Method for curing concrete pavement

Abstract

To provide a curing method for concrete pavement for proactively promoting carbonation (neutralization) at a construction site for concrete pavement used in road pavement.SOLUTION: A curing method for concrete pavement (1) includes a process for performing carbonation curing from a bottom surface (1A) of the concrete pavement (1). The carbonation curing process includes the following steps: supplying carbon dioxide gas (CO2 gas) to a construction site; measuring the CO2 concentration; and controlling the CO2 concentration (e.g., maintained within an appropriate range of 0.5% to 80%) of the CO2 gas supplied in the supply step on the basis of the CO2 concentration measured in the measuring step. Preferably, the process includes measuring the temperature and / or humidity of the atmosphere at the construction site and controlling the temperature and / or humidity of the supplied CO2 gas on the basis of the measurement results.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a carbonation curing technique for promoting carbonation (neutralization) at construction sites for concrete pavements used in the fields of paving roads, airports, etc. [Background technology]

[0002] In concrete, particulate materials are bound and integrated with a binder. Cement concrete uses cement paste as a binder and has the property of forming a hardened body through the hydration reaction of cement. Here, the phenomenon in which calcium hydroxide (Ca(OH)2) and calcium silicate hydrate (CSH) in concrete react with carbon dioxide (CO2) in the air to produce calcium carbonate, resulting in a decrease in the alkalinity of concrete, is called carbonation (or neutralization). If carbonation progresses to the vicinity of the buried rebar in reinforced concrete, cracks will occur due to expansion of the rebar caused by rust, which can lead to damage to the concrete. On the other hand, carbonation allows concrete to absorb and fix carbon dioxide, which contributes greatly to reducing carbon dioxide emissions, an important issue in recent years. Carbonation also densifies concrete, suppressing water penetration into the concrete and improving its durability.

[0003] Taking note of the above-mentioned advantages of carbonation, a method for producing concrete that can achieve the effect of reducing CO2 emissions has been proposed as a conventional technique (see, for example, Patent Document 1). However, the prior art (Patent Document 1) does not take into consideration its application to concrete pavements such as roads and airports. Furthermore, no technology has been proposed to date for increasing the amount of carbon dioxide absorbed by actively promoting carbonation (neutralization) at the construction site for concrete pavements used in roads, airports, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-51422 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been proposed in view of the problems of the prior art described above, and aims to provide a method for curing concrete pavement used in roads, airports, etc., which actively promotes carbonation (neutralization) at the construction site. [Means for solving the problem]

[0006] The curing method for the concrete pavement (1) of the present invention is as follows: A step of performing carbonation curing from the bottom surface (1A) of the concrete pavement (1), In the carbonation curing step, A supply process to supply carbon dioxide gas (CO2 gas) to the construction site; a measuring step of measuring a carbon dioxide concentration; The method is characterized by having a step of controlling the carbon dioxide concentration in the carbon dioxide gas supplied in the supply step based on the carbon dioxide concentration measured in the measuring step (for example, maintaining it within an appropriate range of 0.5% to 80%).

[0007] In the present invention, A layer (2) made of a material with good water permeability and breathability (e.g., porous asphalt mixture, porous concrete, permeable base course, dense-graded asphalt mixture with grooves) is placed below the concrete pavement (1) undergoing carbonation curing, and it is preferable that carbon dioxide gas is supplied to the bottom surface (1A) of the concrete pavement (1) through the layer (2).

[0008] In the present invention, A layer (2) made of a material with good water permeability and breathability is placed below the concrete pavement (1) undergoing carbonation curing, and a perforated pipe (21) with a plurality of through holes (21H) formed in the pipe wall is buried in the layer (2), and it is preferable that carbon dioxide gas is supplied to the bottom surface (1A) of the concrete pavement (1) through the perforated pipe (21).

[0009] Alternatively, in the present invention, A layer (2) made of a material with good water permeability and breathability is placed below the concrete pavement (1) undergoing carbonation curing, and a nonwoven fabric layer (22) is formed at the boundary between the layer (2) and the bottom surface (1A) of the concrete pavement (1), and it is preferable that carbon dioxide gas is supplied to the bottom surface (1A) of the concrete pavement (1) through the nonwoven fabric layer (22).

[0010] Further, in the present invention, A layer (2) made of a material with good water permeability and breathability or a material with poor breathability (e.g., dense-graded asphalt mixture) is placed below the concrete pavement (1) undergoing carbonation curing, and a groove (23) is formed at the boundary between the layer (2) and the bottom surface (1A) of the concrete pavement (1), and it is preferable that carbon dioxide gas is supplied to the bottom surface (1A) of the concrete pavement (1) through the groove (23).

[0011] In the present invention, In the measurement process, it is preferable to measure the carbon dioxide concentration on the carbon dioxide supply source (6) side (upstream side) of the concrete pavement (1) in the carbon dioxide supply system (7: including the carbon dioxide supply pipe 3) that supplies carbon dioxide gas to the bottom surface (1A) of the concrete pavement (1). Alternatively, in the present invention, In the measurement process, it is preferable to measure the carbon dioxide concentration on the carbon dioxide recovery device (9) side (downstream side) of the concrete pavement (1) in the carbon dioxide supply system (7: including the carbon dioxide supply pipe 3) that supplies carbon dioxide gas to the bottom surface (1A) of the concrete pavement (1). In the measuring step, it is preferable to measure the carbon dioxide concentration in the region between the bottom surface (1A) of the concrete pavement (1) and the road surface (upper surface), that is, the so-called "middle part." Alternatively, it is preferable to measure the carbon dioxide concentration in the region further below the bottom surface (1A) of the concrete pavement (1) (layer 2 made of a material with good water permeability and air permeability). In addition, in the present invention, when a perforated pipe (21) is buried in the layer (2) made of a material with good water permeability and air permeability, it is preferable to measure the carbon dioxide concentration in the perforated pipe (21). Furthermore, in the present invention, a layer (2: for example, a layer of porous asphalt mixture) made of a material with good water permeability and air permeability is formed in an area below the concrete pavement (1), and a nonwoven fabric layer (22) is formed at the boundary between the layer (2) made of a material with good water permeability and air permeability on the bottom surface (1A) of the concrete pavement (1), In the measuring step, it is preferable to measure the carbon dioxide concentration in the nonwoven fabric layer (22).

[0012] And in the present invention, A step of measuring the temperature and / or humidity in the atmosphere at the construction site of the concrete pavement (1); It is preferable to include a step of controlling the temperature and / or humidity of gas (sometimes referred to in this specification as "carbon dioxide gas" or "CO2 gas") that has been adjusted to a predetermined CO2 concentration by a CO2 supply device supplied to the construction site based on the measured temperature and / or humidity.

[0013] In the system (30) for performing carbonation curing of the concrete pavement (1) of the present invention, a carbon dioxide concentration measuring device (5: CO2 concentration sensor) that measures carbon dioxide concentration (CO2 concentration); a carbon dioxide supply system (7: carbon dioxide supply source 6 and carbon dioxide supply piping 3) that supplies carbon dioxide gas to the bottom surface (1A) of the concrete pavement (1); The system is characterized by having a control device (10: control unit) that controls the carbon dioxide concentration in the carbon dioxide gas supplied through the carbon dioxide gas supply system (7) (for example, to maintain it within an appropriate range of 0.5% to 80%) based on the carbon dioxide concentration measured by the carbon dioxide concentration measuring device (5). However, in the present invention, instead of the control device (10), an operator can control the carbon dioxide concentration. [Effects of the Invention]

[0014] According to the carbonation curing method for concrete pavement (1) of the present invention having the above-mentioned configuration, carbon dioxide is supplied (into the inside of the concrete pavement 1) from the bottom surface (1A) of the concrete pavement (1), so that the concrete pavement (1) is efficiently carbonated at the construction site, and the bottom surface in particular is densified, thereby improving the bending strength. According to the present invention, the CO2 concentration of the CO2 gas supplied to the bottom surface (1A) of the concrete pavement (1) to be carbonation cured can be maintained within an appropriate range (for example, a range of 0.5% to 80%), so that carbonation is carried out efficiently.

[0015] Furthermore, according to the present invention, the carbonation (neutralization) of the concrete pavement (1) can be actively promoted at the road pavement construction site, thereby reducing carbon dioxide emissions by the amount of carbon dioxide used in carbonating the concrete pavement. As a result, the total amount of CO2 emitted in relation to the concrete production cycle is reduced, thereby meeting the social demand for reduced CO2 emissions.

