Method for designing the mix of cement compositions

Abstract

We aim to reduce CO2 emissions. [Solution] A method for designing the mix of a cement composition having water, cement, and aggregate, comprising listing a first group of combinations of water-cement ratio and air content that satisfy a predetermined compressive strength, and a second group of combinations of unit water content and air content that satisfy a predetermined slump, and selecting the air content, water-cement ratio, and unit water content from the first group and the second group that minimize the unit cement content.

Description

[Technical Field] 【0001】 The present invention relates to a method for designing the formulation of cement compositions. [Background technology] 【0002】 When designing the mix design for concrete (an example of a cement composition) used in structures, the water-cement ratio, unit water content, unit cement content, and other mix properties are determined based on the required design strength of the structure and the fluidity required for workability. While the air content is usually set to a constant value, for example, Patent Document 1 discloses a practical concrete with a higher-than-usual air content. [Prior art documents] [Patent Documents] 【0003】 [Patent Document 1] Japanese Patent Publication No. 2020-176018 [Overview of the project] [Problems that the invention aims to solve] 【0004】 The amount of carbon dioxide (CO2) emitted during concrete production depends on the amount of cement per unit. In typical mix design, the amount of cement per unit (and thus the CO2 emission) is determined by the predetermined strength and fluidity, so there are no mix design options that can reduce CO2 emissions, and there is a risk of high CO2 emissions. Furthermore, Patent Document 1 does not describe a mix design method that can reduce the amount of cement per unit (i.e., reduce CO2 emissions). 【0005】 This invention has been made in view of the above-mentioned problems, and its purpose is to reduce CO2 emissions. [Means for solving the problem] 【0006】 The main invention for achieving the above object is a method for designing the formulation of a cement composition having water, cement, and aggregates, the method comprising: listing a first group of combinations of water-cement ratios and air amounts that satisfy a predetermined compressive strength, and a second group of combinations of unit water amounts and air amounts that satisfy a predetermined slump; and selecting, from the first group and the second group, the air amount, the water-cement ratio, and the unit water amount that minimize the unit cement amount. 【0007】 Other features of the present invention will become apparent from the description of the specification and drawings described below. 【Effects of the Invention】 【0008】 According to the present invention, it is possible to reduce the CO2 emissions. 【Brief Description of the Drawings】 【0009】 [Figure 1] It is a flowchart showing a general method for designing the formulation of concrete. [Figure 2] It is a flowchart showing the method for designing the formulation of concrete of the present embodiment. [Figure 3] It is a diagram showing the relationship between the water-cement ratio and the compressive strength. [Figure 4] It is a diagram showing the relationship between the water-cement ratio, air amount, and compressive strength. [Figure 5] It is a diagram showing the relationship between the unit water amount and the slump. [Figure 6] It is a diagram showing the relationship between the air amount, unit water amount, and slump. [Figure 7] It is a diagram showing the relationship between the cement amount, fine aggregate amount, and restrained water amount. [Figure 8] It is a diagram showing the relationship between the air amount and the unit cement amount. [Figure 9] It is a diagram showing the relationship between the water-cement ratio and the unit cement amount. [Figure 10] It is a diagram showing the relationship between the water-cement ratio and the air amount. [Figure 11] It is a diagram showing an example of the formulation design. [Modes for carrying out the invention] 【0010】 The following information will become clear from the description in the specification and drawings described later. 【0011】 (Aspect 1) A method for designing the mix of a cement composition having water, cement, and aggregate, characterized by listing a first group of combinations of water-cement ratio and air content that satisfy a predetermined compressive strength, and a second group of combinations of unit water content and air content that satisfy a predetermined slump, and selecting from the first group and the second group the air content, water-cement ratio, and unit water content that minimize the unit cement content. 