A design method for concrete cementitious system based on performance and carbon emissions

Abstract

The invention provides a concrete cementitious system design method based on performance and carbon emission, comprising the following steps: obtaining specific component data of clinker and auxiliary cementitious materials in different cementitious systems to form a CaO-SiO2-Al2O3 ratio and performance data set with corresponding performance data; obtaining a CaO-SiO2-Al2O3 ratio and carbon emission data set based on a carbon emission calculation formula; fitting the data set to obtain a fitting formula for the CaO-SiO2-Al2O3 ratio and performance / carbon emission; obtaining a ternary contour map of the CaO-SiO2-Al2O3 ratio and performance / carbon emission according to the fitting formula, and obtaining a CaO-SiO2-Al2O3 ratio range under any carbon emission and performance from the ternary contour map; and deriving the clinker content and auxiliary cementitious material ratio in cement within the CaO-SiO2-Al2O3 range to perform component design of the cementitious system. The present invention can ensure that the concrete cementitious system meets the performance and carbon emission requirements while comprehensively considering the actual conditions such as economic cost and material supply status, and provide guidance for selecting specific material composition.

Description

Technical Field

[0001] The invention belongs to the technical field of cement materials, and in particular relates to a concrete cementitious system design method based on performance and carbon emissions. Background Art

[0002] In traditional cement and concrete production, the cementitious system usually relies on clinker as the main raw material. However, with the development of the construction industry and the improvement of environmental protection awareness, people's attention to carbon emissions and resource consumption is increasing. The production of clinker requires high-temperature calcination, which is energy-consuming and emits a large amount of greenhouse gases such as carbon dioxide. According to the International Energy Agency (IEA), the cement industry alone accounts for about 7% of carbon dioxide emissions in the global industrial sector. These emissions not only have a negative impact on climate change, but also aggravate resource shortages and environmental damage. Driven by the global carbon neutrality and sustainable development goals, the demand for environmentally friendly building materials is increasing.

[0003] Therefore, finding cementitious materials to replace clinker has become one of the research focuses. Cementitious materials rich in silicon-aluminum phases, such as limestone calcined clay cement, are widely regarded as viable alternatives to traditional cement due to their abundant resources, low carbon emissions and excellent engineering properties. However, it is still challenging to design concrete cementitious systems with superior performance and low carbon emissions in practical applications. At present, the cement design method usually selects the appropriate cement type and proportion according to the specific project requirements to meet the design strength, durability and other performance requirements, but does not incorporate carbon emissions into the mix design, resulting in excessive carbon emissions in the cement production process, exacerbating climate change and environmental pollution problems.

[0004] Therefore, it is necessary to propose a concrete cementitious system design method based on performance and carbon emissions, which can combine material properties and engineering requirements to achieve precise control of the cementitious system components, so as to achieve the goal of sustainable development in different engineering application scenarios. Summary of the invention

[0005] The purpose of the present invention is to provide a concrete cementitious system design method based on performance and carbon emissions, which can effectively reduce carbon emissions to the greatest extent while ensuring material strength, and provide a more sustainable cementitious material solution for the cement industry.

[0006] To achieve the above object, a concrete cementitious system design method based on performance and carbon emissions according to the present invention comprises the following steps:

[0007] (1) Obtaining specific component data of clinker and auxiliary cementitious materials in different cementitious systems and corresponding performance data to form a CaO-SiO2-Al2O3 ratio and performance data set;

[0008] (2) Based on the literature research, the carbon emission calculation formula of the CaO-SiO2-Al2O3 ratio was obtained, and the CaO-SiO2-Al2O3 ratio and carbon emission data set was obtained;

[0009] (3) performing model fitting on the data set to obtain a fitting formula for the CaO-SiO2-Al2O3 ratio and performance / carbon emissions;

[0010] (4) obtaining a ternary contour diagram of CaO-SiO2-Al2O3 ratio and performance / carbon emission according to the fitting formula, and obtaining the CaO-SiO2-Al2O3 ratio range under any carbon emission and performance from the ternary contour diagram;

[0011] (5) Within the range of CaO-SiO2-Al2O3, the clinker content in cement and the ratio of auxiliary cementitious materials can be deduced, and the components of the cementitious system can be designed. Within this range of cementitious composition, the cementitious system can meet the requirements of performance and carbon emissions. Then, by comprehensively considering the economic cost and the actual situation of material supply, the specific cementitious material composition is selected.

