JP2656782B2 - Low temperature hydraulic composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a low-temperature hydraulic composition comprising calcium aluminate, oxycarboxylic acids and inorganic salts and having excellent low-temperature strength.

(Prior Art and Problems to be Solved by the Invention) Conventionally, when constructing mortar or concrete, portland cement is mainly used as a binder. In general, the lower the temperature, the slower the hydration of the cement, especially when the temperature falls to 0 ° C or less in a cold season or a freezer.
Since the development of the strength is remarkably delayed and cannot be used for actual use, it is necessary to perform heating curing or heat curing so that the cast concrete does not suffer from frost damage.

However, when a large area is constructed at an extremely low temperature such as −25 ° C., enormous equipment and labor are required, and the amount of energy consumed for implementation is extremely large. There were drawbacks, such as a longer construction period due to slower strength development, and the construction was subject to many restrictions.

The present inventors have solved the above problems, as a result of conducting various studies on a low-temperature hydraulic composition that exhibits strength without applying special curing even at ultra-low temperatures, the use of a specific composition has high strength even at ultra-low temperatures. It has been found that the present invention has been completed and the present invention has been completed.

(Means for Solving the Problems) That is, the present invention provides a calcium aluminate powder,
Oxycarboxylic acids, and one or more inorganic salts selected from the group consisting of carbonates, sulfates, nitrates, nitrites, oxides, hydroxides, thiocyanates, and thiosulfates. The inorganic salts are 0.5 to 15% by weight based on the calcium aluminate powder at 0 ° C.
It is a low-temperature hydraulic composition characterized by curing below.

 Hereinafter, the present invention will be described in detail.

The calcium aluminate powder (hereinafter referred to as “CA powder”) according to the present invention is C ₃ A, C ₁₂ A when CaO is represented by C and Al ₂ O ₃ is represented by A.
₇ , CA, C ₁₁ A ₇ .CaF ₂ and at least one selected from minerals represented by CA ₂ , preferably C ₃ A, C ₁₂ A ₇ , C ₁₁ A ₇
- it is a CaF _2.

These are obtained, for example, by blending alumina as the A source and lime as the C source so as to have the above-described composition and calcining or melting, and those quenched immediately after calcining or melting exhibit particularly good strength development. .

The fineness of the CA powder is not particularly limited,
Normally, it is preferably 3,000 cm ² / g or more, preferably 5,000 cm ²
/ g or more is more preferable. If the fineness is too low, the initial strength expression becomes poor.

Examples of the oxycarboxylic acids include citric acid, tartaric acid, gluconic acid, and the like, and potassium salts and sodium salts thereof.

The amount of oxycarboxylic acids used is 0.05 to CA powder.
2% by weight is preferred.

Further, one or more inorganic salts selected from the group consisting of carbonates, sulfates, nitrates, nitrites, oxides, hydroxides, thiocyanates, and thiosulfates according to the present invention (hereinafter simply referred to as “salts”) Inorganic salts) include carbonates, sulfates, nitrates, nitrites, oxides, hydroxides, chlorides,
Thiocyanates and thiosulfates are exemplified. Of these, alkali metal or alkaline earth metal salts are preferred. It is particularly preferable to use a combination of a carbonate or a sulfate and a nitrate or a nitrite and an oxide or a hydroxide in terms of workability and strength.

The amount of the inorganic salt used is preferably 0.5 to 15% by weight based on the CA powder.

In the present invention, in addition to the above, any mortar or concrete that can exhibit strength after maintaining the fluidity for a certain period of time can be used.

Various admixtures or admixtures can be added as needed. For example, as a dispersing agent, a formalin condensate of naphthalene sulfonate (eg, “Mighty 100” manufactured by Kao Soap Co., Ltd.) or a formalin condensate of melamine sulfonate (eg, product manufactured by Showa Denko KK) Name, "Melment F-10").

