- Strength and Durability
The strength and durability of concrete structure must go hand in hand. Durability is the ability of a structure to resist weathering action, chemical attack, and abrasion, while maintaining minimum strength and other desired engineering properties. In today’s context, designing for strength and durability is synonymous to designing for sustainability. This spirit is appropriately described in CEB/FIP Model Code 1990 :
The national standard codes of practice mostly follow prescriptive approach, dening the exposure conditions, design procedure, choice of building materials, and their application during the construction, without assuring the expected minimum service life of the structure, when these speci-cations are followed. However, in 1996, CEB accepted performance-based approach with explicit attention for the durability-based service life, limit states, and reliability in design. A similar change in approach is also re¤ected in the Indian Standard Code IS 456: 2000 . However, much needs to be done in that area. The objective of the national structural design codes, as in Eurocode 2 , should be to enable the design decision based on the life cycle cost. That will be a major step toward building sustainable structures and in order to do that the mechanisms and the mitigation of structural deterioration due to the attack of deleterious agents need to be understood.