[0012] Furthermore, the specific component data of the clinker and the auxiliary cementitious material in step (1) include the proportion of various materials and the ingredients contained in the materials as well as the proportion of the main oxide components of CaO, SiO2, and Al2O3 in the cementitious system.

[0013] Furthermore, the performance data of the clinker and the auxiliary cementitious material in step (1) are compression resistance, tension resistance, bending resistance, impermeability, ion resistance and durability.

[0014] Furthermore, the carbon emission calculation formula is:

[0015] CE CO2 =CE f +CE p +CE e

[0016] Among them, CE f Carbon dioxide produced by fuel combustion, CE p The carbon dioxide produced during the calcination of calcium carbonate, CE e Carbon dioxide produced by electricity consumption and heat transfer losses.

[0017] Furthermore, it is characterized in that

[0018] CO2 CE generated by electricity consumption and heat transfer losses e The calculation formula is:

[0019] CE e =E×EF e

[0020] Where, E is the power consumption, kJ / kg, EF e It represents the emission factor of electricity generation, kg / kJ;

[0021] Carbon dioxide CE produced during calcination of calcium carbonate p The calculation formula is:

[0022] CE p =M CaO ×44 / 56

[0023] Where M CaO is the mass of calcium oxide in one ton of gelling system; 44 / 56 is the relative molecular mass ratio of CO2 to CaO;

[0024] Carbon dioxide CE produced by fuel combustion f The calculation formula is:

[0025] CE f =M f ×γ×44 / 12

[0026] Where M f is the mass of coal, kg; γ is the carbon content of the fuel, γ = 0.7; 44 / 12 is the ratio of the relative molecular mass of carbon dioxide and carbon.

[0027] Furthermore, the calculation formula for the mass of the coal is:

[0028] M f =Q / C m

[0029] Where, Q is the heat required for cement calcination, kJ / ton cement; C m is the heat of combustion of coal, C m =2×10 7 kJ / kg;

[0030]

[0031] Where ΔH is the enthalpy change required for clinker calcination, kJ / ton cement; m k is the raw material dosage k (k is CaCO3, Al2O3·2SiO2·2H2O, AlO(OH)), kg / ton cement; is the enthalpy change of k converted to oxide, kJ / mol; w x is the mass of clinker x phase in clinker, kg / ton cement; It represents the enthalpy change of CaO, SiO2 and Al2O3 to generate x (x is mainly C2S and C3A), kJ / mol.

[0032] The specific values ​​of are shown in Table 1;

[0033] Table 1

[0034]

[0035] Furthermore, the fitting formula in step (3) is:

[0036] Y=β0+β1X1+β2X2+β3X3+β4X1X2+β5X1X3+β6X2X3+β n-2 X1 n +β n-1 X2 n +β n X3 n

[0037] In the formula, X1 is the proportion of CaO, X2 is the proportion of SiO2, X3 is the proportion of Al2O3, Y is the target performance or carbon emission, β 0-n is the coefficient.

[0038] Furthermore, the value range of X1, X2, and X3 is determined by the content range of each phase in the above data set, with a step size of 0.02, and satisfies the constraint that the total is 1.

[0039] Furthermore, the step (5) is specifically as follows:

[0040] After obtaining the ratio of CaO, SiO2 and Al2O3 under the target performance and carbon emission requirements from the ternary contour map, the CaO content is first determined to deduce the replacement rate of cement clinker, and then the ratio of SiO2 and Al2O3 of the auxiliary cementitious materials that need to be supplemented is obtained through the target mechanical strength obtained from the ternary contour map and the boundary conditions of SiO2 and Al2O3 under carbon emissions.

