Low Carbon Concrete Design Method: Complete Composition Carbon Capture Concrete

Abstract

A method for designing low-carbon concrete compositions, all compositions being capable of absorbing CO2. Low-carbon concrete, all compositions of which are capable of absorbing CO2, comprises cement, supplementary cementitious materials, recycled aggregates, recycled sand, hollow glass microspheres, a superplasticizer, and mixing water. The compositions completely sequester CO2, increasing the amount of carbon captured in the low-carbon concrete, reducing carbon emissions in the concrete industry, and providing environmental benefits. When recycled aggregates and recycled sand are subjected to high-temperature and pressure carbonization, their CO2 absorption is significantly increased, and the performance of the recycled aggregates and recycled sand is improved, resulting in improved workability, mechanical properties, and durability of the concrete.Using hollow glass microspheres to encapsulate CO2 increases carbon capture capacity. At the same time, the ball bearing effect can be used to improve the workability of concrete. Figure 1.

Description

Title of Invention: Method for Designing Low Carbon Concrete: Complete Composition Carbon Capture Concrete Technical field

[0001] The present invention relates to the field of concrete and, more particularly, to a method of designing low carbon concrete compositions, all compositions being capable of absorbing carbon dioxide. CONTEXT

[0002] The issue of greenhouse gas emissions and their impact on climate change is widely recognized globally. There is a growing demand for reducing greenhouse gas emissions to mitigate rising global temperatures. Carbon dioxide (CO2) emissions are one of the major factors in global warming, and emissions from the concrete industry account for a significant portion of the total carbon emissions worldwide. Therefore, it is essential to develop new varieties of low-carbon concrete that can capture CO2, and thus reduce carbon emissions from the concrete industry. Previous studies have explored various techniques for utilizing CO2 in concrete curing, thereby improving the carbon sequestration capabilities of concrete products.However, due to the dense nature of concrete and its low diffusion rates, the carbon sequestration capacity of concrete is limited.

[0003] Concrete composition design represents a fundamental and critical aspect of concrete materials science, having a direct impact on concrete performance. The design process involves the optimization of factors such as workability, mechanical properties, durability and others, to determine the optimal proportions of each constituent in the concrete mix. Currently, the theoretical framework and design methods for conventional materials such as aggregates, sand and cement in concrete production have reached an advanced stage. However, in a dual carbon context, the trajectory of concrete development is gradually moving towards extensive use of low-carbon slag, construction waste, municipal solid waste and other solid waste materials.Changing raw material sources pose a significant challenge to concrete production, potentially rendering conventional design methods inadequate to achieve superior concrete performance. Therefore, there is an urgent need to . develop targeted and scientifically based theories and specific preparation techniques for low-carbon concrete. SUMMARY

[0004] The invention aims to solve at least one of the technical problems existing in the related art.

[0005] To solve the above-mentioned problems, this document proposes a method for designing low-carbon concrete compositions: full-composition carbon capture concrete. The method comprises:

[0006] SL preparing a plurality of raw materials for low-carbon concrete: the plurality of raw materials comprises cement, additional cementitious materials, recycled aggregates, recycled sand, hollow glass microspheres, a superplasticizer and mixing water; and before preparing the low-carbon concrete, the plurality of raw materials completely sequesters CO 2 ;

[0007] S2. Determination of a design strength of low-content concrete carbon:

[0008] The design strength of low carbon concrete is calculated as follows;

[0009] When the design strength grade of low carbon concrete is less than C60, the design strength is calculated according to equation (1): / «u + L5 x & )

[0010] when the design strength grade of low carbon concrete is not less than C60, the design strength is calculated according to equation (2): - L(2)

[0011] where, f CUf is the design strength of low carbon concrete, measured in MPa; is a standard value of compressive strength for a cube of recycled concrete, measured in MPa; and the parameters of equations (1) and (2) are empirical coefficients;

[0012] ° is the standard deviation of the concrete strength, determined by Table 1;

[0013] [Tables 1] Standard values ​​of concrete strength CIO - C25 C25 - C40 C45 - C55 H 4.0 5.0 6.0

[0014] S3. Calculate an effective water / cementitious materials ratio of low-content concrete carbon:

