This topic actually covers significance of durability of concrete. In designing concrete structure once only mechanical properties of concrete in relation to initial coat was considered. We know what are the mechanical properties of concrete? But in recent years we have to concentrate on durability ; here we will learn about these facts.
At first we will start with socio-economic implications. The structures which were constructed having less concern of durability, before reaching its service life, suffer severe or considerable deterioration.
This fact was observed and treated seriously when cost of replacement and repair of concrete structures to rehabilitate them found to be significant portion of total budget of construction.
Let us consider an industrially developed country, where maintenance and repair cost of existing structures is reached 40 % of total cost of overall development and maintenance work. That is only 60% budget is remaining for new construction.
Thus engineers are bound to be conscious about durability due to increase in cost of replacement and increasing emphasis on cost to produce longevity of structures rather than initial cost.
Again durability of structures or materials is closely related to ecology. Dear reader we will finish this topic in next part. There we will learn about how conservation of materials is achieved in concrete industry.