Question

What is Durable concrete ?

Answer 1

Durable concrete is the one that will retain its original form, quality, and serviceability for a long time when exposed to its environment.
The fundamental factor in creating durable concrete is the use of pozzolans and ground granulated blast-furnace slag (GGBFS) and chemical admixtures </strong>in combination with portland cement, and the proper selection of aggregate (proportion, hardness, grading, shape, size, and phase composition). The best means of maximizing the probability that concrete will be durable is to
produce concrete that will provide the desired service for the desired service life in the
environment in which it will be placed and used.
Every concrete mixture should be  proportioned in accordance with exposure conditions, construction considerations, and  structural criteria. Exposure to freezing and thawing, sulfates, deicing chemicals, acids,
  varying moisture conditions, and abrasive loadings should all be considered when selecting materials and proportions.In addition, available materials must be selected to prevent excessive expansion due to alkali-silica reaction (ASR), alkali-carbonate rock reaction, and thermal gradients.
Properties of Concrete

 

Answer 2

http://www.aboutcivil.org/durability-of-concrete.html

Answer 3

Every structure is designed for certain period of years to sustain all the loads acting on it.After that the structure had to collapse and reconstruct again.This period is called durable period.To construct such a structure of higher durability,the concrete should be durable enough to give the required/designed strength.We will make the durable concrete by proper proportions of ingredients.By using good curing techniques,placing,blending,mixing,usage of admixtures also can keep the concrete more durable.