KR20160072834A - Secondary Products of Soil Concrete - Google Patents

Abstract

The present invention relates to a secondary product such as a block, brick, panel, or the like manufactured by an organic/inorganic complex cementless soil concrete composite using a binding material consisting of slag, lime, plaster, and silica fume which are inorganic, and casein which is organic. The present invention provides a secondary product of soil concrete derived by: obtaining an organic/inorganic complex cementless soil concrete composite by mixing an inorganic binding material consisting of 60 to 90 wt% of a slag powder, 3 to 25 wt% of lime, 4 to 10 wt% of plaster, 1 to 10 wt% of a limestone powder, and 0.1 to 5 wt% of silica fume with 10 to 200 parts by weight of soil consisting of any one of red clay, clay, and sand soil, with respect to 100 parts by weight of the soil, and further mixing 0.05 to 10 parts by weight of casein with the mixture, with respect to 100 parts by weight of the inorganic binding material; mixing water with the organic/inorganic complex cementless soil concrete composite in a condition of 5 to 50 wt% of water-mortar ratio (mortar is a composite of soil and an inorganic binding material); and curing the mixture. The secondary product of soil concrete has compressive strength more than or equal to 25 MPa at a material age of 28 and pH less than 9.0 at a material age of 91.

Description

{Secondary Products of Soil Concrete}

The present invention relates to a secondary product such as a block, a brick, a panel, and the like, which is made of a binder composed of inorganic slag, lime, gypsum and silica fume, and an oil-inorganic composite cement concrete composition using an organic substance, casein.

As people's interest in the severity of global environmental pollution grows, much research is being done on the life cycle and environment of building materials. Cement is one of the main building materials used in various architectural elements such as structural materials, finishing materials, secondary products and so on. Until recently, its usage has been steadily increasing. The high strength and durability of the cement satisfy the important mechanical properties required as structural materials of the building, and are used throughout society. Its use range is based on architectural materials and finishing materials, and is used as a secondary product for construction and civil engineering, such as bricks, blocks, piles, and water pipes. Also, it is widely used in waterfront space and marine area, such as shore block, island block, artificial fish, and tetrapod. However, cement has various problems such as a lot of energy consumption, a large amount of warming gas (CO ₂ ) generation, and deforestation in the life cycle. Recently, in order to solve this problem, various studies are being carried out to reduce energy consumption and reduce the generation of carbon dioxide by using a sub-material and sub-materials.

Recently, as people's interest in health has increased, the demand for various building materials has increased. Especially, soil is attracting much attention as an eco-friendly material as a traditional building material. However, there is a problem such as being unstable in water and having low compressive strength. In order to improve such properties, some products such as brick, block, and concrete are produced by mixing cement or white cement. However, in this case, the characteristics of cement with strong alkalinity are large, and the cement does not react with the soil, and the strength of the cement is not properly manifested.

In addition to cement, there are cases of improving the soil properties by adding minerals such as lime and gypsum in order to improve the properties of the soil. However, it has low strength and low resistance to water, resulting in long term durability.

An object of the present invention is to provide a soil concrete composition and a soil concrete secondary product in which the soil is used as a building material, and physical properties such as compressive strength and water resistance are fully expressed without using cement.

The present invention is to improve the physical properties of soil concrete secondary products by adding casein, which is an organic material that has not been used in soil concrete.

Accordingly, the present invention relates to an inorganic binder comprising 60 to 90% by weight of slag fine powder, 3 to 25% by weight of lime, 4 to 10% by weight of gypsum, 1 to 10% by weight of fine limestone powder and 0.1 to 5% by weight of silica fume as clay, Inorganic composite cementitious soil concrete composition obtained by mixing 10 to 200 parts by weight of 100 parts by weight of soil composed of any one or more of the above components and 0.05 to 10 parts by weight of casein with respect to 100 parts by weight of the inorganic binder, Wherein the mortar is a mixture of water and a mortar mixed with the mortar and the inorganic binder in an amount of 5 to 50 wt% and then cured to obtain a soil having a compressive strength of 28 MPa or more at 28 days and a pH of 91 days or less Concrete Secondary Products ".

