Manufacturing method for carbon dioxide fixed concrete

Abstract

To provide a method for manufacturing carbon dioxide gas fixation concrete which suppresses time constraint and place constraint for carbon dioxide gas fixation compared to a conventional method, and can increase an amount of carbon dioxide gas capable of being fixed.SOLUTION: A method for manufacturing carbon dioxide gas fixation concrete that is a method for manufacturing carbon dioxide gas fixation concrete in which a predetermined amount of carbon dioxide gas is fixed to concrete includes: a fresh concrete manufacturing step of manufacturing fresh concrete containing γ-C2S; a prior-to-placing carbon dioxide gas fixing step of supplying a carbon dioxide gas source to the fresh concrete manufactured in the fresh concrete manufacturing step and stirring the mixture, and obtaining carbon dioxide gas fixation fresh concrete in which the carbon dioxide gas is fixed to the fresh concrete; and a post-placing concrete curing step of placing the carbon dioxide gas fixation fresh concrete obtained in the prior-to-placing carbon dioxide gas fixing step and curing the carbon dioxide gas fixation fresh concrete, and obtaining carbon dioxide gas fixation concrete.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing carbon dioxide-fixed concrete. [Background technology]

[0002] The cement used in concrete emits a large amount of carbon dioxide (CO2) during production due to the decarbonation of raw materials and the fuel used during firing. In response to growing interest in curbing climate change in recent years, there is a demand for a significant reduction in carbon dioxide emissions during concrete production.

[0003] As a method for reducing carbon dioxide emissions, blended cement, which is made by mixing granulated blast furnace slag (hereinafter simply referred to as ground granulated blast furnace slag) with cement, is widely used. However, increasing the amount of ground granulated blast furnace slag slows down the hardening process, lengthening the time until demolding, and requires prolonged wet curing to achieve sufficient strength. This leaves issues in terms of construction time and cost.

[0004] Furthermore, Patent Document 1 describes a method for carbonating a concrete mix by supplying carbon dioxide to a concrete mix containing cement, in which carbon dioxide is supplied within three minutes of the start of mixing the concrete mix, and the carbon dioxide supply time is set to 10 seconds to 4 minutes. In the method of Patent Document 1, the timing for supplying carbon dioxide is immediately after the start of mixing the concrete mix. Furthermore, the carbonation time of the concrete mix is ​​short. Therefore, in the method of Patent Document 1, there is a time constraint on carbonation of the concrete mix, and the amount of carbon dioxide that can be carbonated is small. Furthermore, due to the time constraint on carbonation, the concrete mix needs to be carbonated at the location where mixing of the concrete mix begins, so there are also spatial constraints on carbonation of the concrete mix. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 082030 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a method for producing carbon dioxide-fixed concrete that reduces time and location constraints on carbon dioxide fixation and increases the amount of carbon dioxide that can be fixed, compared to conventional methods. [Means for solving the problem]