[0015] for cement, a relationship between the design strength of low carbon concrete and the effective water-cement ratio is determined using equation (3), and in particular for Portland cement CEM I 42.5, a relationship between the design strength of low carbon concrete and the effective water-cement ratio is determined using equation (3):

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] where A and D are constants; when o is greater than or equal to 60 MPa, A=20, D=9; when o is less than 60 MPa, A=25.8, D=-13.4; represents the x eff effective water / cementitious materials ratio of low-carbon concrete; S4. the calculation of an actual water / cementitious materials ratio based on the actual water / cementitious materials ratio of low-carbon concrete: the actual water / cementitious materials ratio is calculated using equation (4): àj(WÙ) X [1 - y (1 - | where, is a mass fraction of the additional cementitious materials in the cementitious material s, and is an active hydration factor of the additional cementitious materials; S5. Calculation of a maximum recommended water quantity based on the strength of low-carbon concrete: the maximum recommended water quantity is calculated based on the design strength of low-carbon concrete according to equation (5): mSWf “ 204- 64 - <X71 ! s ? where, mmax represents the maximum quantity of water (kg / m3); S6. Calculation of a volume fraction v of recycled aggregates and a sand rate S based on the nominal strength of low-carbon concrete: bulk apparent density Pa of recycled aggregates and bulk apparent density Ps of recycled sand are measured in accordance with Chinese Standard JGJ 52-2006; The relationship between the bulk volume fraction of recycled aggregates and the nominal strength of low carbon concrete is given by equation (6): a relationship between the bulk volume fraction of recycled aggregates and the sand content S is given by equation (7): s

[0027] S7. Calculation of a volume fraction of hollow glass microspheres on the basis of the nominal strength of low carbon concrete:

[0028] A relationship between the bulk volume fraction of hollow glass microspheres and the nominal strength of low carbon concrete is given by equation (8):

[0029] S8. the calculation of the dosages of recycled aggregates, recycled sand and microspheres hollow glass:

[0030] the bulk apparent density of the hollow glass microspheres is measured;

[0031] the dosage of recycled aggregates is calculated as follows: •• x ft,

[0032] the dosage of recycled sand is calculated as follows: ~ x ^ / (1 -,ï) (.10 ;

[0033] the dosage of hollow glass microspheres is calculated as follows: oh i "S

[0034] S9. Calculation of an effective water quantity for low carbon concrete and of a dosage of the superplasticizer using the volume method:

[0035] the density Pj of the cementitious materials is calculated using equation (12): a? i 1 "■ XX 02

[0036] where, Pc is the density of the cement (generally 3.15 g / cm3); and Pi is the density of the additional cementitious material, measured in g / cm3;

[0037] The effective water quantity for low carbon concrete is calculated using equation (13):

[0038] where, P» is the density of water (generally 1.0 g / cm3); Pa\ is the apparent density of the recycled carbonated coarse aggregate; Ps\ is the apparent density of the recycled carbonated fine aggregate, measured in kg / m3; is the volume of voids in the concrete, measured at 0.0015 m3;

[0039] depending on the actual amount of water, the dosage of the superplasticizer is calculated using the following equation (14):

[0040] where, A q is the superplasticizer growth coefficient, between 0.05 and 0.06; mvo is the quantity of water for a reference concrete having a slump between 70 and 90 mm and is correlated with the maximum size of the aggregates, as indicated in Table 2;

[0041] [Tables2] maximum size of aggregates / mm 16 20 25 30 mwO / L 230 215 210 205

[0042] S10. comparison of the effective water quantity with the maximum recommended water quantity mmax- and the calculation of a total mass of cementitious materials mj the dosage mc of the cement, and the dosage of the additional cementitious material:

[0043] if the effective water quantity is greater than the maximum water quantity mmax the ratio between the additional cementitious material and the cement is adjusted to increase or decrease the effective water quantity;

[0044] if the effective water quantity is close to the maximum water quantity mmax, the total mass of cementitious materials mj is calculated using equation (15):

[0045] the mc dosage of cement in low carbon concrete is calculated using equation (16):

[0046] The dosage of additional cementitious material in low carbon concrete is calculated using equation (17): t <7 SX

[0047] SI 1. Calculation of an additional quantity of water A mw for recycled aggregates and recycled sand:

[0048] A 1-hour water absorption rate of the recycled aggregates and a water absorption rate of the recycled sand under saturated and dry surface conditions are calculated; then, an additional water quantity A mw for the low-carbon concrete is calculated using equation (18): y S JJ S ~ wa x 4 5¾ x

[0049] S12. calculate a total amount of water Mw for low carbon concrete;

[0050] the total amount of water Mw for low carbon concrete is calculated at using equation (19):

[0051] The invention also provides the low carbon concrete; the low carbon concrete comprises a plurality of raw materials that fully sequester CO2 before mixing begins; and the plurality of raw materials comprises the cementitious materials, the recycled aggregates, the recycled sand, the hollow glass microspheres, the superplasticizer and the mixing water.

[0052] The cementitious material includes cement and additional cementitious materials.

[0053] The cement includes Portland cement, ordinary Portland cement, slag Portland cement, volcanic ash Portland cement, fly ash Portland cement, composite Portland cement, low temperature cement, or calcined clay cement, or a combination thereof.

[0054] Cement is used to react with mixing water to cement low carbon concrete, giving it strength and durability.

[0055] The additional cementitious material includes, but is not limited to, carbonated recycled powder, carbonated slag, carbonated electric furnace slag, carbonated steel slag, or a combination thereof.".

[0056] Recycled aggregates include coarse aggregates and fine aggregates.

[0057] The coarse aggregates comprise construction waste, in particular carbonated, slag in particular carbonate, residue in particular carbonate, or a combination thereof; the particle size of the coarse aggregates is less than 31.5 mm; the coarse aggregates comprise a plurality of carbonizable phases; the plurality of carbonizable phases comprise calcium hydroxide, calcium silicate and calcium aluminate; the plurality of carbonizable phases is used to sequester CO2, forming calcium carbonate which fills microcracks, thereby reducing water absorption and improving strength.

[0058] The fine aggregates comprise construction waste, in particular carbonated, slag, in particular carbonated residue, or a combination thereof; the particle size of the fine aggregates is less than 4.75 mm; the fine aggregates comprise a plurality of carbonizable phases; the plurality of carbonizable phases comprise calcium hydroxide, calcium silicate, and calcium aluminate; the plurality of carbonizable phases are employed to sequester CO2, forming calcium carbonate that fills microcracks, thereby reducing water absorption and increasing strength.

[0059] Recycled sand includes recycled sand, manufactured sand, or a combination thereof; the recycled sand is used to sequester carbon dioxide, with much of the recycled sand being consumed; the recycled sand includes a carbonizable phase, such as hydrocarbons; the hydrocarbons are pressurized at high temperatures to maximize carbon dioxide absorption.

[0060] The superplasticizer, with its air-entraining performance and high water reduction rate, can be used to improve the workability, mechanical properties, and durability of low-carbon concrete; furthermore, the superplasticizer comprises a large number of functional groups capable of sequestering CO2 from the air.

[0061] The mixing water is a solution containing CO2; the mixing water is pressurized to enhance the dissolution of CO2 or is subjected to facilitate chemical reactions with CO2; the mixing water used for the chemical reactions includes metal ions and organic compounds capable of sequestering CO2, including, but not limited to, Mg2+ , Ca2+ , amines, and organic alcoholic compounds.

[0062] Before preparing the low carbon concrete, the plurality of raw materials sequesters CO2 completely.

[0063] The following advantages are associated with low carbon concrete.

[0064] 1. Each of the raw materials sequesters CO2, increasing the amount of carbon captured in low-carbon concrete, thereby reducing carbon emissions in the concrete industry and having beneficial effects on the environment.

[0065] 2. The disclosed method operates as a systematic and self-regulating system.

[0066] 3. Compared with conventional methods of concrete design, the method disclosed uses a lower safety factor, reduces the amount of cementitious materials per unit volume of concrete of the same strength class, and further reduces carbon emissions.

[0067] 4. The method incorporates an algorithm for calculating the amount of additional water necessary and another to determine the optimal dosage of carbonated hollow glass microspheres, thus ensuring the workability of low-carbon concrete.

[0068] 5. The algorithm for calculating the amount of additional water mitigates the compromise of workability resulting from the increase in the water absorption rate of the aggregates, while promoting the hydration of the cement, thus ensuring the improvement of the mechanical properties of low-carbon concrete;

[0069] 6. The disclosed method makes the low carbon concrete denser, which prevents CO2 from escaping from low-carbon concrete.