[0016] Furthermore, according to the present invention, CO2 gas is supplied to the bottom surface (1A) of the concrete pavement (1) to carbonate and cure the concrete pavement (1) from the inside, and the carbonated area becomes dense and does not allow CO2 gas to pass through, so that CO2 gas that has permeated into the concrete pavement (1) is prevented from leaking out of the concrete pavement (1) and diffusing into the atmosphere. Therefore, even if the construction site is not enclosed with a shielding member (4: cover), CO2 gas will not be dispersed into the atmosphere from the construction site, and an increase in CO2 emissions is prevented.

[0017] In the present invention, if the temperature and / or humidity of the concrete pavement 1 is maintained within an appropriate range in the construction site atmosphere, the carbonation curing efficiency of the concrete pavement 1 can be further improved. This has been made clear by the inventors' experiments. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a block diagram showing a first embodiment of the present invention; [Figure 2] FIG. 2 is an explanatory diagram showing the arrangement of a carbon dioxide concentration sensor in the first embodiment. [Figure 3] FIG. 2 is a block diagram showing a first modified example of the first embodiment. [Figure 4] FIG. 2 is a block diagram of the control unit of FIG. 1. [Figure 5] 4 is a flowchart showing a control according to the first embodiment. [Figure 6] FIG. 10 is a block diagram showing a second modified example of the first embodiment. [Figure 7] FIG. 7 is a block diagram of the control unit of FIG. 6. [Figure 8] 10 is a flowchart showing a secondary control of a second modified example of the first embodiment. [Figure 9] FIG. 9 is a flowchart showing a secondary control of a second modified example of the first embodiment, which is a flowchart of control different from that of FIG. 8. [Figure 10] FIG. 10 is a block diagram showing a second embodiment of the present invention. [Figure 11] FIG. 10 is an explanatory diagram showing the arrangement of a carbon dioxide concentration sensor in the second embodiment. [Figure 12] FIG. 10 is a block diagram showing a modified example of the second embodiment. [Figure 13] FIG. 10 is a block diagram showing a third embodiment of the present invention. [Figure 14] FIG. 10 is an explanatory diagram showing the arrangement of a carbon dioxide concentration sensor in the third embodiment. [Figure 15] FIG. 11 is a block diagram showing a modified example of the third embodiment. [Figure 16] FIG. 10 is a block diagram showing a fourth embodiment of the present invention. [Figure 17] FIG. 10 is an explanatory diagram showing the arrangement of a carbon dioxide concentration sensor in the fourth embodiment. [Figure 18] FIG. 10 is an explanatory plan view showing the arrangement of three grooves in the fourth embodiment. [Figure 19] FIG. 11 is a block diagram showing a modified example of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. First, a first embodiment of the present invention will be described with reference to FIGS. In Figure 1, a system 30 for performing carbonization curing of a concrete pavement 1 includes a layer 2 composed of a material with good water permeability and breathability (e.g., porous asphalt mixture, porous concrete, permeable subgrade) placed below the concrete pavement 1, a carbon dioxide supply system 7 (CO2 supply system, carbon dioxide supply source 6) that supplies carbon dioxide gas (CO2 gas) to the bottom surface 1A of the concrete pavement 1, a carbon dioxide concentration measuring device 5 (CO2 concentration sensor) that measures the carbon dioxide concentration (CO2 concentration) at the construction site, a control device 10 (control unit), and a carbon dioxide supply amount adjusting device 8 (CO2 supply amount adjusting device) installed in the CO2 supply piping 3. In this specification, as described above, the CO2 supply pipe 3 and the carbon dioxide supply source 6 (CO2 supply source) may be collectively referred to as a CO2 supply system 7. Also, various CO2 concentration sensors may be collectively referred to as the reference numeral 5.

[0020] In the first embodiment, the layer 2 made of a material with good water permeability and breathability below the concrete pavement 1 is made of any of the above-mentioned materials with good water permeability and breathability: porous asphalt mixture, porous concrete, or permeable base course. Here, porous asphalt, porous concrete, and permeable base course all have good permeability to fluids (including gases) such as CO2 gas. The CO2 supply pipe 3 is connected to the inlet side (CO2 supply source 6 side) of layer 2 made of a material with good water permeability and breathability below the concrete pavement 1, and the outlet side of layer 2 made of a material with good water permeability and breathability is connected to the capture device 9 via a capture pipe 13. Although not shown, there are also provided a mechanism for supplying CO2 gas supplied from the CO2 supply pipe 3 into layer 2 made of a material with good water permeability and breathability, and a mechanism for capturing CO2 gas in layer 2 made of a material with good water permeability and breathability and discharging it to the CO2 capture pipe. The CO2 supply system 7 includes a CO2 supply pipe 3, which merges with a CO2 supply pipe 3E and an air supply pipe 3F at a junction G. The CO2 supply pipe 3E is fitted with a CO2 supply amount adjustment device 8 (e.g., a flow rate adjustment valve) and is connected to a CO2 supply source 6. The air supply pipe 3F is fitted with an air supply amount adjustment device 24 (e.g., a flow rate adjustment valve) and is connected to a blower 20. The CO2 supply amount adjuster 8 and the air supply amount adjuster 24 have the function of receiving control signals from the control unit 10 via signal transmission lines SL4 and SL24, and controlling the CO2 supply amount and air supply amount, respectively.

[0021] In Figure 1, a CO2 concentration sensor 5 is installed upstream (towards the CO2 supply source 6) of a layer 2 made of a material with good water permeability and breathability in the CO2 supply pipe 3. The CO2 concentration sensor 5 and a control unit 10 are connected via a signal transmission line SL1, and the control unit 10 and a CO2 supply amount adjuster 8 are connected via a signal transmission line SL4. Here, the CO2 supply amount adjuster 8 can be configured, for example, by a flow control valve. The control unit 10 has a function of controlling the CO2 concentration in the CO2 gas supplied through the CO2 supply system 7 via the CO2 supply amount adjusting device 8 (for example, controlling so as to maintain the CO2 concentration within an appropriate range of 0.5% to 80%) based on the CO2 concentration measured by the CO2 concentration sensor 5. The function and control of the control unit 10 will be described later with reference to Figs. 4 and 5.

[0022] In Figure 1, CO2 gas supplied from a CO2 supply system 7 (CO2 supply source 6, CO2 supply piping 3) is supplied to layer 2 made of a material with good water permeability and breathability below concrete pavement 1 (CO2 supply process for supplying CO2 gas to the construction site), passes through layer 2 made of a material with good water permeability and breathability, and penetrates into the concrete pavement 1 from below through the bottom surface 1A of the concrete pavement 1. Then, the concrete pavement 1 is carbonation cured from the inside (process for carbonation curing from the bottom surface 1A of the concrete pavement 1). The CO2 gas that flows through layer 2 below the concrete pavement 1, which is made of a material with good water permeability and breathability, but does not react with Ca(OH)2 in the concrete pavement 1, is captured by a capture mechanism (not shown), sent via CO2 capture piping 13 to the CO2 capture device 9, and processed in the CO2 capture device 9.

[0023] In FIG. 2, which shows the arrangement of the CO2 concentration sensor 5 in the first embodiment, a CO2 concentration sensor 5-1 is installed in the CO2 supply pipe 3 on the upstream side (the CO2 supply source 6 side in FIG. 1) of layer 2, which is made of a material with good water permeability and breathability, as in FIG. 1. Alternatively, in FIG. 2, a CO2 concentration sensor 5-2 is installed in the CO2 capture pipe 13 on the downstream side (the CO2 capture device 9 side in FIG. 1) of layer 2, which is made of a material with good water permeability and breathability. In addition, a CO2 concentration sensor 5-3 can be installed in a region within the concrete pavement 1, known as the "middle slope." Alternatively, a CO2 concentration sensor 5-3a can be installed in layer 2, which is the lower layer of the concrete pavement 1 (a layer made of a material with good water permeability and breathability). In FIG. 2, four different positions for disposing the CO2 concentration sensor 5 are shown, and the CO2 concentration sensor 5 may be disposed in any one of them. As shown in Figure 2, one CO2 supply pipe 3 and one CO2 capture pipe 13 are connected to layer 2, which is made of a material with good water permeability and breathability below concrete pavement 1. However, the number of CO2 supply pipes 3 connected to layer 2, which is made of a material with good water permeability and breathability, is not limited to one, and can be determined on a case-by-case basis for each construction site.