[0007] [1] A method for producing carbon dioxide-fixed concrete in which a predetermined amount of carbon dioxide is fixed in concrete, comprising: a fresh concrete production step of producing fresh concrete containing γ-C2S; a pre-casting carbon dioxide fixation step of supplying a carbon dioxide source to the fresh concrete produced in the fresh concrete production step and stirring the fresh concrete to obtain carbon dioxide-fixed fresh concrete in which carbon dioxide is fixed in the fresh concrete; and a post-casting concrete hardening step of pouring and hardening the carbon dioxide-fixed fresh concrete obtained in the pre-casting carbon dioxide fixation step to obtain carbon dioxide-fixed concrete. [2] The method for producing carbon dioxide-fixed concrete according to [1] above, wherein the carbon dioxide fixation step before pouring supplies the carbon dioxide source to the fresh concrete stored in an agitator car. [3] The method for producing carbon dioxide-fixed concrete according to [2] above, wherein the carbon dioxide source is supplied from outside the agitator vehicle in the pre-casting carbon dioxide fixation step. [4] The fresh concrete produced in the fresh concrete production process is 3 The method for producing carbon dioxide fixed concrete according to any one of [1] to [3] above, wherein the concrete contains 1 kg or more and 100 kg or less of γ-C2S per unit weight. [5] A method for producing carbon dioxide-fixed concrete according to any one of [1] to [4] above, in which a step of forcibly fixing the carbon dioxide by further supplying a carbon dioxide source to the carbon dioxide-fixed fresh concrete after casting but before hardening and the carbon dioxide-fixed concrete is not carried out. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for producing carbon dioxide-fixed concrete that reduces time and location constraints on carbon dioxide fixation compared to conventional methods and can increase the amount of carbon dioxide that can be fixed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a flowchart showing an example of a method for producing carbon dioxide fixed concrete according to an embodiment. [Figure 2] FIG. 2 is a graph showing the relationship between the amount of carbon dioxide gas fixed in carbon dioxide gas-fixed fresh concrete and the carbon dioxide gas supply time in the carbon dioxide gas fixation step before pouring. [Figure 3] FIG. 3 is a schematic diagram showing an example of the configuration of the main parts of an agitator vehicle used in the method for producing carbon dioxide-fixed concrete of the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of a carbon dioxide fixation step before pouring using an agitator vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a detailed description will be given based on an embodiment.

[0011] The method for producing carbon dioxide-immobilized concrete of the present invention is a method for producing carbon dioxide-immobilized concrete in which a predetermined amount of carbon dioxide is immobilized in concrete, and comprises: a fresh concrete production step of producing fresh concrete containing γ-C2S; a pre-casting carbon dioxide immobilization step of supplying a carbon dioxide source to the fresh concrete produced in the fresh concrete production step and stirring it to obtain carbon dioxide-immobilized fresh concrete in which carbon dioxide has been immobilized in the fresh concrete; and a post-casting concrete hardening step of pouring and hardening the carbon dioxide-immobilized fresh concrete obtained in the pre-casting carbon dioxide immobilization step to obtain carbon dioxide-immobilized concrete.

[0012] Figure 1 is a flowchart showing an example of a method for manufacturing carbon dioxide-fixed concrete according to an embodiment. As shown in Figure 1, the method for manufacturing carbon dioxide-fixed concrete according to an embodiment includes a fresh concrete manufacturing step S10, a pre-casting carbon dioxide fixing step S20, and a post-casting concrete hardening step S30. The method for manufacturing carbon dioxide-fixed concrete makes it possible to manufacture carbon dioxide-fixed concrete in which a predetermined amount of carbon dioxide is fixed in the concrete.

[0013] In the fresh concrete production process S10, which is part of the manufacturing method for carbon dioxide-fixed concrete, fresh concrete containing γ-C2S (γ-2CaO·SiO2; also known as γ-belite) is produced. Fresh concrete is a fluidized material. If the fresh concrete produced in the fresh concrete production process S10 contains γ-C2S, carbon dioxide can be fixed in the pre-casting carbon dioxide fixation process S20 and subsequent steps, as described below.

[0014] Fresh concrete is a hydraulic composition, and contains at least water (W), cement (C), and aggregates (fine aggregate (S) and coarse aggregate (G)) in addition to γ-C2S.

[0015] The cement (C) contained in the fresh concrete is preferably Portland cement. Portland cement includes ordinary Portland cement (OPC), as well as types such as early-strength, ultra-early-strength, moderate-heat, and low-heat sulfate-resistant, which are specified in JIS R 5210:2019. Fresh concrete can use a blend of one or more of these various Portland cements.

[0016] Furthermore, blast furnace cement (blended cement) containing ground granulated blast furnace slag (BFS) and cement material (C) may be used as the cement (C). The blast furnace cement specified in JIS R 5211:2009 can be used.

[0017] The fine aggregate (S) contained in fresh concrete is an aggregate defined in JIS A 5308, JIS A 5005, JIS A 5002, and JIS A 5011. Examples of fine aggregate (S) include crushed sand, sand, river sand, sea sand, crushed lime sand, recycled aggregate, lightweight aggregate, and heavy aggregate.