[0070] 7. The disclosed method uses solid waste to sequester CO2,

[0071] thereby reducing the cost of concrete and carbon emissions, and promoting the reuse of resources and environmental protection.

[0072] 8. Uniformity of low carbon concrete is achieved by mixing the hollow glass microspheres, water reducer and mixing water.

[0073] 9. The CO2 is preferentially contained in the hollow glass microspheres. Brief description of the drawings

[0074] [Fig-1] [Fig. 1] is a flowchart of a design method for low carbon concrete compositions according to an example of the invention. DETAILED DESCRIPTION

[0075] To further illustrate the invention, examples detailing the method of designing low carbon concrete compositions are described below. It should be noted that the following examples are intended to describe and not limit the invention.

[0076] Example 1

[0077] A low carbon concrete is composed of a plurality of raw materials as follows:

[0078] cement: Portland cement CEM I 42.5;

[0079] additional cementitious material: carbonated fly ash, with an active hydration factor of 0.3;

[0080] coarse aggregates: recycled carbonated coarse aggregates, with an apparent density of 2,600 kg / m3, an apparent density of 1,400 kg / m3, and a water absorption rate in 1 hour of 3.7%; the particle size of the recycled carbonated coarse aggregates is detailed in Table 3;

[0081] Table 3. Granulometry of recycled carbonated coarse aggregates [Tables 3] Sieve size (mm) 31.5 26.5 19.0 16.0 9.5 4.75 Percentages retained (%) 0 0 2 20 63 100

[0082] fine aggregates: fine recycled carbonated aggregates, with an apparent density of 2,610 kg / m3, an apparent density of 1,510 kg / m3, a water absorption rate over 1 hour of 4.6%; the granulometry of the fine recycled carbonated aggregates is detailed in Table 47;

[0083] Table 4. Granulometry of recycled fine carbonate aggregates [Tables 4] Sieve size (mm) 4.75 2.36 1.18 0.60 0.30 0.15 Undersized particles Cumulative percentages 2 14 34 60 85 98 100 retained s(%)

[0084] hollow glass microspheres: filled with CO2 gas, with an apparent density of 205 kg / m3;

[0085] mixing water: a sodium bicarbonate solution prepared by absorbing CO2 with a mass concentration of NaOH of 1%; and

[0086] superplasticizer: polycarboxylate superplasticizer, with a water reduction rate of 20%.

[0087] The compositions of the low carbon concrete were designed as follows:

[0088] SOI: The strength of low carbon concrete was designed to be grade C40:

[0089] 4 15 X » - 40 4 1.5 X 5 J - 47.5 MFA

[0090] S02: An effective ratio between water and cementitious materials was calculated:

[0091] S03: a dosage of 25% of fly ash relative to the total weight of the concrete to low carbon content was added, and a true water / cementitious materials ratio was calculated: X [1 — ^(1 - - 0.42 x [1 - (1 - 0.30) x 025] = 035

[0092] S04: a maximum quantity of water was calculated: 204^4-021^ 204.64 - 0.71 X 47.5 170.9

[0093] S05: a volume fraction Va of the recycled aggregates and a sand rate S were calculated: - 0.635 4 7.11 S = 1.08.....1¾ = LOS.......0.67 = 0.41

[0094] S06: A volume fraction of the hollow glass microspheres was calculated: v* - (70.07 - 0.45 / ^) / 1000 - (70.07-0.45 X 53.0) / 1000 - 0.049

[0095] S07: the dosages of coarse carbonate aggregates, fine carbonate aggregates and hollow carbonated glass microspheres were calculated:

[0096] = ^Xp fl = 0.67 X 1400 938.0^ / m^ 0.41 = X 3 / (1 ■■■■ S) = 938 m & - 1.¾ X / ¾ - 0.049 x 205 ■- 9.6¾ / m 4 S10: An effective water quantity for low carbon concrete was calculated: ?? wwc) j(h-74 = 1000 x1 x 038 650.8 \ 1------0.040 - 0 0015 | x 2600 2610 / 3.0 215

[0097]

[0098]

[0099]

[0100]