[0024] In the illustrated embodiment, CO2 is supplied to the concrete pavement 1 from the bottom surface 1A of the concrete pavement 1, which allows for efficient carbonation and densification of the concrete pavement 1 at the construction site. As a result, the bending strength of the concrete pavement 1 can be improved. In addition, by actively promoting carbonation (neutralization) of concrete pavement 1 at the construction site and having the concrete absorb and fix CO2 gas, CO2 emissions are reduced by the amount of CO2 used to carbonate the concrete pavement, thereby meeting the societal demand for reduced CO2 emissions. Furthermore, CO2 gas is supplied to the bottom surface 1A of the concrete pavement 1, and carbonation curing is performed from the inside of the concrete pavement 1, so the carbonated and densified area does not allow CO2 to pass through, preventing CO2 gas that has permeated into the inside of the concrete pavement 1 from leaking out of the concrete pavement 1 and diffusing into the atmosphere. Therefore, even if the concrete pavement 1 is not enclosed with a cover, CO2 gas is prevented from being released from the construction site. Furthermore, by keeping the CO2 concentration of the CO2 gas supplied to the bottom surface 1A of the concrete pavement 1 within an appropriate range (for example, a range of 0.5% to 80%), efficient carbonation becomes possible. Although not shown, in the first embodiment, it is also possible to provide a nonwoven fabric layer, which will be described later with reference to FIGS. 13 and 14, so that CO2 gas flows through the nonwoven fabric layer.

[0025] FIG. 3 shows a first modified example of the first embodiment. In the first modification shown in Figure 3, the concrete pavement 1 (or its area) undergoing in-situ carbonation curing is surrounded by a cover 4. Even if CO2 leaks from the concrete pavement 1 due to some event, the cover 4 prevents the leaked CO2 from diffusing into the atmosphere, which contributes to reducing CO2 emissions. The carbonation curing system 30-1 shown in FIG. 3 has the same configuration and effects as the first embodiment shown in FIG. 1, except for the cover 4. Explanations of the layer 2 made of a material with good water permeability and breathability, the CO2 supply pipe 3, the CO2 concentration sensor 5, the control unit 10, etc. will be omitted. In the first modified example of FIG. 3, it is also possible to provide a nonwoven fabric layer, which will be described later with reference to FIGS. 13 and 14, so that CO2 gas flows through the nonwoven fabric layer. Other configurations and effects of the first modified example in FIG. 3 are the same as those of the first embodiment in FIG.

[0026] According to the inventor's research, the CO2 concentration in the concrete pavement 1 (or its area) undergoing in-situ carbonation curing is preferably within the range of 0.5% to 80%. This is because cement does not sufficiently carbonate in an atmosphere with a CO2 concentration lower than 0.5%, while carbonation efficiency does not change when the CO2 concentration is higher than 80%. 1 to 3, the CO2 concentration is controlled to be within the range of 0.5% to 80%. This control is performed by a control unit 10, the details of which are shown in FIG.

[0027] In FIG. 4, the control unit 10 has a CO2 concentration comparison block B1, a judgment and control signal generation block B2, and a memory block B3. The CO2 concentration comparison block B1 acquires the measured value of the CO2 concentration in the concrete pavement 1 or the CO2 supply pipe 3 from the CO2 concentration sensor 5 via the signal transmission line SL1-1, the interface I / F, and the signal transmission line SL1-2. At the same time, the target value (or a predetermined target range) of the CO2 concentration for the current control cycle is acquired from the memory block B3 via the signal transmission line SL2. The target value of the CO2 concentration is set within the range of 0.5% to 80%. The CO2 concentration comparison block B1 has the function of comparing the acquired CO2 concentration measurement value with the target value (target predetermined range) of CO2 concentration. The comparison result of the CO2 concentration comparison block B1 is sent to the judgment and control signal generation block B2 via the signal transmission line SL3.

[0028] The judgment and control signal generation block B2 has the function of outputting a control signal to the CO2 supply adjustment device 8 via the signal transmission line SL4-1, interface I / F, and signal transmission line SL4-2 so that the CO2 concentration becomes the target value (target specified range) based on the comparison result by the CO2 concentration comparison block B1 (comparison result between the measured CO2 concentration value and the target CO2 concentration value). The memory block B3 has the function of acquiring and storing in advance information or data necessary to control the CO2 concentration in the CO2 gas supplied to the concrete pavement 1 to perform carbonation curing, and providing this information or data to each function block as needed. The information or data stored in the memory block B3 includes, for example, the target value (target predetermined range) of the CO2 concentration in the control cycle, specification data on the components of the carbonation curing system 30 (the concrete pavement 1, the layer 2 made of a material with good water permeability and breathability, the CO2 supply pipe 3, the CO2 concentration sensor 5, the CO2 supply amount adjuster 8, etc.), and others.

[0029] Control executed in the first embodiment and its first modification shown in FIGS. 1 to 3, in which the CO2 concentration falls within the range of 0.5% to 80%, will be described with reference to FIG. 5, in step S1, the CO2 concentration of CO2 gas is measured either in the concrete pavement 1, in layer 2 (a layer made of a material with good water permeability and air permeability) which is the lower layer of the concrete pavement 1, in the CO2 supply pipe 3, or in the CO2 recovery pipe 13 (measurement step of measuring the CO2 concentration at the construction site of the concrete pavement 1). This measurement is performed by the CO2 concentration sensor 5, and the measurement value is acquired by the CO2 concentration comparison block B1 of the control unit 10. In step S2, the CO2 concentration measured in step S1 is compared with the target value (or target range: predetermined target range) of the CO2 concentration in the control cycle at that time, and it is determined whether the measured CO2 concentration is within the predetermined target range. Step S2 is executed by the CO2 concentration comparison block B1 and the determination and control signal generation block B2. If the result of determination in step S2 is that the measured CO2 concentration is lower than the target predetermined range, the process proceeds to step S3, and if the measured CO2 concentration is higher than the target predetermined range, the process proceeds to step S4. If the measured CO2 concentration is within the target predetermined range ("Yes" in step S2), the process proceeds to step S5.

[0030] In step S3 (when the measured CO2 concentration is lower than the target predetermined range), the CO2 supply amount is increased to increase the CO2 concentration of the CO2 gas supplied to the concrete pavement 1. That is, the CO2 supply amount adjuster 8 increases the flow rate of CO2 gas supplied from the CO2 supply source 6 via the CO2 supply piping 3E, and / or the air supply amount adjuster 24 decreases the flow rate of air (atmospheric air) supplied from the blower 20 via the CO2 supply piping 3F. In step S4, if it is determined that the CO2 concentration measured in step S2 is greater than the target predetermined range, the CO2 concentration is reduced, i.e., the flow rate of CO2 gas supplied from the CO2 supply source 6 is reduced and / or the flow rate of air (atmospheric air) supplied from the blower 20 is increased. Furthermore, in step S5 (when the measured CO2 concentration is within the target predetermined range), the CO2 supply amount is maintained to maintain the CO2 concentration of the CO2 gas supplied to the concrete pavement 1. That is, the flow rate of the CO2 gas supplied from the CO2 supply source 6 is maintained, and the flow rate of the air (atmosphere) supplied from the blower 20 is also maintained. The control in steps S3 to S5 corresponds to "a step of controlling the CO2 concentration in the CO2 gas supplied in the CO2 gas supply step based on the CO2 concentration measured in the CO2 concentration measurement step." The control of steps S3 to S5 is executed by the determination and control signal generation block B2, which receives the comparison result of the CO2 concentration comparison block B1, sending a control signal to the CO2 supply amount adjustment device 8 (for example, a flow rate adjustment valve).

[0031] In step S6, it is determined whether or not the carbonation curing of the concrete pavement 1 by the carbonation curing system 30 is to be ended. In step S6, if carbonation curing is to be ended (step S6 is "Yes"), the control is ended, and if carbonation curing is not to be ended (step S6 is "No"), the control returns to step S1 and continues.

