JPH02137782A - Curing method for concrete part or concrete structure and apparatus therefor - Google Patents

Abstract

PURPOSE:To shorten the curing time while preventing the generation of defects such as floating by preliminarily curing a concrete part in a carbonated medium under specific condition and subjecting the pre-cured product to main curing. CONSTITUTION:Air in a hot-air circulation channel 5 is circulated by closing electromagnetic valves 17a, 17b, 20 and a damper 23, closing an electromagnetic valve 11 and actuating a blower 4, subjected to heat-exchange in a heat- exchanger 6 with hot steam supplied from a boiler 9 and supplied to a mixing apparatus 14. The valve 17b is opened, the steam supplied from the boiler 9 via a feeding system 16b is ejected through a steam ejector 15b into the mixing apparatus and mixed with the air, the mixture is introduced into a curing space 1 via a line 6 while controlling the temperature and humidity to be lower than those of the main curing, the valve 20 is opened to supply a carbonated medium from a bomb 21 via a feeding system 19 and a concrete part is pre-cured. Subsequently, the electromagnetic valves 11, 17b are closed, the electromagnetic valve 17a is opened and the hot steam in the boiler 9 is ejected into the space 1 via a flowcontrolling valve 13, the valve 17a and an ejector 15a to effect the main curing of the concrete part.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for curing concrete members such as precast concrete or concrete structures cast on site.

(Prior art) For example, for concrete members such as precast concrete, in order to shorten the time required for curing in a curing tank, there is a curing method that accelerates curing using a heating medium such as hot air or high-temperature steam. Widely used. Conventionally, such a heating medium has been supplied by a method of unidirectionally supplying hot air or high-temperature steam from a hot air generator or a steam boiler into a curing space of a curing device, or by a method disclosed in, for example, Japanese Patent Laid-Open Publication No. Sho-No. There is a method of circulating the heating medium through a circulation path equipped with a blower, and the latter greatly improves thermal efficiency compared to the former, and can reduce temperature unevenness in concrete members during curing. There is an advantage.

(Problems to be Solved by the Invention) However, when using any of the above-mentioned supply methods, in the conventional curing method, when trying to further shorten the curing time, lifting or thinning occurs on the surface of the concrete member. When such defects occur, the evaluation of the product may drop and the product may not be able to be sold.

In order to prevent the occurrence of such defects, the concrete members poured into the formwork should be cured using the heating medium described above, for example, for 5 to 6 hours in the summer and for 5 to 6 hours in the winter. The product must be left to stand for a long time, about 6 to 10 hours, resulting in very poor productivity.

The present invention is intended to solve the above-mentioned problems, that is, to shorten the natural standing time, improve productivity, and at the same time prevent the occurrence of defects such as lifting and thinning as described above. be. Furthermore, the present invention aims to shorten the curing time of not only concrete members but also concrete structures cast on site while preventing the occurrence of the defects described above.

(Means for Solving the Problems) To explain in detail the present invention for achieving the above-mentioned object, the first configuration is as shown in the conceptual diagram of FIG. In the method of curing the concrete member 2 in the curing space 1 by supplying hot air containing water vapor or high-temperature water vapor from the supply means A or B, respectively, the curing space is cured before the main main curing process. A method for curing a concrete member by providing a pre-curing process in which curing is performed by controlling the temperature and humidity in the curing space 1 lower than in the main curing process, and supplying a carbonation medium into the curing space 1 in the pre-curing process. The main points are as follows.

In addition, the second configuration circulates and supplies hot air containing water vapor into a curing space l divided as shown in the conceptual diagram of FIG. 2 to cure the concrete member 2 in the curing space l. In the method, prior to the main main curing process, a pre-curing process is provided in which the temperature and humidity in the curing space 1 are controlled to be lower than the main curing process, and in the pre-curing process, the above-mentioned The gist of this invention is a method for curing a concrete member by supplying a carbonation medium into a curing space l.

Moreover, as shown in the conceptual diagram of FIG. 3, the third configuration includes means for supplying hot air containing water vapor or high-temperature water vapor into the curing space 1 partitioned by the concrete structure 3 itself to be cured. In the method of curing the concrete structure 3 constituting the curing space 1 by supplying it unidirectionally from A or A, the temperature and humidity in the curing space 1 are adjusted prior to the main main curing process. The gist of this method is to provide a pre-curing process in which curing is performed at a controlled temperature lower than the main curing process, and to supply a carbonation medium into the curing space 1 in the pre-curing process. be.

