Concrete composition and concrete coating containing bacteria having carbon dioxide absorption mechanism, and shotcrete construction method using same

Abstract

The concrete composition and the concrete coating contain bacteria having a carbon dioxide absorption mechanism to improve the durability of the concrete structure and absorb carbon dioxide in the air regardless of light and dark conditions. The method is used in the sprayed concrete construction method. A concrete composition contains a cementitious inorganic binder and an aggregate mixture. The cement-based inorganic adhesive comprises at least one of 1-type ordinary Portland cement, blast furnace slag and fly ash. The aggregate mixture includes a normal aggregate, and a porous material impregnated with basophilic bacteria having a carbon dioxide absorption mechanism and forming glycocalyx. A concrete coating includes a cementitious inorganic binder, an aggregate mixture, and a fibrous material. The fibrous material may include at least one of polyethylene and nylon.

Description

Technical Field

[0001] The present invention relates to a concrete composition and a concrete coating material that absorb carbon dioxide, and a shotcrete construction method using the same. Specifically, the present invention relates to a concrete composition and a concrete coating material containing bacteria that have a carbon dioxide absorption mechanism and form a glycocalyx to absorb carbon dioxide in the air, and a shotcrete construction method using the same. Background Art

[0002] In recent years, as damage caused by climate change has increased, interest in reducing carbon dioxide has increased, which is pointed out as the cause of climate change. Therefore, various efforts are being made to reduce carbon dioxide in various industries. In particular, cement, which is necessary for making concrete in the construction industry, is known to emit more than 0.8 tons of carbon dioxide per 1 ton produced. Therefore, the construction industry is striving to achieve carbon neutrality, which reduces the net emission of carbon dioxide to zero as much as it emits carbon dioxide.

[0003] Generally, cement undergoes a carbonation reaction in which calcium hydroxide (Ca(OH)2) as a hydration product reacts with carbon dioxide (CO2) to produce calcium carbonate (CaCO3). Thus, concrete that absorbs carbon dioxide in the air can be manufactured. However, there is a problem that this carbonation reaction not only reduces the strength of the concrete structure by changing the pH of the cement to neutral, but also becomes a major cause of steel corrosion, thereby significantly reducing the durability of the concrete structure.

[0004] Alternatively, concrete that absorbs carbon dioxide in the air can be produced by utilizing γ-C2S contained in slag, an industrial byproduct produced during the stainless steel manufacturing process. However, this also causes carbonation of cement, which reduces the durability of concrete structures. In addition, since the amount of γ-C2S produced during the stainless steel manufacturing process is very small, there is a problem that it is somewhat difficult to apply this technology to industrial sites.

[0005] Therefore, interest in the development of technology for absorbing carbon dioxide in the air while maintaining the durability of concrete structures is increasing. For example, in the case where a photocatalyst is coated on the surface of a concrete structure, carbon dioxide in the air can be absorbed while maintaining the durability of the concrete structure. However, there is a problem that a concrete structure coated with a photocatalyst absorbs carbon dioxide in a strong ultraviolet environment and has a short service life because the surface coated with the photocatalyst falls off or is easily damaged when exposed to the outside.

[0006] Therefore, it is necessary to develop a technology that absorbs carbon dioxide from the air even in an environment without strong ultraviolet rays while maintaining the durability of the concrete structure. Summary of the invention

[0007] The present disclosure aims to provide a concrete composition and a concrete coating, which can not only improve the durability of concrete structures but also absorb carbon dioxide in the air regardless of light and dark conditions.

[0008] According to the present disclosure, a concrete composition includes a cement-based inorganic binder and an aggregate mixture, the cement-based inorganic binder including at least one of Type 1 ordinary Portland cement, blast furnace slag, and fly ash, the aggregate mixture including normal aggregate and a porous material impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming a glycocalyx.

[0009] The concrete composition may contain 20 to 25 wt % of the cement-based inorganic binder and 75 to 80 wt % of the aggregate mixture.

[0010] The aggregate mixture may contain 70 to 95 volume % of normal aggregate and 5 to 30 volume % of porous material.

[0011] The bacteria may be one or more species selected from the group consisting of Rhodobacter capsulatus, Rhodopseudomonas palustris, Rhodobacter blasticus, and Rhodobacter sphaeroides.