[0032] Next, a second modified example of the first embodiment will be described with reference to FIGS. Experiments conducted by the inventors have revealed that the amount of CO2 absorbed by cement pavement is affected by temperature and humidity. In the second modified example shown in Figure 6, not only the CO2 concentration but also the temperature and humidity at the construction site are measured to control the carbonation of the concrete pavement so that it is optimally carried out. In Figure 6, a system 30-2 for performing carbonation curing of a concrete pavement 1 adds a temperature measuring device 11 (temperature sensor) and a humidity measuring device 12 (humidity sensor) to the system 30 in the first embodiment shown in Figure 1. The arrangement (installation position) of the CO2 concentration sensor 5 is the same as that described with reference to Figures 1 and 2, and the temperature sensor 11 and / or humidity sensor 12 can be arranged in the same locations as the CO2 concentration sensor 5 described with reference to Figures 1 and 2. Although not shown, in the second modified example, the humidity sensor 12 can be omitted. Alternatively, the temperature sensor 11 can be omitted. Although not shown, in the second modified example of FIG. 6, a cover 4 can be provided in the same manner as in FIG. The configuration of the carbonation curing system 30-2 of the second modified example, other than the temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15, is the same as that of the carbonation curing system 30 of the first embodiment, so duplicated explanations will be omitted. 6 controls the temperature and humidity of the CO2 gas to be supplied in addition to the CO2 concentration, and is therefore given a different reference numeral "10-1" from the control unit 10 in FIGS.

[0033] In the carbonation curing system 30-2 of the second modified example shown in FIG. 6, the temperature sensor 11 and / or humidity sensor 12 are arranged in the CO2 supply pipe 3, similar to the CO2 concentration sensor 5. The temperature sensor 11 and the control unit 10-1 are connected via a signal transmission line SL5, and the control unit 10-1 and the temperature adjustment device 14 (arranged on the CO2 supply pipe 3) are connected via a signal transmission line SL9. The humidity sensor 12 and the control unit 10-1 are connected via a signal transmission line SL6, and the control unit 10-1 and the humidity adjustment device 15 (arranged on the CO2 supply pipe 3) are connected via a signal transmission line SL10. The control unit 10-1 has a function of controlling (by the temperature regulator 14) the temperature of the CO2 gas supplied via the CO2 supply system 7 (a function of controlling the temperature within a predetermined range suitable for carbonation curing) based on the temperature measured by the temperature sensor 11. The temperature regulator 14 can be configured by a known device capable of raising and lowering the temperature of the CO2 gas. The control unit 10-1 also has a function of controlling (by the humidity adjusting device 15) the humidity of the CO2 gas supplied via the CO2 supply system 7 (to a predetermined humidity level suitable for carbonation curing) based on the humidity measured by the humidity sensor 12. The humidity adjusting device 15 can be configured using a known device capable of humidifying and dehumidifying CO2 gas. The function and control of the control unit 10-1 will be described later with reference to FIGS.

[0034] In controlling the carbonation of the concrete pavement 1 to be optimal, the CO2 concentration is the primary parameter, with temperature and humidity being secondary parameters. In the second modified example of Fig. 6, the control related to the CO2 supply amount shown in Fig. 5 is also executed. In the second modified example, in addition to the control shown in Fig. 5, the control related to the temperature shown in Fig. 8 and / or the control related to the humidity shown in Fig. 9 are executed independently as secondary controls. Such controls are executed by a control unit 10-1, and the details of the control unit 10-1 are shown in Fig. 7. In FIG. 7, the control unit 10-1 has a CO2 concentration comparison block B1, a judgment and control signal generation block B2, a memory block B3, a temperature and / or humidity comparison block B4, and a temperature and / or humidity judgment and control signal generation block B5. Of the blocks B1 to B5, the CO2 concentration comparison block B1 and the judgment and control signal generation block B2 have the same configuration and effects as the blocks B1 and B2 in the control unit 10 of the first embodiment in Fig. 4, so a duplicated description will be omitted. Here, the memory block B3 in the control unit 10-1 has additional functions compared to the memory block B3 of the control unit 10 in Fig. 4, but the same reference numerals are used.

[0035] The temperature and / or humidity comparison block B4 acquires the measured values ​​of the temperature and / or humidity of the CO2 gas supplied to the concrete pavement 1 from the temperature sensor 11 and / or humidity sensor 12 via the signal transmission lines SL5-1 / 6-1, the interface I / F, and the signal transmission lines SL5-2 / 6-2. At the same time, the target value (or target predetermined range) of the temperature and / or humidity for the current control cycle is acquired from the memory block B3 via the signal transmission line SL7. The temperature and / or humidity comparison block B4 has the function of comparing the acquired temperature and / or humidity measurement value with the temperature and / or humidity target value. The comparison result of the temperature and / or humidity comparison block B4 is sent to the temperature and / or humidity judgment and control signal generation block B5 via a signal transmission line SL8.

[0036] The temperature and / or humidity judgment and control signal generation block B5 has the function of outputting a control signal to the temperature adjustment device 14 and / or humidity adjustment device 15 via the signal transmission lines SL9-1 / 10-1, interface I / F, and signal transmission lines SL9-2 / 10-2 in order to set the temperature and / or humidity to the target value based on the comparison result by the temperature and / or humidity comparison block B4 (the comparison result between the measured value of temperature and / or humidity and the target value of temperature and / or humidity). The memory block B3 stores information and data for controlling the temperature and / or humidity in addition to the information and data for controlling the CO2 concentration described with reference to Fig. 4. The memory block B3 has a function of providing necessary information to each block. The information and data stored in the memory block B3 include, in addition to the information and data described with reference to Fig. 4, specification data for the temperature sensor 11 and / or humidity sensor 12, target values ​​(target predetermined ranges) of the temperature and / or humidity in the control cycle, etc.

[0037] The secondary control executed in the second modification of FIG. 6, that is, the control related to temperature and / or the control related to humidity, will be described with reference to FIGS. 8 and 9. FIG. In FIG. 8 , which shows temperature control, in step S11, the temperature sensor 11 measures the temperature of the CO2 gas supplied to the concrete pavement 1 (a process for measuring the temperature of the atmosphere at the construction site of the concrete pavement 1). As described above, the CO2 gas temperature is measured by the CO2 concentration sensor 5 installed in the CO2 supply pipe 3 on the upstream side (the CO2 supply system 7 side in FIG. 1 ) of layer 2, which is made of a material with good water permeability and breathability, as in the first embodiment. However, the CO2 concentration sensor 5 can also be installed in the CO2 capture pipe 13 on the downstream side (the CO2 capture device 9 side in FIG. 1 ) of layer 2, which is made of a material with good water permeability and breathability. In addition, the CO2 concentration sensor 5 can also be installed in a region within the concrete pavement 1, known as the "midslope." Alternatively, the CO2 concentration sensor 5 can be installed in layer 2, which is the lower layer of the concrete pavement 1 (a layer made of a material with good water permeability and breathability). The measurement value by the temperature sensor 11 is acquired by the temperature and / or humidity comparison block B4 of the control unit 10-1. In step S12, the temperature of the CO2 gas measured in step S11 is compared with the target value or target range of the temperature for that control cycle, and it is determined whether the measured temperature is within the target range. The control of step S12 is executed by the temperature and / or humidity comparison block B4 and the temperature and / or humidity determination and control signal generation block B5. In step S12, if the measured temperature is lower than the target predetermined range, the process proceeds to step S13, and if the measured temperature is higher than the target predetermined range, the process proceeds to step S14. If the measured temperature is within the target predetermined range (step S12 is "Yes"), the process proceeds to step S15.

[0038] In step S13 (if the measured temperature is lower than the target predetermined range), the temperature of the CO2 gas supplied to the concrete pavement 1 is increased. In step S14 (if the measured temperature is higher than the target predetermined range), the temperature of the CO2 gas supplied to the concrete pavement 1 is decreased. In step S15 (if the measured temperature is within the target predetermined range), the temperature of the CO2 gas supplied to the concrete pavement 1 is maintained. The control of steps S13 to S15 corresponds to "a process of controlling the temperature of the CO2 gas supplied to the construction site based on the measured temperature." The control of steps S13 to S15 is executed by receiving the comparison result of the temperature and / or humidity comparison block B4, and the temperature and / or humidity judgment and control signal generation block B5 sending a control signal to the temperature adjustment device 14 (a known device capable of raising and lowering the temperature of gas).

[0039] In step S16, it is determined whether or not to terminate the carbonation curing of the concrete pavement 1 by the carbonation curing system 30-2. If the result of the determination in step S16 is that the carbonation curing is to be ended (step S16 is "Yes"), the control is ended, and if the carbonation curing is not to be ended (step S16 is "No"), the control returns to step S11 and continues.

