Method and system for setting mixing of cement composite mixed with limestone fine powder

Abstract

One embodiment of the present invention provides a method and a system for preparing a cement composite, which predict the production amount of CO2-AFm according to the mixing on the basis of the chemical components of a binder constituting the cement composite, and calculate, therethrough, the optimal mixing ratio of materials such as Portland cement, limestone fine powder and calcined clay, thereby setting the mixing ratio of the cement composite containing a high amount of limestone and having excellent performance.

Description

Method and system for setting cement composite mixture containing limestone fine powder

[0001] The present invention relates to a method for setting a cement composite mix, and more particularly, to a method and system for setting a mix of a cement composite in which limestone fine powder is mixed.

[0002]

[0003] Portland cement is the most commonly used binding material in construction, thanks to its superior strength, durability, and fire resistance. However, the process of calcining limestone (CaCO3), the raw material for Portland cement production, into lime (CaO) releases large amounts of carbon dioxide, which contributes to global warming.

[0004] Limestone powder is an eco-friendly construction material that can be mixed into cement-based materials to maintain the strength, durability, and fire resistance of construction materials while reducing carbon emissions. In particular, the mixing of limestone powder can contribute to improving strength and watertightness by promoting hydration of cement clinker and densifying the microstructure.

[0005] Against this background, development and performance evaluation of limestone fine powder-calcined clay cement composites are in progress, but the ratio of limestone fine powder and calcined clay is generally fixed at 1:2, which limits the improvement of the eco-friendliness and economic feasibility of cement composites.

[0006] Therefore, research is needed on how to optimize the ratio of limestone powder and calcined clay.

[0007] [Prior Art Literature]

[0008] Republic of Korea Patent Publication No. 10-2019-0110281

[0009]

[0010] The technical problem to be achieved by the present invention is to solve the problems of the above-mentioned prior art, and to provide a method for setting a cement composite mixture containing limestone powder in which the ratio of limestone powder to be replaced and calcined clay is optimized.

[0011] In addition, the technical problem to be achieved by the present invention is to provide a cement composite mixing setting system in which limestone fine powder is mixed.

[0012] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0013]

[0014] In order to achieve the above technical task, one embodiment of the present invention provides a method for setting a cement composite mixture containing limestone fine powder.

[0015] In one embodiment of the present invention, a method for setting a cement composite mixing ratio in which limestone fine powder is mixed comprises the steps of: measuring chemical components of Portland cement and calcined clay; setting a substitution ratio of Portland cement for replacing the Portland cement of which chemical components are measured with limestone fine powder and calcined clay; calculating a molar content of Al2O3, SiO2 and SO3 of a cement composite formed by replacing the Portland cement with limestone fine powder and calcined clay according to the set substitution ratio of Portland cement; and calculating a molar content of ettringite (Ca6Al2(SO4)3(OH)) of the cement composite with the SO3 molar content of the cement composite. 12 The method may include calculating the amount of 26H2O) produced, calculating the molar content of Al2O3 consumed due to the production of the ettringite, and calculating the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite; and predicting the amount of CO2-AFm produced from the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed, and adjusting the ratio of limestone powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized, thereby setting the optimized cement composite mix.

[0016] In addition, in one embodiment of the present invention, in the step of setting the optimized cement composite mixture, the following equation 1 may be satisfied to adjust the ratio of limestone fine powder and calcined clay substituted in the cement composite so as to maximize the amount of CO2-AFm produced.

[0017] [Formula 1]

[0018] 5X (Al2O excluding the consumed Al2O3 molar content of the cement composite) mol)<(SiO2mol of cement composite)

[0019] In addition, in one embodiment of the present invention, the ratio of the limestone fine powder and the calcined clay can be adjusted so that the limestone fine powder to be substituted is replaced at a minimum amount while satisfying the above formula 1.

[0020] Additionally, in one embodiment of the present invention, the substitution rate of the Portland cement may be 5 wt% to 70 wt% relative to the total mass of the Portland cement before substitution.

[0021] Additionally, in one embodiment of the present invention, the content of the Portland cement substituted may be equal to the sum of the content of the calcined clay and the limestone fine powder substituted.

[0022] In addition, in one embodiment of the present invention, in the step of analyzing the chemical components of the Portland cement and the calcined clay, the method for analyzing the chemical components of the Portland cement and the calcined clay may include at least one selected from the group consisting of quantitative X-ray diffractometry, X-ray fluorescence, inductively coupled plasma optical emission spectrometry, and Fourier transform infrared spectroscopy.