[0012] The bacteria may be one or more species selected from the group consisting of Thermoproteus, Sulfolobus, Planctomyces and Anammox.

[0013] The porous material may contain at least one of expanded vermiculite, perlite, diatomaceous earth and superabsorbent polymer.

[0014] Porous materials can be impregnated with bacteria under negative pressure conditions.

[0015] According to the present disclosure, a concrete coating comprises a cement-based inorganic binder comprising Type 1 ordinary Portland cement, fly ash, blast furnace slag and polymer powder; an aggregate mixture comprising fine aggregate and a porous material impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming a glycocalyx; and a fiber material comprising at least one of polyethylene and nylon.

[0016] The concrete coating may contain 20 to 50 wt % of a cement-based inorganic binder, 50 to 80 wt % of an aggregate mixture, and 0.1 to 1 parts by volume of a fiber material based on 100 parts by volume of the cement-based inorganic binder and the aggregate mixture.

[0017] The cement-based inorganic binder may contain 30 to 40% by weight of Type 1 ordinary Portland cement, 15 to 25% by weight of fly ash, 40 to 50% by weight of blast furnace slag, and 1 to 10% by weight of polymer powder.

[0018] The polymer powder may be ethylene vinyl acetate (EVA) resin.

[0019] The aggregate mixture may contain 30 volume % to 80 volume % of the fine aggregate and 20 volume % to 70 volume % of the porous material.

[0020] The fiber material may have a diameter of 100 to 140 μm.

[0021] According to the present invention, the sprayed concrete construction method can use any of the above-mentioned concrete coatings.

[0022] The concrete composition and concrete coating according to the present disclosure contain bacteria having a carbon dioxide absorption mechanism and forming glycocalyx, thereby improving the durability of the concrete structure and absorbing carbon dioxide in the air regardless of light and dark conditions.

[0023] Furthermore, the concrete composition and concrete coating according to the present disclosure contain alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming glycocalyx, so that even when the surface of the concrete structure is damaged, the ability to absorb carbon dioxide can be maintained by the bacteria existing inside.

[0024] The concrete composition and concrete coating according to the present disclosure contain a porous material impregnated with bacteria, so that an environment in which bacteria can grow can be formed even inside hardened concrete.

[0025] The concrete coating according to the present disclosure can be easily applied not only to a newly constructed concrete structure but also to an already constructed concrete structure, and can increase the efficiency of carbon dioxide absorption by pouring on the surface of the concrete structure in contact with the atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a diagram showing a mechanism by which bacteria absorb carbon dioxide through the Calvin cycle according to the present disclosure.

[0027] Figure 2 is a diagram showing a mechanism by which bacteria according to the present disclosure absorb carbon dioxide through the reverse tricarboxylic acid (TCA) cycle.

[0028] Figure 3 is a diagram showing the mechanism by which bacteria according to the present disclosure absorb carbon dioxide through the hydroxypropionic acid cycle.

[0029] Figure 4 It is a graph showing the carbon dioxide absorption performance of concrete blocks according to Comparative Example and Experimental Example at 14 days old.

[0030] Figure 5 It is a graph showing the number of bacteria survival in concrete blocks according to Comparative Example and Experimental Example at 14 days old. DETAILED DESCRIPTION

[0031] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0032] In the following description of the embodiments, technologies that are well known in the art and are not directly related to the present disclosure are not described. This is to clearly convey the subject matter of the present disclosure by omitting unnecessary explanations. In the present disclosure, the same or corresponding elements are represented by the same reference numerals.

[0033] The concrete composition according to the present invention comprises a cement-based inorganic binder and an aggregate mixture.

[0034] The cement-based inorganic binder may include at least one of Type 1 ordinary Portland cement, blast furnace slag, and fly ash.The aggregate mixture may include normal aggregate and a porous material impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming a glycocalyx.

[0035] Hereinafter, specific compositions according to the present disclosure will be described in more detail.

[0036] The cementitious inorganic binder may consist of Type 1 ordinary Portland cement alone, but a portion of Type 1 ordinary Portland cement may be replaced with blast furnace slag and fly ash to reduce carbon dioxide emissions during the production of Type 1 ordinary Portland cement.