[0040] In Figure 9, which shows humidity control, in step S21, the humidity of the CO2 gas supplied to the concrete pavement 1 is measured (a process of measuring the humidity in the atmosphere at the construction site of the concrete pavement 1). As described above, the location where the humidity of the CO2 gas is measured is either the upstream side of layer 2 made of a material with good water permeability and breathability, the downstream side of layer 2 made of a material with good water permeability and breathability, the so-called "middle" of an area within the concrete pavement 1, or layer 2 (a layer made of a material with good water permeability and breathability) which is the lower part of the concrete pavement 1. The humidity measurement is performed by humidity sensor 12, and the measurement value of humidity sensor 12 is obtained by temperature and / or humidity comparison block B4. In step S22, the humidity of the CO2 gas to be supplied to the concrete pavement 1 measured in step S21 is compared with the target humidity range (or target value) for the control cycle at that time, and it is determined whether the measured humidity is within the target humidity range. The determination in step S22 is performed by the temperature and / or humidity comparison block B4 and the temperature and / or humidity determination and control signal generation block B5. In step S22, if the measured humidity is lower than the target range, the process proceeds to step S23, and if the measured humidity is higher than the target range, the process proceeds to step S24. If the measured humidity is within the target range (step S22 is "Yes"), the process proceeds to step S25.

[0041] In Figure 9, in step S23 (if the measured humidity is lower than the target predetermined range), the CO2 gas to be supplied to the concrete pavement 1 is humidified (the humidity is increased). In step S24 (if the measured humidity is higher than the target predetermined range), the CO2 gas to be supplied to the concrete pavement 1 is dehumidified (the humidity is decreased). And in step S25 (if the measured humidity is within the target predetermined range), the humidity of the CO2 gas to be supplied to the concrete pavement 1 is maintained. The control of steps S23 to S25 corresponds to "the process of controlling the humidity of the CO2 gas supplied to the construction site based on the measured humidity." The control of steps S23 to S25 is executed by the temperature and / or humidity judgment and control signal generation block B5, which receives the comparison result of the temperature and / or humidity comparison block B4, sending a control signal to the humidity adjustment device 15.

[0042] In step S26, it is determined whether or not to terminate the carbonation curing of the concrete pavement 1 by the carbonation curing system 30-2. If the carbonation curing is to be terminated in step S26 ("Yes" in step S26), the control is terminated. If the carbonation curing is not to be terminated ("No" in step S26), the control returns to step S21 and continues. In the second variant of the first embodiment shown in Figures 6 to 9, the temperature and / or humidity of the concrete pavement 1 can be maintained within an appropriate range in addition to the CO2 concentration of the CO2 gas in the atmosphere at the construction site, so that carbonation curing of the concrete pavement 1 can be carried out more efficiently. Although not shown, in the second modified example of the first embodiment shown in Figures 6 to 9, a nonwoven fabric layer, which will be described later with reference to Figures 13 and 14, can also be provided so that CO2 gas flows through the nonwoven fabric layer. The other configurations and effects of the second modified example of the first embodiment shown in FIGS. 6 to 9 are the same as those of the first embodiment shown in FIGS.

[0043] Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, a perforated pipe 21 having a plurality of through-holes 21H formed in the pipe wall is buried in a layer 2 made of a material with good water permeability and air permeability (porous asphalt mixture, porous concrete, permeable roadbed) that is layered below the concrete pavement 1 in the first embodiment, and a CO2 supply pipe 3 is connected to the perforated pipe 21. In Figure 10, the layer 2 made of a material with good water permeability and air permeability is hatched. 10, a system 30-3 for performing carbonization curing of a concrete pavement 1 according to the second embodiment includes a layer 2 made of a material with good water permeability and air permeability disposed below the concrete pavement 1, a perforated pipe 21 buried in the layer 2, and a CO2 supply system for supplying CO2 gas to the bottom surface 1A of the concrete pavement 1 via the perforated pipe 21. 7 It has the following characteristics. 1, the CO2 supply system 7 includes a CO2 supply pipe 3, which merges with a CO2 supply pipe 3E and an air supply pipe 3F at a junction G. A CO2 supply amount adjuster 8 is installed in the CO2 supply pipe 3E and is connected to the CO2 supply source 6. An air supply amount adjuster 24 is installed in the air supply pipe 3F and is connected to the blower 20. The CO2 supply amount adjuster 8 and the air supply amount adjuster 24 receive control signals from the control unit 10 via signal transmission lines SL4 and SL24, respectively, and have the function of controlling the CO2 supply amount and the air supply amount. The control unit of the second embodiment in FIG. 10 controls the CO2 concentration but does not control the temperature or humidity, and is therefore given the same reference numeral "10" as the control unit 10 of the first embodiment and its first modification in FIG.

[0044] 10, the CO2 supply pipe 3 is connected to a perforated pipe 21 buried in layer 2 at the inlet side (CO2 supply source 6 side) of layer 2, which is made of a material with good water permeability and breathability below the concrete pavement 1. The perforated pipe 21 is connected to the capture device 9 via a capture pipe 13 at the outlet side (CO2 capture device 9 side) of layer 2. A plurality of through holes 21H are formed in the region above the perforated pipe 21, and CO2 gas supplied from the CO2 supply pipe 3 to the perforated pipe 21 passes through the through holes 21H and is supplied into the concrete pavement 1. In FIG. 10 as well, a CO2 concentration sensor 5 is interposed in a CO2 supply pipe 3 at a position upstream of a layer 2 made of a material with good water permeability and air permeability.

[0045] In order to control the CO2 concentration within an appropriate range in the second embodiment, the CO2 concentration sensor 5 and the control unit 10 are connected via a signal transmission line SL1, and the control unit 10 and a CO2 supply amount adjustment device 8 (e.g., a flow rate adjustment valve) (arranged in the CO2 supply piping 3) are connected via a signal transmission line SL4. The control unit 10, the CO2 concentration sensor 5, and the CO2 supply amount adjuster 8 are the same as those explained with reference to FIG. 1, and therefore will not be explained again.

[0046] 10, CO2 gas supplied from a CO2 supply system 7 is introduced into a perforated pipe 21 and supplied into a layer 2 made of a material with good water permeability and air permeability through through holes 21H formed in the perforated pipe 21. The CO2 gas supplied into the layer 2 penetrates into the concrete pavement 1 from the bottom surface 1A of the concrete pavement 1 and carbonates the concrete pavement 1. The CO2 gas that has been introduced into the perforated pipe 21 but has not reacted with Ca(OH)2 in the concrete pavement 1 is discharged to the CO2 recovery device 9 via the CO2 recovery pipe 13.

[0047] In the second embodiment of Figure 10, the perforated piping 21 is connected to the CO2 supply piping 3, so that the CO2 gas supplied from the CO2 supply piping 3 is reliably supplied through the perforated piping 21 into the layer 2 made of a material with good water permeability and breathability. Additionally, CO2 gas that does not react with Ca(OH)2 within the concrete pavement 1 is discharged to the CO2 recovery device 9 via the CO2 recovery pipe 13. Furthermore, since the carbonated areas of the concrete pavement 1 are densified and do not allow CO2 gas to pass through, there is no risk of CO2 gas supplied to the concrete pavement 1 diffusing into the atmosphere and increasing CO2 emissions. Although not shown, in the second embodiment of FIG. 10, the area of ​​the concrete pavement 1 to be carbonation cured can also be enclosed with a cover (see FIG. 3) to prevent CO2 supplied due to some event from diffusing into the atmosphere.

[0048] The arrangement of the CO2 concentration sensor 5 of the second embodiment is shown in Figure 11. In Figure 11, the CO2 concentration sensor 5-1 is installed in the CO2 supply pipe 3 on the upstream side (CO2 supply source 6 side) of the layer 2 made of a material with good water permeability and breathability. However, the CO2 concentration sensor 5-2 can also be installed in the CO2 capture pipe 13 on the downstream side (CO2 capture device 9 side) of the layer 2 made of a material with good water permeability and breathability. The CO2 concentration sensor 5-3 can also be installed in an area within the concrete pavement 1. Furthermore, the CO2 concentration sensor 5-3a can be installed in the layer 2 made of a material with good water permeability and breathability, and the CO2 concentration sensor 5-3b can also be installed in the perforated pipe 21. FIG. 11 shows five different positions for disposing the CO2 concentration sensor 5, but the CO2 concentration sensor 5 may be disposed in any of these positions. In addition, in Figure 11, one perforated pipe 21 is buried in layer 2, which is made of a material with good water permeability and breathability below the concrete pavement 1, and a CO2 supply pipe 3 and a CO2 capture pipe 13 are connected to the perforated pipe 21, but the number of perforated pipes 21 to be buried in layer 2 (and the number of CO2 supply pipes 3 and CO2 capture pipes 13 to be connected to the perforated pipe 21) is determined on a case-by-case basis for each construction site.