[0023] In addition, in one embodiment of the present invention, in the step of calculating the content of Al2O3 and SiO2 excluding the content of Al2O3 consumed in the cement composite, the calculated SO3 content of the cement composite is used as the ettringite (Ca6Al2(SO4)3(OH)) of the cement composite. 12 To calculate the amount of 26H2O produced, it can be calculated according to Equation 2 below.

[0024] [Formula 2]

[0025] (SO3mol of cement composite) / 3=(ettringite mol produced)

[0026] In order to achieve the above technical task, another embodiment of the present invention provides a cement composite mixing setting system in which limestone fine powder is mixed.

[0027] In one embodiment of the present invention, a cement composite mixing setting system mixed with limestone fine powder comprises: a measuring unit for measuring chemical components of Portland cement and calcined clay; a setting unit for setting a substitution rate of Portland cement for replacing Portland cement, the chemical components of which are measured in the measuring unit, with limestone fine powder and calcined clay; and a setting unit for calculating the molar (mol) content of Al2O3, SiO2 and SO3 of a cement composite formed by replacing Portland cement with limestone fine powder and calcined clay according to the substitution rate set in the setting unit, and calculating the molar content of SO3 of the cement composite as the molar content of ettringite (Ca6Al2(SO4)3(OH)) of the cement composite. 12 The method may include an analysis unit that calculates the amount of 26H2O) produced and the molar content of Al2O3 consumed due to the production of the ettringite, and calculates the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite; and a monitoring unit that predicts the amount of CO2-AFm produced from the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite calculated by the analysis unit, and adjusts the ratio of limestone powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized, thereby setting an optimized cement composite mix.

[0028] In addition, in one embodiment of the present invention, the monitoring unit may satisfy the following equation 1 to adjust the ratio of limestone fine powder and calcined clay substituted in the cement composite so as to maximize the amount of CO2-AFm produced.

[0029] [Formula 1]

[0030] 5X (Al2O excluding the consumed Al2O3 molar content of the cement composite) mol)<(SiO2mol of cement composite).

[0031] In addition, in one embodiment of the present invention, the ratio of the limestone fine powder and the calcined clay can be adjusted so that the limestone fine powder to be substituted is replaced at a minimum amount while satisfying the above formula 1.

[0032]

[0033] A method for setting a cement composite mixing ratio containing limestone fine powder according to one embodiment of the present invention can provide an effect of significantly contributing to reducing carbon emissions in the construction industry by providing an eco-friendly construction material with lower carbon emissions compared to conventional Portland cement by containing a large amount of limestone fine powder.

[0034] In addition, the method for setting the mixing ratio of a cement composite mixed with limestone fine powder according to one embodiment of the present invention consumes energy of 80 and 44 kWh per ton, respectively, when producing Portland cement and general limestone fine powder-fired clay cement composites, of which 16 kWh is consumed for clay firing, and since limestone fine powder can be produced only by grinding limestone raw materials, it is possible to provide the effect of minimizing the energy consumed when producing a cement composite through mixing a large amount of limestone fine powder.

[0035] In addition, a cement composite manufactured by a method for setting a cement composite mixing ratio with limestone fine powder according to an embodiment of the present invention can provide an effect of being used as a construction material with excellent durability in water resource facilities such as waterways and dams, and underground structures such as underground parking lots and tunnels, based on excellent watertightness.

[0036] In addition, the method for setting a cement composite mixing ratio in which limestone fine powder is mixed according to one embodiment of the present invention can provide the effect of being used as a low-cost construction material in developing countries where limestone, a raw material for cement, is abundant but processing facilities are lacking by lowering the usage ratio of Portland cement, a processing material.

[0037] Therefore, the present invention can provide an innovative, eco-friendly functional effect that can be applied to all construction fields where Portland cement is used, as a construction material that has improved eco-friendliness, durability, and economic feasibility by calculating the optimal mixing ratio of limestone fine powder.

[0038] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0039]

[0040] Figure 1 is a flowchart showing the steps of a method for setting a cement composite mixture containing limestone fine powder according to one embodiment of the present invention.

