KR19980032056A - Cement admixtures and cement compositions, and methods of making concrete products using the same - Google Patents

Abstract

The present invention provides a cement admixture comprising (1) gypsum, aluminum sulfate and / or alumite, and activated silica, and (2) an alkali metal aluminate or an alkali metal silicate. Or (1) or (2) a cement admixture according to the above (1), (3) a pojoran material, or a latent hydraulic material, containing two or more kinds. 2) Cement admixture of base material, (4) Cement and cement admixture of any of said description (1)-(3), Cement composition characterized by the above-mentioned (5) Said (1)-(3) Using the cement admixture of any of the above, it relates to a concrete production method characterized in that the mortar or concrete is mixed evenly, and after molding to the mold, heat curing at 40 to 100 ℃.

Description

Cement admixtures and cement compositions, and methods of making concrete products using the same

The present invention relates to cement admixtures and cement compositions, and to methods of making concrete products using the same. Specifically, the present invention promotes the condensation of mortar or concrete and the development of short-term strength in heating curing such as steam generation, and is used for early demolding of concrete products.

Conventionally, since concrete secondary products are many kinds and many kinds, and are sold in large quantities, in order to cope with this, it is necessary to prepare many types of molds in secondary product factories, and also the vast product site Needed.

Therefore, various early demolding methods are examined in order to increase the production efficiency with fewer molds.

Conventional means considered as a method of premature demolding include raising the curing temperature, using high hydraulic cement, or using a strong condensation accelerator such as chloride or nitrate, rhodate, which promotes condensation hardening of concrete. It is thought.

However, in the method of forcibly forcing the hydration reaction of such cement, demolding strength within a short time (depending on the shape and weight of the secondary product, the demolding strength of large heavy products is usually 8 to 15 N / mm 2) Even if it can be obtained, the resulting strength is suppressed, there is a problem such as the need to increase the amount of unit cement, etc. in order to secure the design strength.

MEANS TO SOLVE THE PROBLEM The present inventors used the admixture using the production | generation of the etinate containing gypsum, a sulfate band, or alumite, sulfite, bisulfite, or pyrosulfite, in order to solve the fault by the conventional method of accelerating condensation. 4-160042).

However, in this proposal, demolding strength is obtained by heating curing for a short time, and the deterioration of long-term strength is prevented, but rapid hydration reaction of aluminum sulfate and the like is suppressed by sulfite and the like. There has been a problem that the effect of suppressing the generation of heat generation due to thermal expansion, which occurs when the initial curing time is shorter and the heating rate is also faster, has a problem.

MEANS TO SOLVE THE PROBLEM In order to solve the said problem, as a result of earnest research, as a result, it is possible to promote more reasonable condensation, shorten curing time, and increase heat curing rate while ensuring time that can be worked. An early demolding method has been discovered and the present invention has been completed.

That is, this invention contains (1) gypsum, aluminum sulfate and / or alum, and activated silica, (2) alkali metal aluminate or alkali metal silicate 1 (1) or (2) the cement admixture according to the above (1), characterized in that it contains one or two or more species. 2) Cement admixture of base material, (4) Cement and cement admixture of any of said description (1)-(3), Cement composition characterized by the above-mentioned (5) Said (1)-(3) Using a cement admixture of any of the substrates, the mortar or concrete is evenly mixed to provide a method for producing concrete, characterized in that after curing in the mold, heat curing at 40 to 100 ℃.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Gypsum used in the present invention is dihydrate gypsum, hemihydrate gypsum, and soluble type III anhydrous gypsum in addition to type II anhydrous gypsum called insoluble or poorly soluble, and is effective in the expression of long-term strength. And the compounding quantity of this is 6 weight part at most in conversion of CaSO4 with respect to 100 weight part of cement, More preferably, it is 5 weight part or less, and the most preferable range is 0.2-4.0 weight part. If the amount is less than 0.2 parts by weight, the elongation of the long-term strength is small. If it is more than 6 parts by weight, the long-term strength is better developed, but the coagulation delay is increased, and the effect of shortening the curing time and suppressing the heat of heat due to thermal expansion is less. This is undesirable.

Among gypsum, the use of type II anhydrous gypsum called insoluble or poorly soluble is most preferred, and the specific surface area by the Bren method is not particularly limited, but is preferably 2,500 cm 2 / g or more.