[0049] As in the first embodiment, in the second embodiment, the CO2 concentration is controlled to be within the range of 0.5% to 80%. This control is the same as the control in the first embodiment described with reference to FIG. The control unit that executes such control is configured in the same manner as the concrete unit 10 shown in FIG. Although not shown, in the second embodiment shown in Figures 10 and 11, it is also possible to provide a nonwoven fabric layer, which will be described later with reference to Figures 13 and 14, so that CO2 gas flows through the nonwoven fabric layer. Other configurations and effects of the second embodiment shown in FIGS. 10 and 11 are the same as those of the first embodiment shown in FIGS.

[0050] Next, a modified example of the second embodiment will be described with reference to FIG. In the modified example shown in FIG. 12, similar to FIG. 6, not only the CO2 concentration but also the temperature and humidity are measured to control the carbonation of the concrete pavement so as to be optimal. A system 30-4 for performing carbonation curing shown in FIG. 12 adds a temperature sensor 11 and / or a humidity sensor 12 to the system 30-3 shown in FIG. The CO2 concentration sensor 5, temperature sensor 11, and / or humidity sensor in the modified example of Fig. 12 are arranged in the same manner as described with reference to Fig. 11. Although not shown, in the modified example of Fig. 12, either the humidity sensor 12 or the temperature sensor 11 can be omitted. The configuration of the carbonation curing system 30-4 shown in Figure 12 is the same as that of the carbonation curing system 30-3 in Figure 10, except for the temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15, so duplicated explanations will be omitted. The control unit 10-1 in Figure 12 controls the temperature and / or humidity of CO2 gas, similar to the control unit 10-1 of the second modified example of the first embodiment described with reference to Figure 6, and is therefore given the symbol "10-1."

[0051] In the carbonation curing system 30-4 of Figure 12, the temperature sensor 11 and / or humidity sensor 12 are arranged in the CO2 supply pipe 3, just like the CO2 concentration sensor 5, but they can also be arranged in the CO2 recovery pipe 13, the perforated pipe 21, an area in the concrete pavement 1, or an area in the layer 2 made of a material with good water permeability and breathability. In other words, the temperature sensor 11 and / or humidity sensor 12 can be arranged in any of the five locations mentioned above. The configuration for controlling the CO2 concentration, temperature, and / or humidity within an appropriate range is the same as that of the second modified example of the first embodiment shown in Fig. 6. The control unit 10-1, temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15 of the modified example of the second embodiment shown in Fig. 12 are the same as those described with reference to Fig. 6, and therefore, repeated description will be omitted. Although not shown, the modified example of FIG. 12 can also be enclosed by the cover 4.

[0052] The control relating to the CO2 supply amount (CO2 concentration) in the modified example of the second embodiment shown in FIG. 12 is similar to the control described with reference to FIG. The secondary control related to temperature is similar to the control described with reference to Fig. 8, and the secondary control related to humidity is similar to the control described with reference to Fig. 9. The control related to temperature shown in Fig. 8 and / or the control related to humidity shown in Fig. 9 are independent of the control related to CO2 concentration shown in Fig. 5 and are executed as secondary controls. The control unit 10-1 that executes the control in FIG. 5, FIG. 8 and / or FIG. 9 is configured similarly to the concrete unit shown in FIG. Although not shown, in the modified example shown in FIG. 12, it is also possible to provide a nonwoven fabric layer, which will be described later with reference to FIGS. 13 and 14, so that CO2 gas flows through the nonwoven fabric layer. The other configurations and effects of the modified example shown in FIG. 12 are the same as those of the embodiment shown in FIG.

[0053] Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, instead of the perforated piping 21 of the second embodiment, a layer 22 (nonwoven fabric layer) made of nonwoven fabric is formed at the boundary between the concrete pavement 1 and a layer 2 made of a material with good water permeability and air permeability (porous asphalt mixture, porous concrete, permeable roadbed), and a CO2 supply piping 3 is connected to the nonwoven fabric layer 22. In Fig. 13, the nonwoven fabric layer 22 is hatched. In Figure 13, a system 30-5 for performing carbonization curing includes a layer 2 made of a material with good water permeability and breathability that is placed below the concrete pavement 1, a nonwoven fabric layer 22, a CO2 supply system 7 (CO2 supply source 6 and CO2 supply piping 3) that supplies CO2 gas to the bottom surface 1A of the concrete pavement 1 through the nonwoven fabric layer 22, a CO2 concentration sensor 5 that measures the CO2 concentration at the construction site, a control unit 10, and a CO2 supply amount adjustment device 8 that is installed in the CO2 supply piping 3. The nonwoven fabric layer 22 is formed (placed) at the boundary between the layer 2 made of a material with good water permeability and air permeability and the bottom surface 1A of the concrete pavement 1. The control unit 10 of the third embodiment in FIG. 13 controls the CO2 concentration but does not control the temperature or humidity, and is therefore denoted by the same reference numeral "10" as the control unit 10 in FIG.

[0054] The CO2 supply pipe 3 is connected to the inlet side (CO2 supply source 6 side) of the nonwoven fabric layer 22 located at the boundary between the concrete pavement 1 and layer 2. The outlet side (CO2 capture device 9 side) of the nonwoven fabric layer 22 is connected to the capture device 9 via a capture pipe 13. The CO2 gas supplied from the CO2 supply pipe 3 to the nonwoven fabric layer 22 flows through the nonwoven fabric layer 22 and is supplied into the concrete pavement 1. In FIG. 13, a CO2 concentration sensor 5 is installed in a position upstream of the layer 2 of the CO2 supply pipe 3 (on the CO2 supply source 6 side). Although not shown in Figure 13, the CO2 supply pipe 3 and the recovery pipe 13 can be connected not only to the nonwoven fabric layer 22 but also to the layer 2 underneath, which is made of a material with good water permeability and breathability.

[0055] The configuration for controlling the CO2 concentration within an appropriate range in the third embodiment is the same as that shown in Figure 1, with the CO2 concentration sensor 5 and the control unit 10 connected via a signal transmission line SL1, and the control unit 10 and the CO2 supply amount adjustment device 8 connected via a signal transmission line SL4. The functions of the control unit 10, CO2 concentration sensor 5, and CO2 supply amount adjuster 8 in FIG. 13 are the same as those in FIG. 1, and therefore a duplicated explanation will be omitted.

[0056] In FIG. 13, CO 2 gas supplied from a CO 2 supply system 7 passes through a nonwoven fabric layer 22 and is supplied into the concrete pavement 1 from a bottom surface 1 A of the concrete pavement 1, thereby carbonating the concrete pavement 1. The CO2 gas that has not reacted with Ca(OH)2 in the concrete pavement 1 is discharged to the CO2 recovery device 9 via the CO2 recovery pipe 13 connected to the nonwoven fabric layer 22. Although not shown in Figure 13, there is a mechanism for supplying CO2 gas supplied from the CO2 supply pipe 3 into the nonwoven fabric layer 22, and a mechanism for recovering CO2 gas that has not reacted with Ca(OH)2 in the concrete pavement 1 and discharging it into the CO2 recovery pipe 13. Similarly, although not shown in Figure 13, in the third embodiment, the area of ​​the concrete pavement 1 that is to undergo carbonation curing is enclosed with a cover (see Figure 3), which prevents CO2 from leaking into the atmosphere and, in the unlikely event that CO2 does leak, can be used to densify the surface of the concrete pavement 1. Although not shown in FIG. 13, the CO2 supply pipe 3 and the recovery pipe 13 can be connected not only to the nonwoven fabric layer 22 but also to the layer 2 underneath, which is made of a material with good water permeability and breathability.

