JP2916486B2 - Hydraulic cement composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD] The present invention on the industrial, and _{CaO-Na 2 O-Al 2} O 3 based sintered product, to novel cement compositions comprising a blast furnace slag.

[B. Description of the Related Art Conventionally, as an example using the _{CaO-Na 2 O-Al 2} O 3 based baked product obtained by the該焼Narubutsu itself and cement (JP-B-57
−31541) and those obtained by using the calcined material as an admixture (Japanese Patent Application No. 63-63).
−327720).

The former, a _{Na 2 O · 14CaO · 5Al 2} O 3, is a hydraulic cement mainly for the like _{3CaO · SiO 2, 2CaO · SiO} 2 is a main composition of Portland cement, the cement is very quick- When used, several percent by weight of a setting retarder such as gypsum and citric acid are added for use.
The latter, although those patent applications based on the inventive of the present inventors, the contents, CaO, when converted into Na ₂ O and _{Al 2 O 3, CaO-Na} 2 , each in a specific proportion the pulverized O-Al ₂ O ₃ based baked product by adding Portland cement in 3 wt% or more, were admixtures aimed at promoting condensation curing of the cement.

As described above, application development conventional _{CaO-Na 2 O-Al 2} O 3 based baked product was admixture considering the effect of whether to use the minerals of Portland cement, or to it.

There is no known example of a mixture of blast furnace slag and any of the above fired products. Blast furnace slag and CaO-A as similar technologies
l ₂ O ₃ based baked product (e.g., 12CaO · 7Al ₂ O _3, alumina cement) is the degree to which the cement composition prepared by mixing is observed (JP 60-180945, JP-A-1-141844).

[C. Invention As stated try to Problem] above resolution, that _{CaO-Na 2 O-Al 2} O 3 based sintered product itself as hydraulic _{cements, Na 2 O · 14CaO · 5Al} 2 O
_The only one is a ₃ -calcium silicate fired product.

On the other hand, the present inventors have known from an early stage that the above-mentioned admixture itself has hydraulic properties, but when this is used alone as cement, the long-term strength is reduced (second Table, Comparative Example 1), the admixture could not be directly used as a general-purpose cement.

[D. Means for Solving the Problems] Accordingly, the present inventors have developed a new material as a basic material that can be used as a cement for civil engineering and construction while taking advantage of the hydraulic property of a CaO—Na ₂ O—Al ₂ O ₃ fired product. Exploring a new hydraulic cement composition, it was found that a cement obtained by combining the fired product having a specific composition with blast furnace slag has no long-term reduction in strength and can be mass-produced as a general-purpose cement. Thus, a hydraulic cement composition described below was completed.

That is, the present invention relates to compounds the indicated again, CaO is 20 wt% or more, Na ₂ O is _{CaO-Na 2 O-Al 2} O 3 based sintered material is 2% or more by weight and Al ₂ O ₃ is 30 wt% or more And a blast furnace slag and a hydraulic cement composition.

 Hereinafter, the present invention will be described in detail.

_{CaO-Na 2 O-Al 2} O 3 based sintered product for use in the present invention, it is desirable that the CaO, the Na ₂ O and Al ₂ O ₃ is contained more than the specified amount of time, expressed as compound. If the content of CaO is less than 20% by weight, the absolute value of the initial and long-term strength is low, and is not sufficient as a general-purpose cement. If the content of Na ₂ O is less than 2% by weight, the composition becomes close to that of alumina cement, and the strength is lowered by a transition phenomenon or the like in a high temperature environment of 40 ° C. or more, which is not preferable (Table 3, Comparative Example 4). The Al ₂ O ₃ is less than 30 wt%, Al ₂
For O ₃ is too small, the CaO is liberated CaO, present in the calcined product, not only slow down the cure, undesirable digested with resulting expansion cracking (Table 2, Comparative Example 3).

Preparation of _{CaO-Na 2 O-Al 2} O 3 based baked product, Japanese Patent Application No. Sho described above
The method is the same as that described in JP-A-63-327720, but the outline thereof is, for example, a Ca source such as limestone or quick lime, a Na source such as Na ₂ CO _3, and an Al source such as Al ₂ O ₃ or Al (OH) ₃ . Al source (NaAlO ₂
Using a Na-Al shared source may be), such as, the respective source CaO, in terms respectively _{Na 2 O, Al 2 O 3} , calcined pulverized product was mixed with the ratio of the compounds defined After firing at 1500 ℃ or more,
If _{quenching, CaO-Na 2 O-Al} 2 O 3 based sintered product for use in the present invention is produced. Here, the fired product includes not only what has been fired but also what has been obtained by melting a pulverized material.

Construct of the composition is predominantly _{3CaO · 2Na 2 O · 5Al 2} O 3 and / or Na ₂ O · Al ₂ O ₃ and / or glass phases.

The blast furnace slag is, for example, a glassy substance obtained by quenching a melt produced as a by-product of pig iron from a blast furnace for iron making with water, air, steam, or the like.

CaO-Na ₂ O-Al ₂ ratio of O ₃ based sintered product and blast furnace slag, but are not particularly limited, preferred are the former 20
80% by weight, the latter being 80-20% by weight.