[0101] SI 1: a dosage of cementitious materials was calculated: = 173.2 4- 032 = 494.9¾¾ în.. ■■■ m- no = m? x «7 = 494.9 x 0.25 — 123.7^ / m3 S12: An additional amount of water was calculated: Awt^, — Wa X 4- X 3¾ — 3.7% x 938.0 -4 4.6% S13: A total quantity of water was calculated: 4 = 173.2 4 65.1 2383 The compositions of C40 grade low carbon concrete are detailed in Table 5. Table 5 Compositions of low carbon concrete from Example 1 [Tables5] Cement Fly ash Water Superplasticizer Coarse aggregates Fine aggregates Hollow glass microsphere 371.2 123.7 238.3 3.15 938.0 659.8 9.6 Example 2

[0102] A low carbon concrete is composed of a plurality of raw materials as follows:

[0103] cement: Portland cement CEM I 42.5;

[0104] additional cementitious material: recycled carbonated micro-powder, with an active hydration factor of 0.4;

[0105] coarse aggregates: carbonate slag, with an apparent density of 2,400 kg / m3, an apparent density of 1,370 kg / m3 and a water absorption rate over 1 hour of 2.7%; the granulometry of the carbonate slag is shown in Table 6;

[0106] Table 6. Classification of carbonate slags [Tableauxô] Sieve size (mm) 31.5 26.5 19.0 16.0 9.5 4.75 Percentages of retained mulled matter (%) 0 0 4 19 58 100

[0107] fine aggregates: 30% by mass of recycled fine carbonated aggregates and 70% of carbonated slag, with an apparent density of 25 30 kg / m3, an apparent density of 1460 kg / m3, and a water absorption rate over 1 hour of 4.6%; and the particle size distribution of 30% by mass of recycled fine carbonated aggregates and 70% by mass of carbonated slag is detailed in Table 7;

[0108] Table 7. Granulometry of 30% by mass of recycled fine aggregates and 70% by mass of carbonated slag [Tables 7] Sieve size (mm) 4.75 2.36 1.18 0.60 0.30 0.15 Undersized particles Cumulative percentages retained (%) 2 14 36 63 85 95 100

[0109] hollow glass microspheres: filled with CO2 gas, with an apparent density of 205 kg / m3;

[0110] mixing water: prepared by absorbing CO2 with a mass concentration of 0.3% Ca(OH)2 and

[0111] a mass concentration of 1.2% of NaOH; and

[0112] superplasticizer: a high-rate, air-entraining superplasticizer with a water reduction rate of 20%.

[0113] According to the design method of Example 1, the compositions of a low carbon concrete of grade C70 are detailed in Table 8.

[0114] Table 8 Compositions of the low carbon concrete of Example 2 [Tables 8] Cement Powder 1 slag Water Superplasticizer Coarse aggregates Fine aggregates micro glass sphere 488.8 54.3 206.7 7.1 1007.4 644.1 7.2 Comparative example 1

[0115] According to a mix design method for high-performance ordinary concrete, the plurality of raw materials of Example 1 were designed and shown in Table 9. [Tables 9] Cement Powder of 1 slag Water Superplasticizer Coarse aggregates Fine aggregates 350 90 171 9 950 782 Comparative example 2

[0116] According to a mix design method for high-performance ordinary concrete, the plurality of raw materials of Example 2 were designed and shown in Table 10. [Tables 10] Cement Slag powder Water Superplasticizer Coarse aggregates Fine aggregates 480 100 158 11 1032 733 Comparative example 3

[0117] A low carbon concrete comprises a plurality of raw materials as follows:

[0118] cement: Portland cement CEM I 42.5;

[0119] additional cementitious material: second category fly ash;

[0120] coarse aggregates: gravel, with an apparent density of 2,700 kg / m3, with a density apparent of 1,570 kg / m3 and a water absorption rate in one hour of 0.3%; the gravel granulometry is detailed in table 11;

[0121] Table 11. Gravel sizing

[0122] [Tables 11] Sieve size / mm 31.5 26.5 19.0 16.0 9.5 4.75 Cumulative percentages retained / % 0 0 6 16 58 100

[0123] fine aggregates: manufactured sand, with an apparent density of 2,730 kg / m3, an apparent density of 1,590 kg / m3 and a water absorption rate of 0.5% in one hour; the particle size of the manufactured sand is detailed in Table 12;

[0124] Table 12. Classification of manufactured sand [Tables 12] Sieve size / mm 4.75 2.36 1.18 0.60 0.30 0.15 Undersized particles Cumulative percentages retained / % 2 14 34 63 83 96 100

[0125] hollow glass microspheres: filled with CO2 gas, with an apparent density of 205 kg / m3;

[0126]

[0127] mixing water:

[0128] tap water; and

[0129] superplasticizer: polycarboxylate-based superplasticizer, with a water reduction rate of 20%.