The casein added in the present invention improves the fluidity of the soil concrete in a non-hardened state and contributes to reduction of the pH of the soil concrete and reduction of the whitening phenomenon.

The present invention relates to an organic-inorganic hybrid material which does not use cement for solidifying soil, but which has potential for hydraulic reaction of slag and lime, pozzolanic reaction of soil and lime, and solidification of soil and improvement of physical properties according to reaction between lime and casein Provides concrete.

In addition, water and unreacted lime in the soil concrete composition react with soil and casein to lower the pH of the soil composition, thereby reducing the whitening phenomenon of the secondary product.

In addition, due to the addition of casein, the fluidity of the soil concrete composition to which water is added is increased in an uncured state, the viscosity is increased, the warkability is improved, the finishability is improved, Strength is enhanced.

The present invention relates to an inorganic binder comprising 60 to 90% by weight of slag fine powder, 3 to 25% by weight of lime, 4 to 10% by weight of gypsum, 1 to 10% by weight of fine limestone powder and 0.1 to 5% by weight of silica fume as the clay, Inorganic composite cementitious soil concrete composition in which 10 to 200 parts by weight of casein is mixed with 100 to 10 parts by weight of 100 parts by weight of the inorganic binder, Wherein the mortar has a compressive strength of 25 MPa or more at 28 days of age and a pH of less than 9.0 at 91 days of age after mixing with water under the condition of 5 to 50 wt% of mortar (a mixed composition of mortar and inorganic binder) Secondary product ".

The above-mentioned organic-inorganic hybrid cement concrete composition (hereinafter referred to as "soil concrete composition") is a composition which improves the fluidity of the composition by casein and reduces the pH and whitening phenomenon. Since it does not require a firing process, it can be used variously as a constituent material of a secondary product such as block, brick, and panel as an environment-friendly material which does not generate CO ₂ .

The mixing of soil, inorganic binder and casein constituting the soil concrete composition is meaningful to the mixing ratio of each component rather than the time-series step. That is, the soil and the inorganic binder may be mixed and then mixed with the casein, but the soil, the inorganic binder and the casein may be mixed at a time. Of course, the inorganic binder and casein may be mixed first and then mixed with the soil.

The soil may be formed of at least one of clay, clay, and sand, and the mixing ratio of the inorganic binder may be determined depending on the type of the soil.

The soil to be a raw material of the soil concrete composition provided by the present invention may be variously applied from high viscosity clay to sand and silty sand. The soil type, the compressive strength of the soil particles, the water absorption rate, and the drying shrinkage property are different depending on the type and the place to be sampled. The soil of any one of the above-described clay, clay and sand or any soil containing at least two kinds of soil listed above may be used as the raw material of the present invention. However, the mixing ratio of inorganic binder is 100 weight And in the range of 10 to 200 parts by weight.

The inorganic binder comprises slag fine powder, lime, gypsum, limestone fine powder and silica fume. Each of the components constituting the inorganic binder may be separately blended in a state of being finely blended or may be pulverized into a fine powder by mixing the respective materials.

Among these, the slag fine powder is composed mainly of SiO ₂ , Al ₂ O ₃ , CaO, MgO and the like. The slag fine powder does not harden immediately upon contact with water and has potential hydraulic properties such that hardening occurs by stimulation of the stimulant. When the slag fine powder comes into contact with water, Ca ^{2 +} ions are eluted and a coating of amorphous ASH 6 having poor permeability on its surface is formed, water can not penetrate into the slag fine powder particles due to the coating, and other ions of the slag fine powder particles The elution is suppressed and the hydration reaction does not occur. In this case, when an alkaline stimulant is added, OH ^- ions are adsorbed on the slag fine powder and the ASH6 film is destroyed, and ions such as SiO ₂ , Al ₂ O ₃ , CaO and MgO are eluted from the slag and curing reaction occurs. When the reaction starts, Ca ^{2 +} and SiO ₂ ^- ions react with water to form CSH hydrate. In the present invention, lime was used as an alkali stimulant to stimulate such potential hydraulic properties of the slag fine powder.

