JP2009173498A - Hydraulic composition and hardened body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize the fine powder of a siliceous shale which has not been particularly effectively used, and also to provide a hydraulic composition obtaining a hardened body excellent in strength developability and stable in characteristics. <P>SOLUTION: The hydraulic composition is obtained by mixing 1 to 20 mass pts. of the fine powder of siliceous shale with the average particle diameter of 0.5 to 20.0 μm and a BET specific surface area of ≥60 m<SP>2</SP>/g into 100 pts.mass of cement. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic composition using fine powder of siliceous shale and a cured body of the hydraulic composition.

Conventionally, as a cement admixture, a cement admixture in which ashes having pozzolanic activity, for example, ashes such as pulp sludge incineration ash and fly ash, are used as a slurry ultrafine powder has been proposed (see Patent Document 1). Such ashes are easy to mix as cement admixtures and have the effect of improving strength.
Moreover, the hydraulic composition which added pozzolanic fine powders, such as a silica fume and a silica dust, to cement, and improved the intensity | strength is proposed (refer patent document 2). According to this method, a high-strength cured body can be produced by pressure vibration molding of a composition containing cement, pozzolanic fine powder, fine aggregate, and water.

JP 2002-321852 A1 JP 2004-339043 A

However, in the technique using ashes such as pulp sludge incinerated ash and fly ash as cement admixture as disclosed in the above-mentioned Patent Document 1, ashes have a large variation in characteristics, and their strength is improved. In terms of stability of characteristics, it was not always satisfactory.
In addition, in the technology disclosed in the above-mentioned Patent Document 2 in which pozzolanic fine powder such as silica fume is added to cement, most of the silica fume is imported from overseas and is expensive and has a chemical composition and In terms of dispersibility, there was a problem that it was difficult to ensure a stable quality.

  Siliceous shale, on the other hand, is a shale-like rock made of diatomaceous earth formed by the accumulation of diatom plankton remains, and has undergone geological changes due to the effects of earth pressure and geothermal heat. Since the pore volume is very large (more than 3 times) compared to general diatomaceous earth, it has a high humidity control function and is widely used as a humidity control material for underfloor and indoor walls, and as a basic gas adsorption deodorant. It has been. When this siliceous shale is mined, fine powder is generated together with the coarse particles used in the humidity control agent, but there was no effective means for utilizing the fine powder. For this reason, in the past, there were many cases where fine particles were mixed with coarse particles and consumed.

  The present invention has been made in view of the actual state of the background art described above, and its purpose is to achieve effective utilization of fine powder of siliceous shale, which has no particularly effective use, and is excellent in strength development. Another object of the present invention is to provide a hydraulic composition capable of obtaining a cured product having stable characteristics and a cured product of the hydraulic composition.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have added and mixed a predetermined amount of fine powder of siliceous shale to the cement, compared with the case of using ashes. As a result, it was found that a hydraulic composition exhibiting strength development comparable to that obtained when an expensive silica fume was used was obtained, and the present invention was completed.

That is, the present invention provides the following hydraulic compositions and cured bodies [1] to [6].
[1] A hydraulic composition comprising 1 to 20 parts by mass of fine siliceous shale powder with respect to 100 parts by mass of cement.
[2] The hydraulic composition according to [1], wherein the fine powder of the siliceous shale has an average particle size of 0.5 to 20.0 μm.
[3] The hydraulic composition as described in [1] above, wherein the fine powder of siliceous shale has a BET specific surface area of 60 m ² / g or more.
[4] The hydraulic composition according to the above [1], wherein the fine powder of siliceous shale has an API value in the range of 40 to 80% according to a pozzolanic reactive rapid judgment method (API method). object.
[5] The hydraulic composition as described in any one of [1] to [4] above, wherein the siliceous shale is Wakkanai layer siliceous shale.
[6] A cured product obtained using the hydraulic composition according to any one of [1] to [5].

  According to the present invention described above, it is possible to effectively utilize the fine powder of siliceous shale, which has no particularly effective use. That is, the hydraulic composition containing the fine powder of siliceous shale has little variation in characteristics as in the case of ashes, has excellent strength development, and provides a cured product having stable characteristics. In addition, the fine powder of siliceous shale can be supplied more stably than silica fume and is inexpensive, and the hydraulic composition to which the fine powder of siliceous shale of the present invention is added exhibits strength equal to or higher than that to which silica fume is added. Showing gender.