[0041] The specific calculation formula is as follows:

[0042]

[0043]

[0044] In the formula, I c is the cement clinker replacement rate; are the known ratios of CaO, SiO2, and Al2O3 in cement clinker (the normalized ratios of the three); x1, x2, and x3 are the ratios of CaO, SiO2, and Al2O3 under the target performance and carbon emission requirements; x Si is the ratio of SiO2 in the auxiliary cementitious material that needs to be supplemented; Ak The ratio of the auxiliary cementitious material Al2O3 that needs to be supplemented,

[0045] The specific formula for calculating the oxide content is:

[0046] ∑M i *W Si,i =x Si

[0047] ∑M i *W Al,i =x Al

[0048] Where W Si,i is the ratio of SiO2 in material i (the normalized ratio of CaO, SiO2, and Al2O3); W Al,i is the ratio of Al2O3 in material i (normalized ratio of CaO, SiO2, and Al2O3); M i is the proportion of material i in the auxiliary cementitious material; Si is the ratio of SiO2 in the auxiliary cementitious material that needs to be supplemented; Al It is the ratio of the auxiliary cementitious material Al2O3 that needs to be supplemented; material i depends on the auxiliary cementitious material required by the project.

[0049] Compared with the prior art, the present invention has the following advantages:

[0050] 1. This invention innovatively proposes a concrete cementitious system design method based on performance and carbon emissions. By comprehensively considering the mechanical properties and carbon emission requirements of the material, this method provides a new reference standard and judgment method for the design of cementitious materials, which is conducive to the research and development of cementitious systems in the future.

[0051] 2. The present invention provides a low-carbon and performance-oriented design method to determine the ratio of a low-carbon and high-strength cementitious system. This design method can accurately design the optimal oxide content range in the cementitious material to quickly and accurately design the auxiliary cementitious material. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the description and claims, serve to illustrate the embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

[0053] Figure 1 is a flow chart of the method of the present invention;

[0054] Figure 2 It is a ternary contour diagram of CaO-SiO2-Al2O3 content and carbon emission;

[0055] Figure 3 It is the ternary contour diagram of CaO-SiO2-Al2O3 content and mechanical properties;

[0056] Figure 4 It is a ternary contour composite diagram for cement with mechanical properties ≥40MPa and carbon emission ≤830kg CO2 / t;

[0057] Figure 5 It is the ternary contour diagram of CaO-SiO2-Al2O3 content and carbon emission after the carbon emission simulation formula is corrected;

[0058] Figure 6 This is the ternary contour composite diagram of cement with mechanical properties ≥ 40MPa and carbon emissions ≤ 830kg CO2 / t after correcting the carbon emission simulation formula. DETAILED DESCRIPTION

[0059] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0060] Example 1

[0061] This embodiment is mainly aimed at a concrete cementitious system using silicate cement as clinker and including auxiliary cementitious materials such as limestone, calcined clay, coal gangue, tailings, quartz powder, silica fume, fly ash, etc., and the target performance is 28-day compressive strength.

[0062] Take the concrete cementitious system composition design with 28-day mechanical properties ≥ 40MPa and carbon emissions ≤ 830kg CO2 / t cement as an example:

[0063] (1) The specific component data of the clinker and auxiliary cementitious materials ratio and the material content in different cementitious systems were obtained through literature retrieval and the corresponding mechanical property data to form a CaO-SiO2-Al2O3 ratio and mechanical property data set; among them, different cementitious systems mainly refer to cementitious systems rich in silicon and aluminum phases with a high clinker substitution rate, represented by limestone calcined clay cement. The specific component data of clinker and auxiliary cementitious materials mainly include the data of the material ratio and the material content, and the proportion of the main oxide components of CaO, SiO2, and Al2O3 in the cementitious system is calculated and normalized. The corresponding mechanical property data is the 28-day compressive strength of cement.

