JP3017023B2 - Mass concrete casting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a mass concrete
The present invention relates to a method of placing mass concrete, which prevents the occurrence of cracks that occur in concrete due to the heat of hydration of concrete after placing (thick concrete with thick placement).

[0002]

2. Description of the Related Art At the time of casting concrete, heat of hydration is generated when concrete hardens due to a hydration reaction between cement and water. The heat of hydration generally reaches the maximum temperature 2 to 5 days after the concrete is cast, and the hydration reaction continues thereafter, and the strength increases with the hydration reaction. At this time, the maximum temperature of the mass concrete may rise to about 80 ° C. when the ambient temperature is 10 ° C. to 30 ° C.

FIG. 13 is a cross-sectional view of a concrete 51 without a hydration heat reducing agent added thereto, which suppresses the hydration heat generation rate, which is poured into a mold 52. FIG. Temperature change of inner layer at position ₁ and height L ₂ from bottom
3 shows the temperature change of the outer layer at the position of. Although the heat of hydration of the outer layer of the concrete 51 is radiated to the outside, the heat of hydration of the inner layer is hardly radiated to the outside because the cast thickness is large, and the temperature of the inner layer of the concrete 51 is higher than that of the outer layer of the concrete 51. And a temperature difference occurs between the inner layer and the outer layer.

[0004] That is, the outer layer of concrete 51 in wood age t ₀ from pouring, after reaching the maximum temperature T _5, but contracts with temperature drop, the inner layer of concrete 51 contrast, wood age t ₁ temperature rise of up to a maximum temperature T ₁ is expanded along with the following. That is, the outer layer of the concrete 51 for easily radiated to the outside, the maximum temperature of the outer layer with respect to the maximum temperature T ₁ of the inner layer of concrete 51 is lowered and T _5, the temperature difference will become one [Delta] T _3. Further, as shown in FIG. 15, the concrete during the pouring to the timber age t ₁ 51
Of the inner layer, the Young's modulus of the outer layer is increased to E _1, becomes solidified state. For this reason, tensile stress and compressive stress act on the inner layer and the outer layer of the concrete 51 according to the temperature difference between them. In other words, high temperature concrete in the inner layer
Compressive stress is exerted by the outer layer concrete having a lower temperature, while tensile stress is applied to the outer layer concrete by the inner layer concrete. Tensile stress acting on the outer layer of the concrete 51, concrete wood age t ₁ 51
When the temperature difference between the inner layer and the outer layer becomes the maximum value ΔT ₄ (= T ₁ −T ₆ ), the temperature difference becomes the largest and cracks easily occur. When the tensile stress generated in the outer layer of the concrete 51 exceeds the tensile strength of the concrete 51,
Cracks occur in the outer layer of the concrete 51.

[0005] Therefore, as a method of casting mass concrete, there is a method of mixing a hydration heat generation reducing agent into the entire mass concrete to delay a rise in hydration heat and reduce a rise in temperature of the mass concrete (Japanese Patent Application Laid-open No. Sho. 63-11794
No. 1). In this mass concrete, since the heat of hydration is moderate and the heat is easily radiated to the outside, the temperature of the entire mass concrete is lowered, and the temperature difference between the outer layer and the inner layer is reduced. Accordingly, since the tensile stress acting on the outer layer of the concrete 51 due to the temperature difference between the inner layer and the outer layer is reduced, cracks can be prevented. This method of casting mass concrete not only prevents cracks due to internal restraint stress, but also prevents external restraint stress, that is, cracks at the joint of new and old concrete.

[0006]

However, since the hydration heat generation reducing agent is added to the entire mass concrete, a large amount of the hydration heat generation reducing agent is required, resulting in a high cost.

In addition, in the concrete to which the hydration heat reducing agent is added, water for breathing increases, water bubbles accumulate around the aggregate and the reinforcing steel, and the voids due to the water bubbles reduce the strength of the concrete, There is a problem that the adhesive force to the concrete is weakened and the quality of the concrete is deteriorated.

Accordingly, an object of the present invention is to provide a method of placing mass concrete which can prevent cracking at low cost by minimizing the amount of a hydration heat generation reducing agent to be added.

[0009]

In order to achieve the above-mentioned object, a method for casting mass concrete according to claim 1 is provided. And a method of placing mass concrete in which the concrete is placed separately in the placement area of the second concrete to which the hydration heat reducing agent is added and mixed, wherein the tensile stress of the concrete at each position calculated by the temperature stress analysis is reduced. By adjusting at least one of the casting area of the second concrete and the rate of addition of the hydration heat reducing agent so that the tensile strength is equal to or less than the tensile strength of the second concrete,
A step of calculating the second concrete placing area and the rate of addition of the hydration heat reducing agent when the amount of the hydration heat reducing agent is minimized, and the amount of the hydration heat reducing agent being minimized. At the same time, the second concrete of the addition rate of the hydration heat reducing agent when the addition amount of the hydration heat reducing agent is minimized is poured into the casting area, and the second concrete of the second concrete is Casting the first concrete in a casting area other than the casting area.

In the mass concrete casting method according to a second aspect of the present invention, the entire concrete casting area is mixed with the first concrete casting area where no hydration heat reducing agent is added. A method of placing mass concrete in which the concrete is placed separately in the placement area of the second concrete, wherein the tensile stress of the concrete at each position calculated by the thermal stress analysis is equal to or less than the tensile strength of the concrete. And the second concrete placing area and the hydration heat reducing agent when the addition amount of the hydration heat reducing agent is minimized by adjusting at least one of the concrete casting area and the addition rate of the hydration heat reducing agent. Calculating the addition rate of the heat generation reducing agent, and adjusting the addition area of the second concrete placing area and the hydration heat generation reducing agent,
If the tensile stress of the concrete at a certain position calculated by the temperature stress analysis does not fall below the tensile strength of the concrete, the entire casting area is reduced, and the tensile stress of the concrete at each position calculated by the temperature stress analysis is By adjusting the casting area of the second concrete and the addition rate of the hydration heat reducing agent so that the tensile strength is equal to or less than the tensile strength,
Calculating the addition area of the second concrete and the hydration heat reducing agent when the addition amount of the hydration heat reducing agent of the second concrete is minimized; While placing the second concrete having the above-mentioned addition rate of the hydration heat generation reducing agent when the addition amount of the hydration heat generation reducing agent is minimized, the second concrete is placed in the casting area when the addition amount is the minimum. Placing the first concrete in a casting area other than the casting area of the second concrete.

According to a third aspect of the present invention, there is provided a mass concrete casting method, wherein the entire concrete casting area is mixed with the first concrete casting area to which the hydration heat reducing agent is not added and the hydration heat reducing agent is added. What is claimed is: 1. A method for placing mass concrete in which the concrete is placed separately in a placement area of a second concrete, wherein a first value of an addition value of a hydration heat reducing agent of the second concrete and a placement area are set. Step, increasing the addition rate of the hydration heat reducing agent of the second concrete sequentially from the initial value, and setting an adiabatic temperature rise equation based on each addition rate of the hydration heat reducing agent, The second step of calculating the tensile stress of the concrete at each position by the thermal stress analysis based on the ascending equation, and when the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, Serial all droplet region where the predetermined region decreases,
A third step of returning the reduced total casting area as a new total casting area to the second step, and the tensile stress of the concrete at each position calculated in the second step being equal to or less than the tensile strength of the concrete. In the case, a fourth step of calculating the amount of the hydration heat reducing agent added to the second concrete based on the addition rate of the hydration heat reducing agent of the second concrete and the casting area, In the placement area, placing the second concrete having the addition rate of the hydration heat generation reducing agent when the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimized, A fifth step of casting the first concrete in a casting area other than the casting area of the second concrete.

According to a fourth aspect of the present invention, there is provided a method for casting mass concrete, wherein the entire casting area is mixed with the first concrete casting area to which no hydration heat reducing agent is added and the hydration heat reduction agent. What is claimed is: 1. A method for placing mass concrete in which the concrete is placed separately in the placement area of the second concrete, wherein the addition rate of the hydration heat reducing agent of the second concrete and the initial value of the placement area are set. Step, and sequentially increasing the casting area of the second concrete from the initial value, and setting an adiabatic temperature rise formula based on the addition rate of the hydration heat reducing agent, and setting a temperature based on the adiabatic temperature rise formula. A second step of calculating the tensile stress of the concrete at each position by stress analysis; and, if the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, Is reduced by a predetermined area, the reduced total cast area is set as a new total cast area, and a third step is returned to the second step, and the tensile stress of the concrete at each position calculated in the second step is calculated in the second step. Is less than or equal to the tensile strength of the concrete, the amount of the hydration heat reducing agent added to the second concrete is determined based on the rate of addition of the hydration heat reducing agent of the second concrete and the casting area. A fourth step of calculating, and the second concrete having the rate of addition of the hydration heat reducing agent in the placement area when the amount of the hydration heat reducing agent calculated in the fourth step is minimum. And a fifth step of casting the first concrete in a casting area other than the casting area of the second concrete.

