A durable concrete structure requires careful attention to all aspects of design, materials and construction. The environmental conditions to which the concrete will be exposed should be defined at the design stage. These were defined in the design codes such as BS 8110 and ranged from ´Mild´ for indoor conditions to ´Most severe´ for marine structures´. (There are slight variations in the terms used in the various codes.) The Eurocodes for design now defer environmental aspects to the concrete standard EN 206 Concrete.
Minimum cement contents and maximum water/cement ratios are defined in BS EN 206 and, specifically for the UK, the complementary standard BS 8500 for the various conditions, along with minimum concrete strength classes and covers to the reinforcement.
Note that BS 8500 replaced BS 5328, in December 2003. Further information on the effect of various types of cement, and other products, on the long-term durability of concrete can be found in Concrete Society Technical Report 61, Enhancing reinforced concrete durability.