The method of using the low-temperature hydraulic composition of the present invention may be handled in the same manner as ordinary Portland cement, and it hydrates and develops its strength only by kneading with water. It can be kneaded and used as mortar or concrete. The oxycarboxylic acids and the inorganic salts may be mixed with CA powder in advance or used by dissolving in kneading water. Particularly when kneading is performed, dissolving them in kneading water is a preferable method from the viewpoint of kneading properties.

The mortar and concrete obtained in this way exert their ability especially at low temperatures, and develop their strength at 0 ° C or less without heat retention or heat curing, and are used for cold concrete and do not require special equipment. In addition, it is economical, and has an effect of shortening the construction period because it is much faster than Portland cement.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples, but parts in Examples are shown on a weight basis.

Example-1 Ca obtained by melting bauxite and quicklime in an electric furnace
A weight ratio of O to Al ₂ O ₃ is 1: 1 and 100 parts of CA powder mainly composed of C ₃ A (Brain value: 5,500 cm ² / g) is added to sodium citrate (Wako Pure Chemical Industries, Ltd.) as oxycarboxylic acids. 0.5
Part and potassium carbonate as inorganic salts (manufactured by Wako Pure Chemical Industries, Ltd.)
After blending 3 parts and 100 parts of No.5 silica sand, add 30 parts of water and add 2 parts.
After sufficiently kneading in a room at 0 ° C., the mold was filled into a mold of 4 × 4 × 16 cm and cured at a temperature of -5 ° C. and -25 ° C. for a predetermined period. After the cured specimens were left in a room at 20 ° C. for one hour, the compressive strength was measured. As a result, a 264kgf / cm ² at 240 kgf / cm ^2, 7 days 183kgf / cm ^2, 3 days 1 day at the reflux of -5 ℃, 114kgf / cm ² in one day in the curing of -25 ° C., 3 158kgf / c per day
Excellent strength was exhibited at 173 kgf / cm ² in m ² and 7 days.

For comparison, the same experiment was carried out without the oxycarboxylic acid and without the inorganic salt, but it was cured during kneading and could not be kneaded.

Example 2 CA powder was replaced with C ₁₂ A ₇ (Brain value: 6,300 cm ² / g)
When the compressive strength was measured in the same manner as in Example 1 except that 4 parts of slaked lime (manufactured by Chichibu Lime Co., Ltd.) was used as the inorganic salts, curing at -5 ° C. resulted in 251 kgf / cm ² , 3 in one day. day
302kgf / cm ^2, 7 days a 326kgf / cm ^2, excellent strength development in curing of -25 ° C. at 204kgf / cm ^2, 7 days 178kgf / cm ^2, 3 days 1 day 208kgf / cm ² Indicated.

Example-3 In Example-1, except that 4 parts of slaked lime and 5 parts of sodium nitrite (manufactured by Wako Pure Chemical Industries, Ltd.) were used as the inorganic salts, they were kneaded at the same ratio as in Example-1. From -25
It was left at ℃ for 10 minutes. The fluidity that can be sufficiently molded is maintained, and when the mold is molded into a 4 × 4 × 16 cm mold, and the compressive strength is measured, it is 174 kgf / cm ² in one day at -5 ° C. for 3 days.
207kgf / cm ^2, 7 days a 218kgf / cm ^2, Atsuta at 125kgf / cm ² at 122kgf / cm ^2, 7 days 107kgf / cm ^2, 3 days 1 day at the reflux of -25 ° C..

(Effect of the Invention) By using the low-temperature hydraulic composition according to the present invention,
The mortar and concrete works in the cold season and in the refrigerator and freezer can be constructed without any restrictions.

Claims (1)

(57) [Claims] 1. A powder selected from the group consisting of calcium aluminate powder, oxycarboxylic acids, and carbonates, sulfates, nitrates, nitrites, oxides, hydroxides, thiocyanates, and thiosulfates. Alternatively, a low-temperature hydraulic composition comprising two or more inorganic salts, wherein the inorganic salts cure at 0 ° C. or lower, which is 0.5 to 15% by weight based on the calcium aluminate powder.