[0041] Figure 2 is a graph showing the amount of CO2-AFm produced according to the proportion of limestone fine powder in a mixture with a Portland cement replacement ratio of 30 and 50 wt%.

[0042] Figure 3 is a graph showing the amount of unreacted clinker and hydrate produced in the 28-day sample.

[0043] Figure 4 is a graph showing the compressive strength of the sample.

[0044] Figure 5 is a graph showing the water absorption rate of the sample.

[0045]

[0046] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0047] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0048] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0050] The ratio of limestone powder and calcined clay substituted in conventional cement composites was fixed at 1:2, which could not be free from the problem of limiting the improvement of the eco-friendliness and economic feasibility of cement composites.

[0051] To solve these problems, the present invention provides a method and system for setting a cement composite mixture containing limestone powder, which can optimize and set a cement composite mixture manufactured by controlling the ratio of limestone powder and calcined clay to be mixed.

[0052] Below, the present invention will be described with reference to the drawings presented in this specification. Note that the drawings may be exaggerated to illustrate the features of the present invention. In such cases, it is preferable to interpret them in light of the overall intent of this specification.

[0053]

[0054] A method for setting a cement composite mixture containing limestone fine powder according to one embodiment of the present invention is described.

[0055] The present invention relates to an environmentally friendly, high-performance cement composite containing limestone fine powder and metakaolin, and a method for optimizing the mixing ratio, wherein the mixing ratio of Portland cement, limestone fine powder, metakaolin, etc. can be optimized by simulating the hydration behavior of the cement composite.

[0056] To briefly explain the present invention, the present invention predicts the amount of CO2-AFm generated according to the mixing ratio based on the chemical composition of the binder constituting the cement composite, and through this, calculates the optimal mixing ratio of materials such as Portland cement, limestone powder, and calcined clay, thereby enabling the design of a mixing ratio of a cement composite having a high limestone content and excellent performance.

[0057] At this time, by mixing materials such as limestone fine powder and calcined clay into Portland cement, the microstructure of the cement composite can be densified by promoting the formation of CSH gel through a pozzolanic reaction, and through this, the cement composite can be designed to have excellent mechanical performance.

[0058] At this time, the limestone powder:calcined clay ratio with the largest amount of CO2-AFm minerals (monocarbonate, hemicarbonate) must be designed to densify the microstructure of the cement composite.

[0059] The present invention provides a method for setting a mixing ratio of an eco-friendly cement composite containing a large amount of limestone powder by optimizing the limestone powder:calcined clay ratio.

[0060] This will enable the design and development of construction materials with low production costs and low carbon emissions.

[0061] The present invention will be described in detail below.

[0062] Figure 1 is a flowchart showing the steps of a method for setting a cement composite mixture containing limestone fine powder according to one embodiment of the present invention.

[0063] Referring to FIG. 1, a method for setting a cement composite mixing ratio containing limestone fine powder according to an embodiment of the present invention comprises the steps of: measuring chemical components of Portland cement and calcined clay (S100); setting a substitution ratio of Portland cement for replacing the Portland cement, the chemical components of which are measured, with limestone fine powder and calcined clay (S200); calculating the molar (mol) content of Al2O3, SiO2 and SO3 of a cement composite formed by replacing the Portland cement with limestone fine powder and calcined clay according to the set substitution ratio of Portland cement (S300); calculating the SO3 molar content of ettringite (Ca6Al2(SO4)3(OH)) of the cement composite as the SO3 molar content of the cement composite. 12 The method may include a step (S400) of calculating the amount of 26H2O) produced, calculating the molar content of Al2O3 consumed due to the production of the ettringite, and calculating the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite; and a step (S500) of predicting the amount of CO2-AFm produced from the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed, and adjusting the ratio of limestone powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized, thereby setting the optimized cement composite mix.

[0064]

[0065] The first step may include measuring the chemical composition of Portland cement and calcined clay. (S100)

[0066] The chemical composition of Portland cement and calcined clay refers to the content of chemical components such as CaO, SiO2, Al2O3, Fe2O3, SO3, K2O and MgO, for example.

[0067] At this time, the method for measuring the chemical components is not particularly limited as long as it is a method by which the chemical components and contents of the Portland cement and the calcined clay can be measured, but preferably, in the step of measuring the chemical components of the Portland cement and the calcined clay, the method for measuring the chemical components of the Portland cement and the calcined clay may include at least one selected from the group consisting of quantitative X-ray diffractometry, X-ray fluorescence, inductively coupled plasma optical emission spectrometry, and Fourier transform infrared spectroscopy.