[0037] Blast furnace slag is an industrial by-product produced when pig iron is made in the blast furnace of a steel mill, and has the effect of reducing the heat of hydration and also has potential hydraulic properties to improve the long-term strength of concrete structures. Blast furnace slag itself has weak hardening properties, but it has the property of accelerating hardening through the action of calcium hydroxide and sulfates, which are cement hydration products.

[0038] Fly ash corresponds to a fine powder form, and when pulverized coal is incinerated at high temperature in a thermal power plant, when the pulverized coal is melted together with the high-temperature combustion gas and rapidly cooled on the way to the chimney, the fly ash is collected in the form of spherical particles by an electrical or mechanical collector due to surface tension. Adding fly ash to concrete compositions slightly increases the curing time, but has the following advantages: enhanced long-term strength of concrete structures, reduced heat of hydration, suppression of alkali-aggregate reaction, tolerance to sulfates, and improved water tightness.

[0039] The aggregate mixture may contain 70 to 95 volume % normal aggregate and 5 to 30 volume % porous material.

[0040] Normal aggregates may include coarse aggregates and fine aggregates. Here, coarse aggregates are aggregates that retain more than 90% by weight in a 5 mm sieve, preferably gravel can be used. Fine aggregates are aggregates that completely pass through a 10 mm sieve and pass more than 90% by weight in a 5 mm sieve, preferably sand can be used.

[0041] The porous material may include at least one of expanded vermiculite, perlite, diatomaceous earth, and superabsorbent polymers having excellent cation exchange capacity. In this case, the porous material may be impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming glycocalyx.

[0042] When bacteria are simply added during the preparation of the concrete composition, the bacteria may die due to friction and impact during the mixing process of the concrete composition. In addition, during the curing process after mixing the concrete composition, a dry environment is formed due to the reduction of moisture caused by the hydration reaction, and the nutrients and growth sites of the bacteria are reduced due to volume expansion. In addition, the size of the internal pores of the cured concrete composition is 1 μm, which is smaller than the general size of bacteria, making it difficult for bacteria to survive in the pores of the concrete. Due to this effect, the growth activity of bacteria in the hardened concrete composition is inhibited, and most of the bacteria die after about 30 days.

[0043] Therefore, the concrete composition according to the present disclosure includes a porous material impregnated with bacteria, so that an environment in which bacteria can grow can be formed even inside the cured concrete composition.

[0044] The porous material may preferably have an effective moisture content of 40% by volume or more and a porosity of 50% by volume or more, thereby forming an environment in which bacteria can grow. In particular, the porous material has an exchangeable cation (Mg 2+ , Ca 2+ ) has the property of absorbing organic matter and can therefore absorb bacteria and the culture medium required for bacterial growth.

[0045] Generally, in a concrete composition, strongly alkaline calcium hydroxide (Ca(OH)2) is generated during hydration, thereby forming a strongly alkaline environment with a pH of 11-12. Moreover, it is difficult for sufficient light and air to reach the interior of the hardened concrete composition. Therefore, in the present disclosure, it is important to select alkaliphilic bacteria that are insensitive to anaerobic, aerobic, and light / dark conditions and have a carbon dioxide absorption mechanism.

[0046] In addition, the bacteria according to the present disclosure may be alkaliphilic bacteria that not only have a carbon dioxide absorption mechanism but also form a glycocalyx. The glycocalyx is a membrane formed around the bacteria by the metabolic activity of the bacteria, which densifies the internal structure of the concrete structure and reduces the permeability of the concrete structure. Therefore, the glycocalyx can prevent carbonation and freeze-thaw of the concrete structure, and inhibit the intrusion of harmful substances such as sulfates to prevent the deterioration of the concrete structure and improve resistance to salt damage.

[0047] Bacteria according to the present disclosure can be divided into bacteria having a Calvin cycle, a reverse tricarboxylic acid (TCA) cycle, and a hydroxypropionic acid cycle as a carbon dioxide absorption mechanism.

[0048] First, the bacteria having the Calvin cycle as a carbon dioxide absorption mechanism may include one or more species selected from the group consisting of Rhodobacter capsulatus, Rhodopseudomonas palustris, Rhodobacter blasticus, and Rhodobacter sphaeroides, which are found in the photosynthetic bacteria Rhodobacter.