  Hereinafter, the hydraulic composition according to the present invention and the cured body of the hydraulic composition will be described in detail.

Examples of the cement used in the present invention include various Portland cements such as ordinary Portland cement, early-strength Portland cement, medium heat Portland cement, and low heat Portland cement.
Blaine specific surface area of these cements is preferably ^{2500~5000cm 2 / g, 3000~4500cm 2 /} g is more preferable. If the value is less than 2500 cm ² / g, the hydration reaction becomes inactive, and there are disadvantages such as reduced strength and durability after curing. On the other hand, if the value exceeds 5000 cm ² / g, it takes time to grind the cement, and the amount of water increases, so that there are disadvantages such as reduced strength and durability after curing.

  In the present invention, 1 to 20 parts by mass, preferably 5 to 15 parts by mass of fine siliceous shale powder is mixed with 100 parts by mass of the cement. When the amount of siliceous shale is less than 1 part by mass, the initial purpose such as effective use of waste and improvement of strength of the cured product cannot be achieved. On the other hand, when the compounding amount of siliceous shale exceeds 20 parts by mass, the filling rate of the hydraulic composition is lowered, so that there are disadvantages such as reduced strength and durability after curing.

  In the present invention, the fine powder of the siliceous shale to be mixed with the cement preferably has an average particle size of 0.5 to 20.0 μm, more preferably 0.5 to 10.0 μm, particularly It is preferable that it is 0.5-5.0 micrometers. When the value exceeds 20.0 μm, the reactivity of siliceous shale is lowered and it becomes difficult to obtain the effect of strength development, and an alkali silica reaction occurs, and the cured product may expand and break. The smaller the value, the higher the reactivity and the higher the expression of strength. However, when the value is less than 0.5 μm, the amount of water increases, and thus there is a drawback that the strength and durability after curing are reduced. . In addition, the said average particle diameter as used in this specification means the particle diameter of a 50% cumulative volume measured with the laser diffraction scattering type particle size distribution measuring apparatus. Further, the adjustment of the siliceous shale to the above particle diameter is not particularly limited, and may be carried out by ordinary pulverization using an ultrafine pulverizer such as a jet mill, a cross beater mill, a ball mill, etc., if necessary. .

The fine powder of siliceous shale to be mixed with the cement preferably has a BET specific surface area of 60 m ² / g or more, more preferably 80 m ² / g or more, and particularly 100 m ² / g or more. It is preferable that When the value is less than 60 m ² / g, it is not preferable because the effect of strength development is difficult to obtain.

Further, the fine powder of siliceous shale mixed with the cement preferably has a SiO ₂ content of 65% by mass or more. A siliceous shale having a SiO ₂ content of less than 65% by mass is not preferable because it is difficult to obtain the effect of strength.

  In the present invention, the fine powder of siliceous shale mixed with the cement preferably contains opal CT as a constituent mineral. Further, in powder X-ray diffraction by Cu-Kα rays, 2θ = 26. It is preferable that the diffraction intensity of 2θ = 21.5 to 21.9 deg of opal CT with respect to the diffraction intensity at the peak top of 6 deg is in the range of 0.2 to 2.0 when quartz is 1. Is preferably in the range of 0.4 to 1.8, and particularly preferably in the range of 0.5 to 1.5. If the value is less than 0.2, the amount of opal CT rich in reactivity is small, and it is difficult to obtain the effect of strength development. On the other hand, when the value exceeds 2.0, the amount of opal CT is much larger than that of quartz, and such siliceous shale is less resource and less economical.

  Moreover, in the powder X-ray diffraction by the Cu-Kα ray of the siliceous shale, the half width of the peak of 2θ = 21.5 to 21.9 deg of the opal CT is preferably in the range of 0.5 to 3.5 °, more Preferably it is 1.0-3.0 degrees. If the value is less than 0.5 °, the bonding strength of the opal CT crystals increases and the reactivity decreases, which is not preferable. Conversely, when the value exceeds 3.5 °, the growth of crystallites of opal CT is undeveloped, a high specific surface area cannot be obtained, and the reactivity is lowered, which is not preferable. On the other hand, when the value is in the range of 1.0 to 3.0 °, there is a tendency to have a high specific surface area, and the reactivity is increased.