【0012】 According to the cement composition mix design method of Embodiment 1, the amount of cement per unit can be minimized in a mix that satisfies a predetermined compressive strength and a predetermined slump. Therefore, CO2 emissions can be reduced. 【0013】 (Aspect 2) A method for designing the mix of a cement composition according to Embodiment 1, wherein it is desirable to perform a regression analysis with the water-cement ratio and the amount of air as variables to determine the relationship with compressive strength. 【0014】 According to the cement composition design method of Embodiment 2, a relationship between compressive strength and its influencing factors (water-cement ratio, air content) can be obtained. 【0015】 (Aspect 3) A method for designing the mix of a cement composition according to embodiment 1 or 2, wherein it is desirable to perform regression analysis with the unit water content and the air content as variables and determine the relationship with slump. 【0016】 According to the cement composition mix design method of Embodiment 3, a relationship between slump and its influencing factors (air content, unit water content) can be obtained. 【0017】 (Aspect 4) A method for designing the mix of a cement composition according to any one of embodiments 1 to 3, wherein it is desirable to calculate the unit cement amount based on a first relational expression between the water-cement ratio, the amount of air, and the compressive strength, and a second relational expression between the amount of air, the unit water content, and the slump. 【0018】 According to the cement composition mix design method of Embodiment 4, the unit cement amount can be determined from the first relational equation and the second relational equation. 【0019】 (Aspect 5) A method for designing the mix of a cement composition according to any one of embodiments 1 to 4, wherein, with respect to the predetermined compressive strength and the predetermined slump, it is desirable to determine the amount of air, the water-cement ratio, and the amount of water that minimize the unit cement amount, using the amount of air as a variable. 【0020】 According to the cement composition design method of Embodiment 5, the minimum unit amount of cement that satisfies a predetermined compressive strength and a predetermined slump can be determined. 【0021】 (Aspect 6) A method for designing the mix of a cement composition according to any one of embodiments 1 to 5, wherein the amount of air, the water-cement ratio, and the amount of water that minimize the amount of unit cement can be determined with respect to the predetermined compressive strength and the predetermined slump, using the water-cement ratio as a variable. 【0022】 According to the cement composition mix design method of Embodiment 6, the minimum unit cement amount that satisfies a predetermined compressive strength and a predetermined slump can be determined. 【0023】 (Aspect 7) A method for designing the mix of a cement composition according to any one of embodiments 1 to 6, wherein the amount of confined water is calculated based on the amount of cement and the amount of aggregate, and it is desirable that the unit water amount be greater than the amount of confined water. 【0024】 According to the cement composition mix design method of Embodiment 7, the constraint condition on the amount of water per unit (details described later) can be satisfied, which requires that the amount of water per unit unit be greater than the amount of water to be constrained. 【0025】 (Pattern 8) A method for designing the mix of a cement composition having water, cement, and aggregate, comprising: a first group of combinations of a water-cement ratio of 25-57% and an air content of 6.0-40.0% that satisfy a predetermined compressive strength; and a unit water content of 83-162 kg / m³ that satisfies a predetermined slump. 3 A method for designing the mix of a cement composition, characterized by listing a second group of combinations of the first group and an air content of 6.0 to 40.0%, and selecting from the first group and the second group the air content, water-cement ratio, and unit water content that result in the minimum unit cement content. 【0026】 According to the cement composition mix design method of Embodiment 8, the amount of cement per unit can be minimized by making the amount of air a variable in a mix that satisfies a predetermined compressive strength and a predetermined slump. Therefore, CO2 emissions can be reduced. 【0027】 ===Implementation Method=== Before describing this embodiment, we will explain the general mix design for cement compositions. "Mix design" refers to a series of operations to determine the materials and their proportions so as to satisfy the performance requirements of a cement composition (e.g., concrete). "Mix design" refers to the proportion or amount of each material used when preparing a cement composition. In the following explanation, concrete will be used as an example of a cement composition. 