JP4999608B2 - Method for manufacturing ultra-high strength concrete member and method for analyzing unframed procedure - Google Patents

Description

    The present invention relates to a method for manufacturing an ultra-high-strength concrete member that is cured using a heat-insulating formwork, and a method for analyzing a deframement procedure.

    Conventionally, in concrete having a compressive strength of 100 MPa or less and mass concrete used for large structures such as dams, it is known that cracks may occur on the concrete surface after the concrete is placed. The cause of such cracking is considered as follows. In other words, when concrete is placed, the temperature of the concrete as a whole tends to rise uniformly due to the heat of hydration of the cement. However, since the surface part and the concrete in the vicinity thereof are easily dissipated to the outside, A temperature difference will occur. For this reason, although a difference arises in the temperature distortion of the concrete of the central part with high temperature, and the concrete of the surface part with low temperature, since both are integrated, they restrain each other's deformation. As a result, tensile stress acts on the surface concrete, and compressive stress acts on the central concrete.

As a method for reducing such cracks, the temperature of the concrete in the central part and the concrete in the surface part is maintained by keeping the concrete warm by using a heat-insulating formwork during curing and making the temperature distribution in the member uniform. A method for reducing the difference as much as possible is known (see, for example, Patent Document 1). In addition, a method has been proposed in which temperature stress of each element is analyzed by FEM (finite element method) to predict a crack occurrence location (for example, see Patent Document 2).
JP 2001-262754 A JP 2004-171190 A

Recently, ultra-high-strength concrete having a compressive strength exceeding 100 MPa is used in high-rise buildings and the like. In this ultra-high-strength concrete, the amount of cement used is large and the amount of unit cement is also large. Therefore, the amount of heat generated by the hydration reaction when placed and hardened is normal concrete (that is, concrete having a compressive strength of less than 100 MPa). ) And self-shrinkage strain is increased. In addition, it is known that the self-shrinkage strain of ultra-high strength concrete increases with time after pouring, and the increase is higher as the temperature is higher under high temperature conditions due to hydration heat generation. And in such ultra high strength concrete,
・ When curing without using heat insulation formwork ・ Even if heat insulation formwork is used, if the thickness is too thin or too thick, the initial age of the material (specifically, within about 7 days of material age) ) Has a problem of cracking. Moreover, even if the thickness of the heat insulating formwork is appropriate and cracks do not occur at the early stage of aging, cracks may occur at the time of frame removal. Hereinafter, each crack generation and other problems will be described.

(1) Cracking occurs when the thickness of the heat insulating formwork is too thick

    When concrete is placed, the temperature tends to rise due to the heat of hydration of the cement, but if the insulation formwork is thick, the entire concrete is kept warm and the temperature rises uniformly. The temperature difference with concrete is less. In this case, even if the concrete member uses ultra-high-strength concrete, if it is an unreinforced concrete member with no reinforcing bars inside the member, the free strain (that is, the self-shrinkage strain of the surface portion and the central portion) The difference in the total temperature strain) is very small, and the occurrence of cracks due to the fact that they both restrain each other is suppressed. However, in the case of a reinforced concrete member using super high-strength concrete and having reinforcing bars arranged inside the member, the occurrence of cracks may not be suppressed. As the concrete heats up, the reinforcing bars tend to expand. Since the linear expansion coefficient of reinforcing steel and concrete is almost the same, self-shrinkage strain is restrained among the free strain of concrete in contact with the reinforcing steel, and tensile stress (restraint stress) is generated in the part, and the tensile stress Cracking occurs when the stress exceeds the allowable stress (tensile strength). The same applies to the case where the self-shrinkage strain and temperature strain of the concrete member are constrained based on being constrained by other structures (peripheral structures). Tensile stress (restraint stress) is generated in the cracks, and cracks occur when the tensile stress exceeds the allowable stress (tensile strength). In many cases, reinforced concrete members such as column members are placed near the surface of the member. In such a case, if the thickness of the formwork is too thick, the self will try to increase greatly under high temperature conditions. The shrinkage strain is restrained by the reinforcing bars, and cracks are generated on the surface of the member.

