durability index values and cover depths for given
environmental classes and selected binder types.
Limiting durability index values are based on service
life models, which in turn relate to partial factor
design and partly to full probabilistic modelling
of relevant parameters. The South African approach
therefore aims at combining Options 1, 2, and 3, as
presented by fib, to provide a practical tool for durability
design and quality control.
The durability index approach is currently being
applied in a number of large scale construction
projects in South Africa. This is considered a large
step towards improvement of concrete quality and
structural durability. However, much work remains
to be done, in particular generating correlations
between indexes and actual structural performance.
Future research needs in the field of durability index
design and service life modelling are discussed in the
following.