In addition, in the present invention, aluminum sulfate and alumite (allite) are generally sold, and are effective in promoting the condensation effect and the expression of short-term strength by heating curing, but the effect of suppressing thermal expansion and axle is little. And both the crystal water and the plasticized anhydrous salt are used. Even when these are used individually, even when both are used together in arbitrary ratios, it is preferable to mix | blend 2.5 parts by weight with respect to 100 weight part of cement in the total amount of each anhydride conversion, More preferably, It is 2.0 weight part or less and the most preferable range is 0.1-1.5 weight part. If it is less than 0.1 part by weight, the effect of shortening the finishing time and short-term strength are small, and if it exceeds 2.5 parts by weight, workability necessary for molding is not secured or is quenched.

Moreover, since these are highly reactive, the powder or particle size is not particularly limited, and may be used as granules or lozenges sold as they are, or may be used after being crushed.

Moreover, the activated silica used in the present invention is, for example, silica incinerator, fryeratshrium, metakaolin, incineration material of a silicide, aerogel and the like. They are ultrafine, one order thinner than cement, and in combination with gypsum, aluminum sulfate, and / or alum, promote condensation in a very small amount and exhibit excellent effects in shortening the curing time and suppressing thermal expansion.

It is preferable to mix | blend active silica with 2.0 weight part as much as 100 weight part of cement, 1.5 weight part or less is more preferable, The most preferable range is 0.05-1.0 weight part. If it is less than 0.05 weight part, the effect of shortening finishing time is small, and even if it adds exceeding 2.0 weight part, the shortening effect of an opening curing time, etc. do not become large.

In the above, the present cement admixture containing gypsum, aluminum sulfate and / or alumite and activated silica is 10.5 parts by weight or less, preferably 8.5 parts by weight or less, most preferably 0.35 to 6.5 with respect to 100 parts by weight of cement. Parts by weight.

In the present invention, in order to promote the condensation promoting effect by the combination of gypsum, aluminum sulfate and / or alum and activated silica, to shorten the opening curing time and to suppress the thermal expansion and reheating effect, an alkali metal alu Silicates of phosphates or alkali metals are used in combination.

In addition, alkali metal means sodium, potassium and lithium.

As for these compounding quantities, 1.0 weight part is preferable at most with respect to 100 weight part of cement, More preferably, it is 0.8 weight part or less, and the most preferable range is 0.04 to 0.6 weight part. If it is less than 0.04 part by weight, the effect of accelerating condensation is small, and if it exceeds 1.0 part by weight, it may be rapidly formed depending on the cement rod and the kind, which is not preferable.

In the above, the present cement admixture containing gypsum, aluminum sulfate and / or alumite, activated silica and alkali metal aluminate or alkali metal silicate is 11.5 parts by weight or less, preferably 100 parts by weight of cement. Preferably 9.3 parts by weight or less, most preferably 0.39 to 7.1 parts by weight.

Furthermore, in the present invention, in order to promote the strength-expressing effect of the combination of gypsum, aluminum sulfate and / or alumite, activated silica and aluminate of alkali metal or silicate of alkali metal, pozzolan activity A substance or latent hydraulic substance is used together.

Pozorane is composed mainly of SiO2 and Al2O3 and generates cement hydrates by reacting with calcification in the long term. By-products are fired in coal-fired power plants using burned materials and carbon materials of various clay minerals such as bennitite, acidic clay and zeolite. Fry at shoe and the like. In addition, a latent hydraulic substance shows the blast furnace slag which hardens by alkali stimulation.

These are powders different from the above-mentioned activated silica, powders having an order of cement and particle diameter equal to each other and having a powder degree (Bren's porosity of 0.5) of 3,000 to 8,500 cm 2 / g, and are not particularly limited to the powder levels.

Even if their hydration activity is small, they are added together with an aluminate of aluminum sulfate and / or an alkali metal, activated silica of the above ultra fine powder, and the like to promote short-term strength and long-term strength. The reason for this is not clear, but it is also inferred to increase the dispersing effect in the case of mixing the aluminum sulfate and alkali metal aluminate, which are extremely hydrated, and the active silica, which is easy to aggregate and difficult to disperse, in advance. The mixing of cement and the like instead of pojoran and the like does not exhibit a strength effect, and thus it is inferred to be involved in some chemical interaction between the pojoran and the other components.

