KR101626803B1 - Light-weight foamed concrete composite for secondary products and a method for manufacturing concrete secondary products using the same - Google Patents

Abstract

Provided are a light-weight foamed concrete composite for concrete secondary products and a method for manufacturing the concrete secondary products using the same, capable of showing a high strength performance without an autoclave curing. The light-weight foamed concrete composite according to the present invention is composed by mixing a composition including 25-44 wt% of cement, 0.5-18 wt% of an admixture composed of at least one of fly ashes and ground granulated blast furnace slag, 0.5-3 wt% of a gypsum, 28-35 wt% of a fine aggregate, 17-22 wt% of water, and 4-5 wt% of enclosed type foam, with a foam reinforcing agent of 0.01-1.0 parts by weight as an extra with respect to total 100 parts by weight of the cement, the admixture, and the gypsum. The fine aggregate includes 30-40 parts by weight of heavy sand having a grain fineness distribution of 0.9-1.7 mm as crushed sand, and 60-70 parts by weight of fine sand having a grain fineness distribution of 0.9 mm or less. The enclosed type foam is manufactured by mixing 95-99 parts by weight of water and 1-5 parts by weight of an animal foaming agent.

Description

TECHNICAL FIELD The present invention relates to a lightweight foamed concrete composition for a concrete secondary product and a method for manufacturing a secondary product using the same.

The present invention relates to a lightweight foamed concrete composition and a method for manufacturing a secondary product of concrete using the same, and more particularly, to a lightweight foamed concrete composition and a concrete 2 using the same, which is capable of exhibiting high strength performance without autoclave curing And to a method for manufacturing tea products.

Lightweight foamed concrete is a kind of lightweight concrete that is made of lightweight concrete by forming a lot of bubbles inside concrete. Lightweight foamed concrete is generally manufactured through autoclave curing, which is called ALC (Autoclaved Lightweight Concrete). ALC is a structurally stable plate-shaped tobermorite crystal (a) which is obtained through autoclave curing at high temperature and high pressure (180 ° C, 10 atmospheres) by mixing a slurry prepared by mixing calcite, siliceous raw material and foaming agent (aluminum powder) . A specific manufacturing process can be confirmed through [Fig. 1].

Hydrothermal synthesis of calcium silicate acts as a main mechanism for the development of the strength of ALC by hydrothermal reaction in which high temperature and high pressure water are involved in the chemical reaction. The autoclave curing induces hydrothermal synthesis High-temperature and high-pressure environment. As such, ALC produced through a curing environment at high temperature and high pressure is not desirable from the viewpoints of economical efficiency and environment, and therefore, there is a need to develop a lightweight foamed concrete composition that exhibits excellent strength without curing at high temperature and high pressure.

Registration No. 0947926 "Method of manufacturing lightweight foamed concrete using hydrothermal synthesis reaction using waste concrete sludge", 2011. 03. 15. Registered Patent No. 1276166 "Lightweight foamed concrete composition containing thermosetting resin ", 2013. 06. 18.

It is an object of the present invention to provide a lightweight foamed concrete composition and a method of manufacturing a concrete secondary product using the same, which is configured to exhibit high strength performance without undergoing autoclave curing.

In order to solve the above-mentioned problems, the present invention provides a method for producing a cement paste, comprising the steps of: mixing 0.5 to 18 wt% of an admixture composed of 25 to 44 wt% of cement, fly ash and blast furnace slag fine powder, 0.5 to 3 wt% of gypsum, 28 to 35 wt% 22 wt%, and 4 to 5 wt% of closed bubbles in an amount of 0.01 to 1.0 part by weight relative to 100 parts by weight of the total amount of the cement, the admixture and the gypsum, wherein the fine aggregate is 0.9 30 to 40 parts by weight of water-in-oil having a particle size distribution of 1.7 mm and 60 to 70 parts by weight of a mass having a particle size distribution of 0.9 mm or less, wherein the closed type air bubbles contain 95 to 99 parts by weight of water and 1 to 5 A lightweight foamed concrete composition characterized by being produced by blending a " part "

In this case, the animal foam is prepared by hydrolyzing the keratin protein with an acid or an alkali, neutralizing the degradation product, and adding a divalent iron salt or an antiseptic.

