Durability and service life 21
arise in concrete practice about the actual k-values, and about the validity of this k-value concept. Different European member states have different opinions and prescriptions in this respect, as mentioned in the various
national application documents linked to EN 206-1.
It is worth mentioning that k-values are defined based on compressive
strength results, while the effect of the supplementary cementitious materials on durability behaviour can be quite different. This fundamentally
undermines the practical application of the k-value concept. Each durability application of this concept should be done with care!
Because the basic parameters (water/cement ratio, cement content and
concrete strength) can be criticised as governing parameters for the durability of concrete, some attempts are made to ensure durability, e.g. by water
absorption by immersion. This is also implemented in the EN 206-1, as a
possible additional requirement. However, it is to be mentioned that water
absorption by immersion has to be applied with caution (De Schutter and
Audenaert 2004).
1.5.3 equivalent concrete performance
concept (ecPc)
One possible way to overcome everlasting discussions about k-values is
to check the equivalency of concrete performance as described within the
European code EN 206-1. As an alternative to the durability requirements
given as functions of water/cement ratio and cement content, the durability
performance of a specific non-traditional concrete (containing an alternative binder system) can be demonstrated experimentally in comparison with
a generally accepted “deemed to satisfy” concrete, which is fully in agreement with the classical durability requirements. This approach is called the
Equivalent Concrete Performance Concept (ECPC).
As described in the European code EN 206-1, paragraph 5.2.5.3, “The
equivalent concrete performance concept permits amendments to the
requirements in this standard for minimum cement content and maximum water/cement ratio when a combination of a specific addition and a
specific cement is used, for which the manufacturing source and characteristics of each are clearly defined and documented”. The (informative)
Annexe E of EN 206-1 provides further details of the equivalent concrete
performance concept. “Testing should show that the performance of the
concrete containing the addition should be at least equivalent to that of
the reference concrete.” Furthermore, some general guidance is given in
Annexe E, which can form the basis for an actual testing and acceptance
procedure.
Unfortunately, European Standard 206-1 does not give a detailed method
for the practical implementation of the ECPC concept. In Belgium, a standard has been developed for the practical implementation of the ECPC
arise in concrete practice about the actual k-values, and about the validity of this k-value concept. Different European member states have different opinions and prescriptions in this respect, as mentioned in the various
national application documents linked to EN 206-1.
It is worth mentioning that k-values are defined based on compressive
strength results, while the effect of the supplementary cementitious materials on durability behaviour can be quite different. This fundamentally
undermines the practical application of the k-value concept. Each durability application of this concept should be done with care!
Because the basic parameters (water/cement ratio, cement content and
concrete strength) can be criticised as governing parameters for the durability of concrete, some attempts are made to ensure durability, e.g. by water
absorption by immersion. This is also implemented in the EN 206-1, as a
possible additional requirement. However, it is to be mentioned that water
absorption by immersion has to be applied with caution (De Schutter and
Audenaert 2004).
1.5.3 equivalent concrete performance
concept (ecPc)
One possible way to overcome everlasting discussions about k-values is
to check the equivalency of concrete performance as described within the
European code EN 206-1. As an alternative to the durability requirements
given as functions of water/cement ratio and cement content, the durability
performance of a specific non-traditional concrete (containing an alternative binder system) can be demonstrated experimentally in comparison with
a generally accepted “deemed to satisfy” concrete, which is fully in agreement with the classical durability requirements. This approach is called the
Equivalent Concrete Performance Concept (ECPC).
As described in the European code EN 206-1, paragraph 5.2.5.3, “The
equivalent concrete performance concept permits amendments to the
requirements in this standard for minimum cement content and maximum water/cement ratio when a combination of a specific addition and a
specific cement is used, for which the manufacturing source and characteristics of each are clearly defined and documented”. The (informative)
Annexe E of EN 206-1 provides further details of the equivalent concrete
performance concept. “Testing should show that the performance of the
concrete containing the addition should be at least equivalent to that of
the reference concrete.” Furthermore, some general guidance is given in
Annexe E, which can form the basis for an actual testing and acceptance
procedure.
Unfortunately, European Standard 206-1 does not give a detailed method
for the practical implementation of the ECPC concept. In Belgium, a standard has been developed for the practical implementation of the ECPC