[0130] According to the conventional method of concrete design, the compositions of C50 grade concrete are detailed in Table 13.

[0131] Table 13 Compositions of concrete of comparative example 3 [Tables 13] Cement Slag powder Water Superplasticizer Coarse aggregates Fine aggregates 330 100 174 21 1067 791

[0132] Five high-performance concretes were prepared according to Examples 1-2 and Comparative Examples 1-3. Comparative Example 1-2 used conventional raw materials without using the disclosed formulation method, while Comparative Example 3 used conventional raw materials with a specific formulation method.

[0133] Table 14. Performance of concrete prepared in Examples 1-2 and Comparative Examples 1-3 [Tables 14] Slump (mm) Compressive strength after 28 days (MPa) Resistance to freezing and thawing Resistance to chloride ion penetration Resistance to sulfate attack Carbon entrapment (kg / m Ÿ Example 1 220 49.1 Meet design requirements Meet design requirements Meet design requirements 17.2 Example 2 180 79.5 Meet design requirements Meet design requirements Meet design requirements 15.4 Comparative Example 1 20 24.1 Failure to meet design requirements Failure to meet design requirements Failure to meet design requirements of design 10.1 Comparative example 2 10 38.9 Failure to comply with design requirements Failure to comply with design requirements Failure to comply with design requirements 14.5 Comparative example 3 180 59.4 Meet the design requirements Meet the design requirements Meet the design requirements - .

[0134] Referring to Table 14, it is found that the low-carbon concrete of the invention has good workability. The carbon reduction per unit volume of the low-carbon concrete is higher than that of the comparative examples. In addition, the durability indicators of the low-carbon concrete, such as frost resistance, resistance to chlorine ion penetration, and resistance to sulfate attack, meet the design requirements, and the performance is roughly comparable to that of conventional high-performance concrete.

[0135] The method disclosed on the site extensively uses solid waste such as construction waste and slag, which are not generally used in conventional concrete, to sequester CO2. The method addresses the problems related to the workability, mechanical properties and durability resulting from the extensive use of solid waste in low-carbon concrete.