In addition, the lightweight foamed concrete composition according to the present invention has a specific gravity specific gravity of 0.75 to 0.85 and a compressive strength of 4 to 7 MPa.

Further, the present invention is a powder comprising crushed sand and powder composed of (a) 25 to 44 parts by weight of cement, 0.5 to 18 parts by weight of an admixture composed of at least one of fly ash and blast furnace slag fine powder and 0.5 to 3 parts by weight of gypsum, 30 to 40 parts by weight of a fine particle having a particle size distribution of 0.9 to 5 mm and a fine aggregate composed of 60 to 70 parts by weight of a fine particle having a particle size distribution of 0.9 mm or less into a mixer and progressing the dry beam for 25 to 35 seconds; (b) adding 0.01 to 1.0 part by weight of a cell strengthening agent and 17 to 22 parts by weight of water to 100 parts by weight of the powder, and further adding the mixture to a mixer to bake the mixture for 55 to 60 seconds to prepare a cement mortar; (c) 95 to 99 parts by weight of water and 1 to 5 parts by weight of animal foam, and 4 to 6 parts by weight of a closed type bubble are further added to a mixer and mixed with the cement mortar for 85 to 95 seconds to prepare a lightweight foamed concrete composition ; (d) placing the lightweight foamed concrete composition into a concrete secondary product mold; And (e) covering the vinyl or curing tent and performing steam curing. &Quot;

In the step (c), the animal foam is prepared by hydrolyzing the keratin protein with an acid or an alkali, neutralizing the degradation product, and adding a divalent iron salt or an antiseptic.

In the step (d), a fiber mesh may be attached to the inner surface of the mold.

The lightweight foamed concrete composition according to the present invention and the method for producing a concrete secondary product using the same provide the following effects.

1. It is possible to manufacture a high strength lightweight foamed concrete product that exhibits a compressive strength of 4 MPa or more even through steam curing, not by autoclave curing at high temperature and high pressure.

2. Since the pre-bubble method is used to create bubbles in advance, it is not necessary to control the environment such as temperature to induce bubbles in the curing process.

[Fig. 1] is a manufacturing process diagram of an ALC (Autoclaved Lightweight Concrete) on the Internet website of Korea Lightweight Foam Concrete Association.
FIG. 2 is a photograph of a result of a settlement test according to 'KS F 4039 air-bubble concrete for field casting' to verify the physical properties of the lightweight foamed concrete composition according to the present invention.
FIG. 3 is a photograph of a hollow block having a size of 200 × 300 × 600 mm manufactured by a lightweight foamed concrete composition according to an embodiment of the present invention.

Hereinafter, a lightweight foamed concrete composition according to the present invention and a method for producing a concrete secondary product using the same will be described in detail.

1. Lightweight foamed concrete composition

The lightweight foamed concrete composition according to the present invention comprises 0.5 to 18 wt% of an admixture composed of 25 to 44 wt% of cement, at least one of fly ash and blast furnace slag, 0.5 to 3 wt% of gypsum, 28 to 35 wt% of fine aggregate, 17 to 22 wt% And 4 to 5 wt% of closed bubbles, wherein the bubble reinforcing agent is mixed in an amount of 0.01 to 1.0 part by weight relative to 100 parts by weight of the total amount of the cement, the admixture and the gypsum, And 1 to 5 parts by weight of an animal foam.

The lightweight foamed concrete composition is suitable for the production of a lightweight foamed concrete secondary product such as a lightweight foamed concrete panel, having a specific gravity of 0.75 to 0.85 and a compressive strength of 4 to 7 MPa.

The cement may be either one kind of ordinary Portland cement or two or five kinds of Portland cement.