【0028】 <Regarding general concrete mix design> Figure 1 is a flowchart illustrating a typical concrete mix design method. 【0029】 First, select the type of binder to be used (in this case, cement) and other materials to be used (S101). 【0030】 Next, the maximum size of the coarse aggregate is determined (S102). Note that the larger the maximum size, the smaller the unit water volume required to obtain the same slump. 【0031】 Next, the air content is determined (S103). Unless otherwise specified, the air content of concrete is set at 4.5% (tolerance ±1.5%) (JIS A 5308). 【0032】 Next, the water-cement ratio is determined from the design strength required for the structure in question (S104). The design strength (fc) is an index used in structural calculations to determine allowable stress, and specifically refers to the compressive strength of the concrete. 【0033】 Next, the unit water content is determined based on the required fluidity (slump) for workability (S105). Note that the unit water content is set to the upper limit (175 kg / m³ unless otherwise specified). 3 Make sure it does not exceed ). 【0034】 Then, the unit cement quantity that satisfies the design strength and fluidity requirements is determined (S106). 【0035】 As shown in Figure 1, the amount of cement per unit is determined from the predetermined design strength (compressive strength) and fluidity (slump). 【0036】 Incidentally, the amount of carbon dioxide (CO2) emitted during concrete production depends on the amount of cement per unit. In the above mix design method, the amount of cement per unit is determined by the compressive strength and slump, so there is no option for a mix design that can reduce CO2 emissions. Therefore, there is a risk of high CO2 emissions. 【0037】 Therefore, in this embodiment, the amount of cement per unit (in other words, the reduction of CO2 emissions) is achieved by adjusting the amount of air while ensuring a predetermined compressive strength and fluidity. 【0038】 <Regarding the concrete mix design of this embodiment> Figure 2 is a flowchart showing the concrete mix design method of this embodiment. Steps S001 and S002 in Figure 2 correspond to steps S101 and S102 in Figure 1, respectively, so their explanation is omitted. 【0039】 In this embodiment, while the amount of air is fixed (4.5 ± 1.5%) in a typical mix design (Figure 1), the amount of air is not fixed but treated as a variable. Note that while a higher amount of air increases fluidity, it decreases compressive strength. In this embodiment, the desired compressive strength and fluidity are obtained by treating the amount of air, the water-cement ratio, and the unit water content as variables. 【0040】 Specifically, regression analysis is performed with the water-cement ratio and air content as variables to determine the relationship (relational equation) between the water-cement ratio / air content and the design standard strength (compressive strength) (S003: details will be described later). 【0041】 Furthermore, regression analysis is performed with air volume and unit water volume as variables to determine the relationship (relational equation) between air volume / unit water volume and fluidity (slump) (S004: details will be described later). 【0042】 Next, the unit cement content is calculated from the relationship between the water-cement ratio, air content, and design strength (compressive strength), and from the relationship between the air content, unit water content, and fluidity (slump) (S005). The specific calculation method will be described later. 【0043】 Here, as a constraint, the unit water content must be greater than the constrained water content. The constrained water content is the sum of the water content constrained on the surface of the fine aggregate and the water content constrained on the surface of the cement, as will be described later. If the unit water content is less than or equal to the constrained water content (NO in S006), the unit water content is reset (S007) and the process returns to step S005. Also, as with the mix design method in Figure 1, the unit water content must be within the upper limit (175 kg / m³ unless otherwise specified). 3 Also, make sure that it does not exceed ). 【0044】 If the unit water amount is greater than the restrained water amount (YES in S006), for a predetermined compressive strength and a predetermined slump, select the air amount, water-cement ratio, and unit water amount at which the unit cement amount is minimized (that is, determine the unit cement amount) (S008). At this time, the condition at which the unit cement amount is minimized may be selected with the air amount as a variable, or the condition at which the unit cement amount is minimized may be selected with the water-cement ratio as a variable (details will be described later). 