Next, in the fourth configuration, hot air containing water vapor is circulated and supplied into a curing space 1 defined by the concrete structure 3 itself to be cured, thereby curing the concrete structure 3 constituting the curing space 1. In the method, prior to the main main curing process, a pre-curing process is provided in which the temperature and humidity in the curing space 1 are controlled to be lower than the main curing process, and curing is performed,
The gist of this invention is a method for curing a concrete structure in which a carbonation medium is supplied into the curing space during the core curing process.

Next, the fifth configuration is a curing method for concrete members or concrete structures in which the carbonation medium is carbon dioxide gas in the curing method described in item 1, 2, 3, or 4. It is something to do.

Next, the sixth configuration is the first term, the second term, the third term, or the fourth term.
In the curing method described in Section 1, the gist is a curing method for concrete members or concrete structures in which carbonated water is used as the carbonation medium.

Next, in the seventh configuration, heating is carried out in a hot air circulation path 5 that passes through the curing space 1 divided as shown in the conceptual diagram of FIG. The gist of the present invention is a curing device for a concrete member 2 or a concrete structure 3, which comprises a means 6, a humidifying means 7, and a carbonating medium supplying means 8.

Next, in the eighth configuration, in the curing device described in item 7, the carbonation medium supply means 8 is a curing device for the concrete member 2 or concrete structure 3 configured as a carbon dioxide gas injection part. It is.

Next, the ninth configuration is that in the curing device described in item 7, the carbonation medium supply means 8 is a curing device for the concrete member 2 or concrete structure 3 configured as a carbonated water injection part. It is.

Next, in the tenth configuration, as shown in FIG. 5, in the curing device described in item 7, the heating means 6 heats the circulating flow by indirectly exchanging heat with steam from a common boiler 9 In addition, the humidifying means 7 is essentially a curing device for the concrete member 2 or concrete structure 3 configured as a steam injection section from the boiler 9.

Next, an eleventh configuration is the curing device described in item 10, in which the heating means 6 and the humidifying means 7 are concrete members provided with electromagnetic valves that are operated in accordance with the temperature and humidity of the circulating flow, respectively. 2 or a curing device for concrete structures 3.

(Function) As mentioned above, in the main curing process of the present invention,
Hot air or high-temperature steam containing saturated steam is supplied unidirectionally or cyclically into the divided curing space 1, and the curing space 1 is maintained at a temperature of, for example, 50° C. to 70° C. for curing. However, in the pre-curing process, the temperature and humidity in the curing space l are lower than in the main curing process (
For example, curing is performed under controlled conditions (temperature: 35° C. to 50° C., humidity: 50% to 70%). The temperature and humidity conditions of the pre-curing process are similar to those of natural curing in summer, and thin skin does not occur during this pre-curing process, but if sufficient time is not allowed for this pre-curing process. When the main curing process is started, a thin skin often appears about 5 to 10 minutes after the transition. This is because the curing space 1 begins to fill with water vapor and transitions from dry air to humid air, resulting in excess moisture forming approximately 0.1 mm inside from the surface of the concrete member 2. It is thought that this occurs as a result of expansion as the temperature rises during the curing process.

Therefore, in the present invention, as described above, a carbonation medium is supplied into the curing space 1 in the pre-curing process. The carbonation medium can be supplied as carbon dioxide gas or as carbonated water.

By supplying such a carbonating medium, cement reacts with carbon dioxide on the surface of the concrete member 2 or concrete structure 3, forming a calcium carbonate film as shown in the following equation, and is neutralized.

With this calcium carbonate coating, the concrete member 2
The surface of the curing space 1 hardens and its water permeability decreases, so after the film is formed, the atmosphere in the curing space 1 changes from dry air to humid air during the main curing process. However, the film is protected by the film and no excess moisture is generated as described above, so that thin skin etc. do not occur even when the temperature rises during the main curing process.

For this reason, the time required for the pre-curing process may be about the time required for the calcium carbonate film to be sufficiently formed (for example, 30 to 60 minutes), which is the same as the time required for the above-mentioned natural leaving,
That is, it is much shorter than 5 to 6 hours in summer and 6 to 10 hours in winter. In this way, the present invention can forcibly shorten the slow reaction with carbon dioxide in the atmosphere when left in nature, and can therefore significantly shorten the time required for curing with a curing device. As a result, the productivity of the concrete member 2 or the workability of the concrete structure 3 can be improved.