[0049] Second, the bacteria having a reverse TCA cycle as a carbon dioxide absorption mechanism may include one or more species selected from the group consisting of Thermoproteus and Sulfolobus.

[0050] Third, the bacteria having a hydroxypropionate cycle as a carbon dioxide absorption mechanism may be green non-sulfur bacteria, and preferably may contain one or more species selected from the group consisting of Planctomyces and Anammox.

[0051] Hereinafter, the carbon dioxide absorption mechanism of the bacteria according to the present disclosure will be described in more detail.

[0052] Figure 1 is a diagram showing a mechanism by which bacteria absorb carbon dioxide through the Calvin cycle according to the present disclosure.

[0053] refer to Figure 1, the Calvin cycle absorbs 6 molecules of carbon dioxide in the process of synthesizing glucose from ATP and NADPH. The Calvin cycle can be roughly divided into three steps. The first step is the fixation of carbon dioxide, which is catalyzed by an enzyme called rubisco. Rubisco combines ribulose 1,5-bisphosphate (RuBP) composed of 5 carbons with carbon dioxide to form two molecules of triphosphoglycerate (3PG). The second step is a process in which triphosphoglycerate (3PG) is converted into triphosphoglyceraldehyde (G3P) through a reduction process. The triphosphoglyceraldehyde (G3P) thus produced is used to synthesize glucose. Finally, the third step is a reaction in which the regeneration of ribulose 1,5-bisphosphate (RuBP) occurs. The triphosphoglyceraldehyde (G3P) produced in the second step is converted into ribulose 1,5-bisphosphate (rubp) through ribulose monophosphate (RuBP). The regenerated ribulose 1,5-bisphosphate (rubp) can absorb carbon dioxide while repeating the process of combining with carbon dioxide.

[0054] Figure 2 is a diagram showing a mechanism by which bacteria according to the present disclosure absorb carbon dioxide through a reverse TCA cycle.

[0055] refer to Figure 2 , the reverse TCA cycle corresponds to rotating the TCA cycle in the opposite direction and taking in three carbon dioxide molecules in the process of converting carbon dioxide to acetyl-CoA. The reverse TCA cycle uses enzymes such as fumarate reductase (which reduces fumarate to succinate), α-ketoglutarate:ferredoxin oxidoreductase (which transfers electrons received from ferredoxin to carbon dioxide and succinyl-CoA to reduce them to α-ketoglutarate), and ATP citrate lyase, which breaks down citrate to produce oxaloacetate / ester and acetyl-CoA.

[0056] Figure 3 is a diagram showing the mechanism by which bacteria according to the present invention absorb carbon dioxide through the hydroxypropionate cycle.

[0057] refer to Figure 3 , in the process of converting acetyl-CoA into malonyl-CoA, the hydroxypropionate cycle absorbs two molecules of carbon dioxide. Referring to the steps of the hydroxypropionate cycle that absorbs carbon dioxide in detail, first, acetyl-CoA absorbs carbon dioxide to form malonyl-CoA, and malonyl-CoA is converted into propionyl-CoA through hydroxypropionate, which is an intermediate. Then, in the process of carboxylating propionyl-CoA into methylmalonyl-CoA, carbon dioxide is absorbed, and methylmalonyl-CoA is isomerized into succinyl-CoA. Then, succinyl-CoA forms malonyl-CoA, and malonyl-CoA is decomposed into acetyl-CoA and glyoxylate.

[0058] The 3-hydroxypropionate / 4-hydroxybutyrate cycle and the dicarboxylate / 4-hydroxybutyrate cycle are known as carbon dioxide uptake mechanisms, in which the hydroxypropionate cycle is modified.

[0059] The concrete composition according to the present disclosure includes alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming glycocalyx, thereby improving the durability of the concrete structure and absorbing carbon dioxide in the air regardless of light and dark conditions.

[0060] Furthermore, the concrete composition according to the present disclosure contains alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming glycocalyx, so that even when the surface of the concrete structure is damaged, the ability to absorb carbon dioxide can be maintained by the bacteria present inside, and the carbon dioxide absorption rate it exhibits can be 3 to 4 times higher than that by general carbonation of concrete.