[0018] Coarse aggregate (G) contained in fresh concrete is an aggregate defined in JIS A 5308, JIS A 5005, JIS A 5002, and JIS A 5011, and is distinguished from the above-mentioned fine aggregate (S) by particle size, and is classified by whether or not it passes through a 5mm sieve. In practice, fine aggregate (S) is defined as aggregate that passes through a 10mm sieve in its entirety and at least 85% by weight passes a 5mm sieve, while coarse aggregate (G) is defined as aggregate that is retained by at least 85% by weight on a 5mm sieve.

[0019] In addition to the above components, fresh concrete may contain an expansive agent and a retarder. Furthermore, it may further contain other admixtures within the scope of the present invention. Examples of other admixtures include coal ash, fly ash, limestone powder, carbonate compounds such as light calcium carbonate that fixes atmospheric carbon dioxide, water-reducing agents, and superplasticizers.

[0020] The water (W) / cement (C) ratio in fresh concrete is suitably set within the range of preferably 30% or more and 65% or less.

[0021] The fresh concrete produced in the fresh concrete production process S10 is 3 It is preferable that the fresh concrete contains 1 kg or more of γ-C2S per 1 kg / m, more preferably 10 kg or more, and even more preferably 30 kg or more. 3 As a result, the time and location constraints on carbon dioxide fixation can be further reduced compared to the conventional method, and the amount of carbon dioxide that can be fixed can be further increased.

[0022] The fresh concrete produced in the fresh concrete production process S10 is 3 Preferably, fresh concrete contains 100 kg or less of γ-C2S per 100 kg / m, more preferably 50 kg or less, and even more preferably 10 kg or less. 3 If the content is equal to or less than this, it is possible to suppress an increase in material costs due to the use of excessive γ-C2S.

[0023] The γ-C2S substitution rate for the fresh concrete produced in the fresh concrete production step S10 is preferably 0.5% or more, more preferably 5% or more, and even more preferably 10% or more. The γ-C2S substitution rate can be calculated from the ratio of the unit amount of γ-C2S to the unit amount of cement, where γ-C2S is the proportion of the cement amount. When the γ-C2S substitution rate in fresh concrete is 0.5% or more, the time and location constraints on carbon dioxide fixation can be further reduced, and the amount of carbon dioxide that can be fixed can be further increased, compared to conventional fresh concrete that does not contain γ-C2S.

[0024] As shown in Figure 1, in the pre-casting carbon dioxide fixation step S20, which is carried out after the fresh concrete production step S10, a carbon dioxide source is supplied to the fresh concrete produced in the fresh concrete production step S10 and stirred to obtain carbon dioxide-fixed fresh concrete. Carbon dioxide-fixed fresh concrete is fresh concrete in which carbon dioxide has been fixed, and is what is known as carbonated fresh concrete. Carbon dioxide-fixed fresh concrete is a fluidized material.

[0025] In the pre-casting carbon dioxide fixation step S20, when a carbon dioxide source is supplied to fresh concrete, the γ-C2S in the fresh concrete reacts with carbon dioxide, thereby fixing the carbon dioxide in the fresh concrete. This fixation reaction proceeds more preferentially than the cement hydration reaction because the γ-C2S does not hydrate and reacts only with carbon dioxide.

[0026] In the pre-casting carbon dioxide fixation step S20, it is preferable to stir the fresh concrete when the carbon dioxide source is supplied, from the viewpoint of increasing the amount of carbon dioxide fixed in the fresh concrete in a short period of time. Stirring the fresh concrete when the carbon dioxide source is supplied greatly increases the opportunity for the γ-CS in the fresh concrete to come into contact with carbon dioxide, allowing for an efficient reaction.