The calcium carbonate coating is thin (formed only on the surface) so that it does not cause any structural problems for the concrete member 2 or the concrete structure 3. Also, the amount of carbonation medium to be supplied is as follows: It can be set appropriately depending on the conditions such as time, temperature, humidity, etc. of the pre-curing process.For example, when carbon dioxide gas is used as the carbonation medium, the thickness of the calcium carbonate film, that is, the neutralization depth ,
These can be set appropriately depending on the concentration of carbon dioxide gas, temperature, humidity, time, etc.

As shown in the conceptual diagram of FIG. 1 or 3, the method and apparatus of the present invention described above unidirectionally supplies hot air or high-temperature steam containing water vapor into the curing space 1 to It can be applied to a method and apparatus for curing a concrete structure 3, and as shown in the conceptual diagram of FIG. Alternatively, it can be applied to a method and device for curing the concrete structure 3. In the latter method and device, the thermal efficiency can be greatly improved compared to the former, and the temperature of the concrete member 2 during curing can be improved. Advantages include reduced mottling and reduced consumption of carbonated media.

(Embodiment) FIG. 5 is a system diagram showing an embodiment of an apparatus that can suitably carry out the curing method of the present invention by circulating and supplying hot air containing water vapor into the curing space 1. In this configuration, a hot air circulation path 5 passing through the curing space 1 and forming a circulating flow by a blower as the air blowing means 4 is provided with a heat exchanger as a heating means 6 on the downstream side of the air blowing means 4. The heat exchanger 6 is configured such that the high temperature steam from the boiler 9 and the circulating flow from the blower 4 indirectly exchange heat. A solenoid valve 11 is provided in the steam side system 10 of the heat exchanger 6, and the upstream side of the solenoid valve 11 is connected to the downstream side of the flow rate control valve 13 provided in the steam supply system 12 from the boiler 9. ing. Further, on the downstream side of the heat exchanger 6, a mixing device 14 constituting a humidifying means 7 and a carbonating medium supplying means 8 is provided.
has been established. The mixing device 14 is provided with first and second steam injection parts 15a and 15b to constitute the humidifying means 7, and the respective supply systems 16a and 16b are provided with solenoid valves 17a and 17, respectively.
It is connected to the downstream side of the flow rate control valve 13 of the steam supply system 12 via b.

Furthermore, the mixing device 14 is provided with a carbon dioxide gas injection part 18 to constitute a carbonated medium supply means 8, and its supply system 19 is connected to a carbon dioxide gas cylinder 21 via a solenoid valve 20. An intake system 22 is provided on the upstream side of the blower 4 in the circulation system 5.
The system 22 is provided with an electromagnetic damper 23. Further, dampers 24 and 25 are provided on the suction side and the discharge side of the blower 4. Next, reference numeral 26 is a control device, and this control device 26 is connected to the electromagnetic valve 11.17a.

17b, 20, the flow control valve 13, the electromagnetic damper 23, etc., are controlled according to a predetermined time schedule and signals from the temperature sensor 27, humidity sensor 28, etc.

In the above configuration, in the pre-curing process, first close the solenoid valves 17a, 17b, 20 and the solenoid damper 23,
With the solenoid valve 11 open, the blower 4 is operated to circulate the air in the hot air circulation path 5. Due to circulation,
The air that has reached the heat exchanger 6 is heated by indirectly exchanging heat with high-temperature steam from the boiler 9, and then reaches the mixing device 14.

In the mixing device 14, by opening the solenoid valve 17b, the steam supplied from the boiler 9 via the second supply system 16b is injected from the second steam injection part 15b, and the temperature is raised. It mixes with air and humidifies the air. The air heated and humidified in this way, that is, hot air, is introduced into the curing space 1 from the inlet 29 through the circulation path 5, and is used for curing the concrete member 2 or the concrete structure 3, and then passes through the outlet 30. The water then flows back through the circulation path 5 to the upstream side of the blower 4, where it is circulated.