  In the present invention, the fine powder of siliceous shale to be mixed with the cement preferably has a solubility with respect to 20% by mass of sodium hydroxide of 30% by mass or more, more preferably 35% by mass to 70% by mass. It is. When the value is less than 30% by mass, the pozzolanic reactivity is lowered, and it is difficult to obtain strength, which is not preferable.

The reason why the fine powder of siliceous shale used in the present invention has high pozzolanic reactivity is not clear, but it is presumed that a large specific surface area promotes pozzolanic reactivity.
An API method has been proposed as a method for rapidly determining pozzolanic reactivity such as fly ash. This is a method of reacting a suspension obtained by mixing ordinary Portland cement and fly ash in pure water, and calculating the Ca ²⁺ ion consumption rate API (Assessed Pozzolanic-activity Index) by the following formula.

API (%) = (([Ca (C)] − [Ca (F + C)]) / [Ca (c)]) × 100
[Ca (c)]: Ca ²⁺ concentration of standard sample (mg / L)
[Ca (F + C)]: Ca ²⁺ concentration (mg / L) of the evaluation sample

When the API value of siliceous shale is obtained using the above formula, the value of the fine powder of siliceous shale used in the present invention is preferably in the range of 40 to 80%. When the value is less than 40%, it is difficult to obtain an effect of strength development, which is not preferable. Conversely, siliceous shale with a value exceeding 80% is scarce in resources and poor in economic efficiency.
Furthermore, Wakkanai siliceous shale produced in the northern part of Hokkaido can be more preferably used as these siliceous shale. Wakkanai siliceous shale is excellent in grindability and alkali solubility, and is particularly preferable for obtaining the above-mentioned particle size range and reactivity of the present invention.

Fine aggregate can be further mixed in the hydraulic composition comprising the cement according to the present invention and fine powder of siliceous shale. As the fine aggregate, river sand, land sand, sea sand, crushed sand, silica sand and the like or a mixture thereof can be used.
The blending amount of the fine aggregate is preferably 50 to 400 parts by mass with respect to 100 parts by mass of cement from the viewpoint of strength after hardening and durability.

  Moreover, 20-60 mass parts is preferable with respect to 100 mass parts of cements. If the amount of water is less than 20 parts by mass, kneading becomes difficult, and the filling rate of the hydraulic composition is reduced, resulting in a decrease in strength and durability. On the other hand, when the amount of water exceeds 60 parts by mass, there are disadvantages such as reduced strength and durability after curing.

In the present invention, from the viewpoint of further improving the filling rate, strength and durability of the hydraulic composition, the hydraulic composition may be further mixed with inorganic particles having a plain specific surface area larger than that of the cement. Included in the present invention.
Examples of the inorganic particles include slag, limestone powder, feldspar, mullite, alumina powder, carbide powder, and nitride powder.
Moreover, there is no problem in using together with silica fume and fly ash. From the viewpoint of depletion of resources, it is more preferable to use these pozzolanic materials as raw materials and use the present invention in combination from the viewpoint of resource utilization.

  The kneading method of the hydraulic composition of the present invention is not particularly limited, for example, a method in which each material is put into a mixer in a lump and kneaded, materials other than water are put in a mixer and kneaded empty. Thereafter, water can be added and kneaded. The mixer used for kneading may be of any type used for kneading ordinary mortar or concrete. For example, an oscillating mixer, a pan type mixer, a biaxial kneading mixer, or the like is used. Also, the molding method is not particularly limited, and for example, the kneaded material may be put into a predetermined mold and vibration molding may be performed. Further, the curing conditions are not particularly limited, and for example, air curing, steam curing or the like may be performed.

  The cured product obtained by the hydraulic composition of the present invention has stable strength characteristics, such as blocks such as interlocking blocks, flat plates, gratings, assembled soil stoppers, U-shapes, L-shapes, non-muscle / RC tubes It can be suitably used for oval tubes, manholes, sewage troughs, troughs, sleepers and the like.