[0064] (2) Based on the literature research, the carbon emission calculation formula of the CaO-SiO2-Al2O3 ratio was obtained, and the CaO-SiO2-Al2O3 ratio and carbon emission data set was obtained;

[0065] The carbon emission calculation formula is:

[0066] CE CO2 =CE f +CE p +CE e (1)

[0067] From the formula, we can know that carbon dioxide emissions (CE CO2 ) is mainly produced by carbon dioxide (CE f ), carbon dioxide produced during the calcination of calcium carbonate (CE p ) and the carbon dioxide generated by electricity consumption and heat transfer losses (CE e ). Because the carbon dioxide generated by electricity consumption and heat transfer loss is quite different from the production process and production equipment in the factory, this example aims to find a universal carbon emission calculation method, mainly considering the carbon emission of fuel in the clinker calcination production process and the carbon emission generated by the decomposition of calcium carbonate in the calcination process as an example, taking one ton of cement as the measurement unit, the main calculation formula is:

[0068] CE=CE p +CE f (2)

[0069] In the formula,

[0070] CE is total carbon emission, kg CO2 / t cement;

[0071] CE p is the carbon emission generated by the decomposition of calcium carbonate during the production process, kg CO2 / t cement;

[0072] CE f Carbon emissions from fuel combustion, kg CO2 / t cement.

[0073] CE p =M CaO ×44 / 56 (3)

[0074] In the formula,

[0075] M CaO is the mass of calcium oxide in one ton of gelling system;

[0076] 44 / 56 is the relative molecular mass ratio of CO2 to CaO.

[0077] CE f =M f ×γ×44 / 12 (4)

[0078] In the formula,

[0079] M f is the mass of coal, kg;

[0080] γ is the carbon content of the fuel, γ = 0.7;

[0081] 44 / 12 is the ratio of the relative molecular masses of carbon dioxide and carbon.

[0082] M f =Q / C m (5)

[0083] In the formula,

[0084] Q is the heat required for cement calcination, kJ / ton cement;

[0085] C m is the heat of combustion of coal, C m =2×10 7 kJ / kg;

[0086]

[0087] In the formula,

[0088] ΔH is the enthalpy change required for clinker calcination, kJ / ton cement;

[0089] m k is the raw material dosage k (k is CaCO3, Al2O3·2SiO2·2H2O, AlO(OH)), kg / ton cement;

[0090] is the enthalpy change of k converted to oxide, kJ / mol;

[0091] w x is the mass of clinker x phase in clinker, kg / ton cement;

[0092] It represents the enthalpy change of CaO, SiO2, and Al2O3 to generate x (x is mainly C2S and C3A), kJ / mol;

[0093] The specific values ​​of are shown in Table 1;

[0094] Table 1

[0095]

[0096] (3) Fit the model to the data set and obtain the fitting formula between CaO-SiO2-Al2O3 ratio and mechanical properties / carbon emissions;

[0097] In step (3), the ratio of CaO, SiO2 and Al2O3 is used as the independent variable, set as X1, X2 and X3, and the mechanical properties and carbon emissions are used as the dependent variables, set as Y1 and Y2; the data set is fitted with a model to obtain the fitting formula:

[0098] Y1=143.1-391.4X1-76.3X2+418.4X3+364.7X1 2 -1699X3 2

[0099] Y2=751.757+159.56X1-5.96X2-1.849X3 2 +10.251X1X2

[0100] (4) Under given conditions, the value range of X1, X2, and X3 is determined by the content range of each phase in the mechanical properties data set: 0.2≤X1≤0.85, 0.1≤X2≤0.7, 0.02≤X3≤0.3, with a step size of 0.05, and the constraint condition that the sum is 1 (X1+X2+X3=1) is satisfied. The specific fitting data is calculated by mathematical fitting method for different ratios corresponding to each data point on the contour map. The mechanical properties and carbon emissions are calculated, that is, the mechanical strength and carbon emissions under any CaO, SiO2, and Al2O3 ratio. The obtained ternary contour map is shown as follows: Figure 2 , Figure 3 As shown; the CaO-SiO2-Al2O3 ratio under any carbon emission and mechanical properties can be obtained from the ternary contour map; further, the ratio of CaO, SiO2, and Al2O3 under the target mechanical strength and carbon emission requirements can be obtained from the ternary contour map;