【0045】 <Relationship between water-cement ratio, air amount, and strength (compressive strength) (S003)> Figure 3 is a diagram showing the relationship between the water-cement ratio (W / C) and the compressive strength. The horizontal axis of the figure is the water-cement ratio (%), and the vertical axis is the compressive strength (N / mm 2 ) Here, the air amount is also changed and sorted by air amount. Specifically, A0 to A5 in the figure are the air amounts (designed air amounts), and the larger the numerical value, the larger the air amount (A0 < A1 < A2 < A3 < A4 < A5). Note that A0 is 4.5%. In addition, the solid line in Figure 3 shows the relationship between W / C and compressive strength when the air amount is less than 4.5%. 【0046】 When the air amount is the same (for example, A0), as the W / C increases, the compressive strength decreases. That is, when the compressive strength is determined, the value of W / C is fixed to one. 【0047】 On the other hand, when the air amount is changed, the relationship between W / C and compressive strength changes. As a result, there are multiple W / Cs when obtaining the same strength. For example, it can be seen from the figure that there are multiple combinations of air amount and W / C that result in the compressive strength indicated by the dashed line. That is, even if the value of W / C is different, by changing the air amount, the same compressive strength (for example, the compressive strength of the dashed line) can be realized. Thus, it becomes possible to select various water-cement ratios by changing the air amount. 【0048】 Figure 4 is a diagram showing the relationship between the water-cement ratio (W / C), air amount, and compressive strength. The horizontal axis of the figure is the water-cement ratio, air amount (W / C + V Air / k2), and the vertical axis is the compressive strength (N / mm 2 ). Note that k2 included in the horizontal axis is a coefficient (constant). By performing regression analysis with the water-cement ratio and the air content as variables, a relationship (the relationship between the water-cement ratio, air content, and compressive strength) as shown in Fig. 4 can be obtained. 【0049】 In Fig. 4, the relationship between the W / C·air content and the compressive strength can be approximated by a straight line, and its approximation formula is, for example, expressed by the following formula (1). TIFF2026095863000002.tif8150 【0050】 Here, fc: compressive strength (N / mm 2 ) W / C: water-cement ratio V Air : air content (L / m 3 ) k1~k3: coefficients Note that formula (1) corresponds to the first relational formula. Also, formula (1) is an example of the relational formula between the W / C·air content and the compressive strength, and it is not limited to this. For example, fc may be a formula expressed by the product of W / C and V Air . 【0051】 Also, from formula (1), formula (2) can be obtained. TIFF2026095863000003.tif8150 【0052】 <Relationship between air content, unit water content, and fluidity (slump) (S004)> Fig. 5 is a diagram showing the relationship between the unit water content and the slump. The horizontal axis of the diagram is the unit water content (kg / m 3 ), and the vertical axis is the slump (cm). Here, the air content is also changed, and it is organized by air content. In Fig. 5, the air content is shown with the same marks and symbols as in Fig. 3. For example, A0 is an air content of 4.5%. The solid line in the diagram shows the relationship between the unit water content and the slump when the air content is less than 4.5%. 【0053】 When the air volume is the same (e.g., A0), the slump increases as the unit water volume increases. That is, when the slump value is determined, the unit water volume is fixed to one value. 【0054】 On the other hand, when the air volume is changed, the relationship between the unit water volume and the slump changes. As a result, there are multiple unit water volumes when the same slump is obtained (in other words, even if the values of the unit water volume are different, the same slump can be achieved). For example, in Fig. 5, the air volumes are A0, A1, A2, and A3, and the slump values can be set as SL1, SL2, and SL3 (SL1 < SL2 < SL3), respectively. Also, when the desired slump (e.g., SL2) is set, the unit water volume varies depending on the air volume. Specifically, the unit water volume for realizing the same slump becomes smaller in the order of A0, A1, A2, A3 (that is, the larger the air volume, the smaller it becomes). Thus, by changing the air volume, it becomes possible to select various unit water volumes. 【0055】 Fig. 6 is a diagram showing the relationship between the air volume, the unit water volume, and the slump. The horizontal axis of the figure is the air volume · unit water volume (k5V Air +V W ), and the vertical axis is the slump (cm). Note that k5 included in the horizontal axis is a coefficient (constant). By performing regression analysis with the air volume and the unit water volume as variables, a relationship (the relationship between the air volume · unit water volume and the slump) as shown in Fig. 6 can be obtained. 