Concrete Strength
Concrete is measured by its strength capacity. MPa (megapascals) is the metric measurement for psi or pounds per square inch. The BC Building Codes require a minimum MPa for specific concrete projects. Please refer to the table to choose the appropriate MPa when calculating your volume and price.
| Concrete Location |
BCBC Minimum Strength (MPa) |
BCBC Maximum W/C* Ratio |
BCBC Air Content |
Suggested Strength (MPa) |
Maximum W/C Ratio |
Optimum Air Content Range |
| Footing, walls, foundations | 15 | 0.70 | n/a | 20 – 25 | 0.55 – 0.60 | 3 – 5% |
| Interior flatwork | 20 | 0.65 | n/a | 25 – 28 | 0.50 – 0.55 | 3 – 5% |
| Garages, carports | 32 | 0.45 | 5 – 8% | 32 | 0.45 | 5 – 6% |
| Exterior flatwork | 32 | 0.45 | 5 – 8% | 32 | 0.45 | 5 – 7% |
BCBC = BC Building Code 2006: Housing and Small Buildings
Notes
- Concrete is mixed with the correct “air-entrainment” (optimum air content). The following are some general guidelines.
- For garages, carports and any exterior flatwork that will be troweled, keep air in the low range – close to 5%. This will help reduce “crusting“ of the surface and blistering.
- For exterior flatwork that will not be troweled (broomed, exposed, etc.), keep air around 6% for freeze-thaw durability.
- For interior flatwork that will be troweled, keep air around 4%. This will help control bleeding and not cause blistering.
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