[0068] At this time, the reason for measuring the chemical composition of Portland cement is to set the substitution ratio of Portland cement in the subsequent step.

[0069] In addition, the reason for measuring the chemical composition of the calcined clay is to first calculate the content of the calcined clay in order to calculate the molar content of Al2O3, SiO2 and SO3 of the cement composite to be manufactured when substituted according to the substitution ratio of Portland cement in the subsequent step.

[0070] Additionally, since the chemical composition of limestone powder is CaCO3, there is no need to measure the component separately.

[0071]

[0072] In the second step, the method may include setting a substitution ratio of Portland cement for replacing the Portland cement of which chemical composition has been measured with limestone powder and calcined clay. (S200)

[0073] The substitution ratio of the above Portland cement may be 5 wt% to 70 wt% based on the total mass of Portland cement before substitution.

[0074] At this time, if the substitution rate of the above Portland cement is less than 5 wt%, it may have an economic feasibility similar to or lower than that of general Portland cement, which may cause a cost problem, and if it exceeds 70 wt%, the cement clinker that acts as a binding agent may be insufficient, which may cause a problem in that the development of strength of the cement composite is delayed or the strength is reduced.

[0075] At this time, the content of the Portland cement substituted may be equal to the sum of the content of the calcined clay and the limestone fine powder substituted.

[0076] This could mean that the content of Portland cement corresponding to the substitution ratio of Portland cement is entirely replaced by calcined clay and limestone powder, and that no other substances are added.

[0077]

[0078] In the third step, the method may include calculating the molar contents of Al2O3, SiO2, and SO3 of the cement composite formed by replacing the Portland cement with limestone powder and calcined clay according to the set substitution ratio of the Portland cement. (S300)

[0079] At this time, the amount of SiO2, Al2O3, CO2, SO3, etc. can be calculated according to the mixing ratio of Portland cement, limestone powder, and calcined clay of the cement composite, and the amount of each component can be calculated by substituting the mole number in 100 g of the cement composite.

[0080] In addition, since the chemical components of the above-mentioned calcined clay are measured in advance and the content of each chemical component is known, the molar content of Al2O3, SiO2, and SO3 of the cement composite can be simply calculated through calculation.

[0081]

[0082] In the fourth step, the ettringite (Ca6Al2(SO4)3(OH) of the cement composite is prepared by adding SO3 molar content of the cement composite. 12 26H2O) production amount, and calculating the molar content of Al2O3 consumed due to the production of the ettringite, and calculating the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite. (S400)

[0083] The reason for calculating the amount of ettringite produced in the cement composite is that the molar content of Al2O3 must be calculated in order to calculate the amount of CO2-AFm in the subsequent step, and both ettringite and CO2-AFm in the cement composite consume aluminum.

[0084] At this time, when ettringite is formed first and aluminum is consumed, CO2-AFm is generated, and the amount of aluminum that can generate CO2-AFm is reduced.

[0085] Therefore, it is important to calculate the exact molar content of Al2O3 from which CO2-AFm can be produced by calculating the amount of ettringite produced.

[0086] At this time, the following method is used to calculate the amount of ettringite.

[0087] In the step of calculating the contents of Al2O3 and SiO2 excluding the content of Al2O3 consumed in the cement composite, the calculated SO3 content of the cement composite is used as the ettringite (Ca6Al2(SO4)3(OH)) of the cement composite. 12 To calculate the amount of 26H2O produced, it can be calculated according to the following equation 2.

[0088] [Formula 2]

[0089] (SO3mol of cement composite) / 3=(mol of ettringite produced).

[0090] The amount of ettringite produced can be calculated using the method described above.

[0091]

[0092] As a final step, the amount of CO2-AFm produced may be predicted from the molar contents of Al2O3 and SiO2 excluding the molar contents of Al2O3 consumed, and the optimized cement composite mixture may be set by adjusting the ratio of limestone fine powder and calcined clay substituted in the cement composite so as to maximize the amount of CO2-Afm produced. (S500)

[0093] To predict the CO2-AFm production, the molar contents of SiO2, Al2O3, and CO2 in the cement composite were first calculated.