The addition amount of these pozzorans and the like is most preferably 0.1 to 2.0 parts by weight with respect to 100 parts by weight of cement, and even if 2 parts by weight is added, no increase in effect can be expected, and an addition effect can be expected at less than 0.1 parts by weight. none.

In the above, (1) the present cement admixture containing gypsum, aluminum sulfate and / or alumite, activated silica, pozzolan material, latent hydraulic material and one or two or more kinds is 12.5 parts by weight based on 100 parts by weight of cement. 10.5 parts by weight or less, most preferably 0.45 to 8.5 parts by weight, and (2) gypsum, aluminum sulfate and / or alumite, activated silica and aluminate of alkali metal or silicate and alkali of alkali metal. The cement admixture containing egg material, latent hydraulic material or one or two or more kinds is 13.5 parts by weight or less, preferably 11.3 parts by weight or less and most preferably 0.49 to 9.1 parts by weight based on 100 parts by weight of cement.

In the admixture of the present invention, as the amount of unit cement increases or the amount of water cement decreases, the demolding strength is obtained early, so that the long-term strength is high. Preferably, the amount of unit cement exceeds 300 kg / m 3 and the water cement ratio is 55% or less. to be.

In this invention, the mortar concrete which mix | blended the admixture of this invention is shape | molded by a mold, and heat-cure. The heating curing method does not have any means such as steam, heat transfer and hot water, but since the concrete secondary product factory already has steam curing facilities, the method by steam curing is preferable, and the heating temperature is 100 ° C. even if the heating temperature is high. The higher the value, the higher the strength obtained in a short time. On the contrary, the higher the value, the higher the temperature becomes. Since the strength development is slowed below 40 ℃, the time until demolding becomes long, which makes it unsuitable for the purpose of premature demolding. Temperatures above 100 ℃ are difficult to obtain by heating by steam. When it cannot be used and the heating rate is accelerated, it is unpreferable because the heat of a thermal expansion is more likely to occur.

The cement used in the present invention is a mixed cement in which various types of portland cement, non-light cement, and various portland cement are mixed with slug, frying, or silica, and the cement has a short working time and has a strength effect. Use is undesirable because it cannot be expected.

In addition, the method of adding the cement admixture to the concrete of the present invention or the method of mixing by mixing is good as a conventional method, and there is no particular limitation, but the increase in the amount of the cement admixture is mixed with each powder component in advance, or the mixture thereof As a suspension, it may add to the mixer at the time of kneading mortar and concrete, and may mix and add each component separately.

Example

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.

Example 1

Using a mortar blend consisting of 360 g of water, 1,000 g of cement, 1,500 g of sand, and a water-reducing agent as the unit amount, the flow value immediately after winning by changing the type and amount of gypsum, aluminum sulfate, alum, activated silica, etc. The mortar was kneaded by adjusting the compounding quantity of the water reducing agent so that it might fall in the range of 5 mm, and the compression strength at the time of demolding after heat curing was measured as a result of 60 minutes after infusion water. The results are shown in Tables 1 to 3 below.

In addition, although the amount of the water reducing agent was adjusted in the range of 5-20 g as a result, the amount of water reducing agent increased as the compounding quantity of aluminum sulfate, alum and active silica increased.

In addition, the mortar kneading method is a machine of JIS R 5201, and the mixture of the ingredients and cement are added to the kneading bowl while stirring at low speed, and the mixture is stirred for 30 seconds, and then sand is added at a low speed of 30 After stirring for a second, the mixture was further kneaded at a high speed rotation for 60 seconds.

Condensation measurement was carried out by molding a mortar into a container of 6 W × 6 L × 7 H cm using a protruder penetration tester according to ASTM C403, and the numerical value of the pressure gauge when the penetration needle having a diameter of 1.6 cm penetrated 1 cm was measured. Measured.

The mortar kneading and condensation tests were performed at 20 ± 3 ° C. and RH 80% or more indoors.

The specimen for compressive strength test was put into a steam curing furnace 60 minutes after the initial curing (time from kneading to the start of heating curing) under molding using a protrusion bar in a 4 × 4 × 16 cm triple mold. It heated up, heated and cured by steam for 2.5 hours, took out, demolded, and measured the demolding strength (4 hours in kneading) in hot immediately.

In addition, demolded specimens were subjected to exhaustive curing at room temperature of 20 ° C. and RH 60%, and measured at 28 days of strength.