Among the materials constituting the admixture, the fly ash is based on a two-component fly ash specified in KS L 5405, but one of them may also be used. The blast furnace slag fine powder is based on the three types specified in KS L 2563 One or two species can also be used.

The gypsum plays a role of shortening the curing time of the lightweight foamed concrete composition to suppress the extinction of the closed type bubble to the maximum and to suppress the shrinkage of the concrete through a certain degree of expansion at the beginning of hydration. Desulfurized gypsum and the like can be used.

Crushed sand is used as the fine aggregate. Crushed sand is irregular in shape and has an angular shape. When using general crushed sand (particle size of 5.0 mm or less), it breaks bubbles during mixing and adversely affects foamed concrete. do. Therefore, in the present invention, the particle size of the crushed sand is selected, and meshes having a particle size distribution of 0.9 to 1.7 mm and meshes having a particle size distribution of 0.9 mm or less are used in combination. Specifically, the fine aggregate is composed of crushed sand, and is composed of 30 to 40 parts by weight of zirconia having a particle size distribution of 0.9 to 1.7 mm and 60 to 70 parts by weight of zirconia having a particle size distribution of 0.9 mm or less.

The closed bubble is made by mixing the animal foam with water. The animal foam is produced by hydrolyzing a keratin protein, which is a constituent protein of a cat's nose and horn, with an acid or an alkali, neutralizing the degradation product, and adding a divalent iron salt or an antiseptic. The bonding between the partially hydrolyzed hydrolyzate and the iron salt in the animal foam agent has a large surface tension and thus helps to form a stable closed-cell membrane in which the bond between the bubble and the bubble does not occur easily. In addition, the animal foam is a hydrolyzed protein foam, unlike other foaming agents, does not react chemically with the cement slurry and has no risk of causing corrosion of the rebar because it contains no Cl ^- ions.

Conventionally, lightweight foamed concrete has been widely used for synthetic foams and resin soap based foams, and synthetic foams are easily used for bubbles.

The synthetic foam agent generally has an anionic surfactant as its main raw material. The cationic system may neutralize the surface charge of the aggregate or hydrophobize the aggregate to lower workability and adhesion to the cement. The nonionic surfactant has overall , The foaming power is weak and the stability of the bubble in the cement slurry is lowered. A representative synthetic foam based on anionic surfactants is Alkyl Benzene Sulfonate (ABS). However, in the case of bubbles obtained by using ABS, stability and viscosity are high in itself, but when mixed with cement slurry, the hydrophilic property is lowered by Ca ^{2 +} ions generated by cement hydration and formed into large bubbles on the surface of the slurry, There is a problem that stability is lowered.

On the other hand, resin soap based foaming agent means rosin soap in which the resin is dissolved in alkali. Concretely, it is a salt form such as sodium, potassium, triethanolamine or the like of abietic acid which is a main component of the pine rosin, or a salt form added with a maleic acid and a hydrophilic group. Such a resin soap type foaming agent imparts hydrophobicity to concrete , The tendency to inhibit the flowability of concrete has been pointed out as a disadvantage.

The animal foam stabilizer solves the above-mentioned problems of the conventional foam stabilizer and forms a stable closed foam, thereby realizing a lightweight foam concrete composition having excellent physical properties.

The bubble reinforcing agent acts as a thickener to increase the viscosity of the lightweight foam concrete composition to a certain level and to suppress the separation of materials in the slurry. Fatty acid-based non-ionic surfactants are used as the bubbling enhancer, which not only increases the viscosity of the composition but also forms a film on the bubbles, thereby improving the stability of the bubbles in order to maintain the shape of the bubbles during the curing process . On the other hand, it is also possible to use an ethylene-vinyl acetate (EVA) resin as the bubble enhancer.

Hereinafter, specific examples of the lightweight foamed concrete composition according to the present invention will be described with reference to comparative examples.