[0101] (5) The ratio of CaO-SiO2-Al2O3 can be used to infer the clinker content in cement and the ratio of auxiliary cementitious materials, and the components of the cementitious system can be designed. Within this range of cementitious composition, the cementitious system can meet the requirements of mechanical properties and carbon emissions. Then, by comprehensively considering the actual situation such as economic cost and material supply, the specific cementitious material composition is selected.

[0102] Based on the requirements of 28-day mechanical properties ≥ 40MPa and carbon emissions ≤ 830kg CO2 / t cement, the critical lines that meet the target performance contour map are superimposed on the same map, such as Figure 4 As shown. Figure 4 In the figure, the CaO-SiO2-Al2O3 ratio in the shaded area can meet the requirements of mechanical properties and carbon emissions of the cementitious system. Figure 3 It can be directly concluded that the CaO usage is 20% to 31.4%, the SiO2 usage is 53.4% ​​to 70%, and the Al2O3 usage is 7.2% to 23.5%.

[0103] The oxide composition of the known clinker is shown in Table 2, which shows that:

[0104] Table 2

[0105] cement CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[SO3]]> MgO Main ingredients (%) 64.648 21.273 5.223 3.412 0.966 1.307

[0106] The proportion of CaO in the system can be used to infer the replacement rate of Ca phase in the cement component; if the content ratio of CaO, SiO2 and Al2O3 in the cement component is known, the proportion of SiO2 and Al2O3 phases that need to be supplemented can be inferred, thereby selecting the best auxiliary cementitious material. Assuming that x1=28% (20%≤28%≤32%) is selected, the specific calculation formula is as follows:

[0107]

[0108] In the formula, I c is the cement clinker replacement rate;

[0109] are the known ratios of CaO, SiO2 and Al2O3 in cement clinker (normalized ratios of the three);

[0110] x1, x2, and x3 are the ratios of CaO, SiO2, and Al2O3 under the target mechanical strength and carbon emission requirements, respectively;

[0111] x Si The ratio of SiO2 in the auxiliary cementitious material that needs to be supplemented;

[0112] x Al The ratio of auxiliary cementitious material Al2O3 that needs to be supplemented.

[0113] The cement clinker substitution rate is 0.606 from formula (7). Since x1+x2+x3=100%, 53.4%≤x2≤70% and 7.2%≤x3≤23.5%, the boundary conditions of CaO, SiO2 and Al2O3 are:

[0114] x1=28%, x2=53.4%, x3=18.6%

[0115] x1=28%, x2=64.8%, x3=7.2%

[0116] From formula (8) and (9), we can know that 73%≤x Si ≤91.82%, 8.18%≤x Al ≤27%.

[0117] Assuming that the auxiliary cementitious materials are calcined clay and quartz powder, the specific components are shown in Table 3:

[0118] Table 3

[0119] Main components CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[SO3]]> MgO Calcined clay / % 0.898 54.201 34.729 2.4022 0.11 2.57 Quartz powder / % 0 99.5 0.5 0 0 0

[0120] The auxiliary cementitious material is designed to make

[0121] ∑M i *W Si,i =x Si (10)

[0122] ∑M i *W Al,i =x Al (11)

[0123] In the formula,

[0124] x Si The ratio of SiO2 in the auxiliary cementitious material that needs to be supplemented;

[0125] x Al The ratio of the auxiliary cementitious material Al2O3 that needs to be supplemented;

[0126] W Si,i is the proportion of SiO2 component in material i;

[0127] W Al,i is the proportion of SiO2 component in material i;

[0128] M i is the proportion of material i in the auxiliary cementitious material;

[0129] In this embodiment, material i is quartz powder and calcined clay. Assuming that the ratio of calcined clay to quartz powder is 3:7, it is mixed into auxiliary cementitious material and replaces 60.6% of cement clinker. Then, according to formula (10) (11), x Si =88%,x Al =11% (73%≤88%≤91.8%, 8.2%≤11%≤27%); Based on the above analysis, the final designed components are shown in Table 4.