Material used

(1) Cement: Normal portland cement made by Denki Kagaku Kogyo Co., Ltd.

(2) Sand: Himegawa-Suigei River sand, Shigadashi, Japan

(3) Drying machine: Main ingredient naphthalene sulfonate manufactured by Denki Chemical Co., Ltd. (liquid)

A. Gypsum

A-1: Type 1 anhydrous gypsum (fluoric acid generating gypsum, Bren specific surface area 4,000 cm 2 / g)

A-2: 2 water gypsum (reagent, specific surface area 3,800 cm 2 / g)

A-3: Hemihydrate gypsum (Heat treatment of 2 water at 150 ℃, Bren specific surface area 8,000 cm 2 / g)

A-4: Soluble anhydrous gypsum (half heat treatment at 200 ℃, Bren specific surface area 12,000 cm 2 / g)

B. Aluminum Sulfate, etc.

B-1: Aluminum Sulfate 18 Beard (Industrial)

B-2: Alumina of Hiroshimagen Mitsyama is calcined at 650 ° C (pulverized to Bren specific surface area of 6,800 cm 2 / g, purity 90%)

C. activated silica, etc.

C-1: silicadium (BET method specific surface area 25 m 2 / g)

C-2: Fry-at-Shoes (BET method specific surface area 30 ㎡ / g)

C-3: metakaolin (BET method specific surface area 1.4 m 2 / g)

C-4: Aerodyl (BET method specific surface area 160 m 2 / g)

C-5: incineration of outer skin (BET method specific surface area 1.5 ㎡ / g)

In Table 1 and Table 2, when the compounding quantity of gypsum and aluminum sulfate is made constant, and the compounding quantity of active silica is increased, condensation is accelerated as the compounding quantity increases, and it increases to intensity | strength for 4 hours, despite the kind. The activated silica exhibits an effect from 0.01 parts by weight, and promotes condensation and increase of strength for 4 hours up to 0.8 to 1.0 parts by weight, but if it exceeds the effect, the effect does not change or the same flow rate of the water reducing agent is obtained. Since the blending amount increases, there is a tendency for the condensation and the 4 hour strength to decrease slightly (see Experiment Nos. 1-6 to 1-37).

In the case of changing the gypsum compounding amount in Table 2, the improvement of long-term strength is recognized at 0.2 parts by weight regardless of the type, and the long-term strength is increased up to 4 parts by weight without significantly affecting condensation or 4-hour strength. If it is more than that, condensation is delayed, and the strength tends to decrease for 4 hours (see Experiment Nos. 1-39 to 1-55).

In Table 3, aluminum sulfate and the like are markedly promoted from 0.1 parts by weight of remarkable acceleration and increase in strength for 4 hours regardless of their type, and become more remarkable as the amount added increases. A tendency to be suppressed appears (see Experiment Nos. 1-56 to 1-68).

Moreover, even if aluminum sulfate and alum are combined, if the compounding quantity and the compounding quantity by a combination are the same even if it is single, the same condensation acceleration | stimulation and 4-hour intensity | strength will be obtained (experimental numbers 1-65, 1-66 and 1-69, 1-70). Comparison).

Experiment number Plaster Aluminum sulfate and alum Activated silica Pressure gauge readings Strength (N / ㎡) Remarks 4 hours 28 days 1-11-21-31-41-5 -0A-1 2.0- 0- 0A-1 2.0 -0-0B-1 1.0-0B-1 1.0 -0-0-0C-1 0.5- 15321816 12.06.218.711.515.2 50.555.244.650.953.1 Comparative example 1-61-71-81-91-101-111-121-13 A-1 2.0 〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃 B-1 1.0 〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃 C-1 0.05〃 0.10〃 0.30〃 0.50〃 0.80〃 1.00〃 1.50〃 2.00 2230425356575553 17.918.720.621.822.122.521.020.0 53.454.455.755.956.454.955.053.1 Example 1-141-151-161-171-181-191-201-21 A-1 2.0 〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃 B-1 1.0 〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃 C-2 0.05〃 0.10〃 0.30〃 0.50〃 0.80〃 1.00〃 1.50〃 2.00 2532445559585551 18.119.220.921.822.923.620.119.7 51.452.352.751.852.452.051.851.2 Example 1-221-231-241-251-261-271-281-281-29 A-1 2.0 〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃 B-1 1.0 〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃〃 〃 C-3 0.05〃 0.10〃 0.30〃 0.50〃 0.80〃 1.00〃 1.50〃 1.50〃 2.00 182328394552535352 15.116.717.318.619.620.721.321.320.6 52.352.653.052.454.052.651.051.050.8 Example