According to a fifth aspect of the present invention, there is provided a mass concrete casting method, wherein the entire concrete casting area is mixed with the first concrete casting area to which the hydration heat reducing agent is not added and the hydration heat reducing agent is added. What is claimed is: 1. A method for placing mass concrete in which the concrete is placed separately in a placement area of a second concrete, wherein an initial value of an addition rate of the hydration heat reducing agent of the second concrete and an initial value of the placement area are set. A first step of sequentially increasing the addition rate of the hydration heat reducing agent of the second concrete from the initial value of the addition rate, and setting the casting area of the second concrete for each addition rate. While increasing sequentially from the initial value of the region, an adiabatic temperature rise equation based on each addition rate of the hydration exothermic reducing agent is set, and the tensile stress of the concrete at each position is determined by a thermal stress analysis based on the adiabatic temperature rise equation. The second step of calculating If concrete tensile stress of a position calculated by the second step exceeds the tensile strength of concrete, the total droplet formation regions decreases predetermined area,
A third step of returning the reduced total casting area as a new total casting area to the second step, and the tensile stress of the concrete at each position calculated in the second step being equal to or less than the tensile strength of the concrete. In the case, a fourth step of calculating the amount of the hydration heat reducing agent added to the second concrete based on the addition rate of the hydration heat reducing agent of the second concrete and the casting area, The hydration exothermic reducing agent when the addition amount of the hydration exothermic reducing agent is minimized in the casting area when the adding amount of the hydration exothermic reducing agent calculated in the fourth step is minimal. A fifth step of placing the second concrete having the above-mentioned addition rate and placing the first concrete in a placement area other than the placement area of the second concrete. .

According to a sixth aspect of the present invention, there is provided the mass concrete casting method according to any one of the first to fifth aspects, wherein the hydration heat generation reducing agent is added and mixed. The concrete of No. 2 is a plurality of concretes, and each of the addition ratios of the second concrete increases with increasing distance from the first concrete side where no hydration heat generation reducing agent is added.

Further, in the mass concrete casting method of the present invention, the maximum amount of mass concrete is determined by setting the tensile stress of the concrete at each position calculated by the thermal stress analysis to be equal to or less than the tensile strength of the concrete. Thus, the maximum amount of concrete to be poured is poured at one time.

[0016]

According to the mass concrete casting method of the first aspect, the hydration heat generation reducing agent is added and mixed so that the tensile stress of the concrete at each position calculated by the temperature stress analysis is equal to or less than the tensile strength of the concrete. Adjusting at least one of the above-mentioned second concrete placing area and the addition rate of the hydration heat reducing agent, the second concrete placing area when the addition amount of the hydration heat reducing agent is minimized. And the addition rate of the hydration exothermic reducing agent are determined. Then, the second concrete having the addition rate of the hydration heat reducing agent when the addition amount of the hydration heat reducing agent is minimized is poured into the casting area where the addition amount of the hydration heat reducing agent is minimum. At the same time, the first concrete is cast in a casting area other than the second concrete casting area. In other words, when the casting area of the second concrete is increased, the proportion of the area where the hydration heat generation rate is gentle increases with respect to the entire casting area of the mass concrete, and the temperature increase of the entire mass concrete is suppressed. ,
When the addition rate of the hydration heat reducing agent of the second concrete is increased, the hydration heat generation rate of the second concrete increases slowly, and the temperature rise of the first concrete is suppressed,
Suppresses the temperature rise of the entire mass concrete. Therefore, the gradient of the hydration heat generation rate of the second concrete is gentler than that of the first concrete, and the temperature difference between the first concrete and the second concrete is reduced. Thus, since the tensile stress due to temperature expansion is reduced, cracks can be prevented.

As described above, when the tensile stress of the concrete at each of the above positions is equal to or less than the tensile strength of the concrete and the amount of the hydration heat generation reducing agent is minimized, the second concrete placing area and the hydration heat reduction are reduced. Since the second concrete and the first concrete are cast at once by determining the additive ratio of the agent, the hydration heat generation reducing agent can be reduced as much as possible, and the cracking of the mass concrete can be prevented and the cost can be reduced. Further, both the casting area of the second concrete and the addition rate of the hydration heat generation reducing agent are adjusted so that the casting area and the addition amount of the hydration heat generation reducing agent are the minimum addition amount of the hydration heat generation reducing agent. When a plurality of sets are obtained, by selecting the smaller casting area, the amount of the second concrete to be poured can be reduced as much as possible while preventing cracking, and the efficiency of the casting operation can be improved.

Further, according to the method for casting mass concrete of the second aspect, the second concrete is placed so that the tensile stress of the concrete at each position calculated by the thermal stress analysis becomes equal to or less than the tensile strength of the concrete. By adjusting at least one of the casting area and the addition rate of the hydration heat reducing agent,
The casting area of the second concrete and the addition rate of the hydration heat reducing agent when the amount of the hydration heat reducing agent is minimized are determined. At this time, if the tensile stress of the concrete at a certain position calculated by the temperature stress analysis does not become lower than the tensile strength of the concrete even if the casting area of the second concrete and the addition rate of the hydration heat generation reducing agent are adjusted. The addition of the second concrete casting area and the hydration heat generation reducing agent such that the entire casting area is reduced and the tensile stress of the concrete at each position calculated by the temperature stress analysis becomes equal to or less than the tensile strength of the concrete. By adjusting at least one of the rates, the casting area of the second concrete and the rate of addition of the hydration heat reducing agent when the amount of the hydration heat reducing agent added to the second concrete is minimized are determined. Further, when the tensile stress of the concrete at the certain position does not become lower than the tensile strength of the concrete, the entire casting area is reduced, and this is repeated. And
While placing the second concrete of the addition rate of the hydration heat reducing agent when the addition amount of the hydration heat reducing agent is minimized in the casting area when the hydration heat reducing agent is the minimum addition amount, The first concrete is cast in a casting area other than the second concrete casting area.

As described above, the minimum amount of the hydration heat generation reducing agent is added to the second concrete so that the tensile stress of the concrete at each position is equal to or less than the tensile strength of the concrete.
A small amount of the hydration heat reducing agent can prevent cracking of the mass concrete and reduce the cost. Further, both the casting area of the second concrete and the addition rate of the hydration heat generation reducing agent are adjusted so that the casting area where the hydration heat generation reducing agent is the minimum addition amount and the addition rate of the hydration heat generation reducing agent are adjusted. When a plurality of sets are obtained, by selecting the smaller casting area, the amount of the second concrete to be poured can be reduced as much as possible while preventing cracking, and the efficiency of the casting operation can be improved. Furthermore, even if the casting area of the second concrete exceeds, for example, a predetermined upper limit value, or the addition rate exceeds, for example, a predetermined upper limit value, the casting when the addition amount of the hydration heat generation reducing agent is minimized When the region and the amount of the hydration heat reducing agent to be added cannot be determined, the effect of suppressing the temperature rise by the second concrete is increased by reducing the entire casting region, thereby suppressing the overall temperature rise. Then, with the reduced total casting area as a new total casting area, the minimum addition amount of the hydration heat reducing agent is determined, and the maximum casting area that can prevent cracking even when the casting is performed at once is determined. Can be.

According to the mass concrete casting method of the third aspect, the initial value of the addition rate of the hydration heat reducing agent of the second concrete to which the hydration heat reducing agent is added and mixed in the first step. And set the casting area. And the second
In the step, the addition rate of the hydration heat reducing agent of the second concrete is sequentially increased from the initial value, and an adiabatic temperature rise equation based on the addition rate of the hydration heat reduction agent is set, and the temperature based on the adiabatic temperature rise equation is set. Calculate the tensile stress of concrete at each position by stress analysis. If the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area in the third step, and the reduced entire casting area is replaced with a new area. The process returns to the second step as the entire casting area. On the other hand, when the tensile stress of the concrete at each position calculated for each addition rate of the hydration heat reducing agent that has been sequentially increased in the second concrete in the second step is equal to or less than the tensile strength of the concrete,
In the step, the addition amount of the hydration heat generation reducing agent for the second concrete is calculated. Then, in the fifth step, the second concrete having the addition rate of the hydration heat generation reducing agent at the time when the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimized is poured into the casting area. At the same time, the first concrete is cast in a casting area other than the second concrete casting area.

Therefore, the minimum amount of the hydration heat generation reducing agent is added to the second concrete to reduce the tensile stress of the concrete at each position to the tensile strength of the concrete or less.
A small amount of the hydration heat reducing agent can prevent cracking of the mass concrete and reduce the cost. Further, the hydration heat generation reducing agent may be used when the tensile stress of the concrete at a certain position obtained by the temperature stress analysis exceeds the tensile strength of the concrete and the addition rate of the second concrete is within a range from an initial value to, for example, a predetermined upper limit. If the minimum amount of
By reducing the entire casting area, the effect of suppressing the temperature rise by the second concrete is enhanced, and the entire temperature rise can be suppressed. Then, the minimum addition amount of the hydration heat generation reducing agent can be obtained by using the reduced entire casting area as a new entire casting area.

Further, according to the method for placing mass concrete of the fourth aspect, the addition rate of the hydration heat reducing agent of the second concrete to which the hydration heat reducing agent is added and mixed in the first step and the placement are set. Set the initial value of the area. And the second
In the step, the casting area of the second concrete is sequentially increased, and an adiabatic temperature rise equation based on the rate of addition of the hydration heat generation reducing agent is set, and the concrete at each position is subjected to a thermal stress analysis based on the adiabatic temperature rise equation. Calculate the tensile stress respectively. When the tensile stress of the concrete at a certain position calculated in each of the placing areas in the second step exceeds the tensile strength of the concrete, in the third step, the entire placing area is reduced by a predetermined area. The casting area is set as the entire casting area, and the process returns to the second step. On the other hand, when the tensile stress of the concrete at each position calculated in the second step is equal to or less than the tensile strength of the concrete, the amount of the hydration heat reducing agent added to the second concrete is calculated in the fourth step. Then, in the fifth step, the second concrete having the addition rate of the hydration heat generation reducing agent is poured into the casting area where the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimized. And placing the first concrete in a casting area other than the casting area of the second concrete.