(2) Cracking when a heat insulating formwork is not used or a thin heat insulating formwork is used

When concrete is placed, the temperature of the concrete as a whole tends to rise uniformly due to the heat of hydration of the cement. However, if a heat-insulated formwork is not used or a thin heat-insulated formwork is used, the surface part and its neighboring parts Since the heat is easily dissipated to the outside, a temperature difference occurs between the concrete and the concrete at the center. Here, Fig.6 (a) is a stress which shows the stress distribution (the thing on the 1st day, the 3rd day, the 7th day, and the 14th day) in the reinforced concrete member using the super high strength concrete. In the distribution diagram, the horizontal axis shows the center line of the cross section of the reinforced concrete member (Fig. 2 (a)
The distance [mm] from (b) (refer to reference numeral 4) is taken (the right direction from the center line is positive and the left direction is negative), and the vertical axis is the tensile stress [N / mm ² ]. However, the tensile stress of the concrete in the central portion is larger than that of the concrete in the surface portion, and is higher than the tensile strength of the concrete after the 7th day of age. This is because the concrete in the central part is constrained by the concrete in the surface part, and the temperature in the central part is higher than that in the surface part. Since the increase in coefficient is larger than that of concrete on the surface, it can be inferred that the stress (restraint stress) generated when the deformation is constrained is greater than that of the surface. It will be in the state where the accompanying crack may generate | occur | produce. FIG. 6 (b)
FIG. 4 is a schematic view showing a stress change 32 in the central part of the member, a stress change 30 in the surface part of the member, and a stress change 31 in an intermediate part between the central part and the surface part over time. The material age [days] is taken, and the vertical axis is the tensile stress [N / mm ² ]. Also from this figure, it is possible to infer the occurrence of cracks in the central portion of the reinforced concrete member. This phenomenon is the same even in the case of an unreinforced concrete member in which no reinforcing bar is arranged in the member. Conversely, in addition to these conditions, when the core rebar is laid inside the member (center part), the self-shrinkage strain of the free strain of the concrete is constrained by the core rebar. A larger tensile stress (restraint stress) is generated, and cracking occurs when the tensile stress exceeds the allowable stress (tensile strength). For the reasons described above, in order to suppress the occurrence of initial cracks in concrete members using ultra-high-strength concrete, the thickness of the heat-insulated formwork (that is, the heat transfer coefficient) is either too thick or too thin ( In other words, whether it is too small or too large) is not preferable, and there is an appropriate range, which is determined for each member based on concrete mixing, restraint conditions, and curing conditions.

(3) Cracking when removing the frame

By the way, when the thickness of the heat insulation formwork is appropriate, the restraint stress acting on the concrete does not exceed the tensile strength, and no cracks are generated. Here, Fig.7 (a) and Fig.8 (a) are the stress distribution in the reinforced concrete member when the heat insulation formwork with the thickness within the appropriate range is used (age 1st day, 3rd day, 7th day). FIG. 7 (a) is a stress distribution diagram schematically showing the 14th day).
Fig. 8 (a) shows the result of analysis using a relatively thin heat insulation formwork. Fig. 8 (a) shows the result of analysis using a relatively thick heat insulation formwork. It can be inferred that no cracking occurs. On the other hand, if the frame is removed at a time when there is a difference ΔT (° C) between the temperature of the concrete on the surface and the outside air temperature, the surface temperature of the concrete rapidly decreases due to exposure to the outside air. A temperature difference occurs in the central part. As a result, the surface concrete that tends to shrink due to a decrease in temperature and the concrete at the high temperature center restrain each other's deformation, and the surface concrete has tensile stress and the concrete at the central portion has compressive stress. Each works. Such a phenomenon is called thermal shock (Fig. 7 (b)
When ΔT increases, a portion where the tensile stress (restraint stress) exceeds the tensile strength is generated in the surface portion of the concrete and cracks may occur.

