1 Introduction
2 Formulation for the Optimization of Concrete Mixing Proportions
2.1 Object Function
2.1.1 CO2 Emissions of Concrete
Water (kg/kg) | Cement (kg/kg) | Slag (kg/kg) | Sand (kg/kg) | Gravel (kg/kg) | Superplasticizer (kg/kg) |
---|---|---|---|---|---|
0.000,196 | 0.931 | 0.0265 | 0.0026 | 0.0075 | 0.25 |
2.1.2 CO2 Uptake Due to Carbonation
2.1.3 Object Function
2.2 Constraint Conditions
Cement (kg/m3) | Slag (kg/m3) | Water (kg/m3) | Fine aggregate (kg/m3) | Coarse aggregate (kg/m3) | |
---|---|---|---|---|---|
Lower | 50 | 0 | 120 | 640 | 780 |
Upper | 700 | 700 | 250 | 900 | 1050 |
Water-to-binder ratio | Slag-to-binder ratio | Fine aggregate-to-total aggregate ratio | Total aggregate-to-binder ratio | Water-to-solid ratio | |
---|---|---|---|---|---|
Lower | 0.2 | 0 | 0.4 | 2.0 | 0.08 |
Upper | 0.75 | 0.70 | 0.52 | 6.4 | 0.12 |
2.3 Property Evaluation of Slag-Blended Concrete
2.3.1 Strength Development Model
2.3.2 Carbonation Model
2.3.3 Workability Model
2.3.4 Summary of Property Evaluation Model
3 Illustrations of Design Examples
Designed compressive strength (MPa) | Cover depth (mm) | Average temperature (°C) | Relative humidity | |
---|---|---|---|---|
Temperate climate | 25 | 30 | 15 | 0.7 |
3.1 Mixture Design without Climate Change
No climate change | Water (kg/m3) | Cement (kg/m3) | Slag (kg/m3) | Fine aggregate (kg/m3) | Coarse aggregate (kg/m3) | Superplasticizer (kg/m3) |
---|---|---|---|---|---|---|
Mix1: design strength of 25 MPa | 174.06 | 110.21 | 257.16 | 900.00 | 908.40 | 0.85 |
Mix2: design strength of 35 MPa | 174.06 | 110.21 | 257.16 | 900.00 | 908.40 | 0.85 |
Mix3: design strength of 45 MPa | 174.09 | 136.42 | 318.31 | 895.14 | 826.28 | 4.22 |
Mix4: design strength of 55 MPa | 174.48 | 170.05 | 396.78 | 834.18 | 780.00 | 7.01 |
No climate change | Design strength (MPa) | Real strength (MPa) | Slump (mm) | Carbonation depth (mm) | CO2 emissions from materials (kg/m3) | CO2 uptake (kg/m3) | Net CO2 emissions (kg/m3) | CO2 uptake ratio |
---|---|---|---|---|---|---|---|---|
Mix1: design strength of 25 MPa | 25.00 | 35.45 | 177.73 | 30.00 | 118.82 | 14.36 | 104.46 | 0.121 |
Mix2: design strength of 35 MPa | 35.00 | 35.45 | 177.73 | 30.00 | 118.82 | 14.36 | 104.46 | 0.121 |
Mix3: design strength of 45 MPa | 45.00 | 45.00 | 197.96 | 23.46 | 145.05 | 12.37 | 132.69 | 0.085 |
Mix4: design strength of 55 MPa | 55.00 | 55.00 | 217.84 | 17.39 | 178.63 | 10.33 | 168.30 | 0.058 |
3.2 Mixture Design with Climate Change
Climate change | Water (kg/m3) | Cement (kg/m3) | Slag (kg/m3) | Fine aggregate (kg/m3) | Coarse aggregate (kg/m3) | Superplasticizer (kg/m3) |
---|---|---|---|---|---|---|
Mix5: design strength of 25 MPa | 174.04 | 121.04 | 282.43 | 900.00 | 872.07 | 2.42 |
Mix6: design strength of 35 MPa | 174.04 | 121.04 | 282.43 | 900.00 | 872.07 | 2.42 |
Mix7: design strength of 45 MPa | 174.09 | 136.42 | 318.31 | 895.14 | 826.28 | 4.22 |
Mix8: design strength of 55 MPa | 174.48 | 170.05 | 396.78 | 834.18 | 780.00 | 7.01 |
Climate change | Design strength (MPa) | Real strength (MPa) | Slump (mm) | Carbonation depth (mm) | CO2 emissions from materials (kg/m3) | CO2 uptake (kg/m3) | Net CO2 emissions (kg/m3) | CO2 uptake ratio |
---|---|---|---|---|---|---|---|---|
Mix5: design strength of 25 MPa | 25.00 | 39.55 | 187.20 | 30.00 | 129.70 | 14.95 | 114.74 | 0.115 |
Mix6: design strength of 35 MPa | 35.00 | 39.55 | 187.20 | 30.00 | 129.70 | 14.95 | 114.74 | 0.115 |
Mix7: design strength of 45 MPa | 45.00 | 45.00 | 197.96 | 26.02 | 145.05 | 13.72 | 131.34 | 0.095 |
Mix8: design strength of 55 MPa | 55.00 | 55.00 | 217.84 | 19.28 | 178.63 | 11.46 | 167.17 | 0.064 |