[0027] Furthermore, carbon dioxide remains around the carbon dioxide-fixed fresh concrete even after the supply of the carbon dioxide source has stopped. Therefore, even after the supply of the carbon dioxide source has stopped, if the carbon dioxide-fixed fresh concrete is stirred, the γ-CS in the carbon dioxide-fixed fresh concrete will react efficiently with carbon dioxide, further immobilizing the carbon dioxide in the carbon dioxide-fixed fresh concrete.

[0028] The carbon dioxide gas source supplied in the pre-casting carbon dioxide gas fixation step S20 includes a gaseous carbon dioxide gas source containing carbon dioxide gas, and a solid or liquid carbon dioxide gas source that generates carbon dioxide gas at room temperature.

[0029] When the carbon dioxide source is gaseous, it is supplied to the fresh concrete by spraying the gaseous carbon dioxide source onto the fresh concrete. From the viewpoints of ease of supply, ease of handling, ease of availability, etc., the gaseous carbon dioxide source is preferably carbon dioxide gas, a mixed gas containing carbon dioxide gas, or various exhaust gases. Preferred various exhaust gases include exhaust gas from thermal power plants, exhaust gas from boilers, and exhaust gas containing carbon dioxide emitted in the manufacturing process of other products. Furthermore, the humidity and temperature of the exhaust gas may be adjusted, and the adjusted exhaust gas may be used as the gaseous carbon dioxide source.

[0030] When the carbon dioxide gas source is in a solid state, the carbon dioxide gas source is supplied to the fresh concrete by pouring the solid carbon dioxide gas source into the fresh concrete. From the viewpoints of ease of supply, ease of handling, ease of availability, etc., the solid carbon dioxide gas source is preferably dry ice.

[0031] When the carbon dioxide gas source is in a liquid state, the carbon dioxide gas source is supplied to the fresh concrete by injecting the liquid carbon dioxide gas source into the fresh concrete. From the viewpoint of ease of availability of the carbon dioxide gas source, the liquid carbon dioxide gas source is preferably liquefied carbon dioxide.

[0032] As the carbon dioxide gas source, one type of carbon dioxide gas source may be used alone, or two or more types of carbon dioxide gas sources may be used in combination. When two or more types of carbon dioxide gas sources are used in combination, the multiple carbon dioxide gas sources may be supplied separately without overlapping the supply timing, or the multiple carbon dioxide gas sources may be supplied at overlapping times.

[0033] In the pre-pouring carbon dioxide fixation step S20, the lower limit of the temperature of the fresh concrete when the carbon dioxide source is supplied is preferably 10°C or higher, more preferably 20°C or higher, and even more preferably 30°C or higher, and the upper limit is preferably 35°C or lower. As the temperature of the fresh concrete increases within the above temperature range, carbon dioxide can be efficiently fixed in the fresh concrete, and the amount of carbon dioxide fixed in the fresh concrete can be increased in a short period of time.

[0034] In the carbon dioxide fixation process S20 before casting, the substitution rate of γ-C2S and the fresh concrete 1m 3 When carbon dioxide gas is supplied at a constant rate to fresh concrete with the amounts of water (W), cement (C) and γ-CS per unit volume shown in Table 1 so that the total amount of carbon dioxide gas supplied in 5 minutes is 3.3 kg, the amount of carbon dioxide gas fixed in the carbon dioxide gas-fixed fresh concrete (kg / m) is: 3 ) can be estimated for each minute after carbon dioxide gas is supplied as shown in Table 2. Here, the total amount of carbon dioxide gas supplied in 5 minutes, 3.3 kg, is the amount of binder multiplied by 1% (0.01). The binder is the total amount of cement and γ-C2S.

[0035] In addition, the amount of carbon dioxide immobilized in the carbon dioxide-immobilized fresh concrete (kg / m) shown in Table 2 3 The relationship between the temperature (°C) and the carbon dioxide gas supply time (min) is shown in Figure 2.

[0036] [Table 1]

[0037] [Table 2]

[0038] As shown in Tables 1 and 2 and Figure 2, the substitution rate of γ-C2S is 0%, and the amount of γ-C2S contained in fresh concrete is 0 kg / m 3 Compared to ordinary C (concrete not containing γ-C2S), in the carbon dioxide-fixed concrete of the embodiment, the amount of carbon dioxide fixed in the carbon dioxide-fixed fresh concrete increases as the γ-C2S substitution rate and the amount of γ-C2S increase.

