Calculation method of representative value of 28-day compressive strength of concrete and related parameters

Abstract

The purpose of this invention is to address the problems existing in the calculation methods of the representative value of the 28-day compressive strength of concrete in the prior art, and to provide a method for calculating the representative value of the 28-day compressive strength of concrete and related parameters. This includes: 1. Calculation methods for the 28-day compressive strength of concrete, the calculated value of the 28-day compressive strength of cementitious materials, the water-cement ratio, the aggregate fineness modulus, and the dosage of water-reducing agent; 2. Calculation of fcu,o; 3. Calculation of W÷C; 4. Calculation of Q; 5. Calculation of f′ce. This invention's calculation method explains how to calculate the mix proportion parameters of concrete with mineral admixtures and high-flowability concrete. When other conditions are known, it is not necessary to look up tables to directly calculate the water-cement ratio, concrete strength, and verify the dosage of concrete water-reducing agent; the calculated value of the 28-day compressive strength of concrete can be directly verified from the concrete strength value.

Description

Technical Field

[0001] This invention belongs to the field of concrete technology, and specifically relates to a method for calculating the representative value of the 28-day compressive strength of concrete and related parameters. Background Technology

[0002] Existing technologies include the Balromy formula method and the full calculation method for calculating the representative value of the 28-day compressive strength of concrete.

[0003] The shortcomings of the Balromy formula method are as follows: ① The "Test Method for Strength of Cement Mortar (ISO Method)" is a Chinese national standard implemented on May 1, 1999. After adopting the ISO method for cement mortar, due to the change in testing methods, the strength of the same sample is lower than that of the original method (the old standard had a water-cement ratio of 0.44 for silicate cement, ordinary silicate cement, and slag cement, and 0.46 for pozzolanic cement and fly ash cement, with a cement-to-standard sand mass ratio of 1:2.5. The new standard ISO method has a water-cement ratio of 0.50 for all six major cements, with a cement-to-Chinese ISO standard sand mass ratio of 1:3.0). This is roughly one strength grade different from the statistics of construction units. Obviously, the regression coefficients A and B in the Balromy formula for the relationship between water-cement ratio and compressive strength are no longer applicable. ② The water content values ​​for the Borromie formula are derived from tables for dry-hard, plastic concrete, while the sand ratio is derived from tables for concrete with a slump of 10-60mm. For slumps greater than 60mm, the values ​​can be determined experimentally. However, this table is inaccurate and unsuitable for high-slump, high-flowability concrete. ③ Because the water-cement ratio calculated using the Borromie formula differs from the actual laboratory mix proportion by approximately 20% (due to a larger water-cement ratio), the representative value of the 28-day compressive strength of concrete calculated using the Borromie formula lacks predictability.

[0004] The limitations of the full calculation method are as follows: ① Because the full calculation method is based on a universal volumetric model of concrete, it aims to achieve optimal workability and strength performance of HPC simultaneously. The volume ratio of cement paste to aggregate is 35:65. However, this approach has limitations because materials vary significantly across regions. Different materials have different loose densities, apparent densities, and fineness moduli, resulting in different material quantities and varying cement paste to aggregate volume ratios. ② The full calculation method only distinguishes between coarse and fine aggregates, generally using a coefficient of 0.335. This coefficient is not applicable to multi-component fine aggregates. ③ The water-cement ratio calculated using the full calculation method differs from the actual laboratory mix proportion by approximately 25% (due to a larger water-cement ratio). Furthermore, the water-cement ratio formula of the full calculation method cannot represent the true strength of concrete in actual operation because it does not explain the factors related to the strength performance of concrete. In fact, the representative value of the 28-day compressive strength of concrete is related to the calculated value of the 28-day compressive strength of cementitious materials, water-cement ratio, aggregate fineness modulus, water-reducing agent, and air-entraining agent dosage. Therefore, the representative value of the 28-day compressive strength of concrete calculated by the full calculation method is not instructive. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the calculation methods of the representative value of the 28-day compressive strength of concrete in the prior art, and to provide a method for calculating the representative value of the 28-day compressive strength of concrete and related parameters. This invention explains how to calculate the mix proportion parameters of concrete with mineral admixtures and high-flowability concrete. When other conditions are known, it is not necessary to look up tables to directly calculate the water-cement ratio, the representative value of the 28-day compressive strength of concrete, or verify the amount of water-reducing agent used in concrete; the representative value of the 28-day compressive strength of cementitious materials can be directly verified using the calculated value of the 28-day compressive strength of the cementitious materials.

[0006] The technical solution of the present invention is as follows:

[0007] 1. A method for calculating the representative value of the 28-day compressive strength of concrete, where: Ka: solid content of the air-entraining agent in the composite water-reducing agent; Kb: air-entraining rate of the air-entraining agent in the composite water-reducing agent; Q: dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), f′ce: Calculated compressive strength of cementitious material (A% cement + B% mineral admixture) at 28 days (MPa), Wa: Apparent water content of concrete (kg / m³) 3 C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa, including the following steps:

[0008] 1) Calculate the aggregate fineness modulus μ;

[0009] 2) Calculate the air entrainment rate K per unit weight of composite water-reducing agent;

[0010] 3) Calculate the total water used in concrete, W;

[0011] 4) Calculate the representative value of the 28-day compressive strength of concrete, fcu,o.

[0012] 2. A method for calculating the representative value of the 28-day compressive strength of concrete, where: μ: aggregate fineness modulus, Wa: apparent water content of concrete (kg / m³) 3 Ka: Solid content of air-entraining agent in composite water-reducing agent; Kb: Air-entraining rate of air-entraining agent in composite water-reducing agent; Q: Dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), C: Total amount of cementitious materials per cubic meter of concrete (kg / m³) 3 f′ce: Calculated compressive strength (MPa) of A% cement + B% micro-powder mineral admixture cementitious material after 28 days. Calculation of fcu,o includes the following steps:

[0013] 1) Calculate the air entrainment rate K per unit weight of composite water-reducing agent;

[0014] 2) Calculate the total water used in concrete, W;

[0015] 3) Calculate the representative value of the 28-day compressive strength of concrete, fcu,o.

[0016] 3. A method for calculating the representative value of the 28-day compressive strength of concrete, including the following steps when the cement manufacturer, the type of manufactured sand, the slump, or the actual amount of water-reducing agent is adjusted:

[0017] 1) Calculate the aggregate fineness modulus μ;

[0018] 2) Calculate the air entrainment rate K per unit weight of composite water-reducing agent;

[0019] 3) Calculate the total water used in concrete, W;

[0020] 4) Calculate the representative value of the 28-day compressive strength of concrete, fcu,o.