[0061] The porous material is sterilized using nanobubble water, and then completely immersed in a culture medium in which bacteria are cultured at a weight ratio of 1:3 to 1:4, and negative pressure is applied to impregnate the bacteria. Here, the process of applying negative pressure can be performed in a negative pressure container at 15 to 25° C. and 1 to 30 Torr for 20 to 80 minutes, but the embodiment is not limited thereto.

[0062] Nanobubble water for sterilizing porous materials is an ultrafine water droplet bubble containing oxygen, and the bubble contains a large amount of oxygen. For this reason, when the porous material is washed with nanobubble water, the amount of dissolved oxygen inside the porous material can be increased to increase the activity of photosynthetic bacteria. In addition, nanobubble water can remove foreign matter attached to the surface of the porous material, and because the hydroxyl radicals produced in the water have (-) properties, they can be absorbed onto (+) ions as pollutants, thereby removing pollutants. In nanobubble water, oxygen is activated in the air, and nanobubbles are generated to form molecules such as ozone (O3) and hydroxyl (-OH), which can be used as a disinfectant to destroy organisms and volatile organic compounds. In this case, the porous material can be washed with nanobubble water and then dried at 100°C for 6 to 10 hours, but the embodiment is not limited thereto.

[0063] Bacteria can be grown in culture at a rate of 1×10 9The concrete composition according to the present disclosure is cultured at a concentration of 10 cells / mL or more in an incubator at 5 to 50° C. so that the concrete composition according to the present disclosure has a desired carbon dioxide absorption rate. Here, the culture medium may contain, but is not limited to, yeast extract, disodium succinate hexahydrate, and potassium dihydrogen phosphate (KH2PO4). For example, per 1L of purified water, the culture medium may contain 1.0 g / L of yeast extract, 1.0 g / L of disodium succinate hexahydrate, 0.5 mL / L of ethanol, 1 mL / L of ferric citrate solution (0.5%), 0.5 g / L of potassium dihydrogen phosphate (KH2PO4), 0.4 g / L of magnesium sulfate (MgSO47H2O), 0.4 g / L of sodium chloride (NaCl), 0.4 g / L of ammonium chloride (NH4Cl), 0.05 g / L of calcium chloride (CaCl22H2O), and 1 mL / L of trace element solution (trace element solution SL-6).

[0064] The concrete composition according to the present disclosure may contain 20 to 25 wt % of a cement-based inorganic binder and 75 to 80 wt % of an aggregate mixture, preferably 23 wt % of a cement-based inorganic binder and 77 wt % of an aggregate mixture. In this case, the water-binder ratio may be 30 to 50%. Since the manufacturing method of the concrete composition follows a generally known manufacturing method, its description will be omitted.

[0065] Meanwhile, the concrete coating according to the present invention includes a cement-based inorganic binder, an aggregate mixture and a fiber material.

[0066] The cement-based inorganic binder may include Type 1 ordinary Portland cement, fly ash, blast furnace slag and polymer powder. The aggregate mixture may include fine aggregate and a porous material impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming a glycocalyx. The fiber material may include at least one of polyethylene and nylon.

[0067] Hereinafter, the concrete coating according to the present disclosure will be described in more detail.

[0068] The cement-based inorganic binder may consist of Type 1 ordinary Portland cement alone, but a portion of Type 1 ordinary Portland cement may be replaced with blast furnace slag and fly ash to reduce carbon dioxide emitted during the production of Type 1 ordinary Portland cement. For example, the cement-based inorganic binder may contain 30 to 40 weight % of Type 1 ordinary Portland cement, 15 to 25 weight % of fly ash, 40 to 50 weight % of blast furnace slag, and 1 to 10 weight % of polymer powder.

[0069] Here, the polymer powder may improve adhesion to the concrete structure, and an ethylene-vinyl acetate-based (EVA) resin may be used.

[0070] The aggregate mixture may contain 30 to 80% by volume of fine aggregate and 20 to 70% by volume of porous material. Here, the fine aggregate is an aggregate having a diameter of 5 mm or less, and may include sand, bottom ash, and crushed stone.