The appropriate amount of the slag fine powder is 60 to 90 wt% of the binder. When the addition amount of the slag fine powder in the inorganic binder is less than 60 wt%, the sufficient strength of the reactive material is not generated, so that the strength of the soil concrete is low. When the addition amount of the slag fine powder exceeds 90 wt%, the addition amount of the lime is relatively insufficient, so that the long-term strength of the soil concrete due to the reaction of the soil and lime can be lowered, and the brittleness is increased in the reaction product of the slag fine powder .

The lime is obtained by calcining limestone, and can be exemplified by burnt lime, slaked lime, calcium carbonate, and the most suitable form to use is lime lime digested with quicklime. Lime has been traditionally used in construction and civil engineering, and is an alkaline hardenable material.

In the present invention, lime is used as an alkali stimulant to stimulate the latent hydraulic properties of slag, and OH ^- ions of lime break the passive film of slag and stimulate the hydration reaction of slag.

In addition, lime reacts with soil and causes pozzolanic reaction. Among the particles of clay, clay components except silt, sand and gravel react with lime to cause pozzolanic reaction to develop the strength. Such pozzolanic reaction occurs in the long term to improve the compressive strength of soil concrete.

The appropriate amount of lime added in the inorganic binder of the present invention is 3 to 25 wt%.

When the amount of the lime is less than 3 wt%, the amount of the lime is too small, and the potential hydraulic stress of the slag and the pozzolanic reaction with the soil are not smoothly performed, and the strength of the soil concrete is low. In addition, when the amount of lime is more than 25 wt%, attention should be paid to the fact that whitening of the soil concrete occurs due to the increase of surplus lime remaining after the stimulus reaction of the slag and the pozzolan reaction of the lime.

The gypsum is separated according to the water molecules to calcium sulphate in anhydrite (CaSO _4), half of gypsum (CaSO ₄₂ O), and yisuseok (CaSO ₄₂ O). Anhydrous gypsum is classified into Type I, Type II and Type III anhydrous gypsum. Type III anhydrite and half gypsum have α type and β type and are divided into seven types of gypsum. The gypsum forms an ettringite in the reaction with slag and lime, causing expansion at the beginning of the reaction (curing) and forming a long-term stable compound.

The proper amount of gypsum added in the binder of the present invention is 4 to 10 wt%, and when the amount of gypsum added is out of the above range, the compressive strength of the soil concrete is lowered.

The limestone fine powder is calcium carbonate (CaCO ₃ ) as a main component and is a kind of industrial byproducts generated during the cement manufacturing process, and is a very high powdered material. These limestone fine powders seem to contribute to prevention of segregation of concrete, improvement of compressive strength and improvement of watertightness due to void filling effect in the cured state. In recent years, as domestic and foreign resource depletion and environmental pollution have been concentrated, blast furnace slag, fly ash and other mixed materials are used as a binder material to replace cement.

In the present invention, the appropriate amount of the limestone fine powder in the inorganic binder is 1 to 10 wt%. When 1 wt% or less of limestone powder is added, the effect of improving the compressive strength of the soil concrete is not significant and the water tightness is decreased. Also, when the addition amount is 10 wt% or more, the compressive strength of the soil concrete is reduced.

The silica fume is one kind of industrial byproducts generated during the production of silicon, which is obtained by collecting silicon by-products of ultra-fine particles in an electric dust collector. And the compressive strength of the soil concrete is improved due to the filling effect of the pores filling the fine pores.

When the amount of the silica fume is less than 0.1 wt%, the strength of the silica fume is less than 0.1 wt%. When the amount of the silica fume is more than 5 wt%, the amount of the silica fume increases, So that the addition amount is limited within the above range.

On the other hand, casein is a phosphorus protein containing a trace amount of sugar, and is the main component of milk protein and is also referred to as casein. At around pH 4.6, it does not dissolve in water. Due to this property, precipitates are formed when the skim milk is made slightly acidic. The casein described in the pharmacopeia is defined as having a nitrogen content of 15.2 to 16.0 wt% in dried at 100 ° C. These casein is used as a nutritional, emulsion, digestive power test, and massage cream. Old milk is also applied to freshness determination because casein easily coagulates even when a small amount of alcohol is added. The molecular weight of each monomer is from 20,000 to 30,000.