Experiment number Plaster Aluminum sulfate and alum Activated silica Pressure gauge readings Strength (N / ㎡) Remarks 4 hours 28 days 1-301-311-321-331-34 A-1 2.0 〃 〃〃 〃〃 〃〃 〃 B-1 1.0 〃 〃〃 〃〃 〃〃 〃 C-4 0.05〃 0.10〃 0.30〃 0.50〃 0.80 2835484246 16.819.421.323.625.8 54.355.256.055.856.4 Example 1-351-361-37 A-1 2.0 〃 〃〃 〃 B-1 1.0 〃 〃〃 〃 C-5 1.00〃 1.50〃 2.00 524845 20.019.118.3 55.954.253.3 Example 1-38 - 0 B-1 1.0 C-1 0.5 58 19.0 43.2 Comparative example 1-391-401-411-42 A-1 0.2〃 0.5〃 1.0〃 1.5 B-1 1.0 〃 〃〃 〃〃 〃 C-1 0.5〃 〃〃 〃〃 〃 56575554 19.620.723.521.9 49.852.653.856.0 Example 1-431-441-451-46 A-1 3.0〃 4.0〃 5.0〃 6.0 B-1 1.0 〃 〃〃 〃〃 〃 C-1 0.5〃 〃〃 〃〃 〃 49422418 20.619.013.410.5 57.158.259.961.4 Example 1-471-481-49 A-4 0.2〃 0.5〃 1.0 B-1 1.0 〃 〃〃 〃 C-1 0.5〃 〃〃 〃 586063 19.920.721.8 46.049.651.6 Example 1-501-511-52 A-3 1.5〃 2.0〃 3.0 B-1 1.0 〃 〃〃 〃 C-1 0.5〃 〃〃 〃 575559 20.720.018.4 52.152.453.0 Example 1-531-541-55 A-2 4.0〃 5.0〃 6.0 B-1 1.0 〃 〃〃 〃 C-1 0.5〃 〃〃 〃 423121 16.312.49.2 54.655.253.5 Example

Experiment number Plaster Aluminum sulfate and alum Activated silica Pressure gauge readings Strength (N / ㎡) Remarks 4 hours 28 days 1-56 A-1 2.0 B-1 0.1 - 0 6 7.3 52.8 Comparative example 1-571-581-591-601-611-62 A-1 2.0 〃 〃〃 〃〃 〃〃 〃〃 〃 B-1 0.1〃 0.3〃 0.5〃 1.5〃 2.0〃 2.5 C-1 0.5〃 〃〃 〃〃 〃〃 〃〃 〃 172941597291 13.019.321.023.125.828.3 53.754.452.250.946.342.3 Example 1-631-641-651-661-671-68 A-2 2.0 〃 〃〃 〃〃 〃〃 〃〃 〃 B-2 0.1〃 0.3〃 0.5〃 1.5〃 2.0〃 2.5 C-1 0.5〃 〃〃 〃〃 〃〃 〃〃 〃 142335485672 12.817.619.022.524.024.7 51.952.352.750.647.243.9 Example 1-69 A-2 2.0 B-1 0.15 B-2 0.35 C-1 0.5 36 19.2 52.1 Example 1-70 A-2 2.0 B-1 1.0B-2 0.5 C-1 0.5 47 22.3 50.9 Example 1-71 A-1 0.2 B-1 0.1 - 0 16 12.7 50.0 Comparative example 1-721-731-741-751-76 A-1 0.2〃 1.5〃 3〃 4〃 5 B-1 0.1〃 0.9〃 1.2〃 1.5〃 2 C-1 0.05〃 0.3〃 0.7〃 1.0〃 1.5 2050566779 17.520.222.826.128.1 51.953.457.651.147.0 Example (Note) a. Gypsum, aluminum sulfate, alum, activated silica and the like are parts by weight based on 100 parts by weight of cement. Gypsum, aluminum sulfate and alum are measured in terms of anhydrides c. Alumite is also a measure of purity.