[0039] Furthermore, as shown in Fig. 1, in the post-casting concrete hardening step S30, which is carried out after the pre-casting carbon dioxide fixation step S20, the carbon dioxide-fixed fresh concrete obtained in the pre-casting carbon dioxide fixation step S20 is cast and hardened to obtain carbon dioxide-fixed concrete. Carbon dioxide-fixed concrete is concrete in which carbon dioxide has been fixed, and is what is known as carbonated concrete.

[0040] In the post-casting concrete hardening step S30, the carbon dioxide-fixed fresh concrete, which is a fluidized product, is cured and hardened in air without atmosphere control after casting, thereby obtaining carbon dioxide-fixed concrete, which is a hardened product.Since carbon dioxide-fixed concrete fixes carbon dioxide, it contains calcium carbonate.

[0041] After hardening, carbon dioxide gas-fixed concrete contains a large amount of γ-C2S, just like carbon dioxide gas-fixed fresh concrete. Therefore, over a long period of time, the γ-C2S in the carbon dioxide gas-fixed concrete reacts with carbon dioxide in the air (outside air that is not forced), allowing the carbon dioxide gas to be further fixed in the carbon dioxide gas-fixed concrete. The amount of carbon dioxide gas that can be further fixed in carbon dioxide gas-fixed concrete is much greater than the amount of carbon dioxide gas that can be fixed in fresh concrete, which is a fluidized material, or in carbon dioxide gas-fixed fresh concrete.

[0042] Therefore, in the method for manufacturing carbon dioxide-fixed concrete of the embodiment, it is not necessary to carry out a step of forcibly fixing the carbon dioxide (forced carbon dioxide fixation step) by further supplying a carbon dioxide source to the carbon dioxide-fixed fresh concrete and carbon dioxide-fixed concrete after casting but before hardening.

[0043] As described above, carbon dioxide-fixed concrete contains a large amount of γ-CS. Furthermore, compared to fresh concrete and carbon dioxide-fixed fresh concrete, the amount of carbon dioxide that can be fixed in carbon dioxide-fixed concrete is greater. Therefore, even without forcibly supplying a carbon dioxide source to the carbon dioxide-fixed fresh concrete or carbon dioxide-fixed concrete after casting, as in the carbon dioxide fixation step S20 before casting, the carbon dioxide-fixed fresh concrete after casting, and the carbon dioxide-fixed concrete that is the hardened product of the carbon dioxide-fixed fresh concrete, can sufficiently fix carbon dioxide in the air.

[0044] As described above, the manufacturing method of carbon dioxide-fixed concrete according to the above embodiment can reduce the time and location constraints for carbon dioxide fixation compared to conventional methods. Furthermore, carbon dioxide-fixed concrete can sufficiently fix carbon dioxide. Therefore, carbon dioxide-fixed concrete has excellent environmental purification properties.

[0045] Furthermore, even without the forced carbon dioxide fixation process, carbon dioxide fixation concrete can fix more carbon dioxide than conventional concrete. Therefore, if the forced carbon dioxide fixation process is not performed, the additional equipment for the forced carbon dioxide fixation process is not required, which reduces manufacturing costs.

[0046] Figure 3 is a schematic diagram showing an example of the configuration of the main parts of an agitator vehicle used in the manufacturing method of carbon dioxide fixed concrete of this embodiment. As shown in Figure 3, an agitator vehicle 1 has a rotating drum 2 at the rear and a driver's seat 3 at the front. The rotating drum 2 is installed at an angle so that the rear is higher and the front is lower. A rotary drive device 4 for driving the rotating drum 2 to rotate is connected to the rotating drum 2.