Therefore, the minimum amount of the hydration heat generation reducing agent is added to the second concrete so that the tensile stress of the concrete at each position is less than the tensile strength of the concrete.
A small amount of the hydration heat reducing agent can prevent cracking of the mass concrete and reduce the cost. When the minimum addition amount of the hydration heat generation reducing agent is not determined within the range from the initial value to the predetermined upper limit, for example, the second concrete placing area is reduced by reducing the entire casting area. ,
The effect of suppressing the temperature rise by the second concrete can be enhanced, and the entire temperature rise can be suppressed. Then, the minimum addition amount of the hydration heat generation reducing agent can be obtained by setting the reduced entire casting area as a new casting area.

Further, according to the mass concrete casting method of the fifth aspect, the initial value of the addition rate of the hydration heat reducing agent of the second concrete to which the hydration heat reducing agent is added and mixed in the first step. And the initial value of the casting area. And
In the second step, the addition rate of the hydration heat reducing agent of the second concrete is gradually increased from the beginning, and the second
The casting area of concrete is gradually increased from the initial value, and the adiabatic temperature rise formula based on each rate of addition of the hydration exothermic reducing agent is set. Calculate the tensile stress respectively. When the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area in a third step, and the reduced entire casting area is newly added. The process returns to the second step as the entire casting area. On the other hand, when the tensile stress of the concrete at each position calculated in the second step is equal to or less than the tensile strength of the concrete, the amount of the hydration heat reducing agent added to the second concrete is calculated in the fourth step. Then, in the fifth step, the second concrete having the hydration heat reducing agent addition rate is poured into the second concrete placing area where the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimum. At the same time, the first concrete is cast in a casting area other than the second concrete casting area.

Therefore, the second mass concrete
The minimum amount of the hydration heat reducing agent is added to the concrete to reduce the tensile stress of the concrete at each position to the tensile strength of the concrete or less, so that a small amount of the hydration heat reducing agent prevents cracking of the mass concrete, Cost can be reduced. In addition, both the casting area of the second concrete and the addition rate of the hydration heat generation reducing agent are adjusted so that the casting area and the addition rate of the hydration heat generation reducing agent are the minimum addition amount of the hydration heat generation reducing agent. When a plurality of sets are obtained, by selecting the smaller casting area, the amount of the second concrete to be poured can be reduced as much as possible while preventing cracking, and the efficiency of the casting operation can be improved. Further, the addition rate of the hydration heat reducing agent of the second concrete is in a range from the initial value to, for example, a predetermined upper limit, and the casting area is in a range from the initial value to, for example, a predetermined upper limit. If the determined tensile stress of the concrete at a certain position exceeds the tensile strength of the concrete and the minimum amount of the hydration heat reducing agent cannot be determined, the entire casting area is reduced and the second casting area for the entire casting area is reduced. By increasing the concrete casting area, the effect of suppressing the temperature rise by the second concrete can be enhanced, and the minimum amount of the hydration heat generation reducing agent can be determined.

According to the method for placing mass concrete of the sixth aspect, in the method for placing mass concrete of the first or fifth aspect, the second concrete to which the hydration heat generation reducing agent is added and mixed is used. A plurality of layers are added so that the addition rate of each layer increases as the distance from the first concrete side where no hydration heat generation reducing agent is added is increased. Therefore, the first concrete without the hydration heat reducing agent and the second concrete with the hydration heat reducing agent added do not have a rapid temperature change, so that the temperature gradient becomes gentle, and the first concrete does not. The tensile stress due to the temperature difference between the concrete and the second concrete can be reduced to effectively prevent cracking.

According to the mass concrete casting method of the present invention, the maximum amount of mass concrete to be poured is such that the tensile stress of the concrete at each position calculated by the temperature stress analysis is equal to or less than the tensile strength of the concrete. And the maximum amount of concrete to be poured is poured at once.
For example, if the amount of mass concrete to be cast exceeds the above maximum amount of cast concrete, after casting the calculated maximum amount of mass concrete, the remaining concrete is separated after a predetermined time. The concrete is poured and a desired amount of concrete is poured. Accordingly, since the tensile stress of the concrete at each position does not become lower than the tensile strength, the mass concrete with the maximum amount of cast concrete can prevent cracks of the mass concrete.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The mass concrete casting method of the present invention will be described below in detail with reference to embodiments.

(First Embodiment) FIG. 1A shows a first embodiment of the present invention.
1 is a cross-sectional view of a mass concrete to be cast by using the mass concrete casting method of the embodiment, and 1 is a first concrete without a hydration heat reducing agent added in a mold (not shown). Concrete 2 is a second concrete which is immediately poured on the first concrete 1 and to which hydrolyzable tannin is added as an example of a hydration heat generation reducing agent. The second concrete 2 has a vertical casting area L. The second concrete 2 may be a single layer, or may be n layers (placed areas l ₁ , l ₂ ,
l ₃ , l ₄ ,..., l _n ). Further, the entire casting area in the vertical direction of the mass concrete is D, and the casting area is S.
And Therefore, striking region where the first concrete 1 is a D-Σl _i. Where Σ is the sum of 1 to n for i.

[0030] Then, in FIG. 1 (A), the droplet formation regions divided in the second concrete 2 l _1, l _2, ..., an initial value a ₁ of the addition rate of the _{l n, a 2, ...,} a n The tensile stress at each position of the concrete is calculated by a temperature stress analysis described later. Further, as shown in FIG. 1 (B), the respective addition rates a ₁ , a ₂ ,.
_An is increased by Δa, and a second temperature stress analysis is performed.
Thus, sequential striking region where l _1, l _2, ..., the addition rate of the l _n a _1, a
₂ ,... _An are increased by Δa.
As shown in (C), when the tensile stress at each position of the concrete calculated by the temperature stress analysis is increased by jΔa and the tensile strength of the concrete is equal to or less than the tensile strength of the concrete and the amount of the hydration heat reducing agent added is the minimum, the second concrete The addition ratio of No. 2 is determined.

The processing for calculating the minimum addition amount of the hydration heat generation reducing agent for mass concrete will be described below with reference to the flowcharts shown in FIGS.

First, the following basic conditions are set in step S101.

[0033] Concrete striking設温of the set temperature stress calculation model setting concrete of the total droplet region where the lower limit value D _min of setting hydration exothermic reducing additive for concrete droplet region where L set above division layer number n of the D Initial value of the addition rate of the casting area L (a ₁ , a ₂ ,..., A _n )
Setting of the upper limit value _Amax of the addition rate of the hydration heat reducing agent Temporary setting of the minimum addition amount M _min of the hydration heat reducing agent In the setting of the concrete casting temperature in step S101, depending on the season, Since the temperature of the concrete after kneading and transporting is different, the temperature is estimated and determined.
The concrete placement temperature is used at the time of thermal stress analysis. In “setting of thermal stress analysis model” in step S101, an analysis model used for thermal stress analysis, for example, an FEM (finite element method) analysis model is determined. Also,
The upper limit value _Amax of the addition rate of the hydration heat reducing agent is set to 3% by weight as a value that causes less generation of bleeding water in the concrete and does not extremely delay the strength development of the concrete.

Next, in step S102, an initial value of the entire concrete placing area D is set. Then, step S10
Proceeding to 3, the concrete placing area D is compared with the lower limit value _Dmin, and the concrete placing area D becomes the lower limit value D _min.
If it exceeds _min , the process proceeds to step S104. On the other hand, if it is determined in step S103 that the entire concrete placing area D is equal to or smaller than the lower limit value _Dmin , the process ends.

Next, in step S104, the total amount of concrete V ₀ (= S × D) is calculated. Next, step S105
Then, the addition rate A of the hydration heat generation reducing agent is replaced with the initial value. However, when the casting area L is divided into a plurality of layers,
The initial value doping ratio of each layer a _1, a _2, ..., substituting a _n. Then, in step S106, the casting area L of the hydration heat generation reducing agent-added concrete, that is, the second concrete 2, is set. However, when the casting area L is divided into a plurality of layers,
The casting areas l ₁ , l ₂ ,..., L _n of each layer are set respectively.

The initial values a ₁ , a ₂ ,...
a _n is the gradually increases toward a ₁ from the addition ratio a _n of the first concrete 1 side. Furthermore, each droplet region where l _1, l _2, ..., the magnitude of the l _n also has a substantially identical, may be hit region where the different sizes.

Next, by comparing the added factor A and the upper limit value A _max of the heat of hydration reducing agent in step S107, when the addition ratio A is less than the upper limit value A _max, the process proceeds to step S108 shown in FIG.
On the other hand, if the addition rate A is equal to or more than the upper limit value _Amax in step S107, the process proceeds to step S120, and it is determined whether the addition rate A has been registered. For example, the minimum as extremely large values the set value of the temporary amount added M _min, by a minimum amount M _min is determined whether or not smaller than the set value of the temporary minimum amount M _min in steps described below Is determined and the addition rate A
It is determined whether or not has been registered. If the addition rate A is registered in step S120, the process is terminated. On the other hand, if the addition rate A is not registered, the process proceeds to step S121 to reduce the entire concrete placing area D by a predetermined area. Then, the process returns to step S103. In addition,
The case where the second concrete is divided into a plurality layers, hitting region where l _1, l _2, ..., each addition ratio _{l n a 1, a 2,} ..., a n
_Is compared with the upper limit value _Amax as the addition rate A.