[0094] Specifically, the mole numbers of SiO2, Al2O3, and CO2 ([SiO2], [Al2O3], [CO2]) according to the amount of limestone fine powder mixed (N) were calculated, and a total of three conditions were set: [SiO2] < [CO2] - ①, [Al2O3] < [CO2] - ②, and 5X[Al2O3] < [SiO2] - ③. The minimum amount of limestone fine powder mixed satisfying each condition was calculated, and defined as N①, N②, and N③, respectively.

[0095] That is, in the case of N①, it means the minimum amount of limestone powder mixed that satisfies condition ①.

[0096] In the case of N②, it means the minimum amount of fine limestone mixed that satisfies condition ②, and in the case of N③, it means the minimum amount of fine limestone mixed that satisfies condition ③.

[0097] For example, if we first calculate the case where max[N①, N②] < N③,

[0098] 1. When 0 < N < max[N①, N②], aluminum was consumed due to hydrates such as aluminum hydroxide and stratlingite, and CO2-AFm was not generated.

[0099] 2. When max[N①, N②] < N < N③, the amount of CO2-AFm produced increased and the amount of other aluminum hydrates decreased.

[0100] 3. When N③ < N, CO2-AFm becomes the dominant aluminum hydrate (except for ettringite), but as the amount of limestone fine powder added increases, the molar number of Al2O3 decreases, resulting in a decrease in the amount of CO2-AFm.

[0101] As a second example, if min[N①, N②] < N③ < max[N①, N②],

[0102] 1. 0 < N < min[N①, N②]: CO2-AFm was not generated because aluminum was consumed by hydrates such as aluminum hydroxide and stratlingite.

[0103] 2. min[N①, N②] < N < N③: The amount of CO2-AFm produced increased and the amount of other aluminum hydrates decreased.

[0104] 3. N③ < N: CO2-AFm becomes the dominant aluminum hydrate (except for ettringite), but as the amount of limestone fine powder added increases, the Al2O3 mole number decreases, resulting in a decrease in the amount of CO2-AFm.

[0105] Through this, we can see that in both cases where max[N①, N②] < N③ and min[N①, N②] < N③ < max[N①, N②], the largest amount of CO2-AFm is generated when N③ is present.

[0106] Therefore, it can be seen that when the minimum amount of limestone fine powder that satisfies the condition of 5X[Al2O3] < [SiO2], which is N③, is mixed into the cement composite, the amount of CO2-AFm produced is maximized, and it can be seen that the other conditions of [SiO2] < [CO2] - ① and [Al2O3] < [CO2] - ② do not need to be satisfied.

[0107] This means that the minimum amount of limestone powder mixed in that maximizes the production of CO2-AFm can be known by knowing only the Al2O3 and SiO2 molar contents excluding the consumed Al2O3 molar content of the cement composite.

[0108] Therefore, in the step of setting the optimized cement composite mixture, the following equation 1 can be satisfied to control the ratio of limestone fine powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized.

[0109] [Formula 1]

[0110] 5X(Al2O3mol excluding consumed Al2O3mol content of cement composite)<(SiO2mol of cement composite).

[0111] In addition, it can be seen that the ratio of the limestone fine powder and the calcined clay can be adjusted so that the limestone fine powder to be replaced is replaced at a minimum content while satisfying the above equation 1.

[0112] By adjusting the ratio of limestone powder and calcined clay so that the amount of CO2-AFm produced is maximized while the minimum amount of limestone powder is mixed into the cement composite through the above-described method, a cement composite can be manufactured.

[0113] At this time, it is preferable to set the mixing ratio of the manufactured cement composite and water to a ratio of water:cement composite = 3:10 to 5:10 by weight.

[0114] This is because if the mixing ratio of water and the manufactured cement composite is below the aforementioned range, the moisture content of the cement paste may be insufficient, resulting in low workability, and if it exceeds the aforementioned range, excessive moisture may cause bleeding, increasing the porosity of the cement composite and lowering the strength, which may cause problems in developing the strength of the cement composite.

[0115]

[0116] A cement composite mixing setting system incorporating limestone fine powder according to one embodiment of the present invention is described.

[0117] The cement composite mixing setting system containing limestone fine powder according to the present invention can apply all of the contents described in the cement composite mixing setting method containing limestone fine powder described above, and although detailed descriptions of overlapping parts are omitted, the same can be applied even if the descriptions are omitted.

