from 10 to 300 parts by weight, more preferably from 15 to 200 parts by weight, based on 100 parts by weight of cement. If the amount is less than 10 parts by weight, molding of the obtained cement composition becomes difficult, and 30
If the amount exceeds 0 parts by weight, the strength of the hardened cement decreases.

In the cement composition, reinforcing fibers such as aramid fiber, glass fiber, carbon fiber, steel fiber and the like; inorganic fillers such as silica sand, silica stone powder, fly ash and slag, as appropriate, depending on the performance to be provided; Various synthetic resin foams; lightweight aggregates such as inorganic foams and the like can be added.

The method of adding water to the cement composition is not particularly limited as long as it can be uniformly mixed and kneaded.
For example, an omni mixer, an Erich mixer, a universal mixer, or the like can be suitably used.

The method for obtaining a hardened cement body using the cement composition is not particularly limited, and a general method is used, and examples thereof include an injection method, a press method, and an extrusion method. The hardening temperature for obtaining the hardened cement is 1
~ 500 ° C is preferred, more preferably 5-300 ° C
It is. If the temperature is lower than 1 ° C., the curing reaction rate may be remarkably reduced. If the temperature is higher than 500 ° C., the shrinkage at the time of curing increases, and cracks or the like may occur in the obtained cement cured product.

[0022] Fast setting of the cement composition comprises:
In terms of construction efficiency, it is welcome, but when the cement composition is rapidly cured in a short time, usually, the size of the pore size and the distribution of the pore size are both large, and a hardened cement body is obtained. High mechanical strength cannot be obtained.

As described above, of the aluminum compound and the calcium compound having appropriate activities, a cement, an aluminum compound, and a cement compound comprising a calcium compound are prepared by using an appropriately activated compound. If this is mixed with water and rapidly hardened within a short time, the resulting hardened cement can be a dense hardened cement having a small percentage of pores.

In describing the pores of the cement hardened material, the discussion will proceed with the pore diameter and compressive strength three hours after water is added to the cement composition to start the hardening. The hardened cement body of the present invention is characterized in that the volume of pores having a diameter of 10 ³ Å or more per gram of hardened cement body is 0.1 cc or less.

The method for measuring the pore volume and the compressive strength will be described later.
The former method uses a mercury intrusion method
Symmetry, the latter being performed by cement physical test methods
Will be 10^ThreeHas a pore size of Å or more
When the pore volume exceeds 0.1 cc, the hardened cement
The mechanical strength is reduced, and the practical strength is 50 kg / cm.
^TwoIt is difficult to secure the above compressive strength.

[0026]

According to the present invention, by controlling the activity of an aluminum compound and a calcium compound and using them in a cement composition, the composition can be hardened in a short time, and by specifying the size of the pore diameter and the ratio thereof, It is possible to secure a dense cement hardened body having excellent mechanical strength.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 (1) Preparation of active aluminum compound and active calcium compound Aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., C-31, an aluminum compound containing water of crystallization) and slaked lime (manufactured by Kawai Lime Industry Co., Ltd.) , A calcium compound containing water of crystallization), and 20 kg of each was separately charged into an Ultra Fine Mill (AT-20, manufactured by Mitsubishi Heavy Industries, Ltd.),
Further, 520 kg of zirconia balls having a diameter of 10 mm as a ball medium and 100 g of ethanol as a pulverization aid were added, and mechanical energy of 4 kwh / kg was applied to activate aluminum hydroxide and slaked lime.

The mechanical energy applied to the aluminum hydroxide and the slaked lime is the average energy density (the average energy per hour, and is a value obtained by dividing the mechanical energy applied to the compound obtained by the following formula by the processing time. ) For about 8 kWh / kg under operating conditions of about 0.5 kWh / kg. Applied mechanical energy (kWh / kg) = {Amount of power consumed during operation during compound treatment (kWh) −Amount of power consumed during idle operation before compound introduction (kWh)} Amount of treated compound (kg)

(2) Preparation of Hardened Cement The powders of the aluminum compound and calcium compound obtained above were weighed so that the mixing ratio of Al: Ca was 2: 1 in a molar ratio, and mixed with an omni mixer. Thus, an active mixture of both was obtained. 15 parts by weight of the obtained active mixture was added to 100 parts by weight of ordinary Portland cement (manufactured by Chichibu Onoda), and then mixed by an omni mixer to prepare a cement composition. Cement composition 10
With respect to 0 parts by weight, 35 parts by weight of water was injected and mixed to prepare a cement paste to obtain a hardened cement. The obtained cured product was measured for pore size distribution and compressive strength 3 hours after the addition of water to the cement composition by the evaluation method described later, and the results are shown in Table 1.

[0031]

[Table 1]

Example 2 The mixture ratio of Al: Ca of aluminum hydroxide and calcined lime (active without applying mechanical energy) of 1 in molar ratio becomes 1: 1 as in Example 1. An active mixture was weighed as described above, and a cement hardened body was manufactured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 Instead of the cement composition of Example 1, 100 parts by weight of ordinary Portland cement (manufactured by Chichibu Onoda) was used.
A cement hardened body was prepared in the same manner as in Example 1 except that 5 parts by weight of quick-setting agent T-ROCK manufactured by Chichibu Onoda Co. was added, and a cement hardened body was manufactured. The results are shown in Table 1. .

Comparative Example 2 A cement was prepared in the same manner as in Comparative Example 1 except that jet cement (manufactured by Chichibu Onoda) was used as the cement composition instead of the cement composition of Comparative Example 1. A cured product was prepared, and the results are shown in Table 1.

<Evaluation Method> (1) Measurement of Pore Size Distribution Three hours after the cement paste was cast and water was added to the cement composition, it was immersed in acetone to stop the hardening reaction of the cement. Then, a sample was prepared. Drying the sample, breaking it into a measurable size,
Mercury porosimeter (Autopore 922, manufactured by Shimadzu Corporation)
0).

(2) Compressive strength The cement paste was cast into a cylindrical shape having a diameter of 5 cm and a height of 10 cm, and 3 hours after water was added to the cement composition.
After a lapse of time, the compressive strength of the cured product was measured. The measurement of the compressive strength was carried out according to JIS R 5201 (physical test method for cement 9. Strength test).

[0037]

As described above, the hardened cement of the present invention has a high hardening speed, a small number of pores,
Since it is dense and has high mechanical strength, it can be suitably used as a cement hardened body for on-site construction and a concrete secondary product.

Claims (2)

[Claims] 1. A cement, an aluminum compound, and
In a hardened cement body obtained by mixing water with a cement composition composed of a calcium compound, the volume of pores having a diameter of 10 ³ Å or more existing 3 hours after adding water to the cement composition. Is 0.1 cc or less per 1 g of the hardened cement. 2. The hardened cement according to claim 1, wherein the hardened body has a compressive strength of 50 kg / cm ² or more after 3 hours from the addition of water to the cement composition.