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MPA EXPLAINED

MPA – 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.

MPA Explained