Table 1 below shows the combination of the comparative examples for testing the physical properties of the lightweight foamed concrete composition according to the present invention and the combination of the examples according to the present invention. Table 2 shows the results of measuring the physical properties of the lightweight foamed concrete compositions according to the comparative examples according to the formulation of Table 1 and the examples.

In Table 1, W is water, OPC is one kind of ordinary portland cement, F / A is fly ash, gypsum is natural gypsum, S1 is crushed sand and general crushed sand having a particle size of 5 mm or less, S2 is crushed crushed S3 is a mass having a particle size distribution of 0.9 mm or less, FS is a foam enhancer composed of a fatty acid type nonionic surfactant, Foam is a closed type bubble containing 97 wt% of water, And 3 wt% of an animal foam, and the weight per 1 L was 0.08 kg.

division Unit application mass (kg / m3) Foam
(L / m 3) FS
(Kg / m3) W OPC F / A gypsum S1 S2 S3 Comparative Example 1 195 327 85 13 - 105 395 575 0.5 Comparative Example 2 200 346 90 14 300 - - 530 0.5 Comparative Example 3 200 346 90 14 - - 300 530 0.5 Comparative Example 4 200 346 90 14 - 150 150 530 0.5 Example 1 200 346 90 14 - 90 210 530 0.5 Example 2 200 346 90 14 - 105 195 530 0.5

division
Compressive strength (MPa) Slurry specific gravity
(g / cm3) Need for Speed
(g / cm3) Hollow block specific gravity
(g / cm3) 3 days 7 days 28th Comparative Example 1 1.6 3.6 4.2 0.78 0.65 - Comparative Example 2 Settlement caused by bubble vesicles Comparative Example 3 2.3 3.5 4.7 0.94 0.80 0.52 Comparative Example 4 1.4 2.6 3.1 0.96 0.81 0.53 Example 1 2.0 4.0 5.1 0.96 0.81 0.53 Example 2 2.4 4.5 5.3 0.95 0.80 0.52

The components of the respective comparative examples and examples are converted into weight ratios as follows.

In Comparative Example 1, a foam strengthening agent was added to the composition consisting of 16.72 wt% of water, 28.04 wt% of cement, 7.29 wt% of fly ash, 1.11 wt% of gypsum, 42.88 wt% of fine aggregate and 3.95 wt% Gypsum, and 0.12 parts by weight of an outer mortar mixed with 100 parts by weight of the total amount of gypsum. The fine aggregate is a lightweight foamed concrete composition comprising 21 parts by mass and 79 parts by mass.

In the case of the comparative examples 2 to 4, the foam strengthening agent was added to the composition comprising 20.15 wt% of water, 34.86 wt% of cement, 9.07 wt% of fly ash, 1.41 wt% of gypsum, 30.23 wt% of fine aggregate, and 3.95 wt% Wherein the fine aggregate is composed of only a crucible in the case of the comparative example 2 and only the crucible in the case of the comparative example 3, and the fine aggregate is composed of only a mass in the case of the comparative example 3, In the case of Comparative Example 4, 50 parts by mass and mass of 50 mass parts were formed.

In the case of Examples 1 and 2, a foam strengthening agent was added to the composition consisting of 20.15 wt% of water, 34.86 wt% of cement, 9.07 wt% of fly ash, 1.41 wt% of gypsum, 30.23 wt% of fine aggregate, and 3.95 wt% The admixture and the gypsum were mixed in an amount of 0.11 part by weight based on 100 parts by weight of the total amount of the gypsum. The fine aggregate was composed of 30 parts by weight and 70 parts by weight in the case of Example 1, 35 parts by weight of mesophase and 65 parts by weight of silt.

Comparing the physical properties of the lightweight foamed concrete compositions according to the above respective comparative examples and the examples, all of the properties except for Comparative Example 2, in which measurement of physical properties was impossible due to settlement caused by bubble vesicle, appear. However, the lightweight foamed concrete composition according to each of the above comparative examples and examples shows a significant difference in terms of compressive strength. Compressive strengths of Comparative Examples 1, 3 and 4 were relatively low at all ages and less than 5 MPa at 28 days of age. Compared to the comparative examples, the compressive strengths of Examples 1 and 2 are higher than those of Comparative Examples at all ages, but also at least 28 MPa at 28 days. Thus, it can be confirmed that the present invention exhibits excellent physical properties in terms of compressive strength.