(4) Other problems By the way, in order to avoid the cracks as described in (1) to (3) above, the thickness of the heat insulating formwork should be set appropriately, which is caused by cracks caused by thermal shock, that is, temperature difference ΔT. The deframement may be performed when the temperature of the concrete member is lowered to the extent that the tensile stress (restraint stress) does not exceed the tensile strength. Here, FIG. 9 (a)
Is a schematic diagram showing the temperature change of each part of the concrete member when the thickness of the heat insulating formwork is thick, showing that the temperature increased by the above-mentioned heat of hydration also decreases with time in the early age of the material Yes. In the figure, the largest ΔT, that is, ΔTmax within a range in which cracking due to thermal shock does not occur, and the age D _{ΔTmax at} which ΔT becomes _ΔTmax are shown. However, if the thickness of the heat insulating formwork is so thick, it takes time until the age D _ΔTmax where ΔT ≦ ΔTmax is satisfied, and the curing period becomes longer, which may hinder the construction process. . When the thickness of the heat insulating formwork is reduced, FIG. 9 (b)
As shown in Fig. 2, the curing period can be shortened, but the possibility of initial cracking as in (2) above remains. Therefore, in order to prevent the occurrence of initial cracks and cracks due to thermal shock, and to shorten the curing period as much as possible, the speed at which the temperature of the entire member drops is rapid, and the outside temperature A curing method that minimizes the temperature difference from the surface of the concrete member is required (Fig. (C)
reference).

    An object of this invention is to provide the manufacturing method of the ultra high strength concrete member which can avoid a crack generation | occurrence | production and can shorten a curing period.

    Another object of the present invention is to provide an unframed procedure analysis method capable of easily and appropriately obtaining the order and timing of removing the heat insulating members.

The invention according to claim 1, by stacking a plurality of heat insulating members (reference numeral 1 in FIG. 2 (a) (b)) so as to overlap each other, adiabatic frame heat transfer coefficient as a modifiable curing material ( (See reference numerals 2 and 12 in the figure)
Covering the surface of the placed ultra-high strength concrete with the curing material by placing the ultra-high-strength concrete (3) on the constructed heat insulation formwork (2, 12);
When you are curing the ultra-high strength concrete (3), steps to remove the stacked plurality of heat insulating members (1) sequential stepwise vary the heat transfer rate of the curing material as the overlap And a method for producing an ultrahigh strength concrete member.

The invention according to claim 2 is characterized in that, in the invention according to claim 1 , the order and timing of removing the heat insulating member (1) are calculated by an unframed procedure analysis method using a finite element method. .

The invention according to claim 3 is the invention according to claim 2 , wherein the method for analyzing the frame removal procedure is illustrated in FIG. 1 and includes a temperature analysis step (S3) for analyzing the temperature of the concrete, An effective age calculation step (S4) for calculating an effective age, a self-shrinkage strain prediction step (S6) for predicting a self-shrinkage strain amount of the concrete from the temperature and the effective age, and a temperature of the concrete from the temperature. Temperature strain amount prediction step (S7) for predicting strain amount, material property prediction step (S5) for predicting material properties of concrete, and stress for analyzing stress from these self-shrinkage strain amount, temperature strain amount and material properties An analysis step (S8), and an initial crack prediction step for predicting whether or not an initial crack will occur before removal based on the analyzed stress. (S10), and when the initial crack is predicted not to occur, the temperature analysis step (S3), the self-shrinkage strain amount prediction step (S6), the temperature strain amount prediction step (S7), and the material property prediction step ( From S5) and the stress analysis step (S8), a crack prediction step (S11) for predicting whether or not a crack will occur when the heat insulating member is removed, and placement of ultrahigh strength concrete And a curing period determination step (S12) for determining a curing period until the frame is removed.