[0057] FIG. 14 shows the arrangement of the CO2 concentration sensor 5 in the third embodiment. In FIG. 14, a CO2 concentration sensor 5-1 is installed in the CO2 supply pipe 3 on the upstream side (the CO2 supply source 6 side) of the nonwoven fabric layer 22, and a CO2 concentration sensor 5-2 is installed in the CO2 capture pipe 13 on the downstream side (the CO2 capture device 9 side) of the nonwoven fabric layer 22. A CO2 concentration sensor 5-3 can also be installed in an area within the nonwoven fabric layer 22. Furthermore, a CO2 concentration sensor 5-4 can also be installed in the concrete pavement 1 above the nonwoven fabric layer 22. In addition, a CO2 concentration sensor 5-4a can be installed in layer 2 (a layer made of a material with good water permeability and breathability) below the nonwoven fabric layer 22. FIG. 14 shows five positions for disposing the CO2 concentration sensor 5, but the CO2 concentration sensor 5 may be disposed in any of these positions. In addition, in Figure 14, one CO2 supply pipe 3 and one CO2 capture pipe 13 are connected to the nonwoven fabric layer 22, but the number of CO2 supply pipes 3 and CO2 capture pipes 13 connected to the nonwoven fabric layer 22 is determined on a case-by-case basis depending on the construction conditions. Although not shown in Figure 14, the CO2 supply pipe 3 and the recovery pipe 13 can be connected not only to the nonwoven fabric layer 22 but also to the layer 2 underneath, which is made of a material with good water permeability and breathability.

[0058] In the third embodiment, the CO2 concentration is also controlled to be within the range of 0.5% to 80%. This control is similar to the control described with reference to Fig. 5. The control unit that executes this control is configured similarly to the concrete unit 10 shown in Fig. 4. Other configurations and effects of the third embodiment shown in FIGS. 13 and 14 are similar to those of the embodiments shown in FIGS. 1, 2, 4, 5, 10 and 11.

[0059] Next, a modified example of the third embodiment will be described with reference to FIG. In the modified example shown in FIG. 15, similarly to the example described in relation to FIG. 6, not only the CO2 concentration but also the temperature and humidity are measured and controlled. In Figure 15, a system 30-6 for performing carbonation curing of a concrete pavement 1 adds a temperature sensor 11 and / or a humidity sensor 12 to the system 30-5 of Figure 13. The arrangement of the CO2 concentration sensor 5, temperature sensor 11 and / or humidity sensor 12 in Figure 15 is the same as that described with reference to Figure 14. Although not shown, it is possible to omit either the humidity sensor 12 or the temperature sensor 11 in Figure 15. The configuration of the carbonation curing system 30-6 in Figure 15 other than the temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15 is the same as that of the carbonation curing system 30-5 in Figure 13, and redundant description will be omitted. 6 and 12, the control unit 10-1 in FIG. 15 has the function of controlling the temperature and / or humidity of the CO2 gas in addition to the CO2 concentration, and is therefore designated by the reference numeral "10-1."

[0060] 15, the temperature sensor 11 and / or humidity sensor 12 are arranged on the CO2 supply pipe 3, similar to the CO2 concentration sensor 5. Here, the configuration for controlling the CO2 concentration, temperature, and / or humidity within an appropriate range (a target value or a predetermined target range) is the same as in the modified example of FIG. 6. The control unit 10-1, temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15 in FIG. 15 are the same as those explained with reference to FIG. 6, and therefore repeated explanations will be omitted. Although not shown, the modified example of FIG. 15 can also be enclosed by the cover 4.

[0061] The control relating to the CO2 concentration in the modified example of the third embodiment shown in FIG. 15 is similar to that described with reference to FIG. In addition, the secondary control related to temperature is the same as that shown in Figure 8, and the secondary control related to humidity is the same as that shown in Figure 9. As described above, the control related to temperature shown in Figure 8 and / or the control related to humidity shown in Figure 9 are executed independently of the control related to CO2 concentration shown in Figure 5. The control unit that executes control in the modified example of the third embodiment shown in FIG. 15 is configured in the same manner as the concrete unit 10-1 shown in FIG. Other configurations and effects of the modified example of the third embodiment shown in FIG. 15 are similar to those of the third embodiment shown in FIG.

[0062] Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, a groove 23 is formed at the boundary between the concrete pavement 1 and a layer 2 made of a material with good water permeability and breathability (porous asphalt mixture, porous concrete, or permeable base course) or a material with poor breathability (for example, dense-graded asphalt mixture), and a CO2 supply pipe 3 is connected to the groove 23. By forming grooves 23 in a material with poor breathability, CO2 gas can pass through the grooves 23. In other words, unlike the first to third embodiments, the fourth embodiment allows the lower layer 2 of the concrete pavement 1 to be made of a material with poor breathability. In Figure 16, a system 30-7 for performing carbonization curing of a concrete pavement 1 includes a layer 2 placed below the concrete pavement 1, a groove 23 formed at the boundary between the layer 2 and the bottom surface 1A of the concrete pavement 1, a CO2 supply system 7 (CO2 supply source 6 and CO2 supply piping 3) that supplies CO2 gas to the bottom surface 1A of the concrete pavement 1 through the groove 23, a CO2 concentration sensor 5 that measures the CO2 concentration at the construction site, a control unit 10, and a CO2 supply amount adjustment device 8 interposed in the CO2 supply piping 3. Here, the cross-sectional shape of the groove 23 is not particularly limited, and grooves of various cross-sectional shapes such as V-shaped, U-shaped, rectangular cross-section, etc. are applicable. The control unit 10 of the fourth embodiment in FIG. 16 controls the CO2 concentration but does not control the temperature or humidity, and is therefore given the same reference numeral "10" as the control units 10 of the first embodiment and its first variant, second embodiment, and third embodiment.

[0063] 16, the CO2 supply pipe 3 is connected by a known mechanism to the inlet side of a trench 23 formed at the boundary between the concrete pavement 1 and layer 2. The outlet side (CO2 capture device 9 side) of the trench 23 is connected by a known mechanism to the capture pipe 13, which is in communication with the CO2 capture device 9. The CO2 gas supplied from the CO2 supply pipe 3 to the groove 23 flows through the groove 23 and is supplied to the concrete pavement 1. The arrangement of the CO2 concentration sensor 5 will be described later with reference to FIG.

[0064] In the fourth embodiment of Figure 16, in order to control the CO2 concentration within an appropriate range (target value or target predetermined range), similar to the first embodiment of Figure 1, the CO2 concentration sensor 5 and the control unit 10 are connected via a signal transmission line SL1, and the control unit 10 and the CO2 supply amount adjustment device 8 are connected via a signal transmission line SL4. The control unit 10, CO2 concentration sensor 5, and CO2 supply amount adjuster 8 in FIG. 16 are the same as those explained with reference to FIG. 1, and therefore a duplicate explanation will be omitted.

[0065] In FIG. 16, CO 2 gas supplied from the CO 2 supply system 7 enters the concrete pavement 1 from the bottom surface 1 A of the concrete pavement 1 as it flows through the V-shaped cross-section groove 23 , and carbonates the concrete pavement 1 . The CO2 gas that has not reacted with Ca(OH)2 in the concrete pavement 1 is discharged to the CO2 recovery device 9 via the CO2 recovery pipe 13 connected to the trench 23. 16, a mechanism (not shown) is also provided for supplying CO2 gas from the CO2 supply pipe 3 into the trench 23. A mechanism is also provided for discharging CO2 gas that has not reacted with Ca(OH)2 in the concrete pavement 1 from the trench 23 to the CO2 recovery pipe 13. Although not shown in the figure, the area of ​​the concrete pavement 1 that is to undergo carbonation curing can be surrounded by a cover (see Figure 3), which prevents CO2 from leaking into the atmosphere and, in the unlikely event that CO2 does leak, can be used to densify the surface of the concrete pavement 1. Although not shown, in the embodiment of FIG. 16, it is also possible to provide a nonwoven fabric layer as in the third embodiment, so that CO2 gas flows through the nonwoven fabric layer.

