A concrete foundation is the most common mainly because it's the most versatile. Concrete is poured to form to create a base foundation to receive a subsequent concrete slab. This can be any shape and size depending on the nature of the soil and the building project.
FND mixes are specified for foundations, they are used in footings for various buildings where engineers have to have the soil analysed.
The report for the engineer will stipulate the DC class of chemical resistance that is needed on a particular site and the DC value dictates the appropriate FND grade of concrete. e.g. a DC3 level of chemical resistance needs an FND3 so it is quite straightforward.
Types of FND concrete
There are several FND mixes including FND4*.
In ascending numerology the mixes are specified with higher cement contents and lower water cement ratios to produce more durable concretes. So if there are concerns over ground (such as a brown field site) engineers may stipulate a higher FND mix to protect against potential chemical damage to the concrete.
Typical Concrete strength: 35N/mm2 - 28 days
FND concrete applications
Brown field sites, concrete for footings and foundations typically old chemical works, former petrol filling stations, former colliery sites or areas where there are concerns over chemical contamination of soil.