So What Does MPA Mean In Concrete?

A megapascal (MPa) is a measure of the compressive strength of concrete. It lets inspectors know how much pressure can be applied to the concrete before it cracks or fails. 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.

BC BUILDING CODE RECOMMENDED STRENGTHS:
Footings, Walls, Foundations – 20 – 25 MPA
Interior Flatwork – 25 – 28 MPA
Garages, Carports – 32 MPA
Exterior Flatwork – 32 MPA

Please refer to the table below for MPA Levels and their Strengths.

One MPa is equal to one million pascals (Pa); as a pascal is one newton of force per square meter, a megapascal is one million newtons per square meter.

If you have a project that requires a defined strength of concrete – i.e. 20MPa to set the posts for a raised deck – then it is time to call in the experts and have concrete delivered from a ready-mixed truck – It’s the only way to guarantee the structural strength in the concrete.

You may also see concrete requirements expressed as ‘N20/10’ – this is where N means normal class concrete, 20 refers to 20MPa of strength and 10 refers to it containing a maximum aggregate size of 10mm.

The English unit equivalent to MPa is pounds per square inch (psi). While the U.S., U.K., and a few other countries use psi, the majority of countries rely on MPa. Many manufacturers, builders, and suppliers provide product data showing both MPa and psi ratings for concrete materials. To convert psi to MPa, multiply the psi value by 0.0068915. For example, 2,500 psi = 2,500 x 0.0068915, or 18 MPa.

MPa ratings are used by a wide variety of building professionals. The structural engineer determines the required MPa rating for a structure based on the weight and load of the building and its occupants. Builders and contractors can then refer to MPa ratings when choosing materials, pouring concrete, and designing nearby building elements. Inspectors refer to MPa ratings when testing new concrete items, and concrete manufacturers may use these items when recommending products to clients. MPa ratings are also used in pre-engineered concrete facilities during the design and manufacture of precast concrete panels.

The MPa of new concrete is determined using a cylinder-testing process. Inspectors bore concrete cylinders after the surface has dried, or cured, for 28 days. The cylinders must be transported carefully to testing labs, where they are placed on testing machines. These machines usually consist of two heavy plates that are pressed together at either end of the cylinder; the machine subjects the concrete to extremely high compression forces until the cylinder cracks. Multiple tests are performed, and the average MPa is given to builders, engineers, and inspectors for review. If the MPa rating is lower than the design parameter, the concrete may need to be removed and re-poured.

Even more importantly, if the MPA is too low, that can actually influence your floor’s ultimate durability over the years. For that reason, we recommend a minimum of 32MPA for your floor, and if you want a Nil exposure look, we suggest 40mpa or 50mpa.

Low MPA concrete slabs may potentially cause:
– Potential Collapse of Pillars
– Cracks May Occur Easily
– Power Tools May Dent The Slab Easier

20 MPa and 25 MPa compressive strength

• • Commonly used for house slabs, driveways, footings, and footpaths.

  • Residential slabs and footings

A default slump of 100 mm has been adopted by the premix concrete industry to reduce the uncontrolled addition of water on-site and make placing and compacting of concrete easier for concreters.

32 MPa, 40 MPa, 50 MPa compressive strength

Higher strength is commonly used for concrete that will experience greater loads and traffic. This may be specified by engineers or builders to suit the load requirements that the concrete must support during its life