In the present invention, the proper amount of casein added is 0.05 to 10 parts by weight based on 100 parts by weight of the binder. Casein increases the overall fluidity and adhesion of soil concrete to control cracking and contribute to the development of strength. Also, it has a characteristic of reacting with lime, and has a characteristic of controlling the whitening by reacting with lime slag or soil added to the soil concrete composition and unreacted lime, thereby lowering the alkalinity of the soil concrete. However, when the addition amount of casein is less than 0.05 part by weight with respect to 100 parts by weight of the binding material, the effect of improving the fluidity of the soil concrete is insignificant, so that when it is stirred, many troubles occur and the adhesive force becomes insufficient. In addition, when the amount of casein added exceeds 10 parts by weight based on 100 parts by weight of the binder, the fluidity excessively increases, so that the filling effect of the pores between the soil is lowered, and many pores are generated therein and the volume expansion causes difficulty in stirring. And the dimensional error of the product becomes large. In addition, the volume expansion causes a lot of voids inside and causes a decrease in strength.

The soil concrete composition can be used as a variety of products such as concrete packing materials and blocks. However, it is important to secure adequate liquidity for various product characteristics. In the present invention, various fluidity can be expressed according to the physical and chemical properties of the soil, the ratio of the binder and the ratio of the casein, but the same fluidity is not applied to all the applied products. When the soil concrete composition of the present invention is applied to a secondary product such as a block or a brick to be molded into a machine, it may be varied depending on the characteristics of the molding machine. However, It is preferable to lower the w / m as much as possible at a content of 50 wt% or less in the water-mortar ratio (the mortar is a mixed composition of the soil and the inorganic binder, hereinafter referred to as "w / m"). Accordingly, the lower limit of w / m can be lowered to 5 wt%.

The strength of the w / m may be lowered to about 5 wt% depending on the condition of the soil, but the strength is lowered due to the lack of the bonding water necessary for the reaction of the binder, Molding can be difficult. Even if w / m exceeds 50 wt%, it is possible to form secondary products such as bricks, but in this case, there is a problem that the curing period is lengthened and the strength is lowered.

However, when the soil concrete composition provided by the present invention is applied to wet pavement such as road pavement material, pouring material, etc., it is difficult to secure proper fluidity at low w / m. In this case, it is necessary to adjust the w / m to the level of 20 wt%, to increase the amount of casein added, or to obtain the required fluidity by using a fluidizing agent, etc. However, it is necessary to consider an increase in manufacturing cost.

Examples and comparative examples of the soil concrete composition as described above are shown in Table 1 below. In the above Examples and Comparative Examples, the compounding ratio of the binder materials was controlled within the above-mentioned proper range. Comparative Example 1 was an example in which casein was not added in the same manner as in Example 1 except that the other conditions were the same as in Example 2 except that casein was added in an amount more than the above- Yes.

[Table 1]

Table 1 summarizes the examples and comparative examples of the compressive strength change and the pH change according to the addition of casein in Table 1 and Table 2, respectively.

[Table 2]

In the above example, flowability was improved by the addition of casein, and the compressive strength was improved and the pH was reduced.

In the case of the comparative example, when the casein was not added, the strength was somewhat lower and the pH was higher than the casein added formulations. Also, when the addition amount of casein was too high, the fluidity was good, but the foam was generated inside and the volume was expanded and the compressive strength was decreased.

Claims (1)

An inorganic binder composed of 60 to 90 wt% of fine powder of slag, 3 to 25 wt% of lime, 4 to 10 wt% of gypsum, 1 to 10 wt% of fine limestone powder and 0.1 to 5 wt% of silica fume is formed into at least one of clay, Inorganic composite cementitious soil concrete composition in which 10 to 200 parts by weight of casein is mixed with 100 parts by weight of the inorganic binder and 0.05 to 10 parts by weight of the casein is added to 100 parts by weight of the soil, Mixed composition of soil and inorganic binder) Water is mixed in 5 to 50 wt%, cured,
A compressive strength of 28 MPa or more at 25 MPa and a pH of 9.0 or less at 91 days of age.