[0071] The porous material included in the concrete coating according to the present disclosure is the same as the porous material included in the concrete composition according to the present disclosure, and thus a description thereof will be omitted.

[0072] The fiber material may prevent deformation of the concrete coating such as expansion and contraction, and may include at least one of polyethylene and nylon fibers. In this case, the fiber material may have a diameter of 100 to 140 μm, preferably 120 μm.

[0073] The concrete coating according to the present disclosure may include 20 to 50 wt % of a cement-based inorganic binder and 50 to 80 wt % of an aggregate mixture, and may include 0.1 to 1 volume parts of a fiber material based on 100 volume parts of the cement-based inorganic binder and the aggregate mixture. In this case, the water-binder ratio may be 20 to 50%.

[0074] The concrete coating according to the present invention can be used in a shotcrete construction method, which is placed on the surface of a concrete structure by spraying it through a hose using compressed air. The shotcrete structure allows the coating material to enter very small gaps on the surface of the concrete structure and adhere firmly to it, thereby increasing the density and strength of the concrete structure. For example, the concrete coating according to the present disclosure can be compressed and sprayed using a mobile mixer with a capacity of 10 to 60L, a single pump with a pumping force of 40 to 100 bar at 300 to 1000rpm, and an air compressor of 100 to 1000kPa, and can be placed once or twice.

[0075] The concrete coating according to the present disclosure can be easily applied not only to a newly constructed concrete structure but also to an already constructed concrete structure, and can increase the efficiency of carbon dioxide absorption by pouring on the surface of the concrete structure in contact with the atmosphere.

[0076] [Comparative Example and Experimental Example]

[0077] Hereinafter, concrete blocks according to Comparative Examples and Experimental Examples were prepared to confirm the carbon dioxide absorption performance of the concrete composition according to the present disclosure.

[0078] In Comparative Example 1, the concrete block used had a water-cement ratio of 40%, cement of 23% by weight, fine aggregate of 77% by weight, and a unit cement weight of 450 kg / m 3 Here, the aggregate used is crushed fine aggregate.

[0079] In Experimental Example 1, the concrete block used had a water-cement ratio of 40%, contained 23 wt% cement and 77 wt% aggregate mixture, and the unit cement weight was 450 kg / m 3 The aggregate mixture contained 90 volume % of fine aggregate and 10 volume % of porous material. As the porous material used, expanded vermiculite was impregnated in a culture medium in which Rhodobacter capsulatus was cultured in a negative pressure container and then impregnated with the bacteria for 30 minutes by applying a pressure of 10-30 Torr.

[0080] Experimental Example 2 is the same as Experimental Example 1, except that the aggregate mixture of the concrete block contains 80 volume % of fine aggregate and 20 volume % of porous material.

[0081] Experimental Example 3 is the same as Experimental Example 1, except that the aggregate mixture of the concrete block contains 70 volume % of fine aggregate and 30 volume % of porous material.

[0082] Experimental Example 4 is the same as Experimental Example 1, except that the aggregate mixture of the concrete block contains 60 volume % of fine aggregate and 40 volume % of porous material.

[0083] Experimental Example 5 is the same as Experimental Example 1, except that the aggregate mixture of the concrete block contains 50 volume % of fine aggregate and 50 volume % of porous material.

[0084] The mixing ratios of the porous material impregnated with bacteria in the aggregate mixtures of Comparative Example 1 and Experimental Examples 1 to 5 are shown in the following [Table 1].

[0085] [Table 1]

[0086]

[0087] The materials according to Comparative Example 1 and Experimental Examples 1 to 5 were placed in an airtight container saturated with 3000 ppm of carbon dioxide, and the carbon dioxide concentration in the airtight container was checked at 14 days.

[0088] Figure 4 It is a graph showing the carbon dioxide absorption performance of concrete blocks according to Comparative Example and Experimental Example at 14 days old.

[0089] refer to Figure 4 , at 14 days, 100 ppm or less of carbon dioxide was detected in the airtight container into which the concrete blocks of Experimental Examples 2 to 5 were inserted, in which the mixing ratio of the porous material impregnated with bacteria was 20% by volume or more. That is, it was confirmed that the concrete blocks of Experimental Examples 2 to 5 in which the mixing ratio of the porous material impregnated with bacteria was 20% by volume or more showed a carbon dioxide absorption rate of about 96.7% or more.