Generally, in case of using lightweight foamed concrete, foamed bubbles are mixed with cement slurry and then pumped with a pump, so that the volume of the foam is frequently reduced due to the bubble being poured when poured in the field. This phenomenon is a problem caused by the lack of stability of foamed bubbles and the characteristics of equipment. As a result, the increase in the weight per unit volume of lightweight foamed concrete is a main cause of deteriorating the insulation performance and economical efficiency of lightweight foamed concrete. In addition, if the distribution of pores inside lightweight foamed concrete is not constant due to partial vesicles, the stress distribution of lightweight foamed concrete may become uneven and the compressive strength and resistance to cracking tend to decrease.

In order to verify that the lightweight foamed concrete composition according to the present invention can solve such a problem, a settlement test was performed according to the above-described Comparative Example 4, Examples 1 and 2, in accordance with 'KS F 4039 Foamed Concrete for Field Installation' , And the settlement depth was measured after 2 hours after the pouring. In the case of Comparative Example 4, a settlement of 3.5 mm occurred, but in Examples 1 and 2, no settlement occurred. The shape of the test body is shown in FIG. 2, and it can be seen from the results that even if crushed sand is used according to the present invention, the bubbles are stably maintained and the internal pore distribution is formed uniformly and stably.

In addition, a block having a size of 200 x 300 x 600 mm was manufactured by combining the above-described Comparative Examples 1, 3 and 4 and Examples 1 and 2, and a hollow through the block was designed so that the specific gravity of the block itself was 0.50 to 0.60 g / Cm < 3 >. After the curing, curing was performed for 7 days in the room and exposed to the outside. 3 shows photographs taken on the surface of the test specimen at the elapsed time of 56 days outdoors. On the surfaces of the hollow blocks produced by the blending of Comparative Examples 1, 3 and 4, Cracks due to drying shrinkage increased as the number of exposure days increased. However, in the case of the hollow block produced by the blending of Examples 1 and 2, cracking did not occur even after 56 days outdoors. As a result, it can be confirmed that the lightweight foamed concrete composition according to the present invention has excellent crack stability.

In the case of the conventional ALC, the product A of the company shown in the market had a specific gravity of 0.48 g / cm3 and a compressive strength of 4.04 MPa. In case of the product B, the specific gravity of the product was 0.50 g / cm3 and the compressive strength was 4.19 MPa It is confirmed that the physical properties of the lightweight foamed concrete composition according to the present invention are equivalent or superior even when compared with the conventional ALC.

2. Method of manufacturing concrete secondary product

The present invention also provides a method for producing a cement paste, which comprises (a) powder consisting of 25 to 44 parts by weight of cement, 0.5 to 18 parts by weight of an admixture composed of at least one of fly ash and blast furnace slag fine powder and 0.5 to 3 parts by weight of gypsum and crushed sand, 30 to 40 parts by weight of a fine particle having a particle size distribution of 0.9 mm or less and 28 to 35 parts by weight of a fine aggregate composed of 60 to 70 parts by weight of a fine particle having a particle size distribution of 0.9 mm or less, (b) adding 0.01 to 1.0 part by weight of a cell strengthening agent and 17 to 22 parts by weight of water to 100 parts by weight of the powder, and further adding the mixture to a mixer to bake the mixture for 55 to 60 seconds to prepare a cement mortar; (c) 95 to 99 parts by weight of water and 1 to 5 parts by weight of animal foam, and 4 to 6 parts by weight of a closed type bubble are further added to a mixer and mixed with the cement mortar for 85 to 95 seconds to prepare a lightweight foamed concrete composition ; (d) placing the lightweight foamed concrete composition into a concrete secondary product mold; And (e) performing a vapor curing by covering the vinyl or curing tent and further providing a concrete secondary product manufacturing method.