The invention according to claim 4 uses a heat insulating form (see reference numerals 2 and 12 in the figure) constructed by laminating a plurality of heat insulating members (see reference numerals 1 and 2 in FIGS. 2 (a) and (b)). In the unframed procedure analysis method for analyzing the order and timing of removing the heat insulating member (1) when curing high-strength concrete (see reference numeral 3 in the figure)
A temperature analysis step (S3 in FIG. 1) for analyzing the temperature of the concrete;
An effective age calculating step (S4) for calculating the effective age of the concrete;
A self-shrinkage strain amount predicting step (S6) for predicting the self-shrinkage strain amount of the concrete from the temperature and the effective age,
A temperature strain amount prediction step (S7) for predicting the temperature strain amount of the concrete from the temperature;
A material property prediction step (S5) for predicting material properties of the concrete;
A stress analysis step (S8) for analyzing the stress from these self-shrinkage strain amount, temperature strain amount and material properties;
An initial crack prediction step (S10) for predicting whether or not an initial crack will occur before deframement based on the analyzed stress;
When it is predicted that no initial crack will occur, the temperature analysis step (S3), the self-shrinkage strain amount prediction step (S6), the temperature strain amount prediction step (S7), the material property prediction step (S5), and the stress Carrying out the analysis step (S8) and predicting whether or not cracks will occur when the heat insulating member is removed;
Curing period determination step (S12) for determining a curing period from placement of ultra-high strength concrete to removal of the frame,
It is characterized by having.

    Note that the numbers in parentheses are for the sake of convenience indicating the corresponding elements in the drawings, and therefore the present description is not limited to the descriptions on the drawings.

According to the first aspect of the present invention, it is possible to avoid the occurrence of initial cracks by making the initial heat transfer coefficient of the curing material appropriate (for example, the thickness of the heat insulating formwork), and to change the heat transfer coefficient ( For example, by making the timing of removing the heat insulating member appropriate, it is possible to avoid the occurrence of cracks at the time of frame removal and to shorten the curing period.

According to the invention which concerns on Claims 2 thru | or 4 , the order and timing which remove | eliminate a heat insulation member can be easily calculated | required by the finite element method.

    The best mode for carrying out the present invention will be described below with reference to FIGS. Here, FIG. 1 is a flowchart showing an example of the unframed procedure analysis method according to the present invention, and FIGS. 2 (a) and 2 (b) are cross-sectional views respectively showing an example of the configuration of the heat insulating formwork.

The method for producing an ultra high strength concrete member according to the present invention is as follows.
・ The process of placing ultra-high-strength concrete;
A step of covering the surface of the placed ultra-high-strength concrete with a curing material capable of changing the heat transfer rate;
A step of gradually changing the heat transfer coefficient of the curing material when curing the ultra high strength concrete;
It is characterized by comprising.

Here, as a curing material,
(A) Multiple heat insulation members (Fig. 2 (a)
(b) (see reference 1 of FIG. 1) a heat-insulated form constructed by stacking (see reference 2 and 12 in the same figure),
(B) Sheets, blankets, etc. arranged so as to be wound around concrete,
(C) A heating element (for example, an electric blanket) that can be temperature-controlled electrically.
(D) Or a combination of them as appropriate (for example, an anti-drying effect is added by laminating a heat-insulating mold and a water-tight sheet)
Etc. In addition, as a method of changing the heat transfer coefficient step by step,
(A) As will be described later, a method of sequentially removing the plurality of heat insulating members 1 stacked so as to overlap each other
(B) A method of gradually peeling a sheet or blanket wrapped around multiple layers
(C) A method of gradually lowering the temperature of the heating element can be mentioned.