Example 2

Using the mortar of Experiment No. 1-71, 1-72, and 1-73 of Table 3, the kind and addition amount of the aluminate of an alkali metal or the silicate of an alkali metal were changed, and the test similar to Example 1 was performed. The results are shown in Table 4.

Material used

D-1: Sodium Aluminate Anhydrous Salt (Reagent)

D-2: Potassium Aluminate Anhydrous Salt (Reagent)

D-3: Sodium Silicate Anhydrous Salt (Reagent)

In Table 4, in the present invention, the effect of accelerating the condensation of the alkali metal salt, such as the aluminate salt, and the increase in strength for 4 hours is markedly shown (compare Experiment Nos. 2-1, 2-2 with 2-3, 2-4). . In addition, the effect of promoting the condensation of alkali metal salts, such as aluminate salts, and the increase in strength for 4 hours is recognized at 0.04 parts by weight, which is remarkable as the amount of the compound is increased. See numbers 2-5 to 2-12).

Experiment number Type of concrete Alkali metal aluminate silicate Pressure gauge readings Strength (N / ㎡) Remarks 4 hours 28 days 2-12-2 1-71〃 D-2 0.2〃 0.4 1617 13.113.4 50.849.1 Comparative example 2-32-4 1-72〃 D-2 0.2〃 0.4 2536 19.721.6 51.449.8 Example 2-52-62-72-82-92-102-112-12 1-73 yen D-1 0.04〃 0.08〃 0.15〃 0.2〃 0.4〃 0.6〃 0.8〃 1.0 535661687789101142 21.822.724.325.926.928.330.529.3 54.154.553.253.952.151.448.945.7 Example 2-132-14 1-73 yen D-3 0.2〃 0.4 6270 23.124.5 52.250.8 Example (Note) a. Gypsum, aluminum sulfate, activated silica, aluminate of alkali metals, etc. are parts by weight based on 100 parts by weight of cement. Aluminum sulfate is an anhydride equivalent.

Example 3

Using the concrete mix shown in Table 5, A-1, aluminum sulfate B-1, alumite B-2 as gypsum, C-1 as activated silica, and D-1 as aluminate of alkali metals were arbitrarily combined. After kneading the concrete by changing the blending amount, the concrete was molded in a mold having a diameter of φ15 × 30 cm, and the opening curing period (time from kneading to the start of heating curing) was changed, and the thermal expansion ear when rapid heating was performed in steam. The heat generation test was done.

Rapid heating set the vapor curing tank at 75 degreeC in advance, demolded by steam curing for 2.5 hours, and investigated whether the thermal expansion generate | occur | produced.

Moreover, the compressive strength at the time of some demolding was also measured. The results are shown in Table 6.

In addition, 100 liters of concrete was knead | mixed in the room of 20 +/- 3 degreeC using the 200-liter planetary type kneading mixer.

Various components such as gypsum are mixed with cement in advance, kneaded with crushed stone or sand, and mixed with water, and the water is added to the slam into the prescribed range, and the additives used in the examples are added or subtracted. It was adjusted by the post addition method.

In addition, the kneading time was finished by adding kneaded water for 120 seconds.

Aggregate size (mm) Aggregate rate (%) Water cement ratio (%) Slam (cm) Unit weight (㎏ / ㎥) water cement sand broken stone 25 45 44 8 ± 2 163 370 825 1016

In Table 6, the occurrence of the return heat due to thermal expansion means that the heating is performed during the year, and the operation such as injecting is possible.

In the present invention, while ensuring a working time of at least 30 minutes, it is indicated that the thermal expansion silica due to rapid heating positivity is suppressed and the short-term strength is enhanced.