[0130] Table 4

[0131] Components Cement clinker Calcined clay Quartz powder Ratio 0.394 0.1818 0.4242

[0132] Based on the normalized calculation of oxides based on the ratio of cement clinker and auxiliary cementitious materials, it can be seen that CaO accounts for 28.1%, SiO2 accounts for 62.4%, and Al2O3 accounts for 9.5% in this cementitious system, which is within the range of the above-mentioned cementitious system.

[0133] It can be verified from the CaO-SiO2-Al2O3 mechanical properties database that the 28-day mechanical properties of this mix are 40.1MPa≥40Mpa, as shown in Table 5.

[0134] From formulas (2) to (6), it can be seen that the carbon emission is 469.1 kg CO2 / t cement ≤ 830 kg CO2 / t cement, which verifies that the ratio meets the carbon emission requirements.

[0135] Table 5

[0136] CaO proportion / % <![CDATA[Proportion of SiO2 / %]]> <![CDATA[Proportion of Al2O3 / %]]> 28-day mechanical properties / MPa 31.6 58.9 9.5 40.1

[0137] Example 2

[0138] Same as Example 1, except that material i is limestone, quartz powder and calcined clay.

[0139] The oxide components of the clinker and auxiliary cementitious materials are shown in Table 6. It can be seen that:

[0140] Table 6

[0141] Main components CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[SO3]]> MgO cement / % 64.648 21.273 5.223 3.412 0.966 1.307 limestone / % 1 0 0 0 0 0 Calcined clay / % 0.898 54.201 34.729 2.4022 0.11 2.57 Quartz powder / % 0 99.5 0.5 0 0 0

[0142] The proportion of CaO in the system can be used to infer the replacement rate of Ca phase in the cement component; if the content ratio of CaO, SiO2 and Al2O3 in the cement component is known, the proportion of SiO2 and Al2O3 phases that need to be supplemented can be inferred, thereby selecting the best auxiliary cementitious material.

[0143] Known Because limestone, as an auxiliary cementitious material, does not emit carbon dioxide in the production process of cement, the calcium oxide component in the limestone does not participate in the calculation of carbon emissions. Assuming that limestone accounts for 10%, the carbon emission simulation formula is modified to X1 = X1 + 10%. The modified carbon emission simulation formula is:

[0144] Y2=767.713+159.56X1-5.96X2-1.849X3 2 +10.251X1X2+1.0251X2

[0145] The value range of X1, X2, and X3 is determined by the content range of each phase in the mechanical properties data set as 0.2≤X1≤0.85, 0.1≤X2≤0.7, 0.02≤X3≤0.3, with a step size of 0.05, and satisfies the constraint condition that the sum is 1 (X1+X2+X3=1). The specific fitting data is calculated by the mathematical fitting method for the carbon emissions corresponding to each data point on the contour map. The obtained ternary contour map is as follows Figure 5 As shown;

[0146] Based on the requirements of 28-day mechanical properties ≥ 40MPa and carbon emissions ≤ 830kg CO2 / t cement, the critical lines that meet the target compressive strength and carbon emissions contour diagrams are superimposed on the same diagram, such as Figure 6 As shown. Figure 6 In the figure, the CaO-SiO2-Al2O3 ratio in the shaded area can meet the requirements of mechanical properties and carbon emissions of the cementitious system. Figure 3 It can be directly concluded that the CaO usage is 20% to 31.4%, the SiO2 usage is 53.4% ​​to 70%, and the Al2O3 usage is 7.2% to 23.5%.

