Since the appearance of the CE-certification of fly ash in 2005, the type of co-combustion materials and their mixing level with coal has strongly increased in many power stations supplied with coal.
The Direction Board for the certification of fly ash wanted to guarantee that these changes would not affect the durability of concrete made of different exposure classes..
A new BENOR-mark has been proposed and approved in october 2010.
This voluntary attestation allows the power stations to demonstrate the specific ability of using their fly ash with regard to the exposure classes which have been subjected to a certified validation.
Thanks to the BENOR-mark, the concrete plants are exempted from carrying out the complementary tests on their compositions of BENOR concrete produced with fly ash.