[0090] Figure 5It is a graph showing the number of bacteria survival in concrete blocks according to Comparative Example and Experimental Example at 14 days old.

[0091] refer to Figure 5 , at 14 days, it was confirmed that 1.0×10 4 Bacteria with a concentration of 10 cells / mL or more survived in the concrete blocks of Experimental Examples 2 to 5, and the mixing ratio of the porous material impregnated with bacteria in Experimental Examples 2 to 5 was 20% by volume or more.

[0092] Furthermore, in order to confirm the durability of the mixing ratio of the bacteria-impregnated porous material in the concrete composition according to the present disclosure, the compressive strength and the flexural strength in Comparative Example 1 and Experimental Examples 1 to 5 were measured at 28 days and are shown in the following [Table 2].

[0093] [Table 2]

[0094]

[0095] Referring to [Table 2], it was confirmed that the concrete blocks of Comparative Example 1 and Experimental Examples 1 to 5, in which the mixing ratio of the porous material impregnated with bacteria was 50% by volume or less, had a compressive strength of 20 MPa or more at 28 days. In addition, it was confirmed that the concrete blocks of Comparative Example 1 and Experimental Examples 1 to 4, in which the mixing ratio of the porous material impregnated with bacteria was 40% by volume or less, had a flexural strength of 5 MPa or more at 28 days.

[0096] While the invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. A concrete composition comprising: a cement-based inorganic binder comprising at least one of Type 1 ordinary Portland cement, blast furnace slag, and fly ash; and An aggregate mixture comprising normal aggregate and a porous material impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming a glycocalyx.

2. The concrete composition according to claim 1, comprising: 20 to 25 weight % of the cement-based inorganic binder, and 75 to 80 weight % of the aggregate mixture.

3. The concrete composition according to claim 2, wherein the aggregate mixture contains 70 volume % to 95 volume % of the normal aggregate and 5 volume % to 30 volume % of the porous material.

4. The concrete composition according to claim 1, characterized in that The bacteria are one or more species selected from the group consisting of Rhodobacter capsulatus, Rhodopseudomonas palustris, Rhodobacter blasticus, and Rhodobacter sphaeroides.

5. The concrete composition of claim 1, wherein the bacteria is one or more species selected from the group consisting of Thermoproteus, Sulfolobus, Planctomyces, and Anammox.

6. The concrete composition according to claim 1, wherein the porous material contains at least one of expanded vermiculite, perlite, diatomaceous earth and super absorbent polymer.

7. The concrete composition according to claim 1, wherein the porous material is impregnated with the bacteria under negative pressure conditions.

8. A concrete coating comprising: A cement-based inorganic binder comprising Type 1 ordinary Portland cement, fly ash, blast furnace slag and polymer powder; an aggregate mixture comprising fine aggregate and a porous material impregnated with alkaliphilic bacteria having a carbon dioxide absorption mechanism and forming a glycocalyx; and A fiber material includes at least one of polyethylene and nylon.

9. The concrete coating according to claim 8, comprising: 20 to 50 wt % of the cement-based inorganic binder; 50% to 80% by weight of said aggregate mixture; as well as 0.1 to 1 parts by volume of the fiber material based on 100 parts by volume of the cement-based inorganic binder and the aggregate mixture.

10. The concrete coating of claim 9, wherein the cement-based inorganic binder contains 30 wt% to 40 wt% Type 1 ordinary Portland cement, 15 wt% to 25 wt% fly ash, 40 wt% to 50 wt% blast furnace slag, and 1 wt% to 10 wt% polymer powder.

11. The concrete coating according to claim 8, wherein: The polymer powder is ethylene vinyl acetate (EVA) resin.

12. The concrete coating according to claim 9, wherein: The aggregate mixture includes 30 volume % to 80 volume % of the fine aggregate and 20 volume % to 70 volume % of the porous material.

13. The concrete coating according to claim 8, wherein: The fiber material has a diameter of 100 to 140 μm.

14. A sprayed concrete construction method using the concrete coating according to any one of claims 8 to 13.

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