[0118] A cement composite mixing setting system containing limestone fine powder according to one embodiment of the present invention comprises: a measuring unit for measuring chemical components of Portland cement and calcined clay; a setting unit for setting a substitution ratio of Portland cement for replacing Portland cement, the chemical components of which are measured in the measuring unit, with limestone fine powder and calcined clay; and a setting unit for calculating the molar (mol) content of Al2O3, SiO2, and SO3 of a cement composite formed by replacing Portland cement with limestone fine powder and calcined clay according to the substitution ratio set in the setting unit, and calculating the molar content of SO3 of the cement composite as the molar content of ettringite (Ca6Al2(SO4)3(OH)) of the cement composite. 12 The method may include an analysis unit that calculates the amount of 26H2O) produced and the molar content of Al2O3 consumed due to the production of the ettringite, and calculates the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite; and a monitoring unit that predicts the amount of CO2-AFm produced from the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite calculated by the analysis unit, and adjusts the ratio of limestone powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized, thereby setting an optimized cement composite mix.

[0119] In the above monitoring unit, the following equation 1 can be satisfied to control the ratio of limestone fine powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized.

[0120] [Formula 1]

[0121] 5X(Al2O3mol excluding consumed Al2O3mol content of cement composite)<(SiO2mol of cement composite).

[0122] In addition, the ratio of the limestone fine powder and the calcined clay can be adjusted so that the limestone fine powder to be replaced is replaced at a minimum content while satisfying the above formula 1.

[0123] At this time, the system of the aforementioned structure is automatically formed to conveniently manufacture a cement composite mixed with limestone fine powder set to an optimal mixing ratio.

[0124]

[0125] Hereinafter, the present invention will be described in more detail through examples, comparative examples, and experimental examples. These examples, comparative examples, and experimental examples are intended solely to illustrate the present invention, and the scope of the present invention is not limited by these examples, comparative examples, and experimental examples.

[0126]

[0127] Example

[0128] The chemical composition of the raw materials, Portland cement and calcined clay, was analyzed using X-ray fluorescence analysis.

[0129] Table 1 below shows the chemical composition of Portland cement and calcined clay measured by X-ray diffractometry and X-ray fluorescence analysis methods.

[0130] Chemical composition (wt%) Portland cement fired clay CaO 6 4.1 1.0 SiO - 2 0.9 5 0.1 Al 2 O 3 3.0 3 8.4 Fe 2 O 3 3.6 5.9 SO 3 1.8 (1.764) 0.1 K 2 O 0.6 0.6 MgO 4.0 0.1

[0131] As shown in Table 1 above, the chemical composition of Portland cement and calcined clay can be analyzed to determine the content of each component. Next, the substitution ratio of Portland cement was set to 30 wt.% and 50 wt.%, and the SiO2, Al2O3, CO2, and SO3 contents of cement composites having limestone fine powder contents of up to 30 wt.% and 50 wt.% were analyzed. Then, the amount of ettringite formed was calculated from the amount of SO3 of each cement composite having limestone fine powder contents of up to 30 wt.% and 50 wt.%.

[0132] Specifically, in order to calculate the amount of ettringite produced, the mole number of SO3 in the mixtures with substitution ratios of 30 wt.% and 50 wt.% of Portland cement can be obtained by multiplying 1.764, the SO3 content of Portland cement, by 0.7 or 0.5, and then dividing by the molar mass of 80.06, and the values ​​were calculated as 0.01542 and 0.01102 mol / 100 g of binder, respectively.

[0133] This was calculated by dividing the amount of Portland cement substitution rate of 30 and 50 wt.% SO3 by 3, which is 0.005141 and 0.003673 mol / 100 g of binder, respectively.

[0134] After that, the minimum values ​​(N①, N②, N③) of limestone fine powder mixture satisfying the conditions of [SiO2] < [CO2] - ①, [Al2O3] < [CO2] - ②, 5*[Al2O3] < [SiO2] - ③ were calculated as (4.2, 24.0, 15.6), (12.0, 31.0, 40.0) g / 100 g of binder, respectively.

[0135] Figure 2 is a graph showing the amount of CO2-AFm produced according to the proportion of limestone fine powder in a mixture with a Portland cement replacement ratio of 30 and 50 wt%.

[0136] Referring to Figure 2, it can be seen that the amount of CO2-AFm produced is maximum when N③ is present.