Test example

  Hereinafter, although the test example which discovered this invention is described, this invention is not limited by these test examples at all.

[1. Materials used]
The following materials were used.
(1) Cement: Ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd., Blaine specific surface area 3,500 cm ² / g)
(2) Silica shale; Wakkanai siliceous shale from northern Hokkaido (3) Silica fume; Chinese (average particle size 0.4μm)
(4) Fly ash; Australian (average particle size 20 μm)
(5) Sand; Standard sand (JIS R 5201 specified product)
(6) Water; tap water

[2. Preparation of X-ray diffraction and powder of siliceous shale]
Using the powder X-ray diffractometer (RINT2000, Rigaku Co., Ltd.) for the diffraction intensity of powder X-rays by Cu-Kα rays and the half-value width of opal CT for Wakkanai layer siliceous shale from northern Hokkaido used as a material Measured. The diffraction intensity is shown in FIG. 1, and the half width is shown in FIG. The Wakkanai layer siliceous shale from the northern Hokkaido region used has a peak intensity of 2θ = 21.5 to 21.9 deg of opal CT with respect to the diffraction intensity of 2θ = 26.6 deg of quartz. It was 0.68. The half width of the opal CT was 1.4 °.
The Wakkanai layer siliceous shale produced in the northern Hokkaido region was adjusted to five types of siliceous shale powders A to E having different particle sizes by changing the grinding machine and grinding conditions.
The siliceous shale powders A, B, and D were obtained by pulverizing Wakkanai-layer siliceous shale from the northern Hokkaido region with a jet mill (manufactured by Seishin Enterprise Co., Ltd., single-track jet mill STJ-200). The grinding condition of the siliceous shale powder A is 5 kg / h (amount of grinding of 5 kg per hour), the grinding condition of the siliceous shale powder B is 14 kg / h, and the grinding condition of the siliceous shale powder D is 0.5 kg / h. did. Moreover, the siliceous shale powders C and E were obtained by pulverizing Wakkanai-layer siliceous shale from the northern Hokkaido region with a cross beater mill (manufactured by Lecce Co., Ltd., FCP80-2). The siliceous shale powders C and E were pulverized under the condition of a 1.0 mm screen, and the 100 μm sieved product was siliceous shale powder C, and the 150 μm sieved product was siliceous shale powder E.

[3. Measurement of average particle size and BTE specific surface area]
About each siliceous shale powder AE obtained by grinding | pulverization, the average particle diameter was measured. The average particle size was measured using a laser diffraction / scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Microtrac Mode 19320-X100), and the measured particle size of 50% cumulative volume was taken as the average particle size.
Moreover, about each siliceous shale powder AE, the BET specific surface area was measured using Flowsorb2300 by Shimadzu Corporation. Table 1 shows the measured values.

[4. Measurement of API value]
Portland cement (1.5 g) and siliceous shale powder A (1.5 g) were mixed with pure water (50 ml) and reacted at 80 ° C. for 18 hours. The Ca ²⁺ ion concentration in the reaction solution was measured using ICP (plasma emission spectroscopic analyzer). The API values calculated from the obtained values are shown in Table 2 (Test Example 1).
Except for using siliceous shale powder B instead of siliceous shale powder A, API values calculated by the same methods and means as in Test Example 1 are shown in Table 2 (Test Example 2).
Except for using siliceous shale powder C instead of siliceous shale powder A, the API values calculated by the same methods and means as in Test Example 1 are shown in Table 2 (Test Example 3).
Except for using siliceous shale powder E instead of siliceous shale powder A, the API values calculated by the same method and means as in Test Example 1 are shown in Table 2 (Test Example 4).
Except for using fly ash instead of siliceous shale powder A, the API values calculated by the same methods and means as in Test Example 1 are shown in Table 2 (Test Example 5).
Table 2 shows the API values calculated by the same method and means as in Test Example 1 except that silica fume was used instead of siliceous shale powder A (Test Example 6).