[0066] 17, which shows the arrangement of the CO2 concentration sensor 5 of the fourth embodiment, a CO2 concentration sensor 5-1 is installed in the CO2 supply pipe 3 on the upstream side (CO2 supply source 6 side) of the V-shaped cross-section groove 23, and a CO2 concentration sensor 5-2 is installed in the CO2 capture pipe 13 on the downstream side (CO2 capture device 9 side) of the groove 23. A CO2 concentration sensor 5-3 can also be installed in the area above the groove 23, within the concrete pavement 1. Furthermore, a CO2 concentration sensor 5-3a can be installed in layer 2 (a layer made of a material with good water permeability and breathability), which is the lower layer of the concrete pavement 1. FIG. 17 shows four different positions where the CO2 concentration sensor 5 can be placed, and the CO2 concentration sensor 5 may be placed in any one of these positions. 16 and 17, the shape and number of grooves 23 are not limited to one and are determined on a case-by-case basis depending on the carbonation curing construction site. For example, as shown in FIG. 18, three grooves 23-1, 23-2, and 23-3 may be arranged in parallel. In FIG. 18, the CO2 supply pipe 3 branches into three CO2 supply pipes 3-1, 3-2, and 3-3 at branching point 3A. The inlets (CO2 supply source 6 sides) of the three grooves 23-1, 23-2, and 23-3 are connected to the CO2 supply pipes 3-1, 3-2, and 3-3, respectively, and the outlets of the grooves 23-1, 23-2, and 23-3 are connected to the CO2 capture pipes 13-1, 13-2, and 13-3, respectively. The CO2 capture pipes 13-1, 13-2, and 13-3 merge with the CO2 capture pipe 13 at junction 13A. Here, if layer 2 is made of a breathable material (e.g., porous asphalt mixture, porous concrete, permeable roadbed, etc.), it is possible to connect the supply pipe 3 and the recovery pipe 13 to layer 2 made of the breathable material without directly connecting them to trench 23.

[0067] In the fourth embodiment, as in the first, second, and third embodiments, the CO2 concentration is controlled to be within the range of 0.5% to 80%. This control is similar to the control described with reference to Fig. 5. The control unit that executes this control is configured similarly to the concrete unit 10 shown in Fig. 4. Although not shown, it is possible to surround the cover 4 in the fourth embodiment as well. Other configurations and effects of the fourth embodiment shown in FIGS. 16 to 18 are similar to those of the embodiments shown in FIGS. 1, 2, 4, 5, 10, 11, 13, and 14.

[0068] Next, a modified example of the fourth embodiment will be described with reference to Fig. 19. In the modified example shown in Fig. 19, similar to Fig. 6, not only the CO2 concentration but also the temperature and humidity are measured and controlled. The system 30-8 for performing carbonation curing in FIG. 19 is different from the system 30-7 in FIG. 16 in that it additionally includes a temperature sensor 11 and / or a humidity sensor 12. The CO2 concentration sensor 5, temperature sensor 11, and / or humidity sensor in Fig. 19 are arranged in the same manner as described with reference to Fig. 17. Although not shown, in Fig. 19, either the humidity sensor 12 or the temperature sensor 11 can be omitted. The configuration of the system 30-8 in Fig. 19 is the same as that of the system 30-7 in Fig. 16 except for the temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15, and therefore a duplicated description will be omitted. Also, the control unit in Fig. 19 controls the temperature and / or humidity of the CO2 gas in addition to the CO2 concentration, similar to the control unit 10-1 in Fig. 6, and is therefore designated by the reference numeral "10-1."

[0069] In the system 30-8 of Fig. 19, the temperature sensor 11 and / or humidity sensor 12 are installed in the CO2 supply pipe 3 together with the CO2 concentration sensor 5. In the system 30-8 of Fig. 19, the configuration for controlling the CO2 concentration, temperature, and / or humidity within an appropriate range is the same as that described with reference to Fig. 6, with the temperature sensor 11 and control unit 10-1 connected via a signal transmission line SL5, and the control unit 10-1 and temperature adjustment device 14 connected via a signal transmission line SL9. In addition, the humidity sensor 12 and control unit 10-1 are connected via a signal transmission line SL6, and the control unit 10-1 and humidity adjustment device 15 connected via a signal transmission line SL10. The functions of the control unit 10-1, temperature sensor 11, humidity sensor 12, temperature adjustment device 14, and humidity adjustment device 15 of the modified example of the fourth embodiment in Figure 19 are the same as those described above with reference to Figure 6, and redundant explanations will be omitted. Although not shown, the modified example of Fig. 19 can also be surrounded by a cover 4. Similarly, although not shown, the modified example of Fig. 19 can also be provided with a nonwoven fabric layer 22 like that of the third embodiment.

[0070] The control relating to the CO2 concentration in the modified example of the fourth embodiment shown in FIG. 19 is similar to that described with reference to FIG. Additionally, the secondary control related to temperature is the same as that shown in Figure 8, and the secondary control related to humidity is the same as that shown in Figure 9. The control related to temperature shown in Figure 8 and / or the control related to humidity shown in Figure 9 are performed independently of the control related to CO2 concentration shown in Figure 5. The control unit 10-1 in FIG. 19 is configured similarly to the concrete unit 10-1 in FIG. Other configurations and effects of the modified example of the fourth embodiment shown in FIG. 19 are similar to those of the fourth embodiment shown in FIG.

[0071] It should be noted that the illustrated embodiments are merely examples and are not intended to limit the technical scope of the present invention. [Explanation of symbols]

[0072] 1. Concrete pavement 1A: Bottom of concrete pavement 2. A layer made of a material with good water permeability and breathability 3. CO2 supply piping (carbon dioxide supply piping) 4. Cover (covering material) 5. CO2 concentration sensor (carbon dioxide concentration measuring device) 6. CO2 source (carbon dioxide source) 7. CO2 supply system (carbon dioxide supply system) 8. CO2 supply regulator (carbon dioxide supply regulator) 9. CO2 capture equipment (carbon dioxide capture equipment) 10, 10-1... Control unit (control device) 11. Temperature sensor 12. Humidity sensor 13. CO2 recovery piping (carbon dioxide recovery piping) 14...Temperature adjustment device 15...humidity adjustment device 21...Perforated piping 21H...Through holes formed in perforated piping 22...Nonwoven fabric layer 23...Groove 30, 30-1, 30-2, 30-3, 30-4, 30-5, 30-6, 30-7, 30-8... Systems for carbonation curing of concrete pavements

Claims

1. A step of performing carbonation curing from the bottom surface of the concrete pavement, In the carbonation curing step, a supply step of supplying carbon dioxide gas to the construction site; a measuring step of measuring a carbon dioxide concentration; A method for curing a concrete pavement, comprising a step of controlling the carbon dioxide concentration in the carbon dioxide gas supplied in the supply step based on the carbon dioxide concentration measured in the measurement step.

2. A method for curing concrete pavement according to claim 1, wherein a layer made of a material with good water permeability and air permeability is placed below the concrete pavement undergoing carbonation curing, and carbon dioxide gas is supplied to the bottom surface of the concrete pavement through said layer.

3. A method for curing concrete pavement according to claim 1, wherein a layer made of a material with good water permeability and air permeability is placed below the concrete pavement to be carbonation cured, and a perforated pipe with a plurality of through-holes formed in the pipe wall is buried in said layer, and carbon dioxide gas is supplied to the bottom surface of the concrete pavement through said perforated pipe.

4. A method for curing concrete pavement according to claim 1, wherein a layer made of a material with good water permeability and air permeability is placed below the concrete pavement to be carbonation cured, and a nonwoven fabric layer is formed at the boundary between said layer and the bottom surface of the concrete pavement, and carbon dioxide gas is supplied to the bottom surface of the concrete pavement through said nonwoven fabric layer.

5. A method for curing concrete pavement according to claim 1, wherein a layer made of a material with good water permeability and breathability or a material with poor breathability is placed below the concrete pavement to be carbonation cured, and a groove is formed at the boundary between said layer and the bottom surface of the concrete pavement, and carbon dioxide gas is supplied to the bottom surface of the concrete pavement through said groove.

6. measuring the temperature and / or humidity in the atmosphere at a construction site of a concrete pavement; 6. The method for curing a concrete pavement according to claim 1, further comprising a step of controlling the temperature and / or humidity of the carbon dioxide gas supplied to the construction site based on the measured temperature and / or humidity.

7. a carbon dioxide concentration measuring device that measures a carbon dioxide concentration; a carbon dioxide supply system that supplies carbon dioxide gas to the bottom of the concrete pavement; A system for performing carbonation curing of concrete pavement, characterized in that it has a control device that controls the carbon dioxide concentration in the carbon dioxide gas supplied through the carbon dioxide gas supply system based on the carbon dioxide concentration measured by the carbon dioxide concentration measuring device.

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