Next, in step S108, the conditions determined by the next hydration heat generation reducing agent are set.

Setting of Adiabatic Temperature Rise Equation Setting of Young's Modulus and Tensile Strength Expression Equation The “adiabatic temperature rise equation” in step S108 is based on material age t
The adiabatic temperature rise When Q (t) in _{Japan, Q (t) = Q ∞} (1-e -γt) Q ∞: Ultimate adiabatic temperature rise [° C.] gamma: Ultimate adiabatic temperature rise from the wood age 0 days It is a constant relating to the temperature rise rate between reaching the temperature Q _∞. Note that the constants of Q _の and γ are determined by experiments.

The expression of Young's modulus of step S108 is as follows: If the Young's modulus on t-day of material age is E _e (t), E _e (t) = φ (t) × 1.5 × 10 ⁴ × {f ' _C (t)}
^1/2 [kgf / cm ² ] φ (t): It is a correction coefficient of the Young's modulus due to the large influence of creep when the temperature rises. However, on the t age, the compressive strength f ' _C (t) of the concrete on the t age is f' _C (t) = t / (a + bt) x f ' _C (91) [kg
f / cm ² ] a, b: constants f ' _C (91): compressive strength of concrete on the 91st grade [kg]
f / cm ² ].

Further, the “tensile strength expression formula” of step S108 is as follows: f _t (t) = C {f ′ _C (t)} ^1/2 [kgf / cm ² ] C : Constant.

Then, the process proceeds to a step S109, wherein a tensile stress σ of the concrete is calculated by a temperature stress analysis. That is, the mass concrete in the casting area D is subjected to a linear expansion coefficient α.
Is divided into a plurality of isotropic elastic bodies, and the stress ｛σ｝ in each isotropic elastic body after a lapse of T time from the completion of the driving is calculated by the finite element method (｛σ｝ = ｛σ _x σ _y σ _z
γ _xy ｝ ^T ). Note that the initial strain ｛ε ₀と き when the isotropic elastic body having the linear expansion coefficient α receives a temperature change of ΔT is 、 ε ₀ ＝ = ｛ε _x0 ε _y0 ε _z0 γ _xy0 ｝ ^T = ｛αΔT αΔT αΔT 0} ^T alpha: coefficient of linear expansion (℃ _^-1) ΔT: stress {sigma ₀ caused by temperature variation (℃) the initial strain {epsilon _{0}} is, {σ 0} = [D} ] {ε 0} [ D]: Determined by a stress-strain matrix.

Next, in step S110, the concrete tensile stress σ and the tensile strength f are compared. In other words, each position of the concrete (the position of a plurality of divided isotropic elastic bodies)
Is compared with the concrete tensile strength f. If the tensile stress σ is equal to or less than the tensile strength f in step S110, that is, if all the stresses {σ} at each position of the concrete are equal to or less than the tensile strength f, the process proceeds to step S111. On the other hand, if the tensile stress σ exceeds the tensile strength f in step S110, that is, if at least one of the stresses {σ} at each position of the concrete exceeds the tensile strength f, the process proceeds to step S116.

Then, in step S111, the addition amount M of the hydration heat generation reducing agent is calculated.

The amount _{M = Σ {(a i +} jΔa) · l i · S}
(j = 0, 1,...) where Σ is the sum of 1 to n for i. Next, in step S112, the casting amount V of the hydration heat generation reducing agent-added concrete is calculated.

Driving amount V = Σ (l _i · S) where Σ is a sum of 1 to n for i.

Next, by comparing the amount M and the minimum amount M _min of heat of hydration reducing agent, if the addition amount M is equal to or less than the minimum amount M _min, the process proceeds to step S114, the addition amount M of the minimum If it exceeds the addition amount _Mmin , the process proceeds to step S116.

Next, in step S114, the minimum addition amount M _min of the hydration heat generation reducing agent is replaced with the addition amount M. Next, in step S115, the casting area L and the addition rate A of the hydration heat generation reducing agent-added concrete are registered. Then, the process proceeds to step S116 to increase the addition rate A of the hydration heat generation reducing agent by Δa, and then proceeds to step S107.

As described above, the respective addition rates of the casting areas l ₁ , l ₂ ,..., L _n of the second concrete 2 are adjusted, and the tensile stress of the concrete at each position calculated by the temperature stress analysis is adjusted. The minimum addition amount _Mmin of the hydration heat generation reducing agent when is less than the tensile strength of concrete is determined. Then, the second concrete 2 to which the minimum addition amount M _min of the hydration heat reducing agent is added is cast, and the remaining cast obtained by subtracting the cast area of the second concrete 2 from the entire cast area. By pouring the first concrete 1 in the installation area, the amount of the hydration heat generation reducing agent to be added can be reduced as much as possible, and cracking of the mass concrete can be prevented, and the cost can be reduced.

If the minimum addition amount M _min of the hydration heat generation reducing agent is not determined even if the addition rate A of the hydration heat generation reducing agent of the second concrete 2 exceeds the upper limit value _Amax , the concrete Of the second concrete 2 with respect to the entire casting area D of concrete.
By increasing the value, the effect of suppressing the temperature rise can be enhanced, and the minimum addition amount _Mmin of the hydration heat generation reducing agent can be determined. In this case, after the total amount V ₀ of the first concrete 1 and the second concrete 2 has been cast, the remaining concrete is separately cast, and the desired amount of concrete is cast. .

[0051] Moreover, the second concrete 2 is divided into a plurality layers, the initial value of the addition ratio of each layer a _1, a _2, ..., a a _n first
As the distance from the concrete 1 increases, the temperature difference between the first concrete 1 and the second concrete 2 does not change abruptly, the temperature gradient becomes gentle, and cracks occur effectively. Can be prevented.

(Second Embodiment) FIG. 4A shows a second embodiment of the present invention.
1 is a cross-sectional view of mass concrete to be cast using the mass concrete casting method of the embodiment, and reference numeral 11 denotes a first hydrated exothermic reducing agent to be cast into a mold (not shown). Of concrete, 12 is the first concrete 1
1 is a second concrete that is immediately cast on the first concrete and to which hydrolyzable tannin is added as an example of a hydration heat generation reducing agent. The second concrete 12 has a vertical casting area L. The second concrete 12 may be a single layer or may be divided into n layers (placed areas l ₁ , l ₂ , l ₃ ,..., L _n ) in order from the upper side. In addition, thermal stress calculation model, adiabatic temperature rise equation, Young's modulus expression equation,
The tensile strength expression formula and the thermal stress analysis are the same as in the first embodiment, and the description is omitted. Further, D is the entire casting area in the vertical direction of the mass concrete, and S is the casting area.

In FIG. 4 (A), the initial values l ₁ , l ₂ ,
, 1 _n are defined as a ₁ , a ₂ ,..., _An , and the tensile stress of the concrete at each position (position of the plurality of divided isotropic elastic bodies) is calculated by the thermal stress analysis. Furthermore, as shown in FIG. 4 (B), each droplet region where l _1, l _2, ..., and the l _n increases .DELTA.l, the temperature stress analysis for the second time. In this way, the placement areas l ₁ , l ₂ ,..., L _n are sequentially increased by Δl, for example, m + 1
At the time, as shown in FIG. 4 (C), the temperature was increased by mΔl, and when the tensile stress of the concrete at each position calculated by the temperature stress analysis was lower than the tensile strength of the concrete and the amount of the hydration exothermic reducing agent added was the minimum. The casting area of the second concrete 12 is determined.

The processing for calculating the minimum addition amount of the hydration heat reducing agent for mass concrete will be described below with reference to the flowcharts shown in FIGS.

First, the following basic conditions are set in step S201.

[0056] Concrete striking設温of the set temperature stress calculation model setting concrete of the total droplet region where the lower limit value D _min of setting hydration exothermic reducing additive for concrete droplet region where L set above division layer number n of the D Setting of initial value (l ₁ , l ₂ ,..., L _n ) of casting area L Temporary setting of minimum addition amount M _min of hydration heat reducing agent Next, in step S202, Set the initial value. Then, the process proceeds to step S203, and compares the total droplet formation regions D and the lower limit value D _min of the concrete, when all hit region where D concrete exceeds the lower limit value D _min, the flow proceeds to step S204. On the other hand, if it is determined in step S203 that the entire concrete placing area D is equal to or smaller than the lower limit value _Dmin , the process ends.

Next, in step S204, the total amount of concrete V ₀ (= S × D) is calculated. Next, step S205
Then, the addition rate A of the hydration heat generation reducing agent is set. However, if the hit region where L is divided into a plurality layers, the addition ratio of each layer a _1, a _2, ..., set respectively in a _n. Then, in step S206, the next condition, which is determined by the hydration heat generation reducing agent, is set.

Setting of Adiabatic Temperature Rise Formula Setting of Young's Modulus and Tensile Strength Expression Formula Next, in step S 207, the casting area L of the hydration heat reducing agent-added concrete, that is, the second concrete, is replaced with an initial value. However, striking region where L is the case is divided into a plurality of layers, the initial value the droplet formation regions of each layer l _1, l _2, ..., respectively replaced with l _n.

[0059] Each of the above addition rate a _1, a _2, ..., a _n is the gradually increases to a ₁ from the addition ratio a _n of the first concrete 11 side. Further, each of the above-mentioned casting areas l ₁ , l ₂ ,
.., L _n may be approximately the same or may be different in size.