[0137] Accordingly, the mixture having the maximum CO2-AFm production was calculated to have limestone fine powder mixing amounts of 15.6 and 40.0 g / binder 100 g, respectively. At this time, the optimal mixture at a Portland cement replacement ratio of 30 wt% was named P7Mc, and the optimal mixture at 50 wt% was named P5Mc.

[0138] P7Mc and P5Mc samples were produced based on the selected optimal combination (P7Mc, P5Mc).

[0139] At this time, each manufactured sample was sealed and cured at 25°C for 28 days.

[0140] It was produced with ordinary Portland cement paste (hereinafter, P10) and conventional limestone powder-calcined clay cement composites (limestone powder:calcined clay ratio of 1:2, P7Lc, P5Lc).

[0141] The produced paste sample was cured at 25°C for 28 days after sealing, and the mineral composition, compressive strength, and water absorption rate of the paste sample were observed.

[0142] In this way, a cement composite containing the limestone fine powder of the present invention was manufactured.

[0143] These were named P5Mc and P7Mc.

[0144]

[0145] Comparative example

[0146] Portland cement paste sample

[0147] A sample of ordinary Portland cement paste (hereinafter referred to as P10) was prepared.

[0148]

[0149] Sample of cement composite mixed with limestone fine powder and calcined clay (limestone fine powder:calcined clay ratio 1:2)

[0150] A cement composite sample containing limestone fine powder and calcined clay was prepared with a limestone fine powder:calcined clay ratio of 1:2.

[0151] At this time, the cement composite sample in which limestone fine powder:calcined clay ratio was 1:2 substituted at a Portland cement substitution rate of 30 wt% was named P7Lc, and the cement composite sample in which limestone fine powder:calcined clay ratio was 1:2 substituted at 50 wt% was named P5Lc.

[0152]

[0153] Experimental example

[0154] Each paste sample manufactured in the examples and comparative examples was cured at 25°C for 28 days after sealing.

[0155] Figure 3 is a graph showing the amount of unreacted clinker and hydrate produced in the 28-day sample.

[0156] Referring to Fig. 3, it can be seen that the mineral composition of each produced sample is divided into CSH, portlandite, ettringite, hemicarbonate, monocarbonate, CaCO3, gypsum, and unreacted clinker.

[0157] At this time, the largest amount of CO2-AFm (monocarbonate, hemicarbonate) production was observed in the P7Mc and P5Mc samples of the present invention, and it was confirmed that a smaller amount of unreacted clinker existed compared to the P7Lc and P5Lc samples mixed with the same Portland cement.

[0158] Figure 4 is a graph showing the compressive strength of the sample.

[0159] In the results of the compressive strength measurement, it was observed that the higher the Portland cement substitution ratio, the lower the compressive strength on the 28th day. It was confirmed that the cement composite of the present invention manufactured in the example after 14 days of curing exhibited improved compressive strength compared to the conventional limestone fine powder-calcined clay cement composite manufactured in the comparative example.

[0160] Figure 5 is a graph showing the water absorption rate of the sample.

[0161] Table 2 below shows the water absorption coefficient of each sample.

[0162] Sample ID Water absorption coefficient (X10 -3 mm / s 1 / 2 )P101.73P7Lc0.71P7Mc0.72P5Lc6.71P5Mc1.10

[0163] Referring to FIG. 5 and Table 2, the results of measuring water absorption confirmed high impermeability in the sample mixed with limestone fine powder and calcined clay, and in particular, it can be confirmed that the highest impermeability is observed regardless of the substitution ratio of Portland cement in the cement composite (Mc) of the present invention. Accordingly, it can be confirmed that the cement composite manufactured according to the method for setting the mixing ratio of the cement composite mixed with limestone fine powder of the present invention exhibits superior properties compared to existing cement composites, such as excellent compressive strength, high impermeability, and a small amount of unreacted clinker.