Experiment number Various ingredients Curing start time (minutes) and presence or absence of heat regression Demolding Strength (N / ㎡) Remarks A-1 B-1 B-2 C-1 D-1 20 minutes 30 minutes 40 mins 50 minutes 60 mins 3-1 - - - - - U U U U ※U 1.0 Comparative example 3-2 0.5 0.5 - - - U U U U ※U 3.5 〃 3-3 0.5 0.5 - 0.1 - U U U U ※crumb 10.6 Example 3-4 0.5 0.1 - 0.1 0.4 U U U U ※radish 14.3 〃 3-5 1.0 0.5 - 0.2 - U U U U ※radish 12.2 〃 3-6 1.5 1.0 - 0.5 - U U crumb ※radish 16.7 〃 3-7 1.5 - 1.0 0.5 - U U crumb ※radish 16.9 〃 3-8 1.5 - 1.0 0.5 0.4 U crumb ※radish 20.4 〃 3-9 3.0 1.5 - 0.8 - U crumb ※radish 18.6 〃 3-10 3.0 1.5 - 0.8 0.4 U ※radish 24.0 〃 3-11 6.0 2.0 - 1.0 - U U U U ※crumb 11.8 〃 3-12 6.0 2.0 - 1.0 0.4 U U U ※radish 16.9 〃 (Note) a. Aluminum sulfate, alum, activated silica, alkali metal aluminate and the like are parts by weight based on 100 parts by weight of cement. Aluminum sulfate, alum are measured in terms of anhydrides c. Alumite is also a purity equivalent. D. ※ Deformation strength is also measured for the indication e. Yu: In the first half, a heat of periphery develops.

Example 4

Using the mortar of the experiment numbers 1-1, 1-7 of Table 1, and the experiment numbers 2-8 of Table 4, the kind and addition amount of a pozolan material and a latent hydraulic substance were changed, and the test similar to Example 1 was performed. . The results are shown in Table 7. However, the measurement items were 4 hours intensity and 28 days intensity.

Material used

E-1: The bentonite was calcined at 1,200 ° C and ground to a powder degree of 4,500 cm 2 / g.

E-2: The acidic clay was calcined at 800 ° C and ground at 5,000 cm 2 / g

E-3: Fry at shoe (commercially available powder 4,500 cm 2 / g)

E-4: blast furnace slag (powder degree 4,500 cm 2 / g)

Experiment number Type of concrete Pozo eggs Strength (N / ㎡) Remarks 4 hours 28 days 4-1 1-1 E-1 2.0 12.1 50.8 Comparative example 4-24-34-44-54-6 1-7〃〃〃〃 E-1 0.1〃 0.5〃 1.0〃 1.5〃 2.0 19.221.422.322.522.4 55.356.857.658.058.1 Example 4-74-84-94-104-11 1-7〃〃〃〃 E-4 0.1〃 0.5〃 1.0〃 1.5〃 2.0 19.021.621.922.622.6 55.456.357.057.858.0 Example 4-124-134-144-154-16 2-8〃〃〃〃 E-2 0.1〃 0.5〃 1.0〃 1.5〃 2.0 27.028.229.330.630.2 54.355.656.056.956.8 Example 4-17 2-8 E-1 0.5 29.4 58.0 Example 4-184-194-204-21 2-8〃〃〃 E-3 0.1〃 0.5〃 1.5〃 2.0 26.727.929.330.0 54.555.957.957.5 Example 4-22 2-8 E-4 0.5 30.2 57.8 Example

From Table 7, in the experiment No. 4-1 to which only the pozzoran substance was added, there was a small amount of addition, and the effect of adding almost no strength was shown. On the other hand, in the present invention, the addition effect is exhibited at 0.1 parts by weight, and when the amount is increased, the strength is also increased sequentially.

By blending the cement admixture of the present invention containing gypsum, aluminum sulfate and / or alumite and activated silica into mortar or concrete, the condensation speed of mortar and concrete is increased, the curing time is shortened, and the curing time is further reduced. Therefore, it is possible to produce mortar and concrete without suppressing thermal expansion and heat, increasing the short-term strength, and reducing the long-term strength.

Furthermore, by using aluminate of alkali metal and silicate of alkali metal in combination, the setting time can be further shortened, and the effect of suppressing thermal expansion and heat and increasing the short-term strength can also be promoted. In addition, short-term strength and long-term strength can be increased by using pozzorans and latent hydraulic materials in combination.

Therefore, in the concrete secondary product plant, it is possible to shorten the production cycle from mixing of mortar and concrete to demolding and further increasing production efficiency.

Claims (5)

A cement admixture containing gypsum, aluminum sulfate and / or alum and active silica. The cement admixture according to claim 1, further comprising one kind or two or more kinds of aluminates of alkali metals or silicates of alkali metals. The cement admixture according to claim 1 or 2, wherein the pozzoranite material, one or two or more kinds of latent hydraulic substances are contained. A cement composition comprising cement and the cement admixture according to any one of claims 1 to 3. Using the cement admixture according to any one of claims 1 to 3, mortar or concrete is kneaded and molded into a mold, followed by heating and curing at 40 to 100 ° C.