[0047] In the pre-casting carbon dioxide fixation step S20, a carbon dioxide source is preferably supplied to the fresh concrete 30 stored in the agitator wheel 1. The fresh concrete containing γ-C2S produced in the fresh concrete production step S10 is poured from a hopper 5 and stored inside the rotating drum 2. The pre-casting carbon dioxide fixation step S20 can be carried out in the rotating drum 2 by supplying a carbon dioxide source to the fresh concrete 30 stored in the rotating drum 2 of the agitator wheel 1 and stirring it. As a result, carbon dioxide-fixed fresh concrete in which carbon dioxide is fixed in the fresh concrete 30 can be obtained in the rotating drum 2.

[0048] In this pre-casting carbon dioxide fixation step S20 within the rotating drum 2, the carbon dioxide source may be supplied into the rotating drum 2 from a carbon dioxide source supply unit (not shown) connected to the rotating drum 2, but since the existing agitator wheel 1 can be used as is without any modification, it is preferable to supply the carbon dioxide source from outside the agitator wheel 1. Among these, it is preferable to supply the carbon dioxide source into the rotating drum 2 from outside the rotating drum 2 via a hopper 5 from the standpoint of ease of supply into the rotating drum 2 and safety.

[0049] This pre-casting carbon dioxide fixation step S20 using the agitator vehicle 1 may be started at the site where the carbon dioxide fixated fresh concrete is being cast, but from the standpoint of efficiency, it is preferable to start it at the time of shipment from the fresh concrete factory. By supplying fresh concrete containing γ-C2S produced at the fresh concrete factory and a carbon dioxide source to the rotating drum 2 of the agitator vehicle 1 at the time of shipment from the factory, the agitator vehicle 1 can perform the pre-casting carbon dioxide fixation step S20 while traveling to the casting site. Therefore, there is no need to wait at the casting site until the pre-casting carbon dioxide fixation step S20 is completed.

[0050] When discharging the carbon dioxide gas-fixed fresh concrete, the rotating drum 2 is rotated and a screw plate 6 installed inside the rotating drum 2 pushes the carbon dioxide gas-fixed fresh concrete out of a discharge port 7 of the rotating drum 2. The carbon dioxide gas-fixed fresh concrete pushed out of the rotating drum 2 is guided through a scoop 8 to a chute 9 and discharged to the outside. The carbon dioxide gas-fixed fresh concrete discharged in this way is subjected to the post-casting concrete hardening process S30.

[0051] Fig. 4 is a schematic diagram showing an example of a pre-casting carbon dioxide fixation step S20 using an agitator vehicle. As shown in Fig. 4, the pre-casting carbon dioxide fixation step S20 using an agitator vehicle is performed using a gun-type carbon dioxide source supply device 20.

[0052] The carbon dioxide gas source supply device 20 is connected via a hose 21 to a high-pressure gas container (not shown), such as a cylinder or tank, that stores gaseous or liquid carbon dioxide gas. The carbon dioxide gas source supply device 20 is also connected to a power source (not shown). When an operator (not shown) pulls a trigger handle 22 of the carbon dioxide gas source supply device 20, the carbon dioxide gas source that leaves the high-pressure gas container passes through the hose 21 and nozzle 23, and is sprayed from the tip of the nozzle 23 and supplied to the fresh concrete 30 in the rotating drum 2 of the agitator vehicle. The spray speed, spray amount, spray width, etc. of the carbon dioxide gas source can be changed as appropriate based on data from a meter (not shown) mounted on the carbon dioxide gas source supply device 20.

[0053] An operator can operate the carbon dioxide gas source supply device 20 outside the rotating drum 2 to supply the carbon dioxide gas source to the fresh concrete 30 inside the rotating drum 2. In this way, the carbon dioxide gas source can be easily supplied to the fresh concrete 30 inside the rotating drum 2 from outside the rotating drum 2 using the carbon dioxide gas source supply device 20.