[0147] Set x1 = 28% (20% ≤ 21% ≤ 31.4%), and the limestone replacement rate is known to be 10%, so let x1 = 18%. Since x1 + x2 + x3 = 100%, 53.4% ​​≤ x2 ≤ 70% and 7.2% ≤ x3 ≤ 23.5%, we can know that the boundary conditions of CaO, SiO2, and Al2O3 are:

[0148] x1=18%, x2=53.4%, x3=18.6%

[0149] x1=18%, x2=64.8%, x3=7.2%

[0150] From formula (8) and (9), we can know that 63.6%≤x Si ≤78.9%, 7.7%≤x Al ≤23%.

[0151] Assuming that the auxiliary cementitious materials are calcined clay and quartz powder, the specific components are shown in Table 4:

[0152] In this embodiment, material i is limestone, quartz powder and calcined clay. Assuming that the ratio of calcined clay to quartz powder is 6:4, it is mixed into auxiliary cementitious material and replaces 74.6% of cement clinker. Then, according to formula (10) (11), x Si =76%,x Al =23% (63.6%≤76%≤78.9%, 7.7%≤23%≤23%); Based on the above analysis, the final designed components are shown in Table 7.

[0153] Table 7

[0154] Components Cement clinker limestone Calcined clay Quartz powder Ratio 0.254 0.1 0.323 0.323

[0155] Based on the normalized calculation of oxides based on the ratio of cement clinker and auxiliary cementitious materials, it can be seen that CaO accounts for 28.3%, SiO2 accounts for 57.6%, and Al2O3 accounts for 14.1% in this cementitious system, which is within the range of the above-mentioned cementitious system.

[0156] It can be verified from the CaO-SiO2-Al2O3 mechanical properties database that the 28-day mechanical properties of this mix are 64.3MPa≥40Mpa, as shown in Table 8.

[0157] Excluding the calcium oxide content of the limestone, it can be seen from equations (2) to (6) that the carbon emission is 434.1 kg CO2 / t cement ≤ 830 kg CO2 / t cement, which verifies that the mix meets the carbon emission requirements.

[0158] Table 8

[0159] CaO proportion / % <![CDATA[Proportion of SiO2 / %]]> <![CDATA[Proportion of Al2O3 / %]]> 28-day mechanical properties / MPa 26.3 59 14.7 64.3

[0160] Taking this as an example, the composition design of the concrete cementitious system can be carried out for any target mechanical properties and carbon emission calculations, which solves the problem of difficulty in balancing mechanical properties and carbon emission requirements in traditional design methods. Through this method, designers can reasonably adjust the composition ratio of the concrete cementitious system according to specific mechanical properties and carbon emission targets, and achieve precise control of the concrete cementitious system.

[0161] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A concrete cementitious system design method based on performance and carbon emissions, characterized in that: The following steps are involved: (1) Obtain the specific component data and corresponding performance data of clinker and auxiliary cementitious materials in different cementitious systems to form a data set of CaO-SiO2-Al2O3 ratio and target performance; (2) Based on the carbon emission calculation formula, the CaO-SiO2-Al2O3 ratio and carbon emission data set were obtained; (3) Fitting the above data set to obtain the fitting formula between CaO-SiO2-Al2O3 ratio and target performance / carbon emissions; (4) A ternary contour map of CaO-SiO2-Al2O3 ratio and target performance / carbon emission is obtained according to the fitting formula, and the range of CaO-SiO2-Al2O3 ratio under any carbon emission and target performance can be obtained from the ternary contour map; (5) In the range of CaO-SiO2-Al2O3, the clinker content in cement and the ratio of auxiliary cementitious materials are deduced to design the components of the cementitious system; The step (5) is specifically as follows: After obtaining the ratio of CaO, SiO2 and Al2O3 under the target performance and carbon emission requirements from the ternary contour map, the CaO content is first determined to deduce the replacement rate of cement clinker, and then the ratio of SiO2 and Al2O3 of the auxiliary cementitious materials that need to be supplemented is obtained through the boundary conditions of SiO2 and Al2O3 under the target performance and carbon emission obtained from the ternary contour map. The specific calculation formula is as follows: ， In the formula, is the cement clinker replacement rate; are the known ratios of CaO, SiO2 and Al2O3 in cement clinker respectively, and the above ratios of CaO, SiO2 and Al2O3 are the normalized ratios of the three; They are the ratios of CaO, SiO2 and Al2O3 under the target performance and carbon emission requirements respectively; The ratio of SiO2 in the auxiliary cementitious material that needs to be supplemented; The ratio of the auxiliary cementitious material Al2O3 that needs to be supplemented, The specific formula for calculating the oxide content is: ， In the formula, is the ratio of SiO2 component in material i. The above ratio is the normalized ratio of CaO, SiO2 and Al2O3; is the ratio of Al2O3 in material i. The above ratio is the normalized ratio of CaO, SiO2 and Al2O3; is the proportion of material i in the auxiliary cementitious material; The ratio of SiO2 in the auxiliary cementitious material that needs to be supplemented; It is the ratio of the auxiliary cementitious material Al2O3 that needs to be supplemented; material i depends on the auxiliary cementitious material required by the project.