Next, a method for producing the hydraulic cement composition of the present invention will be described.
The composition is a mixture of said _{CaO-Na 2 O-Al 2} O 3 based sintered product and blast furnace slag, the mixing is performed by conventional mixers. If they are powdery agglomerates, they may be individually pulverized and then mixed, or they may be mixed and pulverized after blending both at a predetermined ratio to obtain the hydraulic cement composition of the present invention. The mixing method and the pulverizing method may be performed according to a conventional method.

It is desirable that the hydraulic cement composition and the respective constituent materials obtained as described above have a Blaine specific surface area of 3000 cm ² / g or more.

Using the hydraulic cement composition of the present invention to produce mortar or concrete according to the application, various admixtures such as a conventional retarder, water reducing agent, A pressure agent, fluidizing agent, shrinkage reducing agent, expanding material, etc. May be used as appropriate.

[E. Action] It is not clear why the long-term strength is reduced when only the CaO—Na ₂ O—Al ₂ O ₃ fired product used in the present invention is used as cement.

After curing of the molded body made of the hydraulic cement composition of the present invention, even if it is exposed to a high temperature environment of 40 ° C. or higher, the strength does not decrease (Table 3), because CaO—Na ₂ O—Al ₂ O Na ₂ O incorporated in the crystal phase and / or glass phase of the fired product of ₃ series is gradually released with the progress of hydration, becomes Na ions, stimulates blast furnace slag, accelerates the hydration reaction, It is presumed to promote the production of stable gehlenite hydrate.

[F. Example] ○ Example 1-3, after preparing a cement composition using a _{CaO-Na 2 O-Al 2} O 3 based sintered product and blast furnace slag made in Comparative Examples 1 to 4 below procedure, the mortar The compressive strength was measured.

(CaO-Na preparation of ₂ O-Al ₂ O ₃ based sintered product) of calcium carbonate (manufactured by Okutama Kogyo Co., Ltd.), sodium carbonate (Tokuyama Soda Co., Ltd. "light soda ash") and blended alumina (manufactured by Showa Denko K.K.) The mixed raw material obtained by pulverizing with a ball mill was calcined in an electric furnace at 1000 ° C. for 1 hour, and then calcined at 1650 ° C. for 30 minutes. After firing, compressed air was blown to rapidly cool to obtain various fired products shown in Table 1.

Each baked product is subjected to a Blaine specific surface area of 5100 ± 100c with a ball mill
Milled to m ² / g.

The results of the measurement of the compounds of these pulverized materials and the minerals by X-ray diffraction are shown in the same table.

(Manufacture of cement composition and measurement of strength) The composition (crushed product) shown in Table 1 and blast furnace slag (“Cerament” manufactured by Daiichi Cement Co., Ltd., Brain (specific surface area 4200)
cm ² / g) were mixed in the proportions shown in Table 2 and mixed to obtain the respective cement compositions.

For 500 g of each cement composition, add 1500 g of sand and 250 g of water, knead with a mixer to make a mortar kneaded material,
After being molded to 4 × 4 × 16 cm, it was cured in a moist air at 20 ° C. and a relative humidity of 95% or more for 24 hours, and then demolded. The sand is a mixture of Soma Silica Sand No. 3, No. 4 and Toyoura Standard Sand in a ratio of 1: 1: 1 (weight ratio).

Each of the obtained compacts is continuously subjected to the second process in a humid air under the same conditions.
After curing to the age shown in the table, the compressive strength was measured.
The results obtained are shown in the same table.

Example 4, Comparative Example 5 The mortar using the cement composition was examined for stability in strength when exposed to a high-temperature environment.

A molded article was prepared from each of the cement compositions of Example 2 and Comparative Example 4 in Table 2 in the same procedure as described above.
After curing on days 7, 7 and 28, the compacts of each age were exposed to a high temperature environment at 80 ° C. and a relative humidity of 95% or more for 6 hours, and then the compressive strength was measured. The results obtained were compared with the compressive strength before exposure (second
The results are shown in Table 3 as percentages (intensity ratios) to Tables).

[G. Effect of the Invention] The present invention relates to a novel hydraulic cement compositions comprising a specific _{CaO-Na 2 O-Al 2} O 3 based sintered product and blast furnace slag, conventional _{CaO-Na 2 O-Al 2} O 3 The fired product is significantly different from Portland cement in which the main mineral and retarder are essential components, and has been developed as a general-purpose cement.

The hydraulic cement composition of the present invention is characterized in that the strength does not decrease in long-term aging, and the initial strength is high, not only that the strength does not decrease even when exposed to a high-temperature environment.

In addition, since the fired product can be easily manufactured and the blast furnace slag to be combined is inexpensive and easily available, it is an invention having a great secondary advantage that it can be mass-produced as a general-purpose cement.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI C04B 18:14) (C04B 28/08 22:06) (58) Investigated field (Int.Cl. ⁶ , DB name) C04B 28 / 06,28 / 08,18 / 14 C04B 22/06

Claims (1)

(57) [Claims] (1) 20% by weight or more of CaO, ₂ % by weight or more of Na ₂ O, and
Al ₂ O ₃ is 30 wt% or more _{CaO-Na 2 O-Al 2} O 3 based sintered product and, hydraulic cement composition comprising a blast furnace slag.