[0054] Furthermore, the carbon dioxide gas source supply device 20 preferably includes a carbon dioxide gas source blocking part 24 on the nozzle 23 to prevent the carbon dioxide gas source sprayed from the tip of the nozzle 23 from flowing toward the operator. When the carbon dioxide gas source supply device 20 includes the carbon dioxide gas source blocking part 24, the sprayed carbon dioxide gas source can be prevented from flowing toward the operator, allowing the operator to work safely. It is preferable that the carbon dioxide gas source blocking part 24 is transparent so that the operator can easily check the spraying status of the carbon dioxide gas source. It is also preferable that the carbon dioxide gas source blocking part 24 is umbrella-shaped and extends toward the tip of the nozzle 23.

[0055] The above describes an example in which a carbon dioxide source is automatically supplied using a carbon dioxide source supply device 20 in the pre-pouring carbon dioxide fixation process S20 using an agitator vehicle, but a worker may also manually supply the carbon dioxide source into the rotating drum 2 using a tool or the like.

[0056] In addition, the carbon dioxide fixed concrete obtained by the above manufacturing method has a carbon dioxide fixed concrete 1m 3 The carbon dioxide gas contained per 1000g of concrete is calculated to be derived from calcium carbonate and contains 0.1 kg to 50 kg of carbon dioxide gas. As described above, the method for manufacturing carbon dioxide-fixed concrete according to the embodiment can reduce the time and location constraints on carbon dioxide fixation compared to conventional methods. Therefore, the carbon dioxide-fixed concrete obtained by the above manufacturing method can fix more carbon dioxide gas than conventional methods. The amount of fixed carbon dioxide gas is a value measured by solid thermogravimetric analysis of carbon dioxide-fixed fresh concrete 28 days after hardening.

[0057] Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes all aspects encompassed by the concept and scope of the claims of the present disclosure, and can be modified in various ways within the scope of the present disclosure. [Explanation of symbols]

[0058] 1 agitator car 2 rotating drums 3 Driver's seat 4 Rotational drive unit 5 Hopper 6 screw plates 7 Outlet 8 scoops 9 Shoot 20 Carbon dioxide gas supply device 21 Hose 22 Trigger Handle 23 nozzles 24 Carbon dioxide source cutoff section 30 Fresh concrete

Claims

1. A method for producing carbon dioxide fixed concrete in which a predetermined amount of carbon dioxide is fixed in concrete, comprising the steps of: γ-C ２ A fresh concrete manufacturing process for manufacturing fresh concrete containing S; a pre-casting carbon dioxide immobilization step of supplying a carbon dioxide source to the fresh concrete produced in the fresh concrete production step and stirring the mixture to obtain carbon dioxide immobilized fresh concrete in which carbon dioxide is immobilized in the fresh concrete; a post-casting concrete hardening step of casting and hardening the carbon dioxide-fixed fresh concrete obtained in the pre-casting carbon dioxide fixation step to obtain carbon dioxide-fixed concrete; and In the pre-casting carbon dioxide fixation step, the carbon dioxide source is supplied to the fresh concrete stored in an agitator vehicle, in this method for producing carbon dioxide fixated concrete.

2. 2. The method for producing carbon dioxide-fixed concrete according to claim 1, wherein the carbon dioxide source is supplied from outside the agitator vehicle in the pre-casting carbon dioxide fixation step.

3. The fresh concrete produced in the fresh concrete production step is ３ Around γ-C ２ The method for producing carbon dioxide-fixed concrete according to claim 1 or 2, wherein the concrete contains 1 kg or more and 100 kg or less of S.

4. The method for producing carbon dioxide-fixed concrete according to any one of claims 1 to 3, wherein after the pre-pouring carbon dioxide fixation step, a step of supplying a carbon dioxide source to the carbon dioxide-fixed fresh concrete after pouring to further fix the carbon dioxide in the carbon dioxide-fixed fresh concrete is not carried out.

5. The method for producing carbon dioxide-fixed concrete according to any one of claims 1 to 4, wherein a step of supplying a carbon dioxide source to the carbon dioxide-fixed concrete to further fix the carbon dioxide in the carbon dioxide-fixed concrete is not carried out after the pre-pouring carbon dioxide fixation step.

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