In the step (c), the animal foam is prepared by hydrolyzing a keratin protein with an acid or an alkali, neutralizing the degradation product, and adding a divalent iron salt or an antiseptic.

In addition, a fiber mesh may be attached to the inner surface of the mold in the step (d). In this case, the fiber mesh serves to enhance the rigidity of the lightweight foamed concrete composition and improve the adhesion performance with the plaster or finishing material And improve the quality of the concrete secondary product finally produced.

The method for producing a concrete secondary product according to the present invention is characterized in that cement paste, an admixture and a gypsum are appropriately mixed to produce a cement paste as shown in the step (a) and the step (b) And the steam curing is performed as in the steps (e) and (f). These characteristics are related to each other, and it is possible to manufacture a lightweight foamed concrete product having a compressive strength higher than a certain level through steam curing by preparing cement paste and injecting bubbles in advance in a selective foaming manner. The reason why high temperature and high pressure autoclave curing is required in the production of existing ALC products is to induce a curing reaction for generating a strength and to generate bubbles in the concrete. According to the present invention, curing for strength development and bubble generation No control of the environment is required.

Claims (6)

A mixture of 25 to 44 wt% of cement, 0.5 to 18 wt% of an admixture composed of at least one of fly ash and blast furnace slag, 0.5 to 3 wt% of gypsum, 28 to 35 wt% of fine aggregate, 17 to 22 wt% of water and 4 to 5 wt% of closed- Wherein the foam reinforcing agent is mixed in an amount of 0.01 to 1.0 part by weight relative to 100 parts by weight of the total amount of the cement, the admixture and the gypsum,
The fine aggregate is composed of 30 to 40 parts by weight of crushed sand having a particle size distribution of 0.9 to 1.7 mm and 60 to 70 parts by weight of a clay having a particle size distribution of 0.9 mm or less,
The closed type bubble is prepared by blending 95 to 99 parts by weight of water and 1 to 5 parts by weight of an animal foam,
The animal foam is prepared by hydrolyzing a keratin protein with an acid or an alkali, neutralizing the degradation product, adding a divalent iron salt or an antiseptic,
Wherein the specific gravity and compressive strength at 28 days of age are 0.75 to 0.85 and 4.9 to 7 MPa, respectively.
delete delete (a) 25 to 44 parts by weight of cement, 0.5 to 18 parts by weight of an admixture composed of at least one of fly ash and blast furnace slag fine powder, and 0.5 to 3 parts by weight of gypsum, and crushed sand having a particle size distribution of 1.7 mm 30 to 40 parts by weight of mesophase, and 28 to 35 parts by weight of a fine aggregate composed of 60 to 70 parts by weight of silt having a particle size distribution of 0.9 mm or less are put in a mixer and the dry beam is allowed to proceed for 25 to 35 seconds;
(b) adding 0.01 to 1.0 part by weight of a cell strengthening agent and 17 to 22 parts by weight of water to 100 parts by weight of the powder, and further adding the mixture to a mixer to bake the mixture for 55 to 60 seconds to prepare a cement mortar;
(c) 4 to 6 parts by weight of closed type bubbles prepared by blending 95 to 99 parts by weight of water and 1 to 5 parts by weight of an animal foam agent are further added to the mixer and mixed with the cement mortar for 85 to 95 seconds, Producing a lightweight foamed concrete composition;
(d) placing the lightweight foamed concrete composition for a concrete secondary product in a concrete mold for a concrete product; And
(e) applying a vapor curing over the vinyl or curing tent,
Wherein the animal foam is prepared by hydrolyzing the keratin protein with an acid or an alkali, neutralizing the degradation product, and adding a divalent iron salt or an antiseptic to the animal foam.
delete 5. The method of claim 4,
And a fiber mesh is attached to the inner surface of the mold in the step (d).

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