The method for producing an ultra high strength concrete member according to the present invention is as follows.
A step of stacking a plurality of heat insulating members (see reference numeral 1 in FIGS. 2 (a) and 2 (b)) so as to overlap each other and constructing a heat insulating mold (see reference numerals 2 and 12 in the same figure) as the curing material; ,
A step of placing ultrahigh-strength concrete 3 on the constructed heat insulation formwork (see, for example, reference numerals 2 and 12);
A step of changing the heat transfer rate stepwise by sequentially removing the plurality of heat insulating members 1 stacked so as to overlap when curing the ultra high strength concrete 3;
It is characterized by comprising. In addition, in the case of the heat insulation molds 2 and 12 shown in FIGS. 2 (a) and 2 (b), a plurality of heat insulation members 1 are laminated in all portions, but of course, the present invention is not limited to this. ,
A portion configured by stacking a plurality of heat insulating members 1;
A portion composed of one layer without the heat insulating member 1 being laminated;
You may make it comprise with. In addition, when using a sheet (see (I) above), a blanket (see (I) above) or a heating element (see (B) above) as a curing material, cast concrete before placing concrete. After that, these curing materials may be arranged.

    And the order and timing which remove | eliminate the heat insulation member 1 as mentioned above are good to calculate with the method illustrated in FIG. 1 (that is, the unframed procedure analysis method using the finite element method). Hereinafter, the unframed procedure analysis method will be described with reference to FIG.

In carrying out the unframed procedure analysis method, first, necessary data is input (see S1 and S2). In particular,
・ Concrete data ・ Concrete data ・ Reinforcement data ・ Construction data ・ External temperature environment data ・ Target unframed Dr data ・ Restriction condition data ・ Heat transfer rate condition (type Enter data related to the material, thickness, number of frames, etc.).

Next, a temperature analysis step is performed based on the input data, and the temperature T (t) in the concrete member is analyzed by a finite element method analysis (see S3). Subsequently, an effective age calculation step is performed based on the analyzed temperature to calculate the effective age t _e (t) of the concrete (see S4), and the material properties of the concrete (for example, compressive strength) from the effective age Fc (t _e ), static elastic modulus E (t _e ), tensile strength Ft (t _e ), and creep property φ (t _e )) are predicted (see S5). In addition, the self-shrinkage strain amount prediction step is performed based on the temperature T (t) and the effective age t _e (t) to predict the self-shrinkage strain amount of the concrete (see S6), and the temperature T (t ) Is performed to predict the temperature strain amount of the concrete (see S7). Then, a stress analysis step is performed based on the above-described material characteristics, self-shrinkage strain amount, temperature strain amount, and the like to analyze the temperature stress σt (t) in the concrete member (see S8).

And various evaluations are performed based on the analysis result. In particular,
(1) Evaluate internal restraint stress to predict the presence or absence of initial cracks (that is, cracks that occur before partial de-framework starts) (S10)
(2) If it is predicted that there will be no initial cracks, assume that partial cracking has occurred and change the heat transfer coefficient (thermal boundary condition) settings to conduct stress analysis in order to check for cracks due to thermal shock. Predict (S11),
(3) Evaluating whether the curing period is within a predetermined range (S12),
It is like that. That is, in the above (1), an initial crack prediction step is performed, and it is predicted whether or not an initial crack will occur before the start of partial deframement based on the stress σt (t) analyzed in the stress analysis step S8. When it is predicted that the initial crack will not occur, the temperature analysis step S3, the self-shrinkage strain amount prediction step S6, the temperature strain amount prediction step S7, the material property prediction step S5, and the stress analysis step S8 are performed. Then, it is predicted whether or not cracking will occur when the thermal insulation member 1 is removed (crack prediction step at the time of unframed in (2) above). It is recommended to determine the curing period from the placement of high-strength concrete to the removal of the frame.

By the way, in the temperature analysis step S3 described above, the temperature may be analyzed as follows. That is, the temperature history T (t) of the concrete structure is expressed as a function of the final adiabatic temperature rise K and the adiabatic temperature rise rate constant α as shown in the following equation (1). A history T (t) can be calculated. These values K and α vary according to the unit cement amount C and the concrete placing temperature T _{0 as} in the following formulas (2) and (3), but these values K and α are obtained by experiments. good.