2. The concrete cementitious system design method based on performance and carbon emissions according to claim 1 is characterized in that: The specific component data of the clinker and the auxiliary cementitious material in step (1) include the proportion of various materials and the ingredients contained in the materials as well as the proportion of the main oxide components of CaO, SiO2 and Al2O3 in the cementitious system.

3. The concrete cementitious system design method based on performance and carbon emissions according to claim 1 is characterized in that: The performance data of the clinker and the auxiliary cementitious material in step (1) are compression resistance, tension resistance, bending resistance, impermeability, ion resistance and durability.

4. The method for designing a concrete cementitious system based on performance and carbon emissions according to claim 1, characterized in that: The carbon emission calculation formula is: ， in, Carbon dioxide produced by fuel combustion, The carbon dioxide produced by calcium carbonate during calcination, Carbon dioxide produced by electricity consumption and heat transfer losses.

5. The method for designing a concrete cementitious system based on performance and carbon emissions according to claim 4, characterized in that: Carbon dioxide generated by electricity consumption and heat transfer losses The calculation formula is: ， In the formula, is the power consumption, kJ / kg, It represents the emission factor of electricity generation, kg / kJ; Carbon dioxide produced during the calcination of calcium carbonate The calculation formula is: ， In the formula, is the mass of calcium oxide in one ton of gelling system; 44 / 56 is the relative molecular mass ratio of CO2 to CaO; Carbon dioxide from fuel combustion The calculation formula is: ， In the formula, is the mass of coal, kg; is the carbon content of the fuel, = 0.7; 44 / 12 is the ratio of the relative molecular masses of carbon dioxide and carbon.

6. The method for designing a concrete cementitious system based on performance and carbon emissions according to claim 5, characterized in that: The calculation formula of the mass of the coal is: ， Where, Q is the heat required for cement calcination, kJ / ton cement; The heat of coal combustion, ; ， In the formula, is the enthalpy change required for clinker calcination, kJ / ton cement; is the raw material dosage, k is CaCO3, , AlO(OH), kg / ton cement; is the enthalpy change of k converted to oxide, kJ / mol; is the mass of clinker x phase in clinker, kg / ton cement; It represents the enthalpy change of CaO, SiO2 and Al2O3 to generate x, where x is mainly C2S and C3A, in kJ / mol.

7. The method for designing a concrete cementitious system based on performance and carbon emissions according to claim 1, characterized in that: The fitting formula in step (3) is: ， In the formula, is the proportion of CaO, is the ratio of SiO2, is the ratio of Al2O3, For target performance or carbon emissions, is the coefficient.

8. The method for designing a concrete cementitious system based on performance and carbon emissions according to claim 7, characterized in that: The value range of satisfies the constraint that the sum is 1.

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