Claims

Claims

1. A method of designing low-carbon concrete compositions, all of the compositions being capable of absorbing CO2, and the method comprising: S1. preparing a plurality of raw materials for the low-carbon concrete: the plurality of raw materials comprises cement, additional cementitious materials, recycled aggregates, recycled sand, hollow glass microspheres, a superplasticizer, and mixing water; and before preparing the low-carbon concrete, the plurality of raw materials completely sequester CO2; S2.determine the strength of low-carbon concrete: the design strength of low-carbon concrete is calculated as follows; when the strength grade of low-carbon concrete is less than C60, the design strength is calculated according to equation (1): ni when the strength grade of low-carbon concrete is not less than C60, the design strength is calculated according to equation (2): Âr X - 11 / ^ a) where, is the design strength of low-carbon concrete; f .is the standard value of the compressive strength of a cube of recycled concrete; <T est l'écart-type de la résistance du béton ; S3.the calculation of an effective ratio between water and cementitious materials of low carbon concrete: for cement, a relationship between the design strength of low carbon concrete and the effective water-cement ratio is determined using equation (3): ft S. where A and D are constants; when o is greater than or equal to 60 MPa, A=20, D=9; when o is less than 60 MPa, A=25.8, represents the water / materials ratio effective cementitious low-carbon concrete; S4. the calculation of an actual water / cementitious materials ratio based on the actual water / cementitious materials ratio of low-carbon concrete: the actual water-cement ratio is calculated using equation (4): Mw / b) xh - Va ■■■ MJ > where, / is the true water / cementitious materials ratio of the low-carbon concrete, is a mass fraction of the additional cementitious materials in the cementitious materials, and ki is an active hydration factor of the additional cementitious materials; S5. Calculation of a recommended maximum water quantity based on the strength of low-carbon concrete: the maximum recommended water quantity is calculated based on the design strength of low-carbon concrete according to equation (5): where, mmax represents the maximum quantity of water (kg / m3); S6. Calculation of a volume fraction of recycled aggregates and a sand rate S based on the nominal strength of low-carbon concrete: Bulk apparent density Pa of recycled aggregates and bulk apparent density Ps of recycled sand are measured in accordance with Chinese standard JGJ 52-2006. The relationship between the bulk volume fraction of recycled aggregates and the nominal strength of low carbon concrete is given by equation (6): a relationship between the bulk volume fraction of recycled aggregates and the sand content S is given by equation (7): s -1.68 - ¾ S7. Calculation of a volume fraction of hollow glass microspheres based on the nominal strength of low-carbon concrete: The relationship between the bulk volume fraction of hollow glass microspheres and the nominal strength of low-carbon concrete is given by equation (8): (707 - S8. Calculation of the dosages of recycled aggregate, recycled sand and hollow glass microspheres: the bulk apparent density of the hollow glass microspheres is measured; the dosage of the recycled aggregates is calculated as follows: 5¾ - 8” XP* ' the dosage of recycled sand is calculated as follows: x 8 / (1 - 8} the dosage of hollow glass microspheres is calculated as follows: S9. Calculation of an effective water quantity for low-carbon concrete and a superplasticizer dosage using a volume method: the density Pj of cementitious materials is calculated using equation (12): where, Pc is the density of the cement; and Pi is the density of the additional cementitious material; The effective water quantity for low carbon concrete is calculated using equation (13): "" vv where, Pw is the density of water; Pa] is the bulk density of the recycled coarse carbonate aggregate; Psi is the bulk density of the recycled fine carbonate aggregate; vair is the volume of voids in the concrete; depending on the actual amount of water, the dosage of the superplasticizer is calculated using the following equation (14): where, A t| is the superplasticizer growth coefficient, between 0.05 and 0.06; is the quantity of water for a reference concrete with a slump of between 70 and 90 mm; S10. Comparison of the actual water quantity with the maximum recommended water quantity and the calculation of a total mass of cementitious materials, the dosage mc of the cement, and the dosage of the additional cementitious material: if the effective water quantity is greater than the maximum water quantity mmax the ratio of additional cementing material to cement is adjusted to increase or decrease the effective water quantity; if the effective water quantity is close to the maximum water quantity mmax the total mass of cementitious materials mj is calculated using equation (15): the mc dosage of cement in low carbon concrete is calculated using equation (16): the dosage of additional cementitious material in low carbon concrete is calculated using equation (17): Here?) •• y* < SI 1. Calculation of an additional water quantity A mK for recycled aggregates and recycled sand: a 1-hour water absorption rate of recycled aggregates and a water absorption rate of recycled sand in a saturated surface dry state are calculated; then, an additional water quantity A mw for low-carbon concrete is calculated using equation (18); and 4¾ ■" 5¾ S ; 5¾ XJ S12. calculate a total water quantity for low-carbon concrete; the total water quantity Mw for low-carbon concrete is calculated using equation (19):

2. A method according to claim 1, wherein the cement comprises Portland cement, ordinary Portland cement, slag Portland cement, volcanic ash Portland cement, fly ash Portland cement, composite Portland cement, low temperature cement or calcined clay cement, or a combination thereof.

3. The method of claim 1, wherein the recycled aggregates comprise coarse aggregates and fine aggregates.

4. A method according to claim 3, wherein the coarse aggregates comprise carbonate construction waste, carbonate slag, carbonate tailings or a combination thereof.

5. A method according to claim 3, wherein the fine aggregates comprise carbonate construction waste, carbonate slag, carbonate tailings or a combination thereof.

6. The method of claim 1, wherein the additional cementitious material comprises carbonated recycled powder, carbonated slag, carbonated electric furnace slag, carbonated steel slag, or a combination thereof.

7. Cl. A method according to claim 1, wherein the mixing water is a solution containing CO2.

8. The method of claim 1, wherein the superplasticizer has a water reduction rate of 20%.

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