In the above operation, the temperature of the hot air is controlled by controlling the opening degree of the flow rate control valve 13 by the control device 26 in accordance with the signal from the temperature sensor 27 installed in the curing space 1 or other appropriate places in the circulation path 5. By adjusting the amount tt of high temperature steam flowing into the exchanger 6, the temperature is controlled to a predetermined value. Note that such temperature adjustment may be performed by opening and closing the solenoid valve 11, depending on the case. Furthermore, the humidity of the hot air can be adjusted to a predetermined level by opening and closing the solenoid valve 17b by the control device 26 in response to the signal from the humidity sensor 28 installed in the curing space 1 and other appropriate places in the circulation path 5. However, if the humidity exceeds a predetermined value, the humidity can be lowered by opening the electromagnetic damper 23 and introducing low-humidity outside air into the circulation path 5.

Therefore, at the appropriate time during the pre-curing process, the solenoid valve 20
The carbon dioxide gas supplied from the gas cylinder 21 via the supply system 19 is injected from the injection unit 18 to mix the carbon dioxide gas into the circulating hot air, and the state in which the carbon dioxide gas is mixed with the hot air is maintained for a predetermined period of time. While maintaining the pre-curing process.

The above supply amount of carbon dioxide gas is controlled by the supply pressure and supply time from the gas cylinder 21, that is, the time when the solenoid valve 20 is opened. It is also possible to install a gas concentration sensor and control the opening and closing of the electromagnetic valve 20 based on a signal from the gas concentration sensor to maintain a predetermined concentration. As described above, the carbonation medium can be carbonated water in addition to carbon dioxide gas as described above, and such carbonated water can be appropriately controlled and mixed into the hot air. The carbonation medium may be supplied continuously for a predetermined period of time, as described above, or may be supplied intermittently.

When the predetermined pre-curing process is completed through the above operations, the control device 26 closes the solenoid valves 11 and 17b, and
The solenoid valve 17a is opened. In this state, the high-temperature steam in the boiler 9 flows through the flow rate control valve 13. The high-temperature steam is injected from the first injection part 15a via the electromagnetic valve 17a, and the main curing process proceeds using the high-temperature steam as the main ingredient. Temperature control in this main curing process is performed by controlling the opening degree of the flow rate regulating valve 13 by the control device 26, as in the pre-curing process.

When the main curing process is completed as described above, all the valves are closed, the operation of the blower is stopped, the circulation of hot air is stopped, and the inside of the curing space 1 is gradually cooled.
The curing of the concrete member 2 in the curing space 1 or the concrete structure constituting the curing space 1 is completed.

The amount of carbonation medium supplied in the pre-curing process mentioned above is determined as appropriate, taking into account the cost of supply, the time required for the pre-curing process, and the thickness of the calcium carbonate film, that is, the depth of carbonation. Can be set to . For example, as a result of the implementation, the conditions of the pre-curing process mentioned above, that is, the temperature of 35°C to 50°C.
℃, humidity of 50 to 70%, and maintaining the mixed carbonation medium for 30 minutes maintains a concentration of 0.1% to 80% in terms of carbon dioxide concentration. This made it possible to prevent the formation of thin skin. Of course, conditions with a lower carbon dioxide concentration resulted in less carbon dioxide consumption and lower costs. The carbonation of concrete can be promoted by increasing the temperature or decreasing the humidity when the carbon dioxide concentration is constant, and since the carbonation of concrete becomes deeper with the passage of time, these conditions, i.e. temperature, By appropriately setting the humidity and time, the carbon dioxide concentration can be set outside the above-mentioned range.

(Effects of the Invention) As described above, the present invention supplies hot air containing water vapor or high-temperature water vapor into a partitioned curing space to improve concrete members in the curing space or concrete structures constituting the curing space. In the method and device for curing, prior to the main main curing process, a pre-curing process is provided in which the temperature and humidity in the curing space are controlled to be lower than the main curing process, and the curing process is performed before the main curing process. During the curing process, a carbonation medium such as carbon dioxide gas or carbonated water is supplied into the curing space, so that during the pre-curing process, no thinning occurs during the curing process. Alternatively, the cement on the surface of the structure is reacted with carbon dioxide gas or carbonated water to form a calcium carbonate film with low water permeability, and then the main curing process is started, so even during the main curing process, temperature rise etc. This has the effect of reliably preventing the occurrence of thin skin etc. The time required for the pre-curing process may be about the time required for the calcium carbonate film to be sufficiently formed,
This is much shorter than the time required for natural storage due to the carbonation promotion effect of supplying the carbonation medium, and therefore the time required for curing with a curing device can be significantly shortened, and the concrete This has the effect of improving the productivity of members and the workability of concrete structures. Further, in the present invention, the heating medium such as hot air containing water vapor or high-temperature water vapor may be supplied into the curing space by either a unidirectional supply method or a circulating supply method,
When the latter is applied, thermal efficiency can be greatly improved compared to the former, temperature unevenness in concrete members during curing can be reduced, and consumption of carbonation medium can be reduced. be.