【0056】 In Fig. 6, the relationship between the air volume · unit water volume and the slump can be approximated by a straight line, and its approximate formula is shown by, for example, Equation (3). TIFF2026095863000004.tif6150 【0057】 Here, SL: slump (cm) V Air : air volume (L / m 3 ) V W : unit water volume (L / m 3 ) k4~k6: coefficients Note that equation (3) corresponds to the second relation. Also, equation (3) is just one example of a relationship between unit water / air volume and slump, and is not limited to this. For example, if SL is V W and V Air It may also be expressed as a product of two terms. 【0058】 Furthermore, equation (4) can be obtained from equation (3). TIFF2026095863000005.tif6150 【0059】 <Formula for calculating unit cement quantity (S005)> From equations (2) and (4), the formula for calculating the unit cement content (C) (equation (5)) is obtained. TIFF2026095863000006.tif8150 【0060】 In equation (5), fc (compressive strength) and SL (slump) are set as target values. Also, k1 to k6 are coefficients. Therefore, the amount of air (V Air The amount of cement per unit (C) is determined according to the following: In other words, the amount of cement per unit is calculated from the air-water-cement ratio that satisfies the compressive strength and the air-water ratio that satisfies the slump. 【0061】 <Restrictions (S006)> In this embodiment, the unit water content is used as a variable, but the unit water content (W) is the amount of water (W') constrained on the surface of the cement. C ) and the amount of water (W') that is confined to the surface of the fine aggregate. S The sum of (unit water volume W') and (restricted water volume) must be at a minimum. In other words, the unit water volume (W) must be greater than the restricted water volume (W'). Due to this constraint (unit water volume > restricted water volume), the following constraint equations (equations (6) and (7)) must be satisfied. 【0062】 TIFF2026095863000007.tif17170 【0063】 Here, W: Unit water volume (L / m³) 3 ) W´: Restricted water volume (L / m 3 ) Wj S : Amount of water (L / m³) constrained on the surface of the fine aggregate 3 ) Wj C : Amount of water (L / m³) confined to the surface of the cement 3 ) V S : Amount of fine aggregate V C : amount of cement ρ S :Fine aggregate density ρ C : Cement density k7: Restricted moisture content of fine aggregate k8: Restricted moisture content of cement 【0064】 Figure 7 shows the relationship between cement volume, fine aggregate volume, and restraining water volume. The upper part of Figure 7 shows the relationship between cement volume (V C ) and the amount of water (W') that is confined to the surface of the cement. C The relationship between (V) and (V) is shown. Also, the lower part of Figure 7 shows the amount of fine aggregate (V) S ) and the amount of water (W') that is confined to the surface of the fine aggregate. S This shows the relationship between the two. 【0065】 As shown in the figure, the amount of cement (V C The larger the (W') becomes, the more water (W') is confined to the surface of the cement. C ) is increasing. Also, the amount of fine aggregate (V S The larger the (W') becomes, the more water (W') is confined to the surface of the fine aggregate. S The amount of water used to contain the water is increasing. Therefore, the amount of water used to contain the water is determined by the amount of cement and the amount of fine aggregate, and there is a minimum amount of water (unit water) required for that amount of water used to contain the water. 【0066】 In step S006, the unit cement amount calculated in equation (5) is substituted into equation (7) to check whether the constraint equations (equations (6) and (7)) are satisfied. If they are satisfied (YES in S006), the unit cement amount C is determined. 【0067】 On the other hand, if the constraint equation is not satisfied (NO in S006), return to step 004 and reset the unit water volume so that the unit water volume W is greater than the constrained water volume W'. 【0068】 <Setting the minimum unit cement quantity (S008)> For combinations of water-cement ratio and air content that satisfy a predetermined strength (corresponding to Group 1) and combinations of unit water content and air content that satisfy a predetermined slump (corresponding to Group 2), the air content is varied and each combination is listed, and the minimum value of unit cement content C is determined (S008). 【0069】 In this embodiment, by making the air content a variable, there are multiple unit cement quantities that satisfy the strength and slump conditions. Also, when the W / C ratio falls below a certain value, the required unit water content increases due to constraints, so there is a minimum value for the unit cement quantity. 