In the above-described self-shrinkage strain amount prediction step S6, the self-shrinkage strain amount may be predicted as follows. That is, since the autogenous shrinkage strain amount epsilon _{the as} is, so that given a function of effective ages _{t e ε as = f 4 (} t e),
-The effective age t _e (t) is obtained from the temperature history T (t) obtained in the temperature analysis step S3,
・ Predetermined relational expression ε _as = f ₄ (t _e )
From this, it is preferable to predict the amount of self-shrinkage strain ε _as of each element.

Furthermore, in the above-described temperature strain amount prediction step S7,
The temperature history T (t) obtained in the temperature analysis step S3;
It is preferable to predict the amount of temperature strain ε _T of each element from a predetermined relational expression ε _T = f ₅ (T (t)).

Further, since the compressive strength Fc of each element is given by the function Fc (t _e ) = f ₆ (t _e ) of the effective age t _e (t),
The temperature history T (t) obtained in the temperature analysis step S3;
It is preferable to calculate from a predetermined relational expression Fc (t _e ) = f ₆ (t _e ). Furthermore, the static elastic modulus E (t _e ) of each element is
- the compressive strength Fc (t _e) obtained as described above,
It is preferable to calculate from a predetermined relational expression E (t _e ) = f ₈ (Fc (t _e )). In addition, the creep coefficient φ (t _e ) that considers stress relaxation due to creep is
- Enable ages t _e obtained in the above manner, the compressive strength Fc, and static elastic modulus E and the like,
・ Predetermined relational expression φ (t _e ) = f (t _e , Fc (t _e ), E (t _e ))
It is better to calculate from
Furthermore, the tensile strength Ft (t _e ) of each element is
- the compressive strength Fc (t _e) obtained as described above,
It is preferable to calculate from a predetermined relational expression Ft (t _e ) = f ₇ (Fc (t _e )).

    In the stress analysis, the period to be examined is divided into small sections, and it is performed by sequential calculation considering free strain (that is, the sum of self-shrinkage strain and temperature strain) and material properties over time and stress relaxation due to creep under restraint conditions. . The procedure is described below. First, in each minute section, the free strain increment (that is, the sum of the self-shrinkage strain increment and the temperature strain increment) is calculated. Next, within the constraint conditions set in advance for the free strain increments determined in this way, the elastic coefficient and creep coefficient determined at the analysis target time and all the previous minute sections are used, and each minute section is used. The restraint stress at the time of analysis is calculated from the balance condition that takes into account the stress relaxation due to the progress of creep determined in (1). The crack is checked by comparing the tensile strength obtained as described above and the stress analysis result.

FIG. 3 is a diagram showing an analysis result of the stress analysis step S8 described above, and shows a stress distribution curve in the reinforced concrete member (materials on the first day, the third day, the seventh day, and the 14th day). FIG. 4 is a stress distribution diagram, and FIG. 4 shows the analysis result of the stress analysis step S8 (that is, the stress change of the concrete in the central portion, the stress change in the concrete of the surface portion, and the intermediate between the central portion and the surface portion. It is a figure which shows the stress change in a part) with time. The horizontal axis in FIG. 3 takes a distance [mm] from the center line of the concrete member (see reference numeral 4 in FIGS. 2 (a) and 2 (b)). The vertical axis represents tensile stress [N / mm ² ]. Further, the horizontal axis of FIG. 4 represents the age [day], and the vertical axis represents the tensile stress [N / mm ² ]. According to these analysis results, the stress acting on the concrete does not exceed the tensile strength and cracks are not expected to occur, but the inventors actually cured under the same conditions as in the analysis. However, it was confirmed that neither the initial crack nor the thermal shock crack occurred, and the accuracy of the analysis was good.

    An embodiment of the present invention will be described with reference to FIG.