[0164]

[0165] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0166] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. Step of measuring the chemical composition of Portland cement and calcined clay; A step of setting a substitution ratio of Portland cement for replacing the Portland cement of which chemical composition has been measured with limestone powder and calcined clay; A step of calculating the molar contents of Al2O3, SiO2 and SO3 of a cement composite formed by replacing the Portland cement with limestone powder and calcined clay according to the set substitution ratio of the Portland cement; Etringite (Ca6Al2(SO4)3(OH) of the cement composite with SO3 molar content of the cement composite 12 A step of calculating the amount of 26H2O) produced and calculating the molar content of Al2O3 consumed due to the production of the ettringite, thereby calculating the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite; and A method for setting a cement composite mixture containing limestone fine powder, characterized in that it comprises a step of setting an optimized cement composite mixture by adjusting the ratio of limestone fine powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm production is maximized by predicting the amount of CO2-AFm production from the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed.

2. In paragraph 1, In the step of setting the optimized cement composite mixture, A method for setting a cement composite mixing ratio in which limestone powder is mixed, characterized in that it satisfies the following equation 1 to control the ratio of limestone powder and calcined clay substituted in the cement composite so as to maximize the amount of CO2-AFm produced: [Formula 1] 5X(Al2O3mol excluding consumed Al2O3mol content of cement composite)<(SiO2mol of cement composite).

3. In paragraph 2, Satisfying the above equation 1, A method for setting a cement composite mixing ratio in which limestone fine powder is mixed, characterized in that the ratio of the limestone fine powder and the calcined clay is adjusted so that the limestone fine powder to be replaced is replaced with a minimum content.

4. In paragraph 1, A method for setting a cement composite mixing ratio in which limestone fine powder is mixed, characterized in that the substitution ratio of the above Portland cement is 5 wt% to 70 wt% based on the total mass of Portland cement before substitution.

5. In paragraph 1, A method for setting a cement composite mix with limestone powder, characterized in that the content of the Portland cement substituted is equal to the sum of the content of the calcined clay and the limestone powder substituted.

6. In paragraph 1, In the step of measuring the chemical composition of the above Portland cement and calcined clay, A method for setting a cement composite mixture containing limestone fine powder, characterized in that the method for measuring the chemical components of the above Portland cement and calcined clay comprises at least one selected from the group consisting of quantitative X-ray diffractometry, X-ray fluorescence, inductively coupled plasma optical emission spectrometry, and Fourier transform infrared spectroscopy.

7. In paragraph 1, In the step of calculating the content of Al2O3 and SiO2 excluding the content of Al2O3 consumed in the above cement composite, Ettringite (Ca6Al2(SO4)3(OH) of the above cement composite with the calculated SO3 content of the above cement composite 12 A method for setting a cement composite mix containing limestone fine powder, characterized in that the amount of 26H2O produced is calculated according to the following formula 2: [Formula 2] (SO3mol of cement composite) / 3=(mol of ettringite produced).

8. Measuring unit for measuring chemical composition of Portland cement and calcined clay; A setting unit for setting the substitution ratio of Portland cement for replacing the Portland cement, the chemical components of which are measured in the above measuring unit, with limestone powder and calcined clay; The molar contents of Al2O3, SiO2 and SO3 of the cement composite formed by replacing Portland cement with limestone powder and calcined clay according to the substitution ratio set in the above setting section are calculated, and the SO3 molar content of the cement composite is used as the ettringite (Ca6Al2(SO4)3(OH)) of the cement composite. 12 An analysis unit that calculates the amount of 26H2O) produced and calculates the molar content of Al2O3 consumed due to the production of the ettringite, and calculates the molar content of Al2O3 and SiO2 excluding the molar content of Al2O3 consumed in the cement composite; and A cement composite mixing setting system comprising a monitoring unit for predicting the amount of CO2-AFm produced from the molar contents of Al2O3 and SiO2 excluding the molar contents of consumed Al2O3 of the cement composite calculated in the analysis unit, and for setting the optimized cement composite mixing by adjusting the ratio of limestone powder and calcined clay substituted in the cement composite so that the amount of CO2-AFm produced is maximized.

9. In paragraph 8, In the above monitoring department, A cement composite mixing setting system incorporating limestone powder, characterized in that it satisfies the following equation 1 to control the ratio of limestone powder and calcined clay substituted in the cement composite so as to maximize the amount of CO2-AFm produced: [Formula 1] 5X(Al2O3mol excluding consumed Al2O3mol content of cement composite)<(SiO2mol of cement composite).

10. In paragraph 8, Satisfying the above equation 1, A cement composite mixing setting system incorporating limestone fine powder, characterized in that the ratio of the limestone fine powder and the calcined clay is adjusted so that the limestone fine powder to be replaced is replaced with a minimum content.

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