【0070】 Figure 8 shows an example of the relationship between air content and unit cement content. The horizontal axis represents air content (Air %), and the vertical axis represents unit cement content (C %). 3 ) 【0071】 The figure shows the unit cement amount C when the amount of air is changed, for each combination of target compressive strength (fc) and slump (SL) (see Figure 4 for fc1 to fc3, and Figures 5 and 6 for SL1 and SL2). For example, the triangle shown in the figure represents a target compressive strength of fc1 and a slump of SL2. 【0072】 As shown in Figure 8, there are minimum values ​​for each compressive strength (fc) and slump (SL). For example, in the case of fc1-SL2, when the air content is A in the figure, the unit cement content is at a minimum value C. S Therefore, under the fc1-SL2 conditions, the minimum unit cement amount is that value (C S Set the minimum unit cement amount under other conditions. 【0073】 Note that in Figure 8, the amount of air was used as the variable, but the water-cement ratio may also be used as the variable. 【0074】 Figure 9 shows an example of the relationship between the water-cement ratio and the amount of cement per unit area. The horizontal axis represents the water-cement ratio W / C (%), and the vertical axis represents the amount of cement per unit area C (kg / m³). 3 Figure 10 shows the relationship between the water-cement ratio (W / C) and the amount of air. The horizontal axis of Figure 10 represents the water-cement ratio (W / C) (%), and the vertical axis represents the amount of air (%). In Figure 10, the relationship between the water-cement ratio (W / C) and the amount of air is shown for each combination of target compressive strength (fc) and slump (SL) (the lines connecting each point in Figure 10 represent the same conditions for compressive strength (fc) and slump (SL)). 【0075】 As shown in Figure 10, a linear relationship (straight line) holds between the air content and the water-cement ratio for the desired compressive strength (fc) and slump (SL). Note that, from equation (2), the relationship between air content and water-cement ratio depends on the compressive strength (fc). Therefore, in Figure 10, the lines overlap under the same compressive strength conditions (specifically, fc2-SL1 and fc2-SL2). 【0076】 From the relationship in Figure 10, as shown in Figure 9, a local minimum exists even when the horizontal axis is the water-cement ratio. Even if we find the minimum unit cement amount from the relationship between the water-cement ratio and unit cement amount in Figure 9, the minimum value is the same as in Figure 8 (for example, in the case of fc1-SL2, the minimum value is C S ) 【0077】 As explained above, according to the mix design method of this embodiment, by using the amount of air as a variable, it is possible to determine the minimum unit cement amount that satisfies a predetermined strength and predetermined slump. In other words, it is possible to reduce CO2 emissions. 【0078】 <<Examples>> The mix design method of this embodiment was used to design the mix of a cement composition (concrete in this case) and to conduct quality tests. As a comparative example, a mix design method with a fixed air content (design air content) of 4.5% (Figure 1) was also evaluated. 【0079】 Figure 11 shows an example of the mix design. The air content (set air content) in the mix design table in Figure 11 is the volume ratio of air in the concrete in the mix design, and the air content in the quality test results shows the measured air content in the prepared concrete. Here, both the comparative example and the example show the results when the target design standard strength (compressive strength) and slump are set within a predetermined range. In the following explanation, the values ​​of compressive strength and slump will be explained using the values ​​from the quality test results (Figure 11). 【0080】 (Comparative example) As mentioned above, the comparative example has a fixed air content of 4.5%. Also, the compressive strength conditions (resulting compressive strength 32.9~75.8 N / mm²) 2 As a result, the water-cement ratio (W / C) was 35-60%. Also, under slump conditions (resulting slump of 8.0-21.0 cm), the unit water content (W) was 162-175 kg / m³. 3 The result was as follows: When the unit cement amount was determined for each design strength and fluidity condition, the cement amount was 270-500 kg / m³. 3 That's what happened. 【0081】 (Examples) In this example, the concrete mix design was performed using the concrete mix design method shown in Figure 2. Specifically, the compressive strength is 30.4-45.0 N / mm². 2 A list of combinations (Group 1) of a water-cement ratio (W / C) of 25-57% (preferably 35-57%) and an air content of 6.0-40.0% (preferably 7.0-20.0%) that satisfy the above conditions was compiled. In addition, a unit water content (W) of 83-162 kg / m³ that satisfies a slump of 8.0-22.0 cm was listed. 