    FIG. 5 is a block diagram showing an example of the configuration of an apparatus (de-frame procedure analyzing apparatus) for carrying out the above-described de-frame procedure analysis method. Reference numeral 21 in the figure indicates a stress analysis means for analyzing temperature stress according to S1 to S8 in FIG. 1, and reference numeral 22 indicates an initial crack for predicting whether or not an initial crack will occur before partial removal of the formwork. Reference numeral 23 denotes a prediction means. Reference numeral 23 denotes a heat transfer coefficient changing means for changing the heat transfer coefficient of the heat insulating mold when the initial crack prediction means 22 predicts that no cracks are generated. Reference numeral 24 denotes a crack due to thermal shock. The unframed crack prediction means for predicting the presence / absence of the unframed is shown. Reference numeral 25 denotes unframed confirmation means for confirming whether or not all the heat insulating members have been removed. A curing condition calculation means for calculating a period required for removal (curing period) is shown. Reference numeral 27 denotes an unframed method memory means for temporarily storing an unframed procedure and a curing period. Indicating a proper data extraction means for extracting appropriate data from various data stored in the frame process memory means 27.

    Hereinafter, an example of an analysis method using the above-described apparatus will be described.

    First, when various data are input to the stress analysis means 21 (S1 and S2 in FIG. 1), the stress analysis means 21 executes steps S3 to S8 in FIG. 1 to analyze the temperature stress. Next, the initial crack predicting means 22 predicts the presence or absence of the initial crack (S10 in FIG. 1). Is changed by the heat transfer coefficient changing means 23 (S9 in FIG. 1). Then, the stress analysis means 21 performs a temperature stress analysis (S3 to S8 in FIG. 1), and based on the analysis result, a prediction as to whether cracks due to thermal shock occur at the time of partial deframement is made. 24 (S11 in FIG. 1). When it is predicted that no crack will occur during the partial unframement, the heat transfer coefficient changing means 23 changes the setting of the heat transfer coefficient change with time on the assumption that further partial unframement has been performed (S9 in FIG. 1). Similarly to the above, the stress analysis means 21 analyzes the temperature stress (S3 to S8 in FIG. 1), and the crack removal prediction means 24 predicts the presence or absence of cracks due to thermal shock (FIG. 1). S11). Such an analysis is repeated many times until all the heat insulating members are removed, but the determination of whether or not all the heat insulation molds have been removed is performed by the unframe confirmation means 25, and all the deframes are completed. If it is determined, the curing condition calculation means 26 calculates a curing period, and the unframe method memory means 27 temporarily stores the unframe procedure and the curing period. When the heat insulation form is composed of a large number of heat insulation members, there are many patterns in the order and number of the heat insulation members to be removed. The curing period may be stored in the unframed method memory means 27 in a lump, and appropriate data extraction means 28 may extract appropriate data. For example, the data of the unframed pattern (the unframed procedure or the curing period) that makes the curing period the shortest may be extracted by the appropriate data extraction unit 28, and actual unframed may be performed according to the data.

FIG. 1 is a flowchart showing an example of the unframed procedure analysis method according to the present invention. 2 (a) and 2 (b) are cross-sectional views respectively showing an example of the configuration of the heat insulating formwork. FIG. 3 is a diagram showing an analysis result of the stress analysis step S8 shown in FIG. 1, and is a stress distribution curve in the concrete member (materials on the first day, the third day, the seventh day, and the 14th day). FIG. FIG. 4 is a diagram showing the analysis results of the stress analysis step S8 over time. FIG. 5 is a block diagram showing an example of the configuration of an apparatus (de-frame procedure analyzing apparatus) for carrying out the un-frame procedure analyzing method. 6 (a) is a stress distribution diagram schematically showing the stress distribution in the concrete member, and FIG. 6 (b) is a stress change acting on the concrete in the central part and a stress change acting on the concrete in the surface part. FIG. 5 is a schematic view showing a change in stress over time in an intermediate portion between the central portion and the surface portion. Fig. 7 (a) is a schematic illustration of stress distribution in concrete members (those on the 1st day, 3rd day, 7th day, and 14th day) when a heat-insulated formwork with a thickness within an appropriate range is used. FIG. 7 (b) shows the stress distribution acting on the concrete in the central part, the stress change acting on the concrete in the surface part, the stress change in the concrete surface part, and the central part and the surface. It is a schematic diagram which shows the stress change in the intermediate part between parts with time. Fig. 8 (a) is a schematic illustration of stress distribution in concrete members (those on the 1st, 3rd, 7th, and 14th days) when using a heat insulating formwork with a thickness within the appropriate range. FIG. 8 (b) shows a stress distribution acting on the concrete in the central part, a stress change acting on the concrete in the surface part, and an intermediate part between the central part and the surface part. It is a schematic diagram which shows the stress change in time. FIG. 9 (a) is a schematic diagram showing the temperature change of each part of the concrete member when the thickness of the heat insulation formwork is thick, and FIG. 9 (b) shows the temperature change of each part of the concrete member when the heat insulation formwork is thin. FIG. 9 (c) is a schematic diagram showing the temperature change of each part of the concrete member when the thickness of the heat insulating formwork is appropriate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat insulation member 2 Heat insulation form 3 Super high-strength concrete 12 Heat insulation form S3 Temperature analysis step S4 Effective age calculation step S5 Material characteristic prediction step S6 Self shrinkage strain amount prediction step S7 Temperature strain amount prediction step