  From Table 2, in Test Example 5 using fly ash, the API value was as low as 45%. On the other hand, in Test Examples 1 to 4 using siliceous shale powders A to C and E, the API value was as high as 55 to 63%, which was almost the same as the API value of silica fume of 65%.

[5. Measurement of mortar strength]
100 parts by mass (405 g) of ordinary Portland cement, 11 parts by mass of siliceous shale powder A (45 g), 333 parts by mass of standard sand (1350 g), and 56 parts by mass of tap water (225 g) were charged into a Hobart mixer and kneaded.
The kneaded product was put into a mold having a cross section of 40 mm × 40 mm and a length of 160 mm, and cured at 20 ° C. for 7 days and 28 days to obtain a cured product.
The compression strength of the obtained cured product was measured in accordance with a test method specified in JIS. Further, the density was calculated from the size and mass of the cured body, and the specific strength obtained by dividing the compressive strength by the density was also calculated. The results are shown in Table 3 (Test Example 7).
Table 3 shows the values of compressive strength, density and specific strength calculated by the same method and means as in Test Example 7 except that siliceous shale powder B was used instead of siliceous shale powder A ( Test Example 8).
Compression calculated by the same method and means as in Test Example 7 except that siliceous shale powder B was used in place of siliceous shale powder A and the blending amount of siliceous shale powder B was 25 parts by mass (100 g). The values of strength, density, and specific strength are shown in Table 3 (Test Example 9).
The same method as in Test Example 7 above, except that the siliceous shale powder D was used instead of the siliceous shale powder A, and kneading was difficult, so that the blending amount of tap water was 67 parts by mass (270 g). The values of compressive strength, density and specific strength calculated by the means are shown together in Table 3 (Test Example 10).
Except for using siliceous shale powder E instead of siliceous shale powder A, the values of compressive strength, density and specific strength calculated by the same method and means as in Test Example 7 are shown in Table 3 ( Test Example 11).
Table 3 shows the values of compressive strength, density and specific strength calculated by the same method and means as in Test Example 7 except that fly ash was used instead of siliceous shale powder A (Test Example 12). ).
Except for using silica fume instead of siliceous shale powder A, the values of compressive strength, density and specific strength calculated by the same method and means as in Test Example 7 are shown in Table 3 (Test Example 13). .

From Table 3, in Test Example 12 using fly ash, the compressive strength was 33 N / mm ² (7-day strength), and the specific strength was as low as 15.0 (N / mm ² ) / (g / cm ³ ). . On the other hand, in Test Examples 7 and 8 using the siliceous shale powders A and B, the compressive strength is 44 to 47 N / mm ² (7-day strength), and the specific strength is 20.6 to 21.9 (N / mm). ² ) / (g / cm ³ ), which was high, and a compressive strength and specific strength equal to or higher than those of Test Example 13 using silica fume were obtained.
However, in Test Example 9 in which the amount of siliceous shale powder B was large, the compressive strength and specific strength were low. Moreover, in Test Example 10 using the siliceous shale powder D having a small particle size, the amount of water was increased, and the compressive strength and specific strength of the cured product were reduced. In Test Example 11 using the siliceous shale powder E having a large particle size, the compressive strength and the specific strength were lowered due to the alkali silica reaction.

It is the figure which showed the powder X-ray-diffraction result by a Cu-K alpha ray about the siliceous shale from the Hokkaido northern region used for the test. It is the figure which showed the half value width of opal CT in the powder X-ray diffraction by the Cu-K alpha ray shown in FIG.

Claims (6)

  A hydraulic composition comprising 1 to 20 parts by mass of fine siliceous shale powder with respect to 100 parts by mass of cement.   The hydraulic composition according to claim 1, wherein the siliceous shale fine powder has an average particle size of 0.5 to 20.0 µm. The hydraulic composition according to claim 1, wherein the siliceous shale fine powder has a BET specific surface area of 60 m ² / g or more.   2. The hydraulic composition according to claim 1, wherein the fine siliceous shale powder has an API value in a range of 40 to 80% according to a pozzolanic reactivity rapid determination method (API method).   The hydraulic composition according to any one of claims 1 to 4, wherein the siliceous shale is Wakkanai layer siliceous shale.   The hardening body obtained using the hydraulic composition in any one of Claims 1-5.

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