Next, in Step S208, the casting area L of the hydration heat reducing agent-added concrete is compared with the entire casting area D. If the casting area L is equal to or less than the entire casting area D, FIG. It proceeds to step S209 shown. On the other hand, when the casting area L exceeds the entire casting area D in step S208, the process proceeds to step S220, and the minimum addition amount M _min is obtained in a step described later.
It is determined whether or not the casting area L has been registered.
If is registered, this process ends. On the other hand, if the casting area L is not registered in step S220, the process proceeds to step S221, where the total casting area D of the concrete is reduced by a predetermined area, and the process returns to step S203.

Next, the process proceeds to step S209, where the tensile stress σ of the concrete is calculated by the thermal stress analysis. That is,
The tensile stress σ of the concrete at each position (the positions of the divided plurality of isotropic elastic bodies) is calculated by the thermal stress analysis.

Next, in step S210, the tensile strength f of the concrete is compared with the tensile stress σ. If the tensile strength f is equal to or less than the tensile stress σ, the process proceeds to step S211 while the tensile strength f
Exceeds the tensile stress σ, the process proceeds to step S216.

Then, in step S 211, the addition amount M of the hydration heat generation reducing agent is calculated.

[0064] The addition amount _{M = Σ {a i · (} l i + mΔl) · S}
(m = 0, 1,...) where Σ is the sum of 1 to n for i.

Next, in step S212, the amount V of concrete to be added with the hydration heat generation reducing agent is calculated.

Casting amount V = {{(l _i + mΔl) · S}
(m = 0, 1,...) where Σ is the sum of 1 to n for i. Next, the addition amount M and the minimum addition amount M of the hydration heat generation reducing agent
_If the added amount M is equal to or less than the minimum added amount M _min , the process proceeds to step S214. If the added amount M exceeds the minimum added amount M _min , the process proceeds to step S216.

Next, in step S214, the minimum addition amount M _min of the hydration heat generation reducing agent is replaced with the addition amount M. Next, in step S215, the casting area L and the addition rate A of the hydration heat reducing agent-added concrete are registered. Then, the process proceeds to step S216, where the casting area L of the hydration heat reducing agent-added concrete is set to Δ
Then, the process returns to step S208.

As described above, the second concrete 12
The minimum droplet region where l _1, l _2, ..., adjust the l _n, the heat of hydration reducing agent when the concrete tensile stress of the position calculated by the temperature stress analysis becomes less tensile strength of concrete The addition amount M _min is determined. Then, the second concrete 12 to which the minimum addition amount M _min of the hydration heat generation reducing agent is added is cast, and the remaining cast obtained by subtracting the cast area of the second concrete 12 from the entire cast area. By casting the first concrete 11 in the installation area, the amount of the hydration heat generation reducing agent to be added can be reduced as much as possible, and cracking of the mass concrete can be prevented, and the cost can be reduced.

Further, the minimum amount of addition of the hydration heat reducing agent M _min
Is not found and the casting area L of the hydration heat reducing agent of the second concrete 12 exceeds the entire casting area D of the concrete, the entire casting area D of the concrete is reduced, and the entire concrete area is reduced. Second concrete 12 for casting area D
By increasing the ratio of the casting region L, the minimum amount _Mmin of the hydration heat generation reducing agent can be determined. In this case, after the entire casting area D of the first concrete 11 and the second concrete 12 is cast, the remaining concrete is separately cast to cast a desired amount of concrete.

[0070] Moreover, the second concrete 11 is divided into a plurality layers, the initial value a ₁ of the addition rate of each layer, a _2, ..., so that gradually increases with increasing distance to a _n from the first concrete 12 side Therefore, the temperature difference between the first concrete and the second concrete does not change rapidly, the temperature gradient becomes gentle, and cracks can be effectively prevented.

(Third Embodiment) FIG. 7 is a sectional view of a mass concrete cast by using the mass concrete casting method according to the third embodiment of the present invention. No. 1 hydration exothermic reducing agent placed in
The concrete 22 is a second concrete which is immediately cast on the first concrete 21 and to which hydrolyzable tannin is added as an example of a hydration heat reduction agent. The second concrete 22 has a vertical casting area L. The second concrete 22 may be a single layer, or may be divided into n layers (placed areas l ₁ , l ₂ , l ₃ ,..., L _n ) in order from the upper side. The temperature stress calculation model, the adiabatic temperature rise equation, the Young's modulus expression equation, the tensile strength expression equation, and the temperature stress analysis are the same as in the first embodiment, and description thereof will be omitted. Further, the entire casting area of the mass concrete is D, and the casting area is S. Therefore, the first
Hit region where the concrete 21 is a D-Σl _i. Where Σ is the sum of 1 to n for i.

In FIG. 7A, the initial values l ₁ , l ₂ ,
..., and l _n, each droplet region where l _1, l _2, ..., addition rate initial value a _1, a ₂ of the l _n, ..., as a _n, the tensile stress of the concrete at each position by temperature stress analysis calculate. Further, FIG.
As shown in, successively hitting region where l _1, l _2, ..., a l _n α (> 1)
Doubles increased, addition rate a _1, a _2, ..., a a _n β (> 1) times to thereby increase the tensile stress of the concrete of the respective positions calculated by the temperature stress analysis with the following tensile strength of concrete The casting area L of the second concrete 22 and the addition rate when the amount of the hydration heat reducing agent added is the minimum are determined.

The processing for calculating the minimum addition amount of the hydration heat reducing agent for mass concrete will be described below with reference to the flowcharts shown in FIGS.

First, in step S301, the following basic conditions are set.

[0075] Concrete striking設温of the set temperature stress calculation model setting concrete of the total droplet region where the lower limit value D _min of setting hydration exothermic reducing additive for concrete droplet region where L set above division layer number n of the D Setting of initial value (l ₁ , l ₂ ,..., L _n ) of casting area L Initial value (a ₁ , a ₂ ,..., _An ) of the addition rate of casting area L
Setting of the upper limit value _Amax of the addition rate of the hydration heat reducing agent Temporary setting of the minimum addition amount M _min of the hydration heat reduction agent Minimum setting amount V of the concrete containing the hydration heat reduction agent V
Setting of the temporary _min then sets the initial value of all the droplet region where D concrete in step S302. Then, the process proceeds to step S303, and compares the total droplet formation regions D and the lower limit value D _min of the concrete, the total droplet region where D concrete is larger than the lower limit value D _min, the flow proceeds to step S304. On the other hand, step S303
When the total casting area D of the concrete is equal to or less than the lower limit value _Dmin , this processing is ended.

Next, in step S304, the total amount of concrete V ₀ (= S × D) is calculated. Next, step S305
Then, the addition rate A of the hydration heat generation reducing agent is replaced with the initial value. However, when the casting area L is divided into a plurality of layers,
The initial value doping ratio of each layer a _1, a _2, ..., respectively replaced with a _n.

The initial values a ₁ , a ₂ ,...
a _n is, a ₁ from the addition rate of the first concrete 21 side a _n
To gradually increase. Furthermore, each droplet region where l _1, l _2, ..., the magnitude of l _n, even substantially the same, may be hit region where the different sizes.

Next, by comparing the added factor A and the upper limit value A _max of the heat of hydration reducing agent in step S306, when the addition ratio A is less than the upper limit value A _max, the process proceeds to step S307 shown in FIG.
On the other hand, if the addition ratio A is greater than the upper limit value A _max in step S306, the process proceeds to step S320, been obtained minimum amount M _min and minimum droplet設量V _min in steps described below, hitting region where L,
It is determined whether or not the addition rate A has been registered, and the placement area L,
If the addition rate A has been registered, this processing ends.
On the other hand, if the placement area L and the addition rate A are not registered in step S320, the process proceeds to step S321, in which the area of the entire concrete placement area D is reduced, and the process returns to step S303. Incidentally, the second concrete 22 if it is divided into a plurality of layers, each addition ratio a _1, a _2, ..., compared with the upper limit value A _max as the largest value addition ratio A of a _n.

Next, in step S307, the following conditions are set which are determined by the hydration heat generation reducing agent.

Setting of Adiabatic Temperature Rise Formula Setting of Young's Modulus and Tensile Strength Expression Formula Next, in step S 308, the casting area L of the hydration heat reducing agent-added concrete, that is, the second concrete 22, is replaced with an initial value. However, striking region where L is the case is divided into a plurality of layers, the initial value the droplet formation regions of each layer l _1, l _2, ..., respectively replaced with l _n.

Next, in step S309, the casting area L of the concrete containing the hydration heat reducing agent and the entire casting area D are compared.
If the casting area L is equal to or less than the entire casting area D, step S310
On the other hand, when the casting area L is larger than the entire casting area D, the process proceeds to step S318.

Then, in step S310, the tensile stress σ of the concrete is calculated by the temperature stress analysis. That is, the stress {σ} of the concrete at each position (the positions of the plurality of divided isotropic elastic bodies) is calculated by the thermal stress analysis.

Next, in step S311, the tensile strength f of the concrete is compared with the tensile stress σ, and if the tensile stress σ exceeds the tensile strength f, the process proceeds to step S322, where the concrete containing the hydration heat reducing agent is struck. The setting area L is increased, and the process returns to step S309. On the other hand, if the tensile stress σ is equal to or less than the tensile strength f in step S311, the process proceeds to step S312.