Claims (4)

Laminating a plurality of heat insulating members so as to overlap each other, and building a heat insulating mold as a curing material capable of changing the heat transfer rate ,
Covering the surface of the placed ultra-high-strength concrete with the curing material by placing the ultra-high-strength concrete on the heat-insulated formwork constructed;
When curing the ultra-high-strength concrete, a step of changing the heat transfer rate of the curing material stepwise by sequentially removing the plurality of heat insulating members stacked so as to overlap, and
A method for producing an ultra-high strength concrete member comprising: The order and timing of removing the heat insulating member is calculated by the unframed procedure analysis method using the finite element method,
Method for manufacturing ultra-high strength concrete member according to claim 1, characterized in that. The unframed procedure analysis method includes a temperature analysis step for analyzing a concrete temperature, an effective age calculation step for calculating an effective age of the concrete, and predicting a self-shrinkage strain amount of the concrete from the temperature and the effective age. A self-shrinkage strain amount prediction step, a temperature strain amount prediction step for predicting the temperature strain amount of concrete from the temperature, a material property prediction step for predicting material properties of the concrete, and these self-shrinkage strain amount and temperature strain amount. And a stress analysis step for analyzing stress from the material characteristics, an initial crack prediction step for predicting whether or not an initial crack will occur before deframement based on the analyzed stress, and a case where it is predicted that no initial crack will occur The temperature analysis step, the self-shrinkage strain amount prediction step, and the temperature strain amount prediction step. The step of predicting whether or not cracks will occur when the heat insulation member is removed by performing the material property prediction step and the stress analysis step, and removing from the placement of the ultra high strength concrete. A curing period determination step for determining a curing period up to the frame,
The method for producing an ultra-high-strength concrete member according to claim 2 . In the unframed procedure analysis method for analyzing the order and timing of removing the thermal insulation members when curing ultra-high strength concrete using a thermal insulation form constructed by laminating multiple thermal insulation members,
A temperature analysis step for analyzing the temperature of the concrete;
An effective age calculating step for calculating the effective age of the concrete,
A self-shrinkage strain prediction step for predicting a self-shrinkage strain amount of the concrete from the temperature and the effective age, and
A temperature strain amount prediction step for predicting a temperature strain amount of the concrete from the temperature;
A material property prediction step for predicting material properties of concrete;
A stress analysis step for analyzing stress from these self-shrinkage strain, temperature strain and material properties;
An initial crack prediction step for predicting whether or not an initial crack will occur before deframement based on the analyzed stress;
When it was predicted that no initial crack would occur, the temperature analysis step, the self-shrinkage strain amount prediction step, the temperature strain amount prediction step, the material property prediction step and the stress analysis step were performed, and the heat insulating member was removed. A step of predicting cracks at the time of unframed for predicting whether cracks will occur or not,
Curing period determination step for determining the curing period from placement of ultra-high strength concrete to removal of the frame,
A method for analyzing the unframed procedure characterized by comprising:

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