[0021] 4. A method for calculating the water-cement ratio (W÷C) of concrete, where: Ka: solid content of the air-entraining agent in the composite water-reducing agent; Kb: air-entraining rate of the air-entraining agent in the composite water-reducing agent; Q: dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), Wa: Apparent water content of concrete (kg / m³) 3 f′ce: Calculated compressive strength (MPa) of A% cement + B% mineral admixture binder at 28 days, representative value of measured 28-day compressive strength, and calculation of W÷C: water-cement ratio, including the following steps:

[0022] 1) Calculate the aggregate fineness modulus μ;

[0023] 2) Calculate the air entrainment rate K per unit weight of composite water-reducing agent;

[0024] 3) Assume that the representative value of the 28-day compressive strength of the concrete fcu,o is equal to the design strength value, i.e., the measured representative value of the 28-day compressive strength;

[0025] 4) Calculate the total water used in concrete, W;

[0026] 5) Calculate W ÷ C.

[0027] 5. A method for calculating the 28-day compressive strength of a cementitious material containing A% cement and B% micro-powdered mineral admixtures, where: Ka: solid content of the air-entraining agent in the composite water-reducing agent; Kb: air-entraining rate of the air-entraining agent in the composite water-reducing agent; Q: dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), Wa: Apparent water content of concrete (kg / m³) 3C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 fcu,o: Representative value of 28-day compressive strength of concrete (MPa), calculation of f′ce: Calculated value of 28-day compressive strength of A% cement + B% micro-powder mineral admixture cementitious material (MPa), including the following steps:

[0028] 1) Calculate the aggregate fineness modulus μ;

[0029] 2) Calculate the air entrainment rate K per unit weight of composite water-reducing agent;

[0030] 3) Calculate the total water used in concrete, W;

[0031] 4) Calculate f′ce.

[0032] 6. A method for calculating the dosage of water-reducing agent per cubic meter of concrete, wherein: Ka: solid content of air-entraining agent in composite water-reducing agent, Kb: air-entraining rate of air-entraining agent in composite water-reducing agent, Qg: solid content of water-reducing agent (%), f′ce: calculated value of 28-day compressive strength of cementitious material with A% cement + B% mineral admixture (MPa), fcu,o: representative value of 28-day compressive strength of concrete (MPa), Wa: apparent water content of concrete (kg / m³). 3 C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 The representative value of compressive strength after 28 days was measured, and Q was calculated: the amount of water-reducing agent used per cubic meter of concrete (kg / m³). 3 It includes the following steps:

[0033] 1) Calculate the aggregate fineness modulus μ;

[0034] 2) Calculate the air entrainment rate K per unit weight of composite water-reducing agent;

[0035] 3) Assume that the representative value of the 28-day compressive strength of the concrete fcu,o is equal to the design strength value, i.e., the measured representative value of the 28-day compressive strength;

[0036] 4) Calculate Q.

[0037] 7. A method for calculating the 28-day compressive strength of a cementitious material containing A% cement and B% mineral admixtures, where: fm,o: representative value of the 28-day compressive strength of cement mortar; W: total water consumption per cubic meter of concrete (kg / m³). 3 C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 Calculate f′ce: the 28-day compressive strength (MPa) of A% cement + B% mineral admixture cementitious material, including the following steps:

[0038] 1) Calculate the fineness modulus of the standard quartz sand used in the cement strength test;

[0039] 2) Calculate f′ce.

[0040] 8. The calculation method for the representative value of the 28-day compressive strength of concrete and related parameters mentioned above uses the following formula:

[0041] 1) The formula for calculating μ is:

[0042] Formula 1: μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0043] μ: Aggregate fineness modulus;

[0044] μC: Cement fineness modulus;

[0045] C%: Percentage of cement by weight in aggregates and cementitious materials;

[0046] μF: Fineness modulus of mineral admixtures;

[0047] F%: Percentage of mineral admixtures in the total weight of aggregates and cementitious materials;

[0048] μG1: Fineness modulus of coarse aggregate 1;

[0049] G1%: Percentage of coarse aggregate by weight in total aggregate + cementitious materials;

[0050] μG2: Fineness modulus of coarse aggregate;

[0051] G2%: Coarse aggregate 2% of the total weight of aggregate + cementitious materials;

[0052] μs1: Fineness modulus of fine aggregate 1;

[0053] S1%: The percentage of fine aggregate by weight in the total weight of aggregates and cementitious materials;

[0054] μs2: Fineness modulus of fine aggregate;

[0055] S2%: The percentage of fine aggregates in the total weight of aggregates and cementitious materials;

[0056] 2) The formula for calculating K is:

[0057] Formula 2: Kb = K / Ka

[0058] Kb: Air entrainment rate of the air-entraining agent in the composite water-reducing agent;

[0059] K: Air entrainment rate per unit weight of composite water-reducing agent;

[0060] Ka: Solid content of air-entraining agent in composite water-reducing agent;

[0061] 3) The formula for calculating W is:

[0062] Formula 3: W=Wa+Q×(1-Qg)

[0063] W: Total water used per cubic meter of concrete (kg / m³) 3 ;

[0064] Wa: Apparent water content of concrete (kg / m³) 3 ;

[0065] Q: What is the dosage of water-reducing agent per cubic meter of concrete (kg / m³)? 3 ;

[0066] Qg: Solid content of water-reducing agent (%);

[0067] 4) The formula for calculating fcu,o is:

[0068] Formula 4:

[0069] fcu,o: Representative value of 28-day compressive strength of concrete (MPa);

[0070] f′ce: Calculated compressive strength (MPa) of cementitious material (A% cement + B% mineral admixture) after 28 days;

[0071] C: Total amount of cementitious material per cubic meter of concrete (kg / m³) 3 ;

[0072] K: Air entrainment rate per unit weight of composite water-reducing agent;

[0073] a: Air loss in concrete, generally taken as 0-4;

[0074] 5) The formula for calculating the water-to-binder ratio (W ÷ C) is:

[0075] Formula 4-1:

[0076] 6) One of the formulas for calculating f′ce is:

[0077] Formula 4-2:

[0078] 7) The formula for calculating Q is:

[0079] Formula 4-3:

[0080]

[0081] Derivation of Formula 4-3:

[0082] Substituting formula 3: W=Wa+Q×(1-Qg) into formula 4-2:

[0083]

[0084] have to: Simplified to:

[0085] 8) The second formula for calculating f′ce is:

[0086] Formula 5:

[0087] fm.o: Representative value of 28-day compressive strength of cement mortar (MPa);

[0088] μs: fineness modulus of quartz sand.