Next, in step S312, the addition amount M of the hydration heat generation reducing agent is calculated.

[0085] The addition amount of _{M = Σ (βa i · αl} i · S)
(α ≧ 1, β ≧ 1) where Σ is the sum of 1 to n for i. Further, alpha is striking region where l _1, l _2, ..., indicate the fold increase of l _n, beta is added rate a _1, a _2, ..., indicate the fold increase of a _n.

Next, in step S313, the amount V of concrete to be added with the hydration heat reducing agent is calculated.

Driving amount V = Σαl _i · S (α ≧ 1) where Σ is a sum of 1 to n for i.

Next, in step S314, the addition amount M of the hydration exothermic reducing agent is compared with the minimum addition amount _Mmin , and if the addition amount M is not more than the minimum addition amount _Mmin , the process proceeds to step S315.
If the addition amount M exceeds the minimum addition amount _Mmin , step S3
Continue to 18. Then, by comparing the droplet設量V and a minimum droplet設量V _min of heat of hydration reducing agent addition concrete step S315, when hitting設量V is less than or equal to the minimum droplet設量V _min, the process proceeds to step S316 when striking設量V is larger than the minimum droplet設量V _min, the process proceeds to step S318.

Then, in step S316, the minimum addition amount M _min of the hydration heat generation reducing agent is replaced with the addition amount M, and the minimum placement amount V _min of the hydration heat generation reducing agent-added concrete is replaced with the placement amount V.

Next, in step S317, the casting area L and the addition rate A of the hydration heat reducing agent-added concrete are registered. Then, the process proceeds to step S318, in which the addition rate A of the hydration heat generation reducing agent is increased, and the process returns to step S306.

As described above, the second concrete 22
Of the punching region where _{l 1, l 2, ...,} l n the addition ratio a _1, a _2, ..., by adjusting the a _n, of the concrete for each position calculated by the temperature stress analysis tensile stress of the concrete The minimum addition amount _Mmin of the hydration heat generation reducing agent when the tensile strength becomes equal to or less than that is obtained.
Then, the second concrete 22 to which the minimum addition amount M _min of the hydration heat generation reducing agent is added is cast, and the remaining cast obtained by subtracting the cast area of the second concrete 22 from the entire cast area. By casting the first concrete 21 in the installation area, the amount of the hydration heat generation reducing agent to be added can be reduced as much as possible, and cracking of the mass concrete can be prevented, and the cost can be reduced.

In addition, it is possible to sequentially increase both the casting area L of the second concrete 22 and the addition rate A of the hydration heat reducing agent to obtain the optimum minimum addition amount M _min of the hydration heat reducing agent. it can. Furthermore, the minimum addition amount M of the hydration heat reducing agent is
_{When the min} is not found, the casting area L exceeds the entire casting area D of the concrete, and the addition rate A exceeds the upper limit _Amax , the total casting area D of the concrete is sequentially reduced to reduce the concrete. By increasing the casting area L of the second concrete 22 relative to the entire casting area D, the minimum addition amount _Mmin of the hydration heat reducing agent can be obtained. in this case,
The first concrete 21 and the second concrete 22
After the entire casting area D is cast, the remaining concrete is cast separately.

[0093] Moreover, the second concrete 21 is divided into a plurality layers, the initial value a ₁ of the addition rate of each layer, a _2, ..., so that gradually increases with increasing distance to a _n from the first concrete 22 side So that the first concrete 21 and the second concrete 21
The temperature difference with the concrete 22 does not suddenly change, the temperature gradient becomes gentle, and cracks can be effectively prevented. In the third embodiment, the addition rate a _1, a _2, ..., multiplied by the magnification of α to a _n, striking region where l _1, l _2,
..., but multiplied by the magnification of β to l _n, as in the first embodiment and the second embodiment, the addition rate a _1, a _2, ..., may be increased a _n for each △ a, The casting areas l ₁ , l ₂ ,..., L _n may be increased by Δl.

(Fourth Embodiment) FIG. 10 is a flowchart showing a process for obtaining the maximum amount of concrete to be poured in the method for placing mass concrete according to the fourth embodiment of the present invention. The temperature stress calculation model, adiabatic temperature rise equation, Young's modulus expression equation, tensile strength expression equation and temperature stress analysis are as follows:
This is the same as the first embodiment, and the description is omitted.

First, in step S401, the following basic conditions are set.

Setting of Concrete Casting Temperature Setting of Temperature Stress Calculation Model Setting of Lower Limit Value D _min of Concrete Concrete Casting Area D Next, an initial value is set in the concrete concrete casting area D in step S402. Next, in step S403, the concrete entire casting area D is compared with the lower limit value _Dmin , and the total casting area D
If a is below the lower limit value D _min, the process proceeds to step S404, if the total droplet region where D is less than the lower limit value D _min, the process ends.

Next, in step S404, the tensile stress σ of the concrete at each position is calculated by temperature stress analysis. That is, the tensile stress σ of the concrete at each position (the positions of the plurality of divided isotropic elastic bodies) is calculated by the thermal stress analysis.

Then, in step S405, the tensile stress σ of the concrete is compared with the tensile strength f. If the tensile stress σ exceeds the tensile strength f, the process proceeds to step S407, while the tensile stress σ is equal to or less than the tensile strength f. In this case, the process proceeds to step S406.

[0099] Next, to calculate the total hitting設量V ₀ of concrete in step S406, the processing is terminated.

For example, as shown in FIG.
2 is the area where the mass concrete 41 is to be cast.
_{Assuming max} , when the tensile stress σ of the concrete at each position calculated by the temperature stress analysis exceeds the tensile strength f,
As shown in FIG. 11 (b), the droplet region where D concrete sequentially reducing the D _max to D _min, the tensile stress σ is the tensile falls below the intensity f from the concrete region where D _max of concrete all Da設Find the quantity.

As described above, since the total amount of mass concrete is determined so that the tensile stress σ of the concrete at each position calculated by the temperature stress analysis becomes equal to or less than the tensile strength f, cracking can be prevented. . Then, after the entire casting area D of the mass concrete is cast, the remaining concrete is separately cast to obtain a mass concrete of a desired casting area _Dmax .

In the first, second, third, and fourth embodiments, the thermal stress analysis model calculates the tensile stress σ at each position of the mass concrete by the finite element method. Is not limited to this, the compensation plane method (com
pensation plane method) or the like.

In the first, second, third, and fourth embodiments, mass concrete having a substantially rectangular section is cast.
As shown in FIG. 12A, a mass concrete 43 having a substantially trapezoidal cross section may be used. Further, as shown in FIG. 12B, mass concrete 44 having a substantially T-shaped cross section may be used.

In the first, second, and third embodiments, hydrolyzable tannin was added to the second concretes 2, 12, and 22 as a hydration heat reducing agent. However, the present invention is not limited to this. Dextrin or the like may be added as a heat release reducing agent.

In the first, second, and third embodiments, the upper limit A _max of the addition rate of the second concrete 2, 12, 22 is set.
Is 3% by weight, but the present invention is not limited thereto, and the upper limit of the addition rate of the second concrete may be any addition rate at which the generation of breathing water is small and the strength of the concrete does not decrease.

In the second and third embodiments, the casting area L of the second concrete 11 and 21 is sequentially increased from the initial value to the entire casting area D. May sequentially increase from an initial value to a predetermined upper limit. In the first, second, third, and fourth embodiments, the cracks due to the internal restraint stress of the mass concrete are prevented. However, the external restraint stress, that is, the crack at the joint of the old and new concrete can be prevented.

[0107]

As is apparent from the above description, in the method for casting mass concrete according to the first aspect of the present invention, the first concrete and the hydration heat reducing agent to which no hydration heat reducing agent is added are added to the entire casting area. Is a method of placing mass concrete in which the concrete is divided and poured into the second concrete, wherein the tensile stress of the concrete at each position calculated by the thermal stress analysis is equal to or less than the tensile strength of the concrete. 2 and at least one of the concrete casting area and the addition rate of the hydration heat reducing agent is adjusted so that the addition amount of the hydration heat reducing agent of the second concrete is minimized. The addition rate of the heat generation reducing agent is obtained, and the addition of the hydration heat generation agent is performed when the addition amount of the hydration heat reduction agent is minimized in the casting area where the addition amount of the hydration heat reduction agent is minimum. Second in rate
And placing the first concrete in a casting area other than the casting area of the second concrete.

Therefore, according to the method for placing mass concrete of the first aspect of the present invention, the second embodiment in which the tensile stress of the concrete at each position is equal to or less than the tensile strength of the concrete and the hydration heat reducing agent is added to the minimum amount. The casting area of the concrete and the addition rate of the hydration heat reducing agent are obtained, and the second concrete and the first concrete are poured at once. Can be prevented, and the cost can be reduced. Further, both the placing area of the second concrete and the addition rate of the hydration heat generation reducing agent are adjusted, and the placement area and the addition rate of the hydration heat generation reducing agent, which are the minimum addition amount of the hydration heat generation reducing agent, are adjusted. When a plurality of sets are obtained, by selecting the smaller casting area, the amount of the second concrete to be poured can be reduced as much as possible while preventing cracking, and the efficiency of the casting operation can be improved.

In the method for casting mass concrete according to the second aspect of the present invention, the entire casting area is filled with the first concrete containing no hydration heat reducing agent and the second concrete containing the hydration heat reducing agent. A method of placing mass concrete in which concrete is divided and poured into the concrete, wherein the tensile strength of the concrete at each position calculated by the thermal stress analysis is equal to or less than the tensile strength of the concrete. And at least one of the addition rates of the hydration heat reducing agent is adjusted to obtain the second concrete placing area and the addition rate of the hydration heat reduction agent when the addition amount of the hydration heat reduction agent is minimized. If the tensile stress of the concrete at a certain position calculated by the thermal stress analysis does not become lower than the tensile strength of the concrete, reduce the entire casting area, and calculate each position calculated by the thermal stress analysis. The addition area of the second concrete and the addition rate of the hydration heat reducing agent are adjusted so that the tensile stress of the concrete is equal to or less than the tensile strength of the concrete. The casting area of the second concrete when the amount is minimum and the addition rate of the hydration heat reducing agent are determined, and the water is added to the casting area when the addition amount of the hydration heat reducing agent is minimum. The second concrete having the addition rate of the hydration heat reducing agent when the addition amount of the total heat generation reducing agent is minimized is cast, and the first concrete is placed in the casting area other than the casting area of the second concrete. Is to be cast.

Therefore, according to the method for placing mass concrete of the second aspect of the present invention, a minimum amount of the hydration heat generation reducing agent is added to the second concrete of the mass concrete.
Since the tensile stress of the concrete at each position is equal to or less than the tensile strength of the concrete, a small amount of the hydration heat generation reducing agent can prevent cracking of the mass concrete and reduce the cost. Further, both the casting area of the second concrete and the rate of addition of the hydration heat generation reducing agent are adjusted, and the second concrete casting area and the hydration heat generation reducing amount, which are the minimum amount of the hydration heat generation reducing agent, are adjusted. When a plurality of addition ratios of the agent are determined, by selecting the smaller one of the placing areas, the amount of the second concrete placed is reduced as much as possible while preventing cracking, and the efficiency of the placing operation is improved. be able to. Further, even if the addition area of the second concrete placing area and the hydration heat generation reducing agent is adjusted, if the minimum addition amount of the hydration heat generation reducing agent is not determined, the entire casting area is reduced, Since the casting area of the second concrete with respect to the entire casting area of the concrete is increased and the heat of hydration of the first concrete is radiated through the second concrete, the temperature rise of the first concrete is suppressed. It is possible to determine the minimum amount of the hydration exothermic reducing agent and determine the maximum casting area in which cracking can be prevented even when the casting is performed at once.

Further, in the mass concrete casting method according to the third aspect of the present invention, the entire concrete casting area is mixed with the first concrete casting area where no hydration heat generation reducing agent is added and the hydration heat generation reducing agent is added and mixed. A method for placing mass concrete in which the second concrete is placed separately in the placement area, wherein the initial value of the addition rate of the hydration heat reducing agent of the second concrete and the placement area in the first step In the second step, the addition rate of the hydration heat reducing agent of the second concrete is sequentially increased from the initial value, and an adiabatic temperature rise equation based on each addition rate of the hydration heat reduction agent is set. The tensile stress of the concrete at each position is calculated by the temperature stress analysis based on the adiabatic temperature rise equation, and if the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, the third Step Then, the entire casting area is reduced by a predetermined area, the reduced overall casting area is set as a new overall casting area, and the process returns to the second step, and the concrete of each position calculated at the second step is calculated. When the tensile stress is equal to or less than the tensile strength of the concrete, in the fourth step, the amount of the hydration heat reducing agent of the second concrete added based on the addition rate of the hydration heat reducing agent of the second concrete and the casting area. In the fifth step, the second concrete of the addition rate of the hydration heat generation reducing agent when the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimized in the casting area And the first concrete is cast in a casting area other than the casting area of the second concrete.

Therefore, according to the mass concrete casting method of the third aspect of the present invention, the minimum amount of the hydration heat generation reducing agent is added to the second concrete to reduce the tensile stress of the concrete at each position. Since the strength is not more than the strength, cracking of mass concrete can be prevented with a small amount of the hydration heat generation reducing agent, and the cost can be reduced. Further, when the minimum addition amount of the hydration heat reducing agent is not determined within the range where the addition rate of the second concrete is from the initial value to, for example, a predetermined upper limit, the entire casting area is reduced, and the entire casting area is reduced. The area where the second concrete is poured into the area is enlarged, and the heat of hydration of the first concrete is radiated through the second concrete, so that the temperature rise of the first concrete can be suppressed, and the hydration can be suppressed. By obtaining the minimum amount of the heat generation reducing agent to be added, it is possible to obtain a maximum casting area in which cracking can be prevented even when the casting is performed at once.

Further, in the mass concrete casting method according to the fourth aspect of the present invention, the casting area of the first concrete to which the hydration heat reducing agent is not added and the hydration heat generation reducing agent are added and mixed into the entire casting area. A method for placing mass concrete in which the second concrete is placed separately in the placement area, wherein the addition rate of the hydration heat reducing agent of the second concrete and the initial value of the placement area in the first step Is set, and in the second step, the casting area of the second concrete is sequentially increased from an initial value,
Set the adiabatic temperature rise formula based on the addition rate of the hydration heat reducing agent, calculate the tensile stress of concrete at each position by temperature stress analysis based on the adiabatic temperature rise formula,
If the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area in the third step, and the reduced entire casting area is replaced with a new total. When the tensile stress of the concrete at each of the positions calculated in the second step is equal to or less than the tensile strength of the concrete, the hydration heat reduction of the second concrete is reduced in the fourth step. The addition amount of the hydration exothermic reducing agent is calculated in the fifth step and the second area of the addition rate of the hydration exothermic reducing agent in the casting area when the addition amount of the hydration exothermic reducing agent calculated in the fourth step becomes And placing the first concrete in a casting area other than the casting area of the second concrete.

Therefore, according to the mass concrete casting method of the present invention, the minimum amount of the hydration heat generation reducing agent is added to the second concrete to reduce the tensile stress of the concrete at each position. Since the strength is not more than the strength, cracking of mass concrete can be prevented with a small amount of the hydration heat generation reducing agent, and the cost can be reduced. If the minimum addition amount of the hydration heat generation reducing agent is not determined within the range from the initial value to the predetermined upper limit, for example, the second concrete placing area is reduced, and the entire casting area is reduced. Since the casting area of the second concrete with respect to the setting area is increased, and the heat of hydration of the second concrete is radiated through the second concrete, the temperature rise of the first concrete can be suppressed, The minimum addition amount of the hydration heat reducing agent can be determined, and the maximum casting area in which cracking can be prevented even when the casting is performed at once can be determined.

Further, in the mass concrete casting method according to the fifth aspect of the present invention, the casting area of the first concrete where no hydration heat reducing agent is added and the hydration heat generation reducing agent are added and mixed in all the casting areas. A method for placing mass concrete in which the second concrete is placed separately in the placement area, wherein the initial value of the addition rate of the hydration heat reducing agent of the second concrete and the placement area in the first step The initial value of the addition rate of the hydration heat reducing agent of the second concrete is sequentially increased in the second step, and the casting area of the second concrete is changed from the initial value for each addition rate. Along with the successive increase, an adiabatic temperature rise formula based on the respective addition rates of the hydration heat reducing agent is set, and the tensile stress of the concrete at each position is calculated by a temperature stress analysis based on the adiabatic temperature rise formula. A certain position calculated in the step When the tensile stress of the concrete exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area in the third step, and the reduced entire casting area is set as a new overall casting area, and the above-mentioned second step is performed. Along with returning
When the tensile stress of the concrete at each of the positions calculated in the second step is equal to or less than the tensile strength of the concrete, the amount of the hydration heat reducing agent of the second concrete is calculated in the fourth step, and in the fifth step, In the casting area where the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimum, the addition rate of the hydration heat generation reducing agent when the addition amount of the hydration heat reduction agent is minimum is set. The second concrete is cast, and the first concrete is cast in a casting area other than the second concrete casting area.

Therefore, according to the mass concrete casting method of the fifth aspect of the present invention, the minimum amount of the hydration heat generation reducing agent is added to the second concrete, and the tensile stress of the concrete at each position is reduced. Since the strength is not more than the strength, cracking of mass concrete can be prevented with a small amount of the hydration heat generation reducing agent, and the cost can be reduced. Further, both the casting area of the second concrete and the rate of addition of the hydration heat generation reducing agent are adjusted, and the second concrete casting area and the hydration heat generation reducing amount, which are the minimum amount of the hydration heat generation reducing agent, are adjusted. When multiple addition ratios of the agent are determined, by selecting the smaller one of the casting areas, while preventing cracking,
Minimize the amount of the second concrete poured,
The efficiency of the casting operation can be improved. Further, when the addition rate of the second concrete is in a range from the initial value to, for example, a predetermined upper limit, and the casting area of the second concrete is in a range from the initial value to, for example, a predetermined upper limit, the hydration heat generation reducing agent is used. If the minimum addition amount is not determined, the entire casting area is reduced, the casting area of the second concrete with respect to the entire casting area is increased, and the heat of hydration of the first concrete is reduced to the second concrete. Because the heat is radiated through the second concrete, the temperature rise of the second concrete can be suppressed, and the minimum addition amount of the hydration heat generation reducing agent is determined, and even if the casting is performed at once, the maximum casting area that can prevent cracking is obtained. You can ask.

[0117] The mass concrete casting method of the invention according to claim 6 is directed to the mass concrete casting method according to claim 1 or 5, wherein a hydration heat reducing agent is added and mixed. Are plural, and the addition ratio of each layer is increased as the distance from the first concrete side where no hydration heat generation reducing agent is added is increased.

Therefore, according to the method for placing mass concrete of the sixth aspect of the present invention, the first concrete and the second
The temperature gradient of the concrete becomes gentle, the tensile stress acting on the concrete due to the temperature difference between the first concrete and the second concrete is reduced, and cracks can be effectively prevented.

Further, the mass concrete casting method of the invention according to claim 7 is characterized in that the maximum concrete mass casting amount is set such that the concrete tensile stress at each position calculated by the temperature stress analysis becomes equal to or less than the tensile strength of the concrete. In search of
The above-mentioned maximum amount of concrete is cast at once.

Therefore, according to the mass concrete casting method of the present invention, since the mass concrete of the maximum amount of mass cast is less than the tensile strength of the concrete at each position, it is less than the tensile strength. Cracks in concrete can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of mass concrete cast by using a mass concrete casting method according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a method of placing the mass concrete.

FIG. 3 is a flowchart showing a method of placing the mass concrete.

FIG. 4 is a sectional view of mass concrete cast by using the mass concrete casting method according to the second embodiment of the present invention.

FIG. 5 is a flowchart showing a method of placing the mass concrete.

FIG. 6 is a flowchart showing a method of placing the mass concrete.

FIG. 7 is a cross-sectional view of mass concrete cast by using the mass concrete casting method according to the third embodiment of the present invention.

FIG. 8 is a flowchart showing a method of placing the mass concrete.

FIG. 9 is a flowchart showing a method of placing the mass concrete.

FIG. 10 is a flowchart showing a process for obtaining a maximum casting amount in the mass concrete placing method according to the fourth embodiment of the present invention.

11 (a) is a cross-sectional view of the mass concrete before reducing the entire casting area, and FIG. 11 (b) is a cross-sectional view of the mass concrete after reducing the entire casting area.

12 (a) is a cross-sectional view of a mass concrete having a substantially trapezoidal cross section, and FIG. 12 (b) is a cross-sectional view of a mass concrete having a T-shaped cross section.

FIG. 13 is a sectional view of a conventional mass concrete.

FIG. 14 is a diagram showing temperature changes of an inner layer and an outer layer with respect to the age of the mass concrete.

FIG. 15 is a diagram showing changes in the Young's modulus of the inner layer and the outer layer with respect to the age of the mass concrete.

[Explanation of symbols]

 1,11,21 ... first concrete, 2,12,22 ... second concrete.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hiroaki Shiraishi 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka, Japan Okumura Gumi Co., Ltd. (56) References JP-A-58-156627 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) E04G 21/02 103-104

Claims (7)

(57) [Claims] 1. An entire casting area is divided into a casting area of a first concrete to which a hydration heat reducing agent is not added and a casting area of a second concrete to which a hydration heat reducing agent is added and mixed. A method of placing mass concrete to be installed, wherein the second concrete placing area and the reduction of hydration heat are adjusted so that the tensile stress of the concrete at each position calculated by the thermal stress analysis is equal to or less than the tensile strength of the concrete. Adjusting at least one of the addition rate of the hydration heat reducing agent to obtain the second concrete placing area and the addition rate of the hydration heat reduction agent when the addition amount of the hydration heat generation reducing agent is minimized; In the casting area where the amount of the hydration heat reducing agent is minimized, the second concrete having the above-mentioned hydration heat reducing agent addition rate when the amount of the hydration heat reducing agent is minimized is placed in the casting area. And the second Striking 設方 method of mass concrete, characterized by a step of pouring the first concrete droplet formation regions other than the droplet formation regions of Nkurito. 2. The entire casting area is divided into a casting area of a first concrete to which a hydration heat reducing agent is not added and a casting area of a second concrete to which a hydration heat reducing agent is added and mixed. A method of placing mass concrete to be installed, wherein the second concrete placing area and the reduction of hydration heat are adjusted so that the tensile stress of the concrete at each position calculated by the thermal stress analysis is equal to or less than the tensile strength of the concrete. Adjusting at least one of the addition rate of the hydration heat reducing agent to obtain the second concrete placing area and the addition rate of the hydration heat reduction agent when the addition amount of the hydration heat generation reducing agent is minimized; If the tensile stress of the concrete at a certain position calculated by the temperature stress analysis does not become lower than the tensile strength of the concrete even after adjusting the casting area of the second concrete and the addition rate of the hydration heat reducing agent, It decreased the droplet region where,
By adjusting at least one of the casting area of the second concrete and the rate of addition of the hydration heat generation reducing agent such that the tensile stress of the concrete at each position calculated by the temperature stress analysis becomes equal to or less than the tensile strength of the concrete. Determining the casting area of the second concrete and the rate of addition of the hydration heat reducing agent when the amount of the hydration heat reducing agent added to the second concrete is minimized; While placing the second concrete of the addition rate of the hydration heat reducing agent when the addition amount of the hydration heat generation reducing agent is minimized in the casting area when the addition amount of the minimum is, Casting the first concrete in a casting area other than the casting area of the second concrete. 3. The entire casting area is divided into a casting area of the first concrete to which the hydration heat reducing agent is not added and a casting area of the second concrete to which the hydration heat reducing agent is added and mixed. A method for placing mass concrete to be set, comprising: a first step of setting an initial value of an addition rate of a hydration heat generation reducing agent for the second concrete and a placement area; and a hydration heat of the second concrete. The addition rate of the reducing agent is gradually increased from the initial value, and an adiabatic temperature rise equation based on each addition rate of the hydration heat generation reducing agent is set. The tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area, Decreased A third step of returning the entire casting area as a new overall casting area to the second step; and a case where the tensile stress of the concrete at each position calculated in the second step is equal to or less than the tensile strength of the concrete. A fourth step of calculating an amount of the hydration heat reducing agent added to the second concrete based on the addition rate of the hydration heat reducing agent of the second concrete and the casting area; The second concrete of the addition rate of the hydration heat generation reducing agent when the addition amount of the hydration heat generation reducing agent calculated in the fourth step is minimized, And a fifth step of placing the first concrete in a casting area other than the casting area of the concrete. 4. The entire casting area is divided into a casting area of the first concrete to which the hydration heat reducing agent is not added and a casting area of the second concrete to which the hydration heat reducing agent is added and mixed. A method of placing mass concrete to be set, comprising: a first step of setting an addition rate of a hydration heat reducing agent for the second concrete and an initial value of a placement area; and a placement area of the second concrete. Is sequentially increased from the initial value, and an adiabatic temperature rise formula based on the addition rate of the hydration heat reducing agent is set, and the tensile stress of the concrete at each position is determined by a temperature stress analysis based on the adiabatic temperature rise formula. A second step of calculating, and when the tensile stress of the concrete at a certain position calculated in the second step exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area, and the reduced total casting is performed. region A third step of returning to the second step as a new entire casting area; and if the tensile stress of the concrete at each of the positions calculated in the second step is equal to or less than the tensile strength of the concrete, the second concrete A fourth step of calculating the addition amount of the hydration heat reducing agent added to the second concrete based on the addition rate of the hydration heat reducing agent and the casting area of the second concrete step; In addition, a second concrete having the above-mentioned hydration heat reducing agent addition rate is poured into the casting area where the addition amount of the hydration heat reducing agent is minimized, and the second concrete is poured into the second concrete. A fifth step of placing the first concrete in a placement area other than the placement area. 5. The entire casting area is divided into a casting area of a first concrete to which no hydration heat reducing agent is added and a casting area of a second concrete to which a hydration heat reducing agent is added and mixed. A method of setting mass concrete to be set, comprising: a first step of setting an initial value of an addition rate of a hydration heat generation reducing agent of the second concrete and an initial value of a setting area; The addition rate of the hydration heat reducing agent is sequentially increased from the initial value of the addition rate, and the casting area of the second concrete is sequentially increased from the initial value of the casting area for each addition rate, and the water content is increased. A second step of setting an adiabatic temperature rise equation based on each addition rate of the sum exothermic reducing agent and calculating a tensile stress of concrete at each position by a temperature stress analysis based on the adiabatic temperature rise equation; The calculated position of the When the tensile stress of the cleat exceeds the tensile strength of the concrete, the entire casting area is reduced by a predetermined area, and the reduced total casting area is set as a new overall casting area and the process returns to the second step. And if the tensile stress of the concrete at each of the positions calculated in the second step is equal to or less than the tensile strength of the concrete, based on the addition rate of the hydration heat reducing agent of the second concrete and the casting area. A fourth step of calculating the addition amount of the hydration heat reducing agent added to the second concrete, and the step of calculating the addition amount of the hydration heat reduction agent calculated in the fourth step when the addition amount is minimized. The second concrete of the addition rate of the hydration heat reducing agent when the addition amount of the hydration heat reducing agent is minimized is poured into the casting area, and the casting area of the second concrete is added. Striking 設方 method of mass concrete, characterized in that it comprises a fifth step of pouring the first concrete droplet region where the outer. 6. The mass concrete casting method according to claim 1, wherein a plurality of the second concrete to which the hydration heat reducing agent is added and mixed are provided, and Characterized in that the addition rate of each of the concrete is increased with increasing distance from the first concrete side to which the hydration heat reducing agent is not added. 7. The maximum cast amount of mass concrete is determined so that the tensile stress of the concrete at each position calculated by the thermal stress analysis is equal to or less than the tensile strength of the concrete, and the concrete of the maximum cast amount is simultaneously measured. A method for casting mass concrete, characterized by casting.