[Brief explanation of the drawing]

FIGS. 1 to 4 are system explanatory diagrams conceptually representing the method and apparatus of the present invention, FIG. 5 is a system explanatory diagram representing a specific example of the apparatus of the present invention, and FIG. It is an explanatory diagram showing a process. Code A...Hot air supply means, B...Steam supply means, 1...Curing space, 2...Concrete member, 3.
... Concrete structure, 4... Air blowing means (blower)
), 5... Hot air circulation path, 6... Heating means (heat exchanger), 7... Humidifying means, 8... Carbonation medium supply means, 9... Boiler, 10 =-- Steam system, 11.1
7a, 17b20...Solenoid valve, 12...Steam supply system, 13...Ragakuyu 11-section valve, 14...Mixing device, 15a, 15b...Steam injection unit, 16a, 16b.
... Supply system, 18... Carbon dioxide gas injection section, 19...
Supply system, 21... Gas cylinder, 22... Intake system, 23... Electromagnetic damper 24. 25... Damper 26... Control device, 27... Temperature sensor, 28...
...Humidity sensor, 29...Inlet, 30...Exit. Figure Figure Figure Figure 11!1 @

Claims (11)

[Claims] (1) In a method of curing concrete members in a partitioned curing space by unidirectionally supplying hot air containing steam or high-temperature steam into the curing space, prior to the main curing process, A pre-curing process is provided in which the temperature and humidity in the curing space are controlled to be lower than in the main curing process, and a carbonation medium is supplied into the curing space in the pre-curing process. curing method for concrete members. (2) In a method of curing concrete members in a partitioned curing space by circulating and supplying hot air containing water vapor, the temperature in the curing space is adjusted prior to the main curing process. and a pre-curing process in which curing is performed by controlling the humidity to be lower than that in the main curing process, and in the pre-curing process, a carbonation medium is supplied into the curing space. Method. (3) A method of curing the concrete structure constituting the curing space by unidirectionally supplying hot air or high-temperature steam containing water vapor into the curing space defined by the concrete structure itself. Prior to the main main curing process, a pre-curing process is provided in which curing is performed by controlling the temperature and humidity in the curing space to be lower than the main curing process,
A method for curing a concrete structure, comprising supplying a carbonating medium into the curing space during the pre-curing process. (4) In a method of curing the concrete structure constituting the curing space by unidirectionally supplying hot air containing water vapor or high-temperature steam into the curing space defined by the concrete structure itself to be cured. Prior to the main main curing process, a pre-curing process is provided in which the temperature and humidity in the curing space are controlled to be lower than the main curing process, and in the pre-curing process, the temperature and humidity in the curing space are , a method for curing concrete structures, characterized in that a carbonating medium is supplied. (5) A method for curing a concrete member or concrete structure, characterized in that in the curing method described in item 1, 2, 3, or 4, the carbonation medium is carbon dioxide gas. (6) A method for curing a concrete member or concrete structure, characterized in that in the curing method described in item 1, item 2, item 3, or item 4, the carbonation medium is carbonated water. (7) A concrete member or concrete characterized in that a heating means, a humidifying means, and a carbonating medium supplying means are arranged in a hot air circulation path that passes through a divided curing space and forms a circulating flow using a blowing means. Structure curing equipment. (8) The curing device for concrete members or concrete structures according to item 7, wherein the carbonation medium supply means is configured as a carbon dioxide gas injection member. (9) The curing device for concrete members or concrete structures according to item 7, wherein the carbonation medium supply means is configured as a carbonated water injection member. (10) In the curing device described in item 7, the heating means is configured to heat the circulating flow by indirect heat exchange with steam from a common boiler, and the humidifying means is configured to heat the circulating flow with steam from a common boiler. A curing device for a concrete member or concrete structure, characterized in that it is configured as an injection member. (11) In the curing device according to item 10, heating means,
A curing device for a concrete member or a concrete structure, wherein the humidifying means is provided with a solenoid valve that is operated according to the temperature and humidity of the circulating flow, respectively.