3 (Preferably 100-155 kg / m 3The combinations of ) and an air content of 6.0-40.0% (preferably 7.0-20.0%) (Group 2) were listed. Then, from Group 1 and Group 2, the air content, water-cement ratio, and water content that result in the minimum unit cement content were selected. As a result, the unit cement content was 236-335 kg / m³ 3 That's what happened. 【0082】 Furthermore, when compared under the same compressive strength and slump conditions, the unit cement content was smaller in the example than in the comparative example. For example, when the compressive strength was 33 N / mm² 2 When the slump is 18 cm, the unit cement volume of the comparative example is 287 kg / m³. 3 In contrast, in the embodiment, the unit cement content is 264 kg / m³. 3 Therefore, it was confirmed that CO2 emissions can be reduced. 【0083】 ===Other=== The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof. 【0084】 In the embodiments described above, concrete was used as an example, but the method is not limited to concrete and can be applied to other cement compositions (for example, mortar that does not contain coarse aggregate).

Claims

[Claim 1] A method for designing the mix of a cement composition having water, cement, and aggregate, A first group of combinations of water-cement ratio and air content that satisfy a predetermined compressive strength, A second group of combinations of unit water volume and air volume that satisfy a predetermined slump, List them, From the first group and the second group, the amount of air, the water-cement ratio, and the amount of water per unit area are selected to minimize the amount of cement per unit area. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 2] A method for designing the composition of a cement composition according to claim 1, Regression analysis is performed with the water-cement ratio and the amount of air as variables to determine the relationship with compressive strength. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 3] A method for designing the composition of a cement composition according to claim 1, Regression analysis is performed with the aforementioned unit water volume and air volume as variables to determine the relationship with slump. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 4] A method for designing the composition of a cement composition according to claim 1, The first relational expression between the water-cement ratio, the amount of air, and the compressive strength, The second relational expression between the amount of air and the amount of water per unit, and the slump, The unit cement quantity is calculated based on this. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 5] A method for designing the composition of a cement composition according to claim 1, With respect to the predetermined compressive strength and predetermined slump, the amount of air, the water-cement ratio, and the amount of water are determined, with the amount of air being a variable, so that the amount of unit cement is minimized. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 6] A method for designing the composition of a cement composition according to claim 1, With respect to the predetermined compressive strength and predetermined slump, the amount of air, the water-cement ratio, and the amount of water per unit area are determined, with the water-cement ratio as a variable, so that the amount of cement per unit area is minimized. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 7] A method for designing the mix of a cement composition according to any one of claims 1 to 6, The amount of retained water is calculated based on the amount of cement and the amount of aggregate. The unit water volume is set to be greater than the constrained water volume. A method for designing the formulation of a cement composition, characterized by the features described above. [Claim 8] A method for designing the mix of a cement composition having water, cement, and aggregate, The first group consists of combinations of a water-cement ratio of 25-57% and an air content of 6.0-40.0% that satisfy the specified compressive strength, A unit water volume of 83 to 162 kg / m³ satisfies the specified slump. ３ And the second group consists of combinations of air volume 6.0-40.0%, List them, From the first group and the second group, the amount of air, the water-cement ratio, and the amount of water per unit area are selected to minimize the amount of cement per unit area. A method for designing the formulation of a cement composition, characterized by the features described above.

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