[0089] Compared with the prior art, the advantages of the present invention are:

[0090] This patent explains why high-grade concrete requires small-sized aggregates, and how to calculate mix proportion parameters for concrete with mineral admixtures, wet-mixed tailings sand concrete, and high-flowability concrete. Given that the material parameters are experimentally known, it is not necessary to consult tables to directly calculate the water-cement ratio, concrete strength, or verify the amount of water-reducing agent. The calculated 28-day compressive strength of the cementitious material can be directly verified using the concrete strength value. Detailed Implementation

[0091] Example 1

[0092] Calculate fcu,o according to Formula 4: the representative value of the 28-day compressive strength of concrete (MPa).

[0093]

[0094] The representative value of the 28-day compressive strength of concrete (MPa) depends on the calculated value of the 28-day compressive strength of the cementitious material, the water-cement ratio, the comprehensive fineness modulus of the aggregate, the amount of water-reducing agent, the air entrainment rate of the composite water-reducing agent per unit weight, and the air loss of the concrete.

[0095] The materials used are: PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Anshan Iron and Steel Group; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days, 45 MPa; crushed stone 1 origin: Liaoyang, particle size 5mm~20mm, fineness modulus: 1.71; crushed stone 2 origin: Liaoyang, particle size 5mm~10mm, fineness modulus: 0.9933; artificial sand 1 origin: Anshan, fineness modulus: 3.934; artificial sand 2 origin: Liaoyang, fineness modulus: 3.291; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0096] The experimental results of Example 1-1 are as follows: 2390.3 kg / m³ 3

[0097]

[0098] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0099] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0100] = 3.797 × 5.94% + 0.999 × 2.51% + 1.71 × 19.18% + 0.9933 × 12.79% + 3.934 × 27.40% + 3.291 × 32.19%

[0101] ≈2.843

[0102] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0103] From K = Ka × Kb

[0104] = 0.33% × 3.294 × 10 2

[0105] ≈1.087

[0106] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0107] W = Wa + Q × (1 - Qg)

[0108] =190 + 10.29 × (1 - 0.1833)

[0109] =198.4Kg

[0110] According to Formula 4: Calculate fcu,o: the representative value of concrete compressive strength in MPa. (The air content loss a in concrete is taken as 0).

[0111]

[0112]

[0113] The experimental results for Examples 1-2 are as follows: 2400.3 kg / m³ 3

[0114]

[0115] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0116] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0117] = 3.797 × 7.73% + 0.999 × 3.18% + 1.71 × 18.64% + 0.9933 × 12.5% ​​+ 3.934 × 27.95% + 3.291 × 30.00%

[0118] ≈2.855

[0119] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0120] From K = Ka × Kb

[0121] = 0.33% × 3.294 × 10 2

[0122] ≈1.087

[0123] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0124] W = Wa + Q × (1 - Qg)

[0125] =190 + 10.29 × (1 - 0.1833)

[0126] ≈198.4kg / m 3

[0127] According to Formula 4: Calculate fcu,o: the representative value of concrete compressive strength in MPa. (The air content loss a in concrete is taken as 0).

[0128]

[0129] Conclusion: Formula 4 is valid.

[0130] Example 2

[0131] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete (MPa).

[0132]

[0133] Given: Ka: Solid content of air-entraining agent in composite water-reducing agent; Kb: Air-entraining rate of air-entraining agent in composite water-reducing agent; Q: Dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), f′ce: Calculated compressive strength of cementitious material (A% cement + B% mineral admixture) at 28 days (MPa), μ: Aggregate fineness modulus, Wa: Apparent water content of concrete (kg / m³) 3C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa.

[0134] The materials used are: PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Anshan Iron and Steel Group; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days, 49 MPa; crushed stone 1 origin: Liaoyang, particle size 10mm~25mm, fineness modulus: 4.415; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.972; artificial sand 1 origin: Liaoyang, fineness modulus: 2.356; fine river sand 2 origin: Liaoyang, fineness modulus: 1.494; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0135] The experimental results of Example 2-1 are as follows: 2393.4 kg / m³ 3

[0136]

[0137] Given μ = 2.631

[0138] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0139] From K = Ka × Kb

[0140] = 0.33% × 3.294 × 10 2

[0141] ≈1.087

[0142] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0143] W = Wa + Q × (1 - Qg)

[0144] =200 + 3.36 × (1 - 0.1833)

[0145] ≈202.7kg / m 3

[0146] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0147]

[0148] The experimental results for Example 2-2 are as follows: 2428.8 kg / m³ 3

[0149]

[0150] Given: μ = 2.663

[0151] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0152] From K = Ka × Kb

[0153] = 0.33% × 3.294 × 10 2

[0154] ≈1.087

[0155] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0156] W = Wa + Q × (1 - Qg)

[0157] =195 + 3.80 × (1 - 0.1833)

[0158] ≈198.1kg / m 3

[0159] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0160]

[0161] Conclusion: As shown in the examples, fcu,o can be calculated from Ka, Kb, Q, Qg, f′ce, μ, Wa, C: the representative value of the 28-day compressive strength of concrete in MPa.

[0162] Example 3

[0163] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete (MPa).

[0164]

[0165] Given: Wa: Apparent water content of concrete (kg / m³) 3Ka: Solid content of air-entraining agent in composite water-reducing agent; Kb: Air-entraining rate of air-entraining agent in composite water-reducing agent; Q: Dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), C: Total amount of cementitious materials per cubic meter of concrete (kg / m³) 3 f′ce: Calculated compressive strength (MPa) of A% cement + B% micro-powder mineral admixture cementitious material after 28 days. Calculation of fcu,o includes the following steps:

[0166] The materials used are: PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Ansteel; calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days: 39.5 MPa; crushed stone 1 origin: Liaoyang, particle size 5mm~25mm, fineness modulus: 2.811; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.481; artificial sand origin: Liaoyang, fineness modulus: 2.866; fine river sand origin: Liaoyang, fineness modulus: 1.015; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0167] The experimental results of Example 3-1 are as follows: 2341.3Kg / m 3

[0168]

[0169] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0170] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0171] = 3.797 × 17.52% + 0.999 × 6.78% + 2.811 × 19.63% + 1.481 × 16.12% + 2.866 × 21.50% + 1.015 × 18.46%

[0172] =2.327

[0173] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0174] From K = Ka × Kb

[0175] = 0.33% × 3.294 × 10 2

[0176] ≈1.087

[0177] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0178] W = Wa + Q × (1 - Qg)

[0179] =194.9 + 6.37 × (1 - 0.1833)

[0180] ≈200.1kg / m 3

[0181] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0182]

[0183] The experimental results of Example 3-2 are as follows: 2336.0 kg / m³ 3

[0184]

[0185] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0186] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0187] = 3.797 × 16.16% + 0.999 × 6.32% + 2.811 × 20.14% + 1.481 × 16.39% + 2.866 × 22.01% + 1.015 × 18.97%

[0188] =2.309

[0189] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0190] From K = Ka × Kb

[0191] = 0.33% × 3.294 × 10 2

[0192] ≈1.087

[0193] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0194] W = Wa + Q × (1 - Qg)

[0195] =195.4 + 5.63 × (1 - 0.1833)

[0196] ≈200kg / m 3

[0197] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0198]

[0199] Conclusion: As shown in the examples, fcu,o can be calculated from Wa, Ka, Kb, Q, Qg, C, f′ce, which represents the 28-day compressive strength of concrete in MPa.

[0200] Example 4

[0201] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete (MPa).

[0202]

[0203] When there are changes between the laboratory and the actual materials on site, the water-reducing agent should be adjusted. When the cement manufacturer, the manufactured sand, or the slump changes, the actual amount of water-reducing agent should be adjusted. Calculate: fcuo: the representative value of the 28-day compressive strength of concrete in MPa.

[0204] Example 4-1: The materials used in the laboratory were PO42.5 cement with a fineness modulus of 6.382, originating from Anshan Gangdu Cement Plant. Granulated blast furnace slag powder (micro powder), grade S95, fineness modulus 0.999, originating from Anshan Iron and Steel Group. f′ce: Calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days: 40.17 MPa. Crushed stone 1 originating from Liaoyang, particle size 5mm~25mm, fineness modulus: 2.413. Crushed stone 2 originating from Liaoyang, particle size 5mm~16mm, fineness modulus: 1.446. Artificial sand originating from Liaoyang, fineness modulus: 2.878. Fine river sand originating from Liaoyang, fineness modulus: 0.8740. Polycarboxylate superplasticizer mother liquor originating from Shenyang Shengxinyuan Admixture Co., Ltd. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0205] The experimental results of Example 4-1 are as follows: 2352.1 kg / m³ 3

[0206]

[0207] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0208] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0209] = 6.382 × 14.45% + 0.999 × 6.06% + 2.413 × 22.84% + 1.446 × 21.45% + 2.878 × 19.58% + 0.8740 × 15.62%

[0210] =2.544

[0211] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0212] From K = Ka × Kb

[0213] = 0.33% × 3.294 × 10 2

[0214] ≈1.087

[0215] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0216] W = Wa + Q × (1 - Qg)

[0217] =201.9 + 5.20 × (1 - 0.1833)

[0218] =206.1kg / m 3

[0219] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0220]

[0221] Example 4-2: The actual materials used on site were: PO42.5 cement, fineness modulus 6.382, origin: Gangdu Cement Plant; granulated blast furnace slag powder (micro powder), fineness modulus 0.999, origin: Anshan Iron and Steel Group, micro powder grade S95; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days: 41.0 MPa; crushed stone 1 origin: Liaoyang, particle size 5mm~25mm, fineness modulus: 2.739; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.850; artificial sand origin: Anshan, fineness modulus: 4.116; wet beneficiation iron tailings sand origin: Anshan Qianjiang Mining, fineness modulus: 2.619; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0222] The experimental results of Example 4-2 are as follows: 2406.9 kg / m³ 3

[0223]

[0224] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0225] μ=μC×Ca%+μF×Fa%+μG1×Ga1%+μG2×Ga2%+μs1×Sa1%+μs2×Sa2%

[0226] = 6.382 × 11.99% + 0.999 × 5.20% + 2.739 × 18.78% + 1.850 × 12.44% + 4.116 × 28.05% + 2.619 × 23.53%

[0227] ≈3.332

[0228] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0229] K = Ka × Kb

[0230] = 0.33% × 3.294 × 10 2

[0231] ≈1.087

[0232] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0233] W = Wa + Q × (1 - Qg)

[0234] = 185 + 11.85 × (1 - 0.1833)

[0235] =194.7kg / m 3

[0236] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0237]

[0238] Example 4-3: The materials used are PO42.5 cement, origin: Jidong Cement Plant, fineness modulus: 3.24; granulated blast furnace slag powder (micro powder), origin: Jidong Cement Plant, fineness modulus: 3.812, micro powder grade S95; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days: 45.4 MPa; crushed stone 1, origin: Anshan, particle size 5mm~25mm, fineness modulus: 2.501; crushed stone 2, origin: Anshan, particle size 5mm~16mm, fineness modulus: 1.034; artificial sand 1, origin: Anshan, fineness modulus: 3.113; wet beneficiation iron tailings sand 2, origin: Anqian Mining, fineness modulus: 2.016; ultrafine iron tailings sand 3, origin: Jinhe Mining, fineness modulus: 1.034. The mother liquor of the polycarboxylate superplasticizer, originating from Dalian Kenuo, has a solid content of 18.33%, of which the superplasticizer (polycarboxylate) has a solid content of 16%. The water reduction rate (Jb) of the superplasticizer in the composite superplasticizer is 45% (experimental value). It also contains 2% sodium gluconate, 0.33% air-entraining agent, and an air-entraining rate (Kb) of 3.294 × 10⁻⁶. 2 (Experimental value).

[0239] The experimental results of Example 4-3 are as follows: 2397.5Kg / m 3

[0240]

[0241] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0242] μ=μC×Ca%+μF×Fa%+μG1×Ga1%+μG2×Ga2%+μs1×Sa1%+μs2×Sa2%

[0243] = 3.24 × 6.55% + 3.812 × 2.81% + 2.501 × 19.64% + 1.034 × 19.64% + 3.113 × 20.80% + 2.016 × 14.86% + 1.034 × 15.70% ≈ 2.123

[0244] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0245] K = Ka × Kb

[0246] = 0.33% × 3.294 × 10 2

[0247] =1.087

[0248] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0249] W = Wa + Q × (1 - Qg)

[0250] =200 + 6.49 × (1 - 0.1833)

[0251] =205.3kg / m 3

[0252] According to Formula 4: Calculate fcu,o: the representative value of the 28-day compressive strength of concrete in MPa. (The air content loss a in concrete is taken as 0).

[0253]

[0254] Conclusion: As shown in the examples, when the cement manufacturer, the amount of manufactured sand, and the slump change, the actual amount of water-reducing agent can be adjusted to calculate: fcuo: the representative value of the 28-day compressive strength of concrete in MPa.

[0255] Example 5

[0256] According to formula 4-1:

[0257] Given: Ka: Solid content of air-entraining agent in composite water-reducing agent; Kb: Air-entraining rate of air-entraining agent in composite water-reducing agent; Q: Dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 f′ce: Calculated compressive strength (MPa) of A% cement + B% mineral admixture binder at 28 days, representative value of measured 28-day compressive strength of concrete, Calculation of W÷C: water-cement ratio, including the following steps:

[0258] The materials used are: PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Anshan Iron and Steel Group; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days, 49 MPa; crushed stone 1 origin: Liaoyang, particle size 10mm~25mm, fineness modulus: 4.415; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.972; artificial sand origin: Liaoyang, fineness modulus: 2.676; fine river sand origin: Liaoyang, fineness modulus: 1.494; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0259] The experimental results of Example 5 are as follows: 2409.4 kg / m³ 3

[0260]

[0261] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0262] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0263] = 3.797 × 10.43% + 0.999 × 4.31% + 4.415 × 19.95% + 1.972 × 15.42% + 2.676 × 30.61% + 1.494 × 19.27%

[0264] ≈2.731

[0265] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0266] From K = Ka × Kb

[0267] = 0.33% × 3.294 × 10 2

[0268] ≈1.087

[0269] Assuming the representative value of the 28-day compressive strength of concrete is equal to the design strength value:

[0270] fcu,o = 33.53 MPa

[0271] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0272] W = Wa + Q × (1 - Qg)

[0273] =200 + 4.35 × (1 - 0.1833)

[0274] ≈203.6Kg / m 3

[0275] Calculate the W / C ratio (water-cement ratio) using formula 4-1. (Take the air content loss 'a' in concrete as 0).

[0276]

[0277] Conclusion: As shown in the examples, W÷C: water-cement ratio can be calculated from Ka, Kb, Q, f′ce, and the measured representative value of compressive strength after 28 days.

[0278] Example 6

[0279] According to formula 4-2, calculate f′ce: the 28-day compressive strength (MPa) of the cementitious material containing A% cement and B% mineral admixtures.

[0280] Formula 4-2:

[0281]

[0282] Given: Ka: Solid content of air-entraining agent in composite water-reducing agent; Kb: Air-entraining rate of air-entraining agent in composite water-reducing agent; Q: Dosage of water-reducing agent per cubic meter of concrete (kg / m³). 3 Qg: Solid content of water-reducing agent (%), Wa: Apparent water content of concrete (kg / m³) 3 C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 fcu,o: Representative value of 28-day compressive strength of concrete (MPa), calculation of f′ce: Calculated value of 28-day compressive strength of A% cement + B% micro-powder mineral admixture cementitious material (MPa), including the following steps:

[0283] Example 6-1: The materials used are PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Anshan Iron and Steel Group; calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days: 49.0 MPa; crushed stone 1 origin: Liaoyang, particle size 10mm~25mm, fineness modulus: 4.415; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.972; artificial sand origin: Anshan, fineness modulus: 3.075; fine river sand origin: Liaoyang, fineness modulus: 1.494; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0284] The experimental results of Example 6-1 are as follows: 2388.4 kg / m³ 3

[0285]

[0286] According to Formula 1: Calculate μ: Aggregate fineness modulus

[0287] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0288] = 3.797 × 7.80% + 0.999 × 3.21% + 4.415 × 20.41% + 1.972 × 15.37% + 3.075 × 33.94% + 1.494 × 19.27%

[0289] ≈2.864

[0290] According to Formula 2: Calculate K: Air entrainment rate per unit weight of composite water-reducing agent.

[0291] K = Ka × Kb

[0292] = 0.33% × 3.294 × 10 2

[0293] ≈1.087

[0294] According to Formula 3: Calculate W: Total water used in concrete (kg / m³) 3

[0295] W = Wa + Q × (1 - Qg)

[0296] =205 + 3.36 × (1 - 0.1833)

[0297] ≈207.7kg / m 3

[0298] Calculate f′ce according to Formula 4-2. (Take the air content loss a in concrete as 0).

[0299]

[0300] The experimental results of Example 6-2 are as follows: 2393.4 kg / m³ 3

[0301]

[0302] Calculate μ according to Formula 1:

[0303] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0304] = 3.797 × 9.82% + 0.999 × 4.11% + 4.415 × 20.78% + 1.972 × 15.98% + 3.075 × 31.51% + 1.494 × 17.81%

[0305] ≈2.882

[0306] Calculate K according to Formula 2:

[0307] From K = Ka × Kb

[0308] = 0.33% × 3.294 × 10 2

[0309] ≈1.087

[0310] Calculate W according to Formula 3:

[0311] W = Wa + Q × (1 - Qg)

[0312] =200 + 3.36 × (1 - 0.1833)

[0313] =202.7

[0314] Calculate f′ce according to Formula 4-2. (Take the air content loss a in concrete as 0).

[0315]

[0316] Conclusion: As can be seen from the examples, f′ce can be calculated from Ka, Kb, Q, Qg, Wa, C, fcu,o.

[0317] Example 7

[0318] According to formula 4-3:

[0319]

[0320] Given: Ka: Solid content of air-entraining agent in composite water-reducing agent; Kb: Air-entraining rate of air-entraining agent in composite water-reducing agent; Qg: Solid content of water-reducing agent (%); f′ce: Calculated compressive strength (MPa) of cementitious material with A% cement + B% mineral admixtures after 28 days; fcu,o: Representative compressive strength (MPa) of concrete after 28 days; Wa: Apparent water content of concrete (kg / m³). 3 C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 The representative value of compressive strength after 28 days was measured, and Q was calculated: the amount of water-reducing agent used per cubic meter of concrete (kg / m³). 3 It includes the following steps:

[0321] Example 7-1: The materials used are PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Anshan Iron and Steel Group; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days, 46 MPa; crushed stone 1 origin: Liaoyang, particle size 5mm~25mm, fineness modulus: 2.811; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.481; artificial sand 1 origin: Anshan, fineness modulus: 2.866; fine river sand 2 origin: Liaoyang, fineness modulus: 1.502; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0322] The experimental results of Example 7-1 are as follows: 2424.9 kg / m³ 3

[0323]

[0324] Calculate μ according to Formula 1:

[0325] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0326] = 3.797 × 14.09% + 0.999 × 5.82% + 2.811 × 19.46% + 1.481 × 14.77% + 2.866 × 29.31% + 1.502 × 16.55%

[0327] =2.448

[0328] Calculate K according to Formula 2:

[0329] From K = Ka × Kb

[0330] = 0.33% × 3.294 × 10 2

[0331] ≈1.087

[0332] Assuming the representative value of the 28-day compressive strength of concrete is equal to the design strength value:

[0333] fcu,o = 63.20 MPa

[0334] Calculate Q using formula 4-3: (Take the air content loss a in concrete as 0).

[0335]

[0336] Example 7-2: The materials used are PO42.5 cement, fineness modulus 3.797, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder), micro powder grade S95, fineness modulus 0.999, origin: Anshan Iron and Steel Group; f′ce: calculated compressive strength of 70% cement + 30% micro powder cementitious material after 28 days, 49 MPa; crushed stone 1 origin: Liaoyang, particle size 10mm~25mm, fineness modulus: 4.415; crushed stone 2 origin: Liaoyang, particle size 5mm~16mm, fineness modulus: 1.972; artificial sand origin: Liaoyang, fineness modulus: 2.676; fine river sand origin: Liaoyang, fineness modulus: 1.494; polycarboxylate superplasticizer mother liquor origin: Dalian Kenuo. The composite water-reducing agent has a solid content of 18.33%, of which the water-reducing agent (polycarboxylate) has a solid content of 16%. The water reduction rate Jb of the composite water-reducing agent is 45% (experimental value). Sodium gluconate is added at 2%, and sodium dodecylbenzenesulfonate (air-entraining agent) is added at 0.33%. The air-entraining rate Kb of the composite water-reducing agent is 3.294×10⁻⁶. 2 (Experimental value).

[0337] The experimental results of Example 7-2 are as follows: 2409.4 kg / m³ 3

[0338]

[0339] Calculate μ according to Formula 1:

[0340] μ=μC×C%+μF×F%+μG1×G1%+μG2×G2%+μs1×S1%+μs2×S2%

[0341] = 3.797 × 10.43% + 0.999 × 4.31% + 4.415 × 19.95% + 1.972 × 15.42% + 2.676 × 30.61% + 1.494 × 19.27%

[0342] ≈2.731

[0343] Calculate K according to Formula 2:

[0344] From K = Ka × Kb

[0345] = 0.33% × 3.294 × 10 2

[0346] ≈1.087

[0347] Assuming the representative value of the 28-day compressive strength of concrete is equal to the design strength value.

[0348] fcu,o = 33.53 MPa

[0349] Calculate Q using formula 4-3: (Take the air content loss a in concrete as 0).

[0350]

[0351] Conclusion: As shown in the examples, Q can be calculated from Ka, Kb, Qg, f′ce, fcu,o, Wa, C, and the representative value of the measured 28-day compressive strength.

[0352] Example 8

[0353] In the above embodiments, it is known that: fm,o: representative value of 28-day compressive strength of cement mortar, W: total water consumption per cubic meter of concrete (kg / m³) 3 C: Total cementitious volume per cubic meter of concrete (kg / m³) 3 μs: Fineness modulus of standard quartz sand used in cement strength testing; f′ce: Calculated 28-day compressive strength (MPa) of A% cement + B% mineral admixture cementitious material.

[0354] 8-1: Calculation of the fineness modulus of standard quartz sand used in cement strength testing

[0355] 500 grams

[0356] sieve aperture size 4.75mm 2.35mm 1.18mm 0.6mm 0.3mm 0.15mm end Screening residue 0 0.07 111.65 206.35 29.80 49.55 102.6 Separate sieve residue 0 0.014％ 22.33％ 41.27％ 5.96％ 9.91％ 20.52％ Cumulative screening residue 0 0.014％ 22.34％ 63.61％ 69.57％ 79.48％ 100％

[0357] μs=(A2+A3+A4+A5+A6-5A1)÷(100-A1)

[0358] = (0.014 + 22.34 + 63.61 + 69.57 + 79.48 - 5 × 0) ÷ (100 - 0)

[0359] =2.350

[0360] 8-2. Calculate f′ce according to Formula 5: Calculated value of 28-day compressive strength (MPa) of A% cement + B% mineral admixture cementitious material.

[0361]

[0362] Experiment 8-2-1: Given: Materials used are PO42.5 cement, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder) S95, origin: Jidong Cement Plant; f′ce: 70% cement + 30% micro powder; fm,o: representative value of 28-day compressive strength of cement mortar, 54.16 MPa; standard quartz sand used for cement strength test, origin: Xiamen; cement 315g, micro powder 135g, quartz sand 1350g, water 225g; Calculate f′ce: calculated value of 28-day compressive strength of A% cement + B% micro powder cementitious material (MPa):

[0363] From Formula 5:

[0364] Experiment 8-2-2: Given: Materials used are PO42.5 cement, origin: Jidong Cement Plant; granulated blast furnace slag powder (micro powder) S95, origin: Jidong Cement Plant; f′ce: 70% cement + 30% micro powder; standard quartz sand for cement strength testing, origin: Xiamen; cement 315g, micro powder 135g, quartz sand 1350g, water 225g; fm,o: representative value of 28-day compressive strength of cement mortar, 58.97MPa. Calculate f′ce: calculated value of 28-day compressive strength (MPa) of A% cement + B% micro powder cementitious material.

[0365] From Formula 5:

[0366] 8-3. List of calculations for f′ce in cementitious material mortar strength test:

[0367]

[0368] Conclusion: Based on experiments 8-1, 8-2-1 to 8-2-2, and examples 1 to 7, given fm,o, W, C, and μs, f′ce can be calculated.

[0369] Conclusion: This patent explains why high-grade concrete requires aggregates with small particle sizes, because the aggregate's overall fineness modulus is small, according to the formula... The calculated result is relatively large. The reason for the low strength of wet-processed iron tailings sand concrete is the large aggregate fineness modulus, according to the formula... The calculated result is relatively small. And the formula... This paper explains the relationship between fm,o (representative 28-day compressive strength in MPa of cement mortar) and f′ce (calculated 28-day compressive strength in MPa of A% cement + B% micro-powder cementitious material). It also explains how to calculate mix proportion parameters for concrete with mineral admixtures and high-flowability concrete. When other conditions are known, it is not necessary to consult tables to directly calculate the water-cement ratio (W÷C), the representative 28-day compressive strength of concrete (fcu,o), or verify the amount of water-reducing agent (Q). The calculated 28-day compressive strength of cementitious material (f′ce) can be directly verified using the representative concrete strength value.

Claims

1. A method of calculating a representative value of the 28-day compressive strength of concrete, characterized in that, Known: Ka: air entraining agent content in the composite water reducing agent, Kb: air entraining rate of the air entraining agent in the composite water reducing agent, Q: water reducing agent dosage per cubic meter of concrete kg / m³, Qg: water reducing agent solid content%, ƒ´ce: cementitious material 28-day compressive strength calculated value Mpa, Wa: apparent water content of concrete kg / m³, C: total cementitious material per cubic meter of concrete kg / m³, calculated ƒcu,o: concrete 28-day compressive strength representative value MPa, including the following steps: 1) Calculate the aggregate comprehensive fineness modulus µ; The calculation formula of µ is: Formula 1: µ=µC×C%+µF×F%+µG1×G1%+µG2×G2%+µs1×S1%+µs2×S2%; µ: aggregate comprehensive fineness modulus; µC: cement fineness modulus; C%: cement accounts for the total weight of aggregate + cementitious material percentage; µF: mineral admixture fineness modulus; F%: mineral admixture accounts for the total weight of aggregate + cementitious material percentage; µG1: coarse aggregate 1 fineness modulus; G1%: coarse aggregate 1 accounts for the total weight of aggregate + cementitious material percentage; µG2: coarse aggregate 2 fineness modulus; G2%: coarse aggregate 2 accounts for the total weight of aggregate + cementitious material percentage; µs1: fine aggregate 1 fineness modulus; S1%: fine aggregate 1 accounts for the total weight of aggregate + cementitious material percentage; µs2: fine aggregate 2 fineness modulus; S2%: fine aggregate 2 accounts for the total weight of aggregate + cementitious material percentage; 2) Calculate the air entraining rate K of the composite water reducing agent per unit weight; The calculation formula of K is: Formula 2: Kb=K / Ka; Kb: air entraining rate of the air entraining agent in the composite water reducing agent; K: air entraining rate of the composite water reducing agent per unit weight; Ka: air entraining agent content in the composite water reducing agent; 3) Calculate the total water content W of the concrete; The calculation formula of W is: Formula 3: W=Wa+Q×(1-Qg); W: total water content per cubic meter of concrete kg / m³; Wa: apparent water content of concrete kg / m³; Q: water reducing agent dosage per cubic meter of concrete kg / m³; Qg: water reducing agent solid content%; 4) Calculate the concrete 28-day compressive strength representative value ƒcu,o; The calculation formula of ƒcu,o is: Formula 4: fcu,o = f'ce ÷ { } x ; ƒcu,o: concrete 28-day compressive strength representative value MPa; ƒ´ce: cementitious material 28-day compressive strength calculated value MPa; C: total cementitious material per cubic meter of concrete kg / m³; K: air entraining rate of the composite water reducing agent per unit weight; a: loss of air content of concrete, generally 0-4.

2. A method of calculating a representative value of the 28-day compressive strength of concrete, characterized in that, Known: µ: aggregate comprehensive fineness modulus, Wa: apparent water content of concrete kg / m³, Ka: air entraining agent content in the composite water reducing agent, Kb: air entraining rate of the air entraining agent in the composite water reducing agent, Q: water reducing agent dosage per cubic meter of concrete kg / m³, Qg: water reducing agent solid content%, C: total cementitious material per cubic meter of concrete kg / m³, ƒ´ce: cementitious material 28-day compressive strength calculated value Mpa, calculated ƒcu,o, including the following steps: 1) Calculate the air entraining rate K of the composite water reducing agent per unit weight; The calculation formula of K is: Formula 2: Kb=K / Ka; Kb: air entraining rate of the air entraining agent in the composite water reducing agent; K: air entraining rate of the composite water reducing agent per unit weight; Ka: air entraining agent solid content in composite water reducing agent; 2) Calculate the total water content W of concrete; The calculation formula of W is: Formula 3: W = Wa + Q × (1-Qg); W: total water content of concrete per cubic meter kg / m³; Wa: apparent water content of concrete kg / m³; Q: water reducing agent dosage per cubic meter of concrete kg / m³; Qg: solid content of water reducing agent%; 3) Calculate the representative value of 28-day compressive strength of concrete ƒcu,o The calculation formula of ƒcu,o is: Formula 4: fcu,o = f'ce ÷ { } x ; ƒcu,o: representative value of 28-day compressive strength of concrete MPa; ƒ´ce: calculated value of 28-day compressive strength of cementitious materials Mpa; C: total amount of cementitious materials per cubic meter of concrete kg / m³; K: air entraining rate of composite water reducing agent per unit weight; a: air content loss of concrete, generally 0-4.

3. A method for calculating a parameter related to a representative value of 28-day compressive strength of concrete, characterized by, The relevant parameters are water-cement ratio W÷C of concrete; It is known that Ka: air entraining agent solid content in composite water reducing agent, Kb: air entraining rate of air entraining agent in composite water reducing agent, Q: water reducing agent dosage per cubic meter of concrete kg / m³, Qg: solid content of water reducing agent%, Wa: apparent water content of concrete kg / m³, ƒ´ce: calculated value of 28-day compressive strength of cementitious materials Mpa, measured 28-day compressive strength representative value, calculate W÷C: water-cement ratio, including the following steps: 1) Calculate the comprehensive fineness modulus µ of aggregate; The calculation formula of µ is: Formula 1: µ = µC × C% + µF × F% + µG1 × G1% + µG2 × G2% + µs1 × S1% + µs2 × S2%; µ: comprehensive fineness modulus of aggregate; µC: cement fineness modulus; C%: percentage of cement in the total weight of aggregate + cementitious materials; µF: mineral admixture fineness modulus; F%: percentage of mineral admixture in the total weight of aggregate + cementitious materials; µG1: coarse aggregate 1 fineness modulus; G1%: percentage of coarse aggregate 1 in the total weight of aggregate + cementitious materials; µG2: coarse aggregate 2 fineness modulus; G2%: percentage of coarse aggregate 2 in the total weight of aggregate + cementitious materials; µs1: fine aggregate 1 fineness modulus; S1%: percentage of fine aggregate 1 in the total weight of aggregate + cementitious materials; µs2: fine aggregate 2 fineness modulus; S2%: percentage of fine aggregate 2 in the total weight of aggregate + cementitious materials; 2) Calculate the air entraining rate K of composite water reducing agent per unit weight; The calculation formula of K is: Formula 2: Kb = K / Ka; Kb: air entraining rate of air entraining agent in composite water reducing agent; K: air entraining rate of composite water reducing agent per unit weight; Ka: air entraining agent solid content in composite water reducing agent; 3) Assume that the representative value of 28-day compressive strength of concrete ƒcu,o is equal to the design strength value, i.e. the measured representative value of 28-day compressive strength; 4) Calculate the total water content W of concrete; The calculation formula of W is: Formula 3: W = Wa + Q × (1-Qg); W: total water content of concrete per cubic meter kg / m³; Wa: apparent water content of concrete kg / m³; Q: water reducing agent dosage per cubic meter of concrete kg / m³; Qg: solid content of water reducing agent%; 5) Calculate W÷C; The calculation formula of W÷C is: Formula 4-1: W ÷ C = .​ 4. A method for calculating a parameter related to a representative value of 28-day compressive strength of concrete, characterized by, The relevant parameters are A% cement + B% micro-powder mineral admixture cementitious materials 28-day compressive strength calculated value; Known: Ka: air entraining agent content in the composite water reducing agent, Kb: air entraining rate of air entraining agent in the composite water reducing agent, Q: water reducing agent dosage per cubic meter of concrete kg / m³, Qg: water reducing agent solid content%, Wa: apparent water content of concrete kg / m³, C: total amount of cementitious materials per cubic meter of concrete kg / m³, ƒcu,o: representative value of 28-day compressive strength of concrete MPa, calculated ƒ´ce: calculated value of 28-day compressive strength of cementitious materials Mpa, including the following steps: 1) Calculate the comprehensive fineness modulus µ of aggregate; The calculation formula of µ is: Formula 1: µ=µC×C%+µF×F%+µG1×G1%+µG2×G2%+µs1×S1%+µs2×S2%; µ: comprehensive fineness modulus of aggregate; µC: cement fineness modulus; C%: cement accounts for the total weight percentage of aggregate + cementitious materials; µF: mineral admixture fineness modulus; F%: mineral admixture accounts for the total weight percentage of aggregate + cementitious materials; µG1: coarse aggregate 1 fineness modulus; G1%: coarse aggregate 1 accounts for the total weight percentage of aggregate + cementitious materials; µG2: coarse aggregate 2 fineness modulus; G2%: coarse aggregate 2 accounts for the total weight percentage of aggregate + cementitious materials; µs1: fine aggregate 1 fineness modulus; S1%: fine aggregate 1 accounts for the total weight percentage of aggregate + cementitious materials; µs2: fine aggregate 2 fineness modulus; S2%: fine aggregate 2 accounts for the total weight percentage of aggregate + cementitious materials; 2) Calculate the air entraining rate K of unit weight composite water reducing agent; The calculation formula of K is: Formula 2: Kb=K / Ka; Kb: air entraining rate of air entraining agent in the composite water reducing agent; K: air entraining rate of unit weight composite water reducing agent; Ka: air entraining agent content in the composite water reducing agent; 3) Calculate the total water consumption W of concrete; The calculation formula of W is: Formula 3: W=Wa+Q×(1-Qg); W: total water consumption per cubic meter of concrete kg / m³; Wa: apparent water content of concrete kg / m³; Q: water reducing agent dosage per cubic meter of concrete kg / m³; Qg: water reducing agent solid content%; 4) Calculate ƒ´ce The calculation formula of ƒ´ce is: Equation 4-2: f'ce = fcu,o x { } ÷ .

5. A method for calculating a parameter related to a representative value of 28-day compressive strength of concrete, characterized by, The relevant parameters are water reducing agent dosage per cubic meter of concrete; Known: Ka: air entraining agent content in the composite water reducing agent, Kb: air entraining rate of air entraining agent in the composite water reducing agent, Qg: water reducing agent solid content%, ƒ´ce: calculated value of 28-day compressive strength of cementitious materials Mpa, ƒcu,o: representative value of 28-day compressive strength of concrete MPa, Wa: apparent water content of concrete kg / m³, C: total amount of cementitious materials per cubic meter of concrete kg / m³, measured 28-day compressive strength representative value, calculated Q: water reducing agent dosage per cubic meter of concrete kg / m³, including the following steps: 1) Calculate the comprehensive fineness modulus µ of aggregate; The calculation formula of µ is: Formula 1: µ=µC×C%+µF×F%+µG1×G1%+µG2×G2%+µs1×S1%+µs2×S2%; µ: comprehensive fineness modulus of aggregate; µC: cement fineness modulus; C%: cement accounts for the total weight percentage of aggregate + cementitious materials; µF: mineral admixture fineness modulus; F%: mineral admixture accounts for the total weight percentage of aggregate + cementitious materials; µG1: coarse aggregate 1 fineness modulus; G1%: coarse aggregate 1 percentage in total weight of aggregate + cementitious materials; µG2: coarse aggregate 2 fineness modulus; G2%: coarse aggregate 2 percentage in total weight of aggregate + cementitious materials; µs1: fine aggregate 1 fineness modulus; S1%: fine aggregate 1 percentage in total weight of aggregate + cementitious materials; µs2: fine aggregate 2 fineness modulus; S2%: fine aggregate 2 percentage in total weight of aggregate + cementitious materials; 2) Calculate air entraining rate K of composite water reducing agent per unit weight; The calculation formula of K is: Formula 2: Kb=K / Ka; Kb: air entraining rate of air entraining agent in composite water reducing agent; K: air entraining rate of composite water reducing agent per unit weight; Ka: solid content of air entraining agent in composite water reducing agent; 3) Assume that the representative value of 28-day compressive strength of ƒcu,o concrete is equal to the design strength value, i.e. the measured 28-day compressive strength representative value; 4) Calculate Q The calculation formula of Q is: Formula 4-3: Q = { } ÷ {(1 - Qg) ÷ C }.

6. A method for calculating a parameter related to a representative value of 28-day compressive strength of concrete, characterized by, The relevant parameters are A% cement + B% mineral admixture cementitious materials 28-day compressive strength calculation value; Known: ƒm,o: cement mortar 28-day compressive strength representative value, W: total amount of water per cubic meter of concrete kg / m³, C: total amount of cementitious per cubic meter of concrete kg / m³, calculate ƒ´ce: cementitious materials 28-day compressive strength calculation value Mpa, including the following steps: 1) Calculate the fineness modulus µs of standard quartz sand for cement strength test; µs = (A2+A3+A4+A5+A6-5A1) ÷ (100-A1) ; Wherein, A1 is the cumulative percentage of quartz sand retained on a 4.75mm sieve, A2 is the cumulative percentage of quartz sand retained on a 2.35mm sieve, A3 is the cumulative percentage of quartz sand retained on a 1.18mm sieve, A4 is the cumulative percentage of quartz sand retained on a 0.6mm sieve, A5 is the cumulative percentage of quartz sand retained on a 0.3mm sieve, A6 is the cumulative percentage of quartz sand retained on a 0.15mm sieve; 2) Calculate ƒ´ce Equation 5: f'ce= f'm.o x x μs; ƒm.o: cement mortar 28-day compressive